DE102014200678A1 - Method for operating a battery - Google Patents

Abstract

The present invention relates to a method for producing a gentle state of charge of a battery for a standstill time, wherein the gentle state of charge above a minimum state of charge, which is above the total discharge, and wherein the gentle state of charge, in particular below a maximum state of charge, which is below a full charge , comprising the method steps: a) recording the current state of charge of the battery; b) receiving cell discharge data of the battery; c) recording standstill time data having a desired downtime of the battery; d) evaluating the standstill time data taking into account the cell charge data while determining a gentle state of charge of the battery; e) comparing the current state of charge and the gentle state of charge; and f) optionally issuing a loading recommendation. Such a method allows a particularly gentle and safe downtime of a battery and ensures the battery capacity even after the downtime.

Description

The present invention relates to a method of operating a battery. More particularly, the present invention relates to a method for producing a gentle state of charge of a battery for a standstill time for improving the longevity thereof during the standstill period.

State of the art

Electrochemical energy storage devices, such as lithium-ion batteries, are widely used in many daily applications. They are used, for example, in computers such as laptops, cell phones, smart phones, and other applications such as wind turbines. Even with the currently highly advanced electrification of vehicles, such as motor vehicles, such batteries offer advantages.

In particular, during a longer downtime, battery cells usually discharge gradually. The disadvantage here may be that from a certain depth of discharge the battery can not deliver electrical power and thus can not be used. If the battery is further discharged, it can even lead to irreversible damage in many types of batteries, which force a replacement of the battery. This can be disadvantageous, for example, in electrically powered vehicles when they are parked without a charger or for a longer period of time.

From the document WO 00/04620 A2 For example, a system and method for monitoring a vehicle battery is known in which the state of charge of the battery, a battery backup capacity, and other defined factors are communicated to the driver of the vehicle.

The document KR 1020100060155 A describes a system and method for optimizing generation control of a vehicle battery in which charging is performed in response to a weather forecast.

Disclosure of the invention

• a) Aufnehmen des momentanen Ladezustands der Batterie;
• b) Aufnehmen von Zellentladungsdaten der Batterie;
• c) Aufnehmen von Stillstandzeitdaten aufweisend eine gewünschte Stillstandzeit der Batterie;
• d) Auswerten der Stillstandzeitdaten unter Berücksichtigung der Zellentladungsdaten unter Ermittlung eines schonenden Ladezustands der Batterie;
• e) Vergleichen des momentanen Ladezustands und des schonenden Ladezustands; und
• f) gegebenenfalls Ausgeben einer Ladeempfehlung.

The present invention is a method for producing a gentle state of charge of a battery for a downtime, wherein the gentle state of charge is above a minimum state of charge, which is above the total discharge, and wherein the gentle state of charge, in particular below a maximum state of charge, which is below a full charge is, comprising the method steps:

• a) recording the current state of charge of the battery;
• b) receiving cell discharge data of the battery;
• c) recording standstill time data having a desired downtime of the battery;
• d) evaluating the standstill time data taking into account the cell charge data while determining a gentle state of charge of the battery;
• e) comparing the current state of charge and the gentle state of charge; and
• f) optionally issuing a loading recommendation.

The method described above for producing a gentle state of charge of a battery for a standstill time makes it possible in a particularly simple manner to set a charging state of a battery such that the battery is not damaged and, advantageously, operation of a component equipped with a battery continues even after a standstill period is possible and the battery is protected, so that a particularly long life of the battery is possible.

