DE102019216961A1 - Method for charging at least two electrical energy storage devices and a vehicle - Google Patents

Abstract

A method for charging at least two electrical energy storage devices and a vehicle, wherein in a first method step a respective operating parameter of the respective electrical energy storage device is recorded, wherein in a second method step the electrical energy storage devices whose operating parameters are below a first limit value are charged, with a third Method step, when a value of an operating parameter of an electrical energy store reaches the first limit value, the charging process for this electrical energy store is interrupted, wherein in a fourth process step a value of an operating parameter of a last electrical energy store reaches the first limit value, whereby it is checked in a fifth process step, whether the values of the operating parameters of all electrical energy stores are within a value range below the first limit value, wherein in a sixth method step, if in the fifth ver driving step the value of the operating parameter of an electrical energy store is below the range of values, this electrical energy store is charged until its operating parameter reaches the first limit value, wherein in a seventh process step, when all the operating parameters are within the range of values below the first limit value, all electrical energy stores are charged simultaneously be, the charging process for all electrical energy storage is ended in an eighth method step.

Description

Field of invention

The present invention relates to a method for charging at least two electrical energy stores and a vehicle.

State of the art

The US 2016/0094067 A1 discloses a charging unit for multiple batteries.

The US 2017/0141589 A1 shows a battery system that connects a variety of battery types by means of a switch.

Disclosure of the invention

The essence of the invention in the method for charging at least two electrical energy stores is that the method has the successive method steps: in a first method step a respective operating parameter of the respective electrical energy store is recorded, with the electrical energy store in a second method step whose operating parameters are below a first limit value, are charged, wherein in a third method step, when a value of an operating parameter of an electrical energy store reaches the first limit value, the charging process for this electrical energy store is interrupted, in a fourth process step a value of an operating parameter of a last electrical energy store reached the first limit value, it being checked in a fifth method step whether the values of the operating parameters of all electrical energy stores within ei nes range of values lie below the first limit value, wherein in a sixth process step, if in the fifth process step the value of the operating parameter of an electrical energy store is below the value range, this electrical energy store is charged until its operating parameter reaches the first limit value, wherein in a seventh process step, if all operating parameters are within the range of values below the first limit value, all electrical energy stores are charged simultaneously, with the charging process for all electrical energy stores being terminated in an eighth method step when a value of an operating parameter of an electrical energy store reaches a second limit value.

The background to the invention is that, by means of the method, electrical energy stores with different operating states, in particular charge states, can be charged simultaneously and thereby quickly. The charging process is suitable for any number of electrical energy stores.

The limit value for the operating parameter is advantageously less than 90% and greater than 70% of a maximum value of the operating parameter, in particular it is 80% of the maximum value.

According to an advantageous embodiment, the operating parameters of the electrical energy storage device are recorded continuously during the method. As a result, the method can be adapted to the current operating parameters of the electrical energy storage device.

It is advantageous if, in the third method step, as soon as an operating parameter of a further electrical energy store reaches the first limit value, the charging process for the further electrical energy store is also interrupted. The charging processes for the individual electrical energy stores are thus gradually interrupted as soon as the value of the operating parameter of the respective electrical energy store reaches the first limit value. Only when the value of the operating parameter of the last electrical energy store, which had the lowest value at the beginning of the method, reaches the limit value in the fourth method step, the method is continued with the fifth method step.

The second limit value is advantageously greater than the first limit value.

It is also advantageous if the electrical energy stores are charged with a constant current in the second method step. As a result, a maximum charging power can be set, since the electrical energy stores are robust against high charging powers below the first limit value.

According to a further advantageous embodiment, the electrical energy store (s) are charged with a constant voltage in the sixth method step and / or in the seventh method step. When charging with constant voltage, the electrical energy storage devices are charged gently, so that damage to the electrical energy storage devices can be avoided.

It is advantageous here if the electrical energy store (s) whose charging process was interrupted in the third method step relaxes. Thus, a balancing process following the charging method can be used to adjust the operating parameters of the electrical Energy storage can be dispensed with. In addition, the loading capacity increases.

