WO2020051756A1 - Method for operating battery system and battery system - Google Patents

Method for operating battery system and battery system Download PDF

Info

Publication number
WO2020051756A1
WO2020051756A1 PCT/CN2018/104948 CN2018104948W WO2020051756A1 WO 2020051756 A1 WO2020051756 A1 WO 2020051756A1 CN 2018104948 W CN2018104948 W CN 2018104948W WO 2020051756 A1 WO2020051756 A1 WO 2020051756A1
Authority
WO
WIPO (PCT)
Prior art keywords
battery
current
threshold
temperature
battery system
Prior art date
Application number
PCT/CN2018/104948
Other languages
French (fr)
Inventor
Zheng HAO
Christoph Woll
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to EP18933245.5A priority Critical patent/EP3849836A4/en
Priority to CN201880097391.XA priority patent/CN112638694A/en
Priority to PCT/CN2018/104948 priority patent/WO2020051756A1/en
Publication of WO2020051756A1 publication Critical patent/WO2020051756A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/21—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having the same nominal voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/22—Balancing the charge of battery modules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/25—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by controlling the electric load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
    • H02J7/007194—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/545—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/549—Current
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • the invention relates to a method for operating a battery system in an electric vehicle, whereat the battery system comprises at least on battery module with at least one battery cell and a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system.
  • the invention also relates to a battery system comprising at least on battery module with at least one battery cell and a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system.
  • Batteries convert chemical energy into electrical energy.
  • rechargeable batteries are known to be able to be charged and discharged several times.
  • Battery modules comprise several battery cells that are connected electrically in series or in parallel.
  • Battery systems comprise several battery modules that are connected electrically in series or in parallel.
  • lithium ion battery cells are used in rechargeable batteries or battery systems.
  • Lithium ion battery cells have a relatively high energy density.
  • Lithium ion battery cells have a positive electrode called cathode, and a negative electrode called anode.
  • the anode and the cathode are divided from one another by means of a separator.
  • the electrodes and the separator are surrounded by an electrolyte.
  • Rechargeable lithium ion battery cells are used for instance in motor vehicles, in particular in electric vehicles (EV) , in hybrid electric vehicles (HEV) and in plug-in hybrid electric vehicles (PHEV) .
  • Battery systems comprising lithium ion battery cells are used inter alia in electric vehicles to supply a current to an electric motor for driving the electric vehicle.
  • Battery systems with lithium ion battery cells are operated at a wide temperature range. However, at high temperatures, for example above 60°C, the battery cells may be damaged. Hence, when battery cells reach high temperatures, current and power output must be reduced to prevent further heating.
  • battery systems comprise a management system which is capable of determining the battery temperature and the battery current. Thereat, the management system includes appropriate control software for executing an appropriate method for controlling and supervising the battery system in order to prevent overheating of the battery cells.
  • the document WO 2017/115091 A1 discloses a battery management system for use in charging a rechargeable battery.
  • the battery management system comprises a controller and a temperature sensor, wherein the temperature sensor is configured to provide a temperature signal based on a temperature of the rechargeable battery, and wherein the controller is configured to control a charging current for charging the rechargeable battery based on the temperature signal.
  • the charging current is tapered down as a function of increasing temperature.
  • the document US 2003/090238 A1 discloses a method and an apparatus for controlling the charge and discharge currents in a battery as a function of temperature.
  • a battery When a battery is charged or discharged in an environment that approaches its design operating temperature extreme, the currents are reduced to limit self-heating of the battery and thus extend the useful operating environment temperature range.
  • a temperature sensor is coupled to a controller to sense the battery temperature. The temperature information is used to set a suitable charging or discharging current.
  • a method for operating a battery system in an electric vehicle is proposed.
  • the battery system serves in particular to supply a battery current to an electric motor for driving the electric vehicle.
  • the battery system comprises at least one battery module with at least one battery cell and a management system that is capable of determining a battery temperature of the battery system and the battery current flowing through the battery system.
  • the management system is also capable of reducing said battery current if appropriate.
  • the battery current is reduced when the battery temperature is between a first threshold and a second threshold and when the battery current is greater than a first limit value. Such a reduction of the battery current is also called derating.
  • the battery current is reduced by means of a control loop when the battery temperature is between the second threshold and a third threshold.
  • the first threshold is smaller than the second threshold, and the second threshold is smaller than the third threshold. Hence, the first threshold is smaller than the third threshold.
  • control loop which is active when the battery temperature is between the second threshold and the third threshold is arranged to control the battery current such that the battery temperature reaches the second threshold which is smaller than the third threshold.
  • the battery current is reduced according to a predefined characteristic curve when the battery temperature is between the first threshold and the second threshold.
  • the predefined characteristic specifies a dependency of the reduction of the battery current from a required current.
  • the battery current is the current that really flows through the battery system.
  • the required current is a current which is required by a user or by the electric motor to fulfil a user's requirement, for example on acceleration or on going uphill.
  • the reduction of the battery current is zero when the required current is smaller than the first limit value. That means, there is no reduction of the battery current when the battery current is quite small, for example when the electric vehicle is running evenly on low speed. As a relatively small battery current does not cause a significant rise in temperature, a reduction of such a small battery current does not significantly lower the battery temperature.
  • the dependency of the reduction of the battery current from the required current is linear when the required current is between the first limit value and a second limit value.
  • the reduction of the battery current is constant when the required current is greater than the second specific limit. That means, there is a constant reduction of the battery current by a defined percentage when the battery current is quite high, for example when the electric vehicle is going uphill or is accelerating.
  • the battery system comprises a plurality of battery modules electrically connected in parallel.
  • each battery module preferably comprises a plurality of battery cells electrically connected in series and/or in parallel.
  • the battery system comprises at least one battery module with at least one battery cell.
  • the battery system also comprises a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system.
  • the management system is also capable of reducing said battery current if appropriate.
  • the management system of the battery system is designed to execute the method according to the invention.
  • the method according to the invention allows reducing the temperature of the battery module, if appropriate, by means of a minimum reduction of the battery current.