The present invention thus relates to a method for operating a battery. Such a battery may, for example, comprise at least one electrochemical cell arranged in a housing with an electrode arrangement comprising a first electrode and a second electrode and an electrolyte which contacts them. An electrochemical cell can be designed essentially as known from the prior art. For example, for the exemplary case of a lithium-ion battery, the anode may include or be made of metallic lithium or a material that can intercalate lithium ions. For example, such an anode material may be applied to a current collector, such as scored. Exemplary anode materials include graphite or lithium titanate. The cathode can accordingly, likewise for the purely exemplary case of a lithium-ion battery, for example nickel-manganese-cobalt-oxide (NMC) or lithium-cobalt-oxide (LiCoO ₂ ) be configured and also applied to a current conductor be. Optionally, the cathode material as well as the anode material may be present in a binder, such as polyvinylidene fluoride (PVDF), for example, along with a conductive additive, such as an electrically conductive carbon compound, such as graphite.

The electrolyte can likewise be, for example, a solid electrolyte in a manner known per se or comprise a solvent in which one or more electrically conductive salts are dissolved. For example, aprotic solvents, such as for example, ethylene carbonate, propylene carbonate, dimethyl carbonate or diethyl carbonate. Furthermore, as the electrically conductive salt lithium hexafluorophosphate (LiPF ₆ ) can be used. For example, the electrolyte may be located in pores of a separator disposed between the electrodes. The separator may for example be a particular porous plastic film, such as formed from polypropylene.

For example, but not limiting in a battery described above, in the method described above in the operation of the battery, in particular before and / or during a downtime a gentle state of charge can be set. A gentle state of charge is in particular such a state of charge, which is above a minimum state of charge, which is above the total discharge, and which lies in particular or advantageously below a maximum state of charge, which is below a full charge. Thus, the gentle state of charge is especially one which is in a medium state of charge and thus can prevent a deep discharge and advantageously also a full charge. A deep discharge may in particular be such a state of charge, in which an irreversible damage to the battery can take place. A full charge can also be a no longer increasable state of charge, which can lead to overheating of the battery and thus to a risk in the extreme of the overcharge.

Thus, the present method is based in particular on the fact that batteries can be damaged in a full discharge or a deep discharge under certain circumstances and possibly irreversibly damaged after a deep discharge and are no longer chargeable. On the other hand, a full charge can also have a negative effect on the battery, as, for example, aging of the battery in a maximum state of charge can proceed the most.

Thus, the gentle state of charge can ensure that the state of charge during the downtime of the battery is always in a middle, gentle for the battery area, which effectively prevents both excessive aging as well as a deep discharge and thus irreversible damage. For example, a state of charge (SOC) may range from greater than or equal to 5% to less than or equal to 95%, based on a total (de-) charge. The determination of the SOC can be carried out in particular immediately or after a sufficient rest period of, for example, 1 h and / or for example by voltage measurement and retroactive calculation of the SOC by means of the OCV (SOC) characteristic curve (OCV = open circuit voltage, rest voltage).

The longevity of the battery can be significantly increased according to the invention. Furthermore, it can be effectively prevented that the battery can no longer be charged, in particular after a standstill period, so that it can be ensured that the battery can still work as desired, even after a standstill period. Therefore, the above-described method is particularly effective when the battery is subjected to a longer downtime. Thus, the present method can in particular allow a gentle state of charge during a downtime.

In the context of the present invention, a standstill time can be understood to mean a state in which there is no intentional or only reduced supply of energy to a consumer in which the battery is switched off, for example. Furthermore, a standstill may, for example, be understood as a state in which one or a plurality of optionally present consumers, in particular a main consumer, is not supplied with energy, but one or a plurality of optionally present consumers can still be supplied with energy and thus the Battery works in a reduced mode. For example, a standstill time can be understood as a state in which, for example, in an electrically driven vehicle, the electric motor is not supplied with electrical power, but further, subordinate consumers, such as a clock or an alarm system, are still supplied with energy.

In order to be able to carry out the method described above, this method according to method step a) comprises recording the instantaneous state of charge of the battery. Thus, in this method step, as is generally known from the prior art, the instantaneous state of charge of the battery, that is currently present in method step a), is detected, as is generally known. The instantaneous state of charge can serve as a basis for the above-described method.