According to a further advantageous embodiment, according to the third method step, it is continuously checked whether the value of the operating parameter of a relaxing electrical energy store has dropped to a value below the value range, the relaxing electrical energy store as soon as the value of an operating parameter has dropped to a value below the value range is charged again until the value of the operating parameter reaches the first limit value again, in particular wherein the electrical energy store is charged with a constant current. As a result, the sixth method step can be dispensed with, since in the fifth method step the values of the operating parameters of all electrical energy stores are within the value range below the first limit value. The charging process can therefore be accelerated even further.

The essence of the invention in the vehicle, having at least one first electrical energy store and a second electrical energy store, in particular wherein the vehicle is set up to charge the electrical energy store by means of a method as described above or according to one of the claims related to the method, is that the vehicle has a single charging device and a switching unit, wherein the switching unit is arranged between the charging device and the electrical energy storage device, wherein the switching unit is set up, the charging device with the first electrical energy storage device or with the second electrical energy storage device or with the first electrical energy storage device and to connect the second electrical energy store.

The background to the invention is that a vehicle with several independent electrical energy stores has only a single integrated charging device. The electrical energy stores can be connected to or disconnected from the charging device by means of the switching unit, depending on their operating parameters.

The electrical energy stores can advantageously be charged simultaneously or individually by means of the charging device and the switching unit. As soon as an electrical energy store is fully charged or up to a first or second limit value, it can be disconnected from the charging device and the other electrical energy store can be charged further.

Further advantageous embodiments of the present invention are the subject of the subclaims.

According to an advantageous embodiment, the vehicle has a first electric motor and a third electric motor, the first electric motor being fed from the first electrical energy store, the third electric motor being fed from the second electrical energy store. As a result, a single charging device can be used for two independent drives.

It is also advantageous if the vehicle has a first drive axle, a first gearbox and a second electric motor, the first drive axle being connectable to the first electric motor and / or the second electric motor by means of the first gearbox. The drive can thus be implemented redundantly and the availability of the vehicle is improved.

It is advantageous if the first gear is designed as a summation gear and / or coupling gear.

According to a further advantageous embodiment, the vehicle has a control unit which is connected in a signal-conducting manner to the switching unit, the charging device and the electrical energy stores. The control unit is advantageously designed as a central control unit of the vehicle.

The control unit is advantageously set up to control the switching unit. The switching unit can therefore be carried out simply and inexpensively, since all evaluations and control decisions for the charging process can be carried out by the control unit.

It is advantageous if the control unit is set up to receive and evaluate signals from sensors of the electrical energy storage device. As a result, the switching unit can be controlled as a function of the evaluated sensor signals.

It is also advantageous if the vehicle has a connection means that is connected to the charging device in an electrically conductive manner. The charging device can be connected to an external charging station by means of the connection means.

The above configurations and developments can be combined with one another as desired, provided that it makes sense. Further possible configurations, developments and implementations of the invention also include combinations, not explicitly mentioned, of features of the invention described above or below with regard to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

Figure list

In the following section, the invention is explained on the basis of exemplary embodiments from which further inventive features can result, but to which the scope of the invention is not restricted. The exemplary embodiments are shown in the drawings.

• 1 eine schematische Darstellung eines erfindungsgemäßen Fahrzeugs 1,
• 2 Spannungswerte (U1, U2, U3, U4) von vier elektrischen Energiespeichern (6, 9) zu einem ersten Zeitpunkt,
• 3 die Spannungswerte (U1, U2, U3, U4) der vier elektrischen Energiespeicher (6, 9) zu einem zweiten Zeitpunkt und
• 4 ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens 100 zum Laden von zumindest zwei elektrischen Energiespeichern (6, 9).

Show it:

• 1 a schematic representation of a vehicle according to the invention 1 ,
• 2 Voltage values (U1, U2, U3, U4) of four electrical energy storage devices ( 6th , 9 ) at a first point in time,
• 3 the voltage values (U1, U2, U3, U4) of the four electrical energy stores ( 6th , 9 ) at a second point in time and
• 4th a flow chart of a method according to the invention 100 for charging at least two electrical energy storage devices ( 6th , 9 ).