  • driving pleasure remains to a large extend also when a derating is necessary to reduce the temperature of the battery module.
  • the reduction of the battery current when the battery temperature is between the first threshold and a second threshold allows counteracting a rise in temperature at an early stage.
  • the reduction of the battery current by means of the control loop allows counteracting a rise in temperature at an early stage.
  • the method according to the invention hence is quite flexible and allows adequate reduction of the battery current.
  • Figure 1 a schematic view at a battery system
  • Figure 2 a schematic diagram with a predefined characteristic curve specifying a dependency of the reduction of the battery current from a required current
  • Figure 3 a schematic diagram of a control loop for the reduction of the battery current.
  • Figure 1 shows a schematic view at a battery system 10 in an electric vehicle which is connected to a power electronic circuit 23.
  • the power electronic circuit 23 is a multilevel converter.
  • a three-phase electric motor 25 of the electric vehicle is connected with the power electronic circuit 23 via three phase conductors.
  • the power electronic circuit 23 serves for supplying electrical energy to the electric motor 25.
  • the battery system 10 comprises a plurality of battery modules 5 that are electrically connected in parallel. Thereat, each of the battery modules 5 comprises a plurality of battery cells 2 that are electrically connected in series. The battery cells 2 also may be connected in parallel as well as in series within said battery modules 5. Presently, all of the battery modules 5 are shaped identically.
  • a switch 65 is arranged electrically between the battery system 10 and the power electronic circuit 23.
  • a battery current IB can flow through the battery system 10 and through the power electronic circuit 23.
  • module currents IM are flowing through the battery module 5 of the battery system 10.
  • the battery current IB corresponds to the sum of the module currents IM that are flowing through the battery modules 5 that are connected in parallel.
  • the battery system 10 further comprises a management system 20 in particular for controlling and supervising the battery modules 5.
  • the management system 20 is also connected to the power electronic circuit 23, for example by means of a digital bus-system.
  • the management system 20 is also connected to the switch 65 and is capable of controlling said switch 65, in particular of opening and closing said switch 65.
  • the battery system 10 comprises a temperature sensor which is not shown here and which is connected to the management system 20.
  • the management system 20 comprises appropriate circuitry to process signals from the temperature sensor and to determine a battery temperature of the battery system 10.
  • the battery system 10 also comprises a current sensor which is not shown here and which is connected to the management system 20.
  • the management system 20 comprises appropriate circuitry to process signals from the current sensor and to determine the battery current IB flowing through the battery system 10.
  • the management system 20 is capable of reducing the battery current IB flowing through the battery system 10 if appropriate.
  • the management system 20 may open the switch 65 and hence the battery current IB is turned off.
  • the management system 20 may also send respective commands to the power electronic circuit 23 to reduce the battery current IB.
  • Figure 2 shows a schematic diagram with a predefined characteristic curve specifying a dependency of a reduction factor RF of the battery current IB from a required current IR.
  • the battery current IB is reduced according to said predefined characteristic curve when the battery temperature is between a first threshold T-Warn and a second threshold T-Der.
  • the reduction factor RF of the battery current IB is zero when the required current IR is smaller than a first limit value L1.
  • the reduction factor RF of the battery current IB is a first factor F1 when the required current IR is equal to the first limit value L1.
  • the reduction factor RF of the battery current IB is a second factor F2 when the required current IR is equal to a second limit value L2.
  • the reduction factor RF of the battery current IB is linear between the first factor F1 and the second factor F2 when the required current IR is between the first limit value L1 and the second limit value L2.
  • the reduction factor RF of the battery current IB is the second factor F2 when the required current IR is greater than the second limit value L2.
  • the battery current IB is turned off, in particular by opening the switch 65, when the battery temperature is greater than a third threshold T-Max.
  • the first threshold T-Warn is smaller than the second threshold T-Der, and the second threshold T-Der is smaller than the third threshold T-Max.
  • the first threshold T-Warn is thus smaller than the third threshold T-Max.
  • FIG 3 shows a schematic diagram of a control loop 100 for the reduction of the battery current IB.
  • the control loop 100 is designed as a cascade control loop which is described inter alia in "Grundkurs der Regelungstechnik” by Dr. -Ing. L. Merz and Dr. -Ing. H. Jaschek, 10 th edition, 1990, chapter 1.5.1.3 "Kaskadenregelnik” .
  • the control loop 100 serves for the reduction of the battery current IB when the battery temperature is between the second threshold T-Der and the third threshold T-Max.
  • the control loop 100 is arranged to control the battery current IB such that the battery temperature reaches the second threshold T-Der.
  • the control loop 100 is contained within the management system 20.
  • the control loop 100 contains a setpoint adjuster 101 by means of which the second threshold T-Der is adjustable.
  • a temperature of the battery system 10 is measured by means of a temperature sensor 103. Respective signals from the temperature sensor 103 are processed by a temperature measuring converter 104 of the management system 20. Hence, the management system 20 determines the battery temperature of the battery system 10.
  • a difference between the second threshold T-Der and the battery temperature of the battery system 10 is calculated. Said difference is fed to a first controller 121.
  • Said first controller 121 is designed as a PID controller which is able to execute proportional, integral and differential control operations.
  • the first controller 121 outputs a signal which represents a current value. Said current value indicates by which amount the required current IR is to be reduced.
  • a driver torque request adjuster 125 the required current IR for the electric motor 25 for driving the electric vehicle is adjusted.
  • the required current IR is calculated by means of a current calculator 105.
  • Respective signals from the current calculator 105 are processed by a current converter 106 of the management system 20.
  • a difference between the current value which is output by the first controller 121 and the required current IR adjusted in the driver torque request adjuster 125 is calculated. Said difference is fed to a second controller 122.
  • Said second controller 122 is also designed as a PID controller which is able to execute proportional, integral and differential control operations. The second controller 122 outputs an actuating variable that is fed to the battery system 10 in order to control the battery current IB.
  • the control loop 100 shown in figure 3 deviates from the cascade control loop described in "Grundados der Regelungstechnik" .
  • Said cascade control loop contains a closed inner loop and a closed outer loop.
  • the control loop 100 shown in figure 3 contains a closed outer loop which includes the setpoint adjuster 101, the first subtraction point 111, the first controller 121, the temperature sensor 103, the temperature measuring converter 104 and an inner loop as described below.
  • the control loop 100 shown in figure 3 contains an inner loop which includes the driver torque request adjuster 125, the current calculator 105, the current converter 106, the second subtraction point 112, the second controller 122 and a model of the battery system 10. However, said inner loop of the control loop 100 is not closed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Secondary Cells (AREA)