For example, this method step as well as the further method steps can be performed by and / or with a battery management system, which is designed, for example, by the provision of suitable software or hardware components for carrying out such a method.

Furthermore, the above-described method according to method step b) comprises the reception of cell discharge data of the battery. This step is therefore based on the fact that batteries, such as lithium-ion batteries, during a downtime not maintain their state of charge unchanged but due to different Influences during a standstill even without the active desired supplying a consumer with electrical energy can take place a certain discharge. In this case, the cell discharge data may comprise a very wide variety of data which are directly or indirectly related to the cell discharge during a standstill time, as explained in detail below.

According to method step c), the method described above further comprises recording standstill time data having a desired downtime of the battery. The standstill time data thus include, in particular, data relating to parameters of a desired downtime of the battery. In particular, the standstill time data include the desired duration of a standstill time or a desired downtime of the battery. The standstill time data may be input, for example, by the user of a device such as an electrically driven vehicle equipped with a battery, and particularly a battery management system that can perform a prescribed method. Furthermore, the standstill time data can be entered as components of a predetermined time program for operating the battery or for operating an electrical consumer as in the battery management system.

In accordance with method step d), the standstill time data recorded in method step c) are evaluated taking into account the cell charge data recorded in method step b), with the result of determining a gentle state of charge of the battery. Thus, in this process step, the data previously recorded in process steps a) to c) by the battery management system or the corresponding data entered into the battery management system, for example using a suitable algorithm, are evaluated to determine a state of charge, which causes the battery during the entire downtime or even after the downtime and thus when switching on the battery is still in a gentle state of charge. In this case, the gentle state of charge, for example, a "worst-case" scenario into account, so evaluate all data to a maximum discharge, or it can be a realistic estimate possible.

If the gentle state of charge has been determined as explained above, the comparison of the instantaneous state of charge and the gentle state of charge determined in process step d) takes place in accordance with method step e). It is thus determined in this step, whether the current state of charge of the battery is sufficient to cause no deep discharge during the downtime and it can also be determined whether a charge can take place without having to carry out a full charge.

So that the battery has a gentle state of charge before a defined standstill or can be added to it, in step f) optionally outputting a charging recommendation takes place. In the event that the current state of charge corresponds to a gentle state of charge, a charge recommendation may possibly fail or a charging recommendation may include that a charge is not necessary. In the event that the state of charge is below a gentle state of charge and thus a charging should take place, so that the battery enters a gentle state of charge, can be displayed to what extent a charge should take place. Thus, it may be possible that, as explained in detail above, the battery neither a deep discharge happens during the downtime, nor takes place an excessive charge of the battery, so as to avoid premature aging by a full charge.

The charging recommendation can therefore be used so that the battery is only charged to a standstill so far that the state of charge sufficient to cause deep discharge during downtime or exemplified in an electrically driven vehicle such that the number of desired parking days less than or equal the number of gentle park days.

In particular, when issuing a charging recommendation, an emergency program can advantageously be included or used which, after the standstill period, does not allow a consumer to be supplied with energy but prevents a deep discharge. In particular, when issuing such a charging recommendation, a full charge can be prevented even with long downtime due to the low required charge volume, so that especially in this way a conservation of the battery can be made possible even with long downtime. In this embodiment, for example, a gentle state in a comparatively low state of charge can be made possible, for example in a range from greater than or equal to 5% to less than or equal to 20% relative to a complete (de-) charge, the abovementioned values depending on the Standstill time data and cell discharge data of the battery are to be selected.

Within the scope of an embodiment, the method can be part of a method for Operate a motor vehicle battery and can be the downtime the parking duration of a motor vehicle. In particular, in motor vehicles parking operations can often mean longer downtime of the battery, in particular vehicle batteries are exposed to external influences such as in particular the temperature, so that the above-described method can be particularly advantageous in vehicle batteries.

