Method for Operating an Electrical Energy Store of an Electrically Operable Motor Vehicle

Abstract

A device operates an electrical energy store for supplying components of an electrically operable motor vehicle, wherein operating limits are defined in each case for one or more characteristic variables of the energy store. A control unit prevents the operating limits from being exceeded during normal operation of the energy store. The device has an interface for receiving a user-side request message from an apparatus, the request message including change information about an intended shift in the operating limit of at least one of the characteristic variables. The device has a computing unit which is designed, upon receipt of the request message, to check and permit the shifting of the operating limit of at least one of the characteristic variables in accordance with at least one operational history which is stored for the energy store and which represents information derived from one or more of the characteristic variables of the energy store about past operating conditions of the energy store if at least one of the following conditions is satisfied: information determined from the at least one operational history and representing the current state of health satisfies a predetermined criterion; and/or a monetary transaction initiated by the computing unit in accordance with the current state of health has been completed.

Claims

1.-20. (canceled)

21. A device for operating an electrical energy store for supplying power to components of an electrically operable motor vehicle, wherein operational limits are defined in each case for one or more characteristic variables of the energy store, wherein exceeding of the operational limits is prevented, during normal operation of the energy store, by a control unit, comprising: an interface for receiving, from an appliance, a user-side request message which contains modification information relating to an intended shift in an operational limit of at least one of the characteristic variables; an arithmetic logic unit, which is designed to check, on reception of the request message, the intended shift in the operational limit of at least one of the characteristic variables depending on at least one operation history which is stored for the energy store and represents information derived from one or more of the characteristic variables of the energy store and relating to past operating conditions of the energy store, and to permit said intended shift when at least one of the following conditions has been met: (i) information, which is established from the at least one operation history and represents the present state of health, meets a preset criterion; (ii) a monetary transaction initiated by the arithmetic logic unit depending on the present state of health has been concluded.

22. The device according to claim 21, wherein the criterion is considered as being met by the arithmetic logic unit when the established information is greater than a previously determined, aging-dependent limit threshold value at the time of the determination of the characteristic variable.

23. The device according to claim 21, wherein the criterion is considered as being met by the arithmetic logic unit when the established information is greater than a previously determined, aging-dependent design threshold value at the time of the determination of the characteristic variable.

24. The device according to claim 21, wherein the criterion is considered as being met by the arithmetic logic unit when the established information is less than the previously determined, aging-dependent design threshold value at the time of the determination of the characteristic variable.

25. The device according to claim 21, further comprising: a data memory, in which the at least one operation history is stored for the energy store.

26. The device according to claim 25, wherein the data memory is a data memory assigned to the energy store as a whole.

27. The device according to claim 25, wherein the energy store comprises a number of storage cell modules, a data memory element is assigned to each of the storage cell modules, wherein a totality of the data memory elements forms the data memory.

28. The device according to claim 25, wherein the energy store comprises a number of storage cell modules, each of the storage cell modules having a number of storage cells, a data memory element is assigned to each of the storage cells, wherein a totality of the data memory elements forms the data memory.

29. The device according to claim 25, wherein the data memory is designed to exchange data with the control unit of the energy store and to transmit, as part of a data communication, the one or more characteristic variables or the at least one operation history.

30. The device according to claim 29, wherein the data memory is designed to transmit, as part of the data communication with the control unit, a credential for an authentication.

31. The device according to claim 21, wherein the arithmetic logic unit is designed to simulate the state of health corresponding to a requested exceeding of the operational limit by way of a model of the energy store in order to check the effect of the requested exceeding of the operational limit of at least one of the characteristic variables.

32. The device according to claim 21, wherein the arithmetic logic unit is a vehicle-external arithmetic logic unit.

33. A method for operating an electrical energy store for supplying power to components of an electrically operable motor vehicle, wherein operational limits are defined in each case for one or more characteristic variables of the energy store, wherein exceeding of the operational limits is monitored during normal operation of the energy store by a control unit, the method comprising the steps of: receiving, from an appliance, a user-side request message which contains modification information relating to an intended shift in the operational limit of at least one of the characteristic variables; checking, via an arithmetic logic unit, the intended shift in the operational limit of at least one of the characteristic variables depending on at least one operation history which is stored for the energy store and represents information derived from one or more of the characteristic variables of the energy store, and relating to past operating conditions of the energy store, on reception of the request message, and permitting the shift when at least one of the following conditions has been met: (i) information, which is established from the at least one operation history and represents the present state of health, meets a preset criterion; (ii) a monetary transaction initiated by the arithmetic logic unit depending on the present state of health has been concluded.

34. The method according to claim 33, wherein the criterion is established as being met by the arithmetic logic unit when the established information is greater than a previously determined, aging-dependent limit threshold value at the time of the determination of the characteristic variable.