In 1 is the drive train of the vehicle according to the invention 1 shown.

• - eine erste Antriebsachse 3,
• - eine zweite Antriebsachse 14,
• - ein erstes Getriebe 2
• - ein zweites Getriebe 13,
• - einen ersten Elektromotor 19,
• - einen zweiten Elektromotor 4,
• - einen dritten Elektromotor 12,
• - einen vierten Elektromotor 15,
• - einen ersten elektrischen Energiespeicher 6,
• - einen zweiten elektrischen Energiespeicher 9,
• - einen ersten Umrichter 18,
• - einen zweiten Umrichter 5,
• - einen dritten Umrichter 10,
• - einen vierten Umrichter 16,
• - eine Ladevorrichtung 7,
• - eine Schalteinheit 8,
• - ein Anschlussmittel 11 und
• - eine Steuereinheit 17.

The vehicle 1 indicates:

• - a first drive axle 3 ,
• - a second drive axle 14th ,
• - a first transmission 2
• - a second gearbox 13th ,
• - a first electric motor 19th ,
• - a second electric motor 4th ,
• - a third electric motor 12th ,
• - a fourth electric motor 15th ,
• - a first electrical energy storage device 6th ,
• - A second electrical energy store 9 ,
• - a first converter 18th ,
• - a second converter 5 ,
• - a third converter 10 ,
• - a fourth converter 16 ,
• - a loading device 7th ,
• - a switching unit 8th ,
• - a connection means 11 and
• - a control unit 17th .

The first drive axle 3 is by means of the first gear 2 with the first electric motor 19th and / or the second electric motor 4th connectable, in particular couplable. The first drive axle 3 is by means of the first electric motor 19th and / or the second electric motor 4th drivable.

The second drive axle 14th is by means of the second gear 13th with the third electric motor 12th and / or the fourth electric motor 15th connectable, in particular couplable. The second drive axle 14th is by means of the third electric motor 12th and / or the fourth electric motor 15th drivable.

The first transmission 2 and / or the second transmission 13th is designed as a coupling gear and / or summation gear.

The first electric motor 19th is electrically conductive with the first inverter 18th connected. This is the first electric motor 19th from the first converter 18th fed. The first converter 18th is electrically conductive to the first electrical energy store 6th connected. The first converter 18th is set up from a DC voltage of the first electrical energy store 6th an alternating voltage for the first electric motor 19th to generate.

The second electric motor 4th is electrically conductive to the second inverter 5 connected. This is the second electric motor 4th from the second inverter 5 fed. The second converter 5 is electrically conductive to the first electrical energy store 6th connected. The second converter 5 is set up from a DC voltage of the first electrical energy store 6th an alternating voltage for the second electric motor 4th to generate.

The third electric motor 12th is electrically conductive with the third inverter 10 connected. This is the third electric motor 12th from the third converter 10 fed. The third converter 10 is electrically conductive to the second electrical energy store 9 connected. The third converter 10 is set up from a direct voltage of the second electrical energy store 9 an alternating voltage for the third electric motor 12th to generate.

The fourth electric motor 15th is electrically conductive with the fourth inverter 16 connected. This is the fourth electric motor 15th from the fourth inverter 16 fed. The fourth converter 16 is electrically conductive to the second electrical energy store 9 connected. The fourth converter 16 is set up from a direct voltage of the two electrical energy stores 9 an alternating voltage for the fourth electric motor 15th to generate.

The first electrical energy stores are preferably used 6th and the second electrical energy store 9 executed in the same way, in particular they have the same storage capacity and / or the same maximum voltage and / or the same maximum charging current and / or the same maximum discharge current.

