Method for temperature-dependent adjustment of a charging current for a charging process of an electrochemical energy storage device

Abstract

Method for temperature-dependent adjustment of a charging current for a charging process of at least one electrochemical energy storage device of an electrically driven vehicle.

Description

The invention is based on a method for temperature-dependent adaptation of a charging current for a charging process of at least one electrochemical energy store of an electrically drivable vehicle, a device for operating an electrochemical energy store, a computer program and / or a use of a method for temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle according to the preamble of the independent claims.Prior ArtIn the future, electrically drivable trucks are charged at charging station with high electrical power ("megawatt charging"). In the prior art, there is the disadvantage of the absence or lack of cooling of the battery, which ultimately means a loss of range, since no energy can be charged into the battery in the cooling phases.In particular for electrically drivable trucks, the time is an important factor in order to be able to absorb as large an amount of energy as possible in prescribed resting pauses.Document DE 10 2011 089 293 A1 discloses a battery charge control method for a vehicle.Document DE 10 2021 206 010 A1 discloses a system and method for battery precooling.It is the object of the present invention to further improve the prior art. This object is achieved by the features of the independent claims.Disclosure of the InventionAdvantages of the InventionThe procedure according to the invention having the characterizing features of the independent claims has the advantage over the related art that the method for temperature-dependent adaptation of a charging current for a charging process of at least one electrochemical energy store of an electrically drivable vehicle comprises the following steps:defining a maximum charging current variable, which represents a maximum permissible charging current as a function of a temperature of the electrochemical energy store;detecting an actual temperature variable, which represents at least one instantaneous temperature of the electrochemical energy store;determining a setpoint charging current variable, which represents a charging current for the electrochemical energy store that is permissible at the present temperature, as a function of the detected actual temperature variable on the basis of the maximum charging current variable;adapting the charging current for the charging process of the electrochemical energy store as a function of the setpoint charging current variable.Interruptions in the charging process can advantageously be reduced if the predetermined temperature limit values are not exceeded, in particular in the absence of or inadequate cooling of the electrochemical energy store. As a result, for example, as much energy as possible can be stored in electrochemical energy stores even in short pauses of a truck driver. This is advantageously possible even at high temperatures with a maximum possible charging current without disconnection occurring by a battery management system (BMS) of the electrochemical energy store.In this case, the charging currents go into a type of "derating" and are reduced accordingly. For the charging process, this means that electrically drivable vehicles, for example an electrically drivable truck (truck), can be charged with a maximum temperature-dependent charging current and not with a maximum electric current provided by a charging station, which can range up to a few thousand amperes.In this method according to the invention, the charging current is predefined by a respectively established temperature profile of the electrochemical energy store, which is usually at least a few minutes. As a result, advantageously, no pulsed charging takes place in a high frequency range.Further advantageous embodiments are the subject matter of the dependent claims.Advantageously, the determination of the setpoint charging current variable takes place in such a way that a maximum charging current of a charging current level is achieved as a function of the temperature of the electrochemical energy store without the charging process being interrupted due to thermal heating of the electrochemical energy store.Thus, although less energy is supplied with the method according to the invention in comparison with an electrochemical energy store having a very good cooling system, much more energy is supplied in comparison with a prion allocation which would determine and interrupt the charging process.The method for temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of the preceding claims further comprises the steps:comparing the target charge current magnitude with a predetermined target charge current threshold;charging the electrochemical energy store with a first type of charging current, which represents an alternating current, when the setpoint charging current variable falls below the setpoint charging current threshold value; orcharging the electrochemical energy store with a second charging current type, which represents a direct current, when the setpoint charging current variable exceeds the setpoint charging current threshold value.A combination of alternating current and direct current is advantageously possible with a CCS plug. The charging current type is also not limited to direct current or alternating current; it can also advantageously change from direct current to alternating current if, for example, only small currents are allowed.The maximum charging current variable is stored in a temperature-dependent characteristic diagram and takes into account further variables, in particular the state of health (SOH) of the electrochemical energy store, and also an inertia of a thermal system of the electrochemical energy store.The temperature-dependent characteristic diagram advantageously comprises data of electrochemical energy storage cells according to a data sheet of the cell manufacturer. In addition to exceeding temperature limit values, the inertia of the thermal system also takes into account a safety margin in order to be able to counter-drive in good time with smaller charging currents.The charging current variable is stored in a control unit of the electrochemical energy store and / or a control unit of a charging device that can be connected to the electrochemical energy store, and / or the setpoint charging current variable is determined by the control unit of the electrochemical energy store and / or the control unit of the charging device.The charging current for the charging process of the electrochemical energy store is adjusted by the control unit of the electrochemical energy store and / or the control unit of the charging device.A device for operating an electrochemical energy store comprises at least one temperature sensor for detecting a temperature of the electrochemical energy store, and at least one means, in particular an electronic battery management control unit, which are configured to carry out the steps of the method according to the invention for temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle.According to an advantageous embodiment of the invention, a computer program is provided, comprising instructions which cause the device for operating a battery to execute the method steps according to the invention.Furthermore, a machine-readable storage medium is provided on which the computer program is stored.A method according to the invention for temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle and / or of a device for operating an electrochemical energy store is advantageously used in electrochemical energy stores for electric vehicles, electric motor vehicles, fuel cell vehicles, hybrid vehicles, plug-in hybrid vehicles, aircraft, pedelecs and / or e-bikes.Brief Description of the FiguresExemplary embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.The following are shown: FIG. 1 shows a schematic profile of a temperature-dependent charging current; and FIG. 2 shows a schematic illustration of a flow diagram of an embodiment of a method according to the invention.DETAILED DESCRIPTION OF THE EMBODIMENTSLike reference numerals designate like device components throughout the figures.FIG. 1 shows a schematic profile of a temperature-dependent charging current 100.A duration t of a charging process is plotted on the abscissa, a charging power P dependent on the charging current is plotted on a first ordinate, and a temperature T of an electrochemical energy store is plotted on a second ordinate.The electrochemical energy store is initially charged at a first charging current level 101( 1) with a charging power P of 50 kW. As a result, in an example first time period 104, a temperature profile 102 of the electrochemical energy store decreases.Starting from a time t 1, the electrochemical energy store is charged at a second charging current level 101 ( 2) with a charging power P of 160 kW. As a result, in an exemplary second time period 105, the temperature profile 102 of the electrochemical energy store increases. Before a maximum temperature 103 is reached, which would lead to an interruption of the charging process or to a lowering of a charging priority, the charging current is reduced to a third charging current level 101( 3), as a result of which the charging power P decreases from 160 kW to 50 kW and the electrochemical energy store cools down as a result.As a result, in the unfavourable case, the charging current changes back and forth between two current intensities, but the charging process does not change between the states of charging and non-charging, which advantageously leads to the possibility of permanent charging.The charging current thus always moves below a predefined temperature limit and advantageously stores a maximum amount of energy in the electrochemical energy store. Although this does not achieve cooling of the electrochemical energy store, which would allow even higher charging currents, it is charged continuously.FIG. 2 shows a schematic representation of a flow chart of an embodiment of a method according to the invention.In a first step 200, a maximum charging current variable, which represents a maximum permissible charging current as a function of a temperature T of the electrochemical energy store, is established.In step 201, an actual temperature variable is detected, which represents at least one instantaneous temperature T of the electrochemical energy store.In step 202, a setpoint charging current variable is determined, which represents a charging current for the electrochemical energy store permissible at the instantaneous temperature T, as a function of the detected actual temperature variable on the basis of the maximum charging current variable.In step 203, the charging current for the charging process of the electrochemical energy store is adapted as a function of the setpoint charging current variable.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2011 089 293 A1