35. The method according to claim 33, wherein the criterion is established as being met by the arithmetic logic unit when the established information is greater than a previously determined, aging-dependent design threshold value at the time of the determination of the characteristic variable.

36. The method according to claim 33, wherein the criterion is established as being met by the arithmetic logic unit when the established information is less than a previously determined, aging-dependent design threshold value at the time of the determination of the characteristic variable.

37. The method according to claim 33, wherein on reception of the request message, as part of a data communication, the one or more characteristic variables or the at least one operation history is transmitted from the energy store to the arithmetic logic unit for determining the information.

38. The method according to claim 37, wherein as part of the data communication, a credential of a data memory for authentication is transmitted to the arithmetic logic unit.

39. The method according to claim 33, wherein the arithmetic logic unit simulates the state of health corresponding to the requested exceeding of the operational limit by way of a model of the energy store in order to check the effect of the requested exceeding of the operational limit of at least one of the characteristic variables.

40. A computer product comprising a non-transitory computer readable medium having stored thereon software code modules which, when executed by a processor, carry out: receiving a user-side request message which contains modification information relating to an intended shift in the operational limit of at least one of the characteristic variables; checking via the intended shift in the operational limit of at least one of the characteristic variables depending on at least one operation history which is stored for the energy store and represents information derived from one or more of the characteristic variables of the energy store, and relating to past operating conditions of the energy store, on reception of the request message; and permitting the shift when at least one of the following conditions has been met: (i) information, which is established from the at least one operation history and represents the present state of health, meets a preset criterion; (ii) a monetary transaction initiated depending on a present state of health has been concluded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a schematic illustration of a device according to an embodiment of the invention for operating an electrical energy store.

[0030] FIG. 2 is a graph visualizing the state of health of the electrical energy store shown in FIG. 1 as a function of time or a covered distance, wherein the principal procedure of an exemplary method according to the invention is illustrated using the graph.

[0031] FIG. 3 is a development of the graph shown in FIG. 2 which illustrates the profile of the state of health over time or a covered distance and possible shifts, derived therefrom, in the operational limits of individual characteristic variables.

[0032] FIG. 4 is a schematic illustration illustrating threshold values defined for various characteristic variables of an electrical energy store.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows a device for operating an electrical energy store 10. The electrical energy store 10 represents an energy store for supplying power to components of an electrically operable vehicle, in particular a drive machine thereof. The electrical energy store 10 comprises a number of storage cell modules 100, 200, 300. The number of storage cell modules 100, 200, 300 can be selected in principle as desired. Each of the storage cell modules 100, 200, 300 in turn comprises a number of storage cells, wherein, by way of example, storage cells 101, . . . , 105 are only illustrated in the storage cell module 100.

[0034] In a preferred configuration, each of the storage cells 101, . . . , 105 of a respective storage cell module 100, 200, 300 has a data memory 111, . . . , 115. The data memory 111, . . . , 115 has, in addition to the possibility of storing various data which will be described in more detail below, communication capabilities for data interchange with a control unit 20 of the electrical energy store 10 and optionally means for determining one or more characteristic variables of the assigned storage cells 101, . . . , 105. Characteristic variables of the energy store which are stored may be, for example, various histograms of past operating states of the respective voltages, charging and/or discharging currents, temperatures and states of charge (SoC), in each case in the form of maximum, minimum and average values. Furthermore, a so-called credential, i.e. a unique identification feature, of the assigned storage cell 101, . . . , 105 is stored in the data memory. The credential is protected by cryptographic methods and can be verified by a receiver of the credential. The data memories 111, . . . , 115 can, for this purpose, also have an arithmetic logic unit, which is suitable for implementing cryptographic operations. The data memories 111, . . . , 115 of respective storage cells 101, . . . , 105 represent data memory elements within the meaning of the invention, wherein the totality of all of the data memory elements forms a data memory of the electrical energy store 10.

[0035] Although it is preferred if each of the storage cells 101, . . . , 105 of a respective storage cell module 100, 200, 300 has in each case such a data memory 111, . . . , 115, in one modification provision may be made for corresponding data memories 110, 210, 310 to be provided only for a respective storage cell module 100, 200, 300. If a data memory 110, 210, 310 is assigned to a respective storage cell module 100, 200, 300, these represent data memory elements. The totality of the data memory elements forms a data memory of the electrical energy store 10. In a further alternative configuration, such a data memory 11 may also be assigned only to the electrical energy store 10 as a whole.

[0036] The control and monitoring of the electrical energy store 10 takes place by means of a control unit 20 assigned to the electrical energy store 10. The control unit 20 is designed, for example, to monitor operational limits defined for various characteristic variables (voltage U, current I, temperature T, state of charge SoC, etc.) and to prevent these operational limits from being exceeded during normal operation of the energy store.