The ones in the vehicle 1 integrated charging device 7th is by means of the connection means 11 Can be electrically connected to an external charging station. The loading device 7th is set up the first electrical energy store 6th and / or the second electrical energy store 9 to load. This is between the loading device 7th and the electrical energy storage ( 6th , 9 ) the switching unit 8th arranged. The switching unit 8th is set up, the charging device 7th with one or both electrical energy storage devices ( 6th , 9 ) to be connected in an electrically conductive manner. The switching unit 8th Switching means on.

The control unit 17th is signal-conducting with the electrical energy storage ( 6th , 9 ), the converters ( 5 , 10 , 16 , 18th ), the loading device 7th and the switching unit 8th connected, in particular by means of a data bus, for example by means of a CAN bus. Preferably the control unit is 17th by means of the switching unit 8th with the loading device 7th connected. The control unit 17th is set up to record an operating state, in particular a state of charge, of a respective electrical energy store ( 6th , 9 ) to record and evaluate and the switching unit 8th and / or the charging device 7th depending on the operating status of the respective electrical energy storage device ( 6th , 9 ) head for.

Preferably the control unit is 17th as the central control unit of the vehicle 1 executed. As the central control unit of the vehicle 1 is the control unit 17th signal-conducting with sensors and an operator interface of the vehicle 1 connected.

According to a further exemplary embodiment not shown in the figures, the vehicle has an electrical energy store and / or a further redundant electrical energy store for each electric motor. All electrical energy stores can be connected to the charging device by means of the switching unit, so that each electrical energy store can be charged individually or a subset of the electrical energy stores or all electrical energy stores can be charged at the same time.

In 2 are a first voltage value U1 of a first electrical energy store 6th , a second voltage value U2 of a second electrical energy store 9 , a third voltage value U3 of a third electrical energy store and a fourth voltage value U4 of a fourth electrical energy store at a first point in time of the method according to the invention 100 shown.

At the first point in time, all voltage values (U1, U2, U3, U4) of the electrical energy storage ( 6th , 9 ) below the first voltage limit value Ucc. The first voltage limit value is greater than 3 V and less than 3.5 V and is preferably 3.2 V. This corresponds to a state of charge between 70% and 90%, preferably 80% of a maximum state of charge.

The first electrical energy storage device 6th has the lowest voltage with the first voltage U1. The second electrical energy store 9 has the second lowest voltage with the second voltage U2. The third electrical energy store has the third voltage U3 the highest tension. The fourth electrical energy store has the fourth voltage U4, the second largest voltage.

During the subsequent charging with constant current, the voltages of the electrical energy storage devices increase ( 6th , 9 ) at. First reaches the third tension U3 of the third electrical energy store the first voltage limit value Ucc. As soon as the third tension U3 has reached the first voltage limit value Ucc, the charging process for the third electrical energy store is interrupted and the third electrical energy store is relaxed. The fourth voltage U4 of the fourth electrical energy store then reaches the first voltage limit value Ucc. As soon as the fourth voltage U4 has reached the first voltage limit value Ucc, the charging process for the fourth electrical energy store is interrupted and the fourth electrical energy store is relaxed. The second voltage then reaches U2 of the second electrical energy store 9 the first voltage limit value Ucc. As soon as the second voltage U2 has reached the first voltage limit value Ucc, the charging process for the second electrical energy store is started 9 interrupted. Finally, at a second point in time, the first voltage reaches U1 of the first electrical energy store 6th the first voltage limit value Ucc.

In 3 are the first voltage U1, the second voltage U2, the third voltage U3 and the fourth voltage U4 at the second point in time of the method 100 shown.

The first voltage U1 corresponds to the first voltage limit value Ucc and thus has the highest voltage. Due to the relaxation, the second, third and fourth voltages (U2, U3, U4) have dropped again. The third tension U3 is the smallest. All voltage values (U1, U2, U3, U4) are within a voltage range ΔU below the first voltage limit value Ucc.

The voltage range ΔU is defined in such a way that electrical energy stores whose voltages are within this voltage range ΔU can be charged with constant voltage at the same time. The expansion of the voltage range ΔU is less than 10 V, in particular less than 5 V, preferably less than 1 V.