[0004] DE 10 2021 206 010 A1

[0005]

Claims

Method for temperature-dependent adaptation of a charging current (100) for a charging process of at least one electrochemical energy store of an electrically drivable vehicle, comprising the steps: - (200) defining a maximum charging current variable (103) which represents a maximum permissible charging current as a function of a temperature (T) of the electrochemical energy store; - (201) detecting an actual temperature variable which represents at least one instantaneous temperature (T) of the electrochemical energy store; - (202) determining a setpoint charging current variable which represents a charging current for the electrochemical energy store permissible at the instantaneous temperature (T) as a function of the detected actual temperature variable on the basis of the maximum charging current variable (103); - (203) adaptation of the charging current (100) for the charging process of the electrochemical energy store as a function of the setpoint charging current variable.Method for temperature-dependent adaptation of a charging current (100) for a charging process of an electrochemical energy store of an electrically drivable vehicle according to Claim 1, wherein the determination of the setpoint charging current variable takes place in such a way that a maximum charging current of a charging current level (101(1), 101(2), 101(3)) is achieved as a function of the temperature (T) of the electrochemical energy store without the charging process being interrupted on account of thermal heating of the electrochemical energy store.Method for temperature-dependent adaptation of a charging current (100) for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of the preceding claims, further comprising the steps: - comparing the setpoint charging current variable with a predefined setpoint charging current threshold value; - charging the electrochemical energy store with a first charging current type which represents an alternating current if the setpoint charging current variable falls below the setpoint charging current threshold value; or - charging the electrochemical energy store with a second charging current type which represents a direct current if the setpoint charging current variable exceeds the setpoint charging current threshold value.Method for temperature-dependent adaptation of a charging current (100) for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of the preceding claims, wherein the maximum charging current variable is stored in a temperature-dependent characteristic diagram and takes into account further variables, in particular the state of health (SOH) of the electrochemical energy store, and an inertia of a thermal system of the electrochemical energy store.Method for temperature-dependent adaptation of a charging current (100) for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of the preceding claims, wherein the charging current variable is stored in a control unit of the electrochemical energy store and / or a control unit of a charging device which can be connected to the electrochemical energy store and / or the setpoint charging current variable is determined by the control unit of the electrochemical energy store and / or the control unit of the charging device.Method for temperature-dependent adaptation of a charging current (100) for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of the preceding claims, wherein the charging current for the charging process of the electrochemical energy store is adapted by the control unit of the electrochemical energy store and / or the control unit of the charging device.Device for operating an electrochemical energy store, comprising at least one temperature sensor for detecting a temperature (T) of the electrochemical energy store, and at least one means, in particular an electronic battery management control unit, which are configured to carry out the steps of the method for temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of Claims 1 to 6.A computer program comprising instructions for causing the apparatus of claim 7 to perform the method steps of any one of claims 1 to 6.A machine readable storage medium having stored thereon the computer program of claim 8.Use of a method for the temperature-dependent adaptation of a charging current for a charging process of an electrochemical energy store of an electrically drivable vehicle according to one of Claims 1 to 6 and / or of a device for operating an electrochemical energy store according to Claim 7 in electrochemical energy stores for electric vehicles, electric motor vehicle, fuel cell vehicles, hybrid vehicles, plug-in hybrid vehicles, aircrafts, pedelecs and / or e-bikes.

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