As part of a further embodiment, a charger for setting a gentle state of charge can be controlled in dependence on the charging recommendation according to method step f). Thus, the outputting of a charging recommendation to a battery charger can take place, in particular, wherein charging of the battery takes place in response to the charging recommendation or charging state recommendation. In this case, a charging of the battery can be terminated after reaching a state of charge according to the charging recommendation. In this embodiment, a fully automated charging of the battery before and / or during a standstill can thus be made possible because a full charge can be safely prevented. In this embodiment, a gentle state of charge can thus be adjusted automatically before the downtime or when starting the downtime by the charger, so that a gentle shutdown of the battery can be made possible. In this case, such a control can take place only at the beginning of the downtime, or even during a downtime in the event that the downtime takes too long to stay in a gentle state of charge of the battery. In the latter case, one or a plurality of intermediate charges can thus take place during the standstill period, which protect the battery from deep discharge and furthermore ensure that deep discharging does not take place even after a very long standstill time, but charging the battery is still possible.

Within the scope of a further embodiment, the cell charge data may be selected from the group consisting of battery manufacturer specifications, cell charge data of past shutdowns, leakage currents, self-discharge currents, temperature data, aging data or a combination of the aforementioned cell charge data. In particular, in this embodiment, the cell discharge data thus allow a particularly accurate and accurate determination of a cell discharge during downtime, so that the gentle state of charge can be determined particularly safe and reliable. In this case, for example, the data determined by the manufacturer of the battery concerning a cell discharge may be suitable. These can be deposited in the battery management system, for example. Furthermore, cell discharge data of past shutdowns can be considered, which may also be deposited in the battery management system, for example, which may update the manufacturer's specifications. Furthermore, leakage currents can be considered, in particular estimated leakage currents from the driving operation, which can be ascertainable from the difference of the charge state determined from the current integral (state of charge, SOC) and the charge state determined from the rest voltage. Furthermore, self-discharge currents, and in particular those calculated by a model, which takes into account the state of charge, the state of health (SOH), the pre-standstill stress and the temperature can be considered. In particular, a combination of several or all of the aforementioned data may be used as cell discharge data. It can thus be considered that a correct or the most likely discharge is assumed, for example, depending on the cell type, the state of charge and the state of preservation of the battery. Cell discharge data are thus in particular those which, due to internal or inherent properties of the battery, have an effect on discharging the battery during the standstill period.

Within the scope of a further embodiment, the standstill data can also have temperature data, data relating to active consumers or a combination of the aforementioned data in addition to a desired standstill time. In this embodiment, a particularly advantageous assessment of the downtime and thus a discharge taking place during this downtime can thus be made possible. In this case, for example, temperature data are taken into account, which presumably exist during the standstill period, since, for example, the temperature can have a great influence on the discharge of the battery. The temperature data can be entered or recorded, for example, with the aid of an online weather forecast. This can be realized, for example, by the battery management system establishing an online connection and thus, for example, ascertaining online data relating to the probable weather during the downtime. Furthermore, data concerning active consumers powered by the battery, such as a clock in a vehicle, may be considered as these may also alter the state of charge of the battery. Standstill data are therefore in particular those data which trigger an external influence on the battery during the standstill period.

In the context of a further refinement, in the case of issuing a charging recommendation in accordance with method step f), a total discharge in a higher priority than a full charge can be taken into account. In this embodiment can thus be particularly To ensure that a deep discharge and thus the risk of irreversible damage is prevented. A full charge, which although an increased aging but no irreversible damage to the battery brings with it, however, may be possible if necessary. In other words, a full charge may take place, for example, if during off-time a deep discharge would otherwise occur due to a too low state of charge.