Then all electrical energy storage devices ( 6th , 9 ) are charged at the same time until their voltage reaches a second voltage limit value Ucv. The charging process is then ended.

In 4th is a timing diagram of the method according to the invention 100 for charging at least two electrical energy storage devices ( 6th , 9 ) of a vehicle 1 shown. The vehicle points 1 a single charger 7th , a switching unit 8th and at least one first and second electrical energy store ( 6th , 9 ) on.

In a first process step 101 a respective operating parameter, in particular a state of charge and / or a voltage (U1, U2, U3, U4), of the respective electrical energy store ( 6th , 9 ) detected.

In a second process step 102 the electrical energy storage ( 6th , 9 ) whose operating parameters are below a first limit value, in particular below a first voltage limit value Ucc, charged with a constant current. The operating parameters of the electrical energy storage ( 6th , 9 ) continuously recorded.

In a third process step 103 reaches a value of an operating parameter of an electrical energy storage device ( 6th , 9 ) the first limit value. The charging process for this electrical energy storage device ( 6th , 9 ) interrupted and the electrical energy storage ( 6th , 9 ) relaxed. As soon as an operating parameter of another electrical energy storage device ( 6th , 9 ) reaches the first limit value, the charging process for the further electrical energy storage ( 6th , 9 ) also interrupted and the further electrical energy storage ( 6th , 9 ) relaxed.

In a fourth process step 104 reaches a value of an operating parameter of a last electrical energy store at a second point in time ( 6th , 9 ) the first limit value. At the second point in time, the values of the operating parameters of all electrical energy storage devices ( 6th , 9 ) reached the first limit value, but have partly decreased again due to the relaxation.

In a fifth process step 105 it is checked whether the values of the operating parameters of all electrical energy storage devices ( 6th , 9 ) lie within a value range below the first limit value, in particular within a voltage range ΔU below the first voltage limit value Ucc.

In a sixth process step 106 if at the second point in time the value of the operating parameter of an electrical energy storage device ( 6th , 9 ) is below the range of values, this electrical energy storage ( 6th , 9 ) charged with constant voltage until its operating parameter reaches the first limit value.

In a seventh process step 107 after the fifth process step 105 or after the sixth process step 106 If all operating parameters are within the value range below the first limit value, all electrical energy storage devices ( 6th , 9 ) charged with constant voltage.

In an eighth process step 108 the charging process for all electrical energy storage devices ( 6th , 9 ) ends when a value of an operating parameter of an electrical energy store reaches a second limit value which is above the first limit value, in particular a second voltage limit value Ucv.

According to a further embodiment of the method, after the third method step 103 continuously checked whether the value of the operating parameter of an electrical energy storage device ( 6th , 9 ) has dropped to a value below the value range during the relaxation. As soon as such a drop in the operating parameter has been determined, the relevant electrical energy storage device ( 6th , 9 ) is charged again with constant current until the value of the operating parameter reaches the first limit value again.

An electrical energy store is understood here to be a rechargeable energy store, in particular having an electrochemical energy storage cell and / or an energy storage module having at least one electrochemical energy storage cell and / or an energy storage pack having at least one energy storage module. The energy storage cell can be implemented as a lithium-based battery cell, in particular a lithium-ion battery cell. Alternatively, the energy storage cell is designed as a lithium polymer battery cell or a nickel-metal hydride battery cell or a lead-acid battery cell or a lithium-air battery cell or a lithium-sulfur battery cell.