[0037] The control unit 20 is connected to a user interface 1, for example a man-machine interface (MMI) of the motor vehicle in which the electrical energy store 10 is provided. A user of the motor vehicle is given the opportunity via the user interface 1 to transmit request messages which contain modification information relating to an intended shift in the operational limits of one or more characteristic variables of the electrical energy store 10. Processing of the request message takes place in particular on the side of a vehicle-external arithmetic logic unit, in particular a backend of the manufacturer of the motor vehicle. For communication required for this purpose, the device also has a vehicle-side transceiver unit 30.

[0038] The vehicle-side transceiver unit 30 is designed to communicate with a vehicle-external (backend) transceiver unit 40. The transceiver unit 40 for its part is connected to a vehicle-external arithmetic logic unit 50. Furthermore, the backend comprises an invoicing system 60 coupled to the arithmetic logic unit 50 and a simulation unit 70 coupled to the arithmetic logic unit 50.

[0039] It should be noted that the processing of a user-side request message does not necessarily need to take place in a vehicle-external arithmetic logic unit. In an alternative configuration, components provided for this purpose can also be implemented on the vehicle side.

[0040] A user of the motor vehicle may submit a request for an additional quick-charge operation via the user interface 1, for example, by means of generating a request message. An additional quick-charge operation requires that the charging of the electrical energy store 10 takes place with a current which is (substantially) higher than that used for normal charging. The request can also comprise, for example, a temporary increase in the power by a certain value, for example in order to be able to achieve an increased maximum speed with the motor vehicle. This would require that the discharging current and/or the voltage would be increased. A request can also comprise an increase in the range by a certain percentage, which would entail a lower depth of discharge than a preset threshold value.

[0041] The control unit receiving the request message now transmits the credentials of the storage cells 101, . . . , 105 via the vehicle-side transceiver unit 30 to the vehicle-external transceiver unit 40, which transmits the information to the arithmetic logic unit 50. With the aid of the credentials, the processing of the information contained in the request message can be made secure. Whether the shift in the operational limit of one or more characteristic variables which is contained in the request message is permitted or refused is established depending on the present state of health, which is determined from an operation history stored for the energy store. The operation history represents information derived from one or more of the characteristic variables (in particular voltage U, current I, temperature T, state of charge SoC) of the energy store and relating to past operating conditions of the energy store. These are stored in the data memory (whether it be in the data memory 11 assigned to the energy store 10 as a whole or the data memory elements of the storage cell modules or the storage cells). The operation history is in particular in the form of histograms of the past operating states and enables, by virtue of a comparison with a previously stored worst case scenario, the decision as to whether, for technical reasons, a shift in the operational limits of at least one of the characteristic variables is possible or not.

[0042] Alternatively or in addition, the enabling of the shift in the limit value can take place by means of an initiated monetary transaction. Enabling is implemented, for example, when a user account could be debited, via the invoicing system 60, a monetary amount which takes into consideration the impairment of the aging response owing to the temporary shift in the operational limit of at least one of the characteristic variables. As a result, for example, any repair work which may be necessary prior to expiry of the predicted guarantee time can be taken into consideration in monetary terms. The arithmetic logic unit 50 can request, for the purpose of determining the state of health, the operation history or operation histories which are stored in the data memory of the energy store 10, as a result of which the operation history or histories are transmitted from the vehicle-side transceiver unit 30 to the vehicle-external transceiver unit 40.

[0043] The data received from the arithmetic logic unit 50 can be passed on from the arithmetic logic unit to the simulation unit 70 before a decision is made with respect to enabling of the request message. In the simulation unit 70, a model of the electrical energy store is developed in order to simulate the effect of the requested temporary shift in the operational limit of at least one of the characteristic variables. Depending on the simulation result, for example, the value of the monetary transaction can be determined or else, for technical reasons, permission of the requested shift in the operational limit of at least one of the characteristic variables can be refused or granted.

[0044] The principle on which the invention is based therefore consists in that of providing the energy store, in particular the individual storage cells, with an authentication possibility and stored operation histories in order to transmit the operation histories to a (vehicle-external) arithmetic logic unit. A user-side request message as to whether operational limits can be temporarily shifted, in particular extended, is then negotiated by the arithmetic logic unit 50. If the shift in the operational limits is permitted by the arithmetic logic unit 50, the transmission of a corresponding enable message to the control unit 20 of the electrical energy store takes place. Under the control of the control unit 20, the temporarily newly set operational limits can then be processed. The shift in the operational limits can be taken into consideration either by the monetary transaction and/or a reduction in the guarantee time.