In the context of a further embodiment, when outputting a charging recommendation according to method step f), an additional charging reserve can be taken into account. Such a charge reserve can serve as a safety margin, for example, so that a deep discharge can be prevented even in the case of unfavorable discharging processes. Furthermore, a safety reserve can serve to prevent not only deep discharge but also to allow the electrical appliance to be operated for at least a limited period of time after the standstill period. For example, it can be ensured in an electrically operated vehicle that even after a downtime, such as after a parking, still a limited distance can be covered. Thus, in this embodiment, the driver prior to parking the vehicle enter the planned parking duration and receive a charging recommendation based on which optionally allows charging or can be set such that a particularly gentle downtime for the battery is made possible and the vehicle is still movable , The charge reserve, for example, an additional charge in a range of greater than or equal to 10%, for example greater than or equal to 15% to less than or equal to 30%, based on the gentle state of charge, have.

Within the scope of a further embodiment, the method may comprise the further method step: g) displaying a gentle downtime. In particular, method step g) can take place before or during method step f). In this embodiment, for example, a number of gentle parking days can be displayed to a driver of a vehicle, ie a period during which a discharge can not lead to a total discharge or where only such a discharge occurs, so that there is still a charge reserve and the vehicle thus still moving or the battery can still be charged. This can for example be realized by a corresponding analog or digital display, which may be part of the battery management system or connected to it. In this case, after an input of the desired downtime and about changed temperature data together with the charging recommendation, a further adapted display of gentle downtime can be made possible.

Optionally, a warning may also be issued if the desired input downtime can not be done with a gentle state of charge. In this case, for example, an alternative charging recommendation can be issued, which is accompanied by a full charge, for example, and / or an indication can be issued that an intermediate charge should take place and / or an indication of a reduction in the downtime can be made.

Furthermore, in the event that a total discharge threatens, for example, a corresponding warning, for example, on a display, and / or to a preset telephone number, for example via SMS, and / or by an e-mail to a default e-mail address issued become. In this case, it can be responded to, for example, that a discharge can be accelerated in unforeseen ways, for example due to a fault or damage to the battery. In this case, appropriate countermeasures can be taken. The same can be provided for example by a change in the gentle downtime, for example, by unforeseen changes such as the standstill data, such as the temperature.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 00/04620 A2 [0004]
• KR 1020100060155 A [0005]

Claims (10)

A method for producing a gentle state of charge of a battery for a standstill time, wherein the gentle state of charge is above a minimum state of charge, which is above the total discharge, and wherein the gentle state of charge, in particular below a maximum state of charge, which is below a full charge, lies, comprising steps: a) recording the current state of charge of the battery; b) receiving cell discharge data of the battery; c) recording standstill time data having a desired downtime of the battery; d) evaluating the standstill time data taking into account the cell charge data while determining a gentle state of charge of the battery; e) comparing the current state of charge and the gentle state of charge; and f) optionally issuing a loading recommendation. The method of claim 1, wherein the method is part of a method for operating a motor vehicle battery and wherein the downtime is the parking duration of a motor vehicle. Method according to one of claims 1 or 2, wherein, depending on the charging recommendation in accordance with method step f), a charging device for setting a gentle state of charge is activated. Method according to one of claims 1 to 3, wherein the standstill time data are received by input to a battery management system. The method of claim 1, wherein the cell discharge data is selected from the group consisting of battery manufacturer information, cell discharge data of past stoppages, leakage currents, self-discharge currents, temperature data, aging data or a combination of the aforementioned cell charge data. Method according to one of claims 1 to 5, wherein the downtime data in addition to a desired downtime further temperature data, data concerning active consumers or a combination of the aforementioned data. The method of claim 6, wherein the temperature data is recorded with the aid of an online weather forecast. Method according to one of claims 1 to 7, wherein in the output of a charging recommendation according to method step f) a deep discharge in higher priority than a full charge is taken into account. Method according to one of claims 1 to 8, wherein in the output of a charging recommendation according to method step f) an additional charge reserve is taken into account. Method according to one of claims 1 to 9, wherein the method comprises the further method step: g) Display of a gentle downtime.