A vehicle here means a land vehicle, in particular a passenger car or a bus or a truck or a mobile work machine or a driverless transport system, or a watercraft or a Understood aircraft. The vehicle can be designed to be autonomously controllable.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• US 2016/0094067 A1 [0002]
• US 2017/0141589 A1 [0003]

Claims (12)

Method (100) for charging at least two electrical energy stores (6, 9), comprising the method steps that follow one another in time: wherein a respective operating parameter of the respective electrical energy store (6, 9) is recorded in a first method step (101), wherein in a second method step (102) the electrical energy stores (6, 9), the operating parameters of which are below a first limit value, are charged, wherein in a third method step (103), when a value of an operating parameter of an electrical energy store (6, 9) reaches the first limit value, the charging process for this electrical energy store (6, 9) is interrupted, wherein in a fourth method step (104) a value of an operating parameter of a last electrical energy store (6, 9) reaches the first limit value, wherein in a fifth method step (105) it is checked whether the values of the operating parameters of all electrical energy stores (6, 9) are within a value range below the first limit value, wherein in a sixth method step (106), if in the fifth method step (105) the value of the operating parameter of an electrical energy store (6, 9) is below the value range, this electrical energy store (6, 9) is charged until its operating parameter reaches the first limit value reached, wherein in a seventh method step (107), when all operating parameters are within the range of values below the first limit value, all electrical energy stores (6, 9) are charged simultaneously, wherein in an eighth method step (108) the charging process for all electrical energy stores (6, 9) is ended when a value of an operating parameter of an electrical energy store reaches a second limit value. Method (100) according to Claim 1 , characterized in that the operating parameters of the electrical energy store (6, 9) are recorded continuously during the process. Method (100) according to one of the preceding claims, characterized in that in the third method step (103) as soon as an operating parameter of a further electrical energy store (6, 9) reaches the first limit value, the charging process for the further electrical energy store (6, 9) likewise is interrupted. Method (100) according to one of the preceding claims, characterized in that the second limit value is greater than the first limit value. The method (100) according to any one of the preceding claims, characterized in that the electrical energy store (6, 9) in the second method step (102) are charged with a constant current, and / or that the electrical energy store (s) (6, 9) in the sixth method step (106) and / or in the seventh method step (107) are charged with a constant voltage. Method (100) according to one of the preceding claims, characterized in that the electrical energy storage device (s) (6, 9) whose charging process was interrupted in the third method step (103) relaxes. Method (100) according to Claim 6 , characterized in that after the third method step (103) it is continuously checked whether the value of the operating parameter of a relaxing electrical energy store (6, 9) has dropped to a value below the value range, wherein as soon as the value of an operating parameter drops to a value below the Value range has decreased, the relaxing electrical energy store (6, 9) is charged again until the value of the operating parameter reaches the first limit value again, in particular the electrical energy store (6, 9) being charged with constant current. Vehicle (1) having at least a first electrical energy store (6) and a second electrical energy store (9), in particular wherein the vehicle (1) is set up to store the electrical energy store (6, 9) by means of a method according to one of the Claims 1 to 7th to charge, characterized in that the vehicle (1) has a single charging device (7) and a switching unit (8), the switching unit (8) being arranged between the charging device (7) and the electrical energy storage device, the switching unit (8 ) is set up to connect the charging device (7) to the first electrical energy store (6) or to the second electrical energy store (9) or to the first electrical energy store (6) and the second electrical energy store (9). Vehicle (1) after Claim 8 , characterized in that the vehicle (1) has a first electric motor (19) and a third electric motor (12), the first electric motor (19) being fed from the first electric energy store (6), the third electric motor (12) is fed from the second electrical energy store (9). Vehicle (1) after Claim 8 or 9 , characterized in that the vehicle (1) has a first drive axle (3), a first gearbox (2) and a second electric motor (4), the first drive axle (3) being connected to the first electric motor (19) and / by means of the first gearbox (2) or the second electric motor (4) can be connected, in particular wherein the first gear (2) is designed as a summation gear and / or coupling gear. Vehicle (1) according to one of the Claims 8 to 10 , characterized in that the vehicle (1) has a control unit (17) which is connected in a signal-conducting manner to the switching unit (8), the charging device (7) and the electrical energy stores (6, 9), in particular wherein the control unit (17) is set up to control the switching unit (8) and / or to receive and evaluate signals from sensors of the electrical energy stores (6, 9). Vehicle (1) according to one of the Claims 8 to 11 , characterized in that the vehicle (1) has a connection means (11) which is electrically conductively connected to the charging device (7).

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