[0045] The shift in the operational limit(s) of characteristic variables of the electrical energy store forms the basis of the consideration described below. FIG. 4 shows, by way of example, normalized value ranges for the characteristic variables of the battery voltage U.sub.bat,n of the charging current I.sub.charg,n and the battery temperature T.sub.bat,n. A normal range NB is, for example, in a range of between 20% and 80% of the normalized value ranges. The limits of an upper and lower design reserve range ARo and ARu are, for example, between 80% and 90% and between 10% and 20% of the normalized value ranges. Unusable ranges NNBo and NNBu which damage the storage cells of the electrical energy store 10 are, for example, between 90% and 100% and 0% and 10%. The selected ranges and the limit values resulting between adjacent ranges are selected arbitrarily for the purposes of illustration.

[0046] The control unit 20 is designed to keep the respective characteristic variables in their normal range, for example between 20% and 80%, during normal operation. If the request for a shift in the operational limit of at least one of the characteristic variables (U, I, T) is granted, the capacity utilization of the upper or lower design reserve range ARo and ARu is temporarily enabled. The unusable range NNBo and NNBu should be avoided under all circumstances since here direct and unpredictable damage to the storage cells of the energy store can take place.

[0047] As described at the outset, the electrical energy store 10 is dimensioned under the assumption of a worst case scenario. The worst case scenario is based on the most severe operating conditions and customer requests which are characterized by attempts and experiences from the past by a temperature collective, a load collective and generally histograms of the characteristic variables of the energy store and the operating states thereof. The worst case scenario results in a characteristic K1 (FIGS. 2 and 3) which in this case shows, by way of example, a state of health SoHc of the battery capacity depending on a design. The design may be, for example, a lifetime t guaranteed to the customer in years or a guaranteed running power s in km. The characteristic K1 indicates the worst case scenario, starting from a state of health SoHc=100% at the beginning of the life cycle up to a state of health SoHc=0% at the end of the life cycle, i.e. up to expiry of the guaranteed running time t.sub.exp or running power s.sub.exp. The state of health SoHc=0% indicates, for example, that the still maximally usable battery capacity is, for example, 70%.

[0048] The typical user will use the energy store far below the most severe operating conditions, with the result that an actual profile of the state of health, which is characterized by K2 in FIGS. 2 and 3, results owing to the operation history detected over the course of the use of the motor vehicle and the energy store. At time t.sub.1 or at a specific running power s.sub.1, there is a difference between the characteristic K1 of the worst case scenario and the actual profile of the state of health according to characteristic K2. The greater the spacing between the two characteristics at the time of a request message (expressed by the arrow R), the less critical temporary exceeding of or a shift in the operational limits of at least one characteristic variable is. If the state of health SoHc is therefore greater than the state of health of the worst case scenario at time t.sub.1 or at running time s.sub.1, which represents the design threshold value, from a technical point of view the request for a shift in the operational limit of at least one characteristic can be granted. This results in a different predicted profile of the further state of health, which is characterized by the dashed line K2′. Since at the expected end of life of the energy store there is still a sufficiently large reserve R′ (corresponding to the spacing between the characteristics K1 and K2), the temporary shift in the limit value of at least one characteristic variable will have no effect on an expected guarantee case, with the result that the shift in the operational limit cannot or does not need to be provided, or only at a low price.

[0049] In contrast, FIG. 3 shows an exemplary embodiment in which, at time t.sub.1 or at running time s.sub.1, there is only a small reserve R of the states of health between the characteristics K1 and K2. A simulation of the requested shift in the operational limit of the at least one characteristic variable could therefore result in the characteristic K1 being exceeded up until the permission is withdrawn at time t.sub.2 or at running time s.sub.2. As a result, it is no longer possible to guarantee that, at the originally calculated time t.sub.exp or at the originally calculated running power s.sub.exp, the energy store will still provide the power assured for customer requests. Instead, the state of health SoHc=0% is present at an earlier time t.sub.exp, new or at an earlier running power s.sub.exp, new. The permission for enabling of the operational limit of the at least one characteristic variable can therefore be made depending on the conclusion of a monetary transaction. In this case, the consideration is based on the fact that exceeding of the operational limit of the at least one characteristic variable does not necessarily need to result in a defect in or damage to the energy store, but a certain probability of an early problem will occur. As a result, a corresponding financial reserve can be formed by the monetary transaction.

LIST OF REFERENCE SYMBOLS

[0050] 1 user interface [0051] 10 energy store [0052] 11 chip with credential [0053] 20 control unit [0054] 30 vehicle-side transceiver unit [0055] 40 backend transceiver unit [0056] 50 arithmetic logic unit [0057] 60 invoicing system [0058] 70 simulation unit [0059] 100, 200, 300 storage cell module [0060] 101, . . . , 105 storage cells of storage cell module 100 [0061] 110, 210, 310 chip with credential [0062] 115 chip with credential [0063] K1, K2 characteristics [0064] U, I, T, SoC characteristic variables