Abstract

A method for operating a battery system (10) in an electric vehicle, the battery system (10) comprising at least one battery module (5) with at least one battery cell (2), and a management system (20), capable of determining a battery temperature of the battery system (10) and a battery current flowing through the battery system (10) and capable of reducing said battery current, wherein the battery current is reduced when the battery temperature is between a first threshold and a second threshold and when the battery current is greater than a first limit value (L1); the battery current is reduced by means of a control loop when the battery temperature is between the second threshold (T-Der) and a third threshold (T-Max); and the battery current is turned off when the battery temperature is greater than the third threshold (T-Max). A battery system (10), comprising at least on battery module (5) with at least one battery cell (2), and a management system (20), capable of determining a battery temperature of the battery system (10) and a battery current flowing through the battery system (10) and capable of reducing said battery current, wherein the management system (20) is designed to execute the method.

Description

[Title established by the ISA under Rule 37.2] METHOD FOR OPERATING BATTERY SYSTEM AND BATTERY SYSTEM
The invention relates to a method for operating a battery system in an electric vehicle, whereat the battery system comprises at least on battery module with at least one battery cell and a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system. The invention also relates to a battery system comprising at least on battery module with at least one battery cell and a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system.
State of the Art
Electrical energy can be stored by means of batteries. Batteries convert chemical energy into electrical energy. Particularly, rechargeable batteries are known to be able to be charged and discharged several times. Battery modules comprise several battery cells that are connected electrically in series or in parallel. Battery systems comprise several battery modules that are connected electrically in series or in parallel.
Especially, lithium ion battery cells are used in rechargeable batteries or battery systems. Lithium ion battery cells have a relatively high energy density. Lithium ion battery cells have a positive electrode called cathode, and a negative electrode called anode. The anode and the cathode are divided from one another by means of a separator. The electrodes and the separator are surrounded by an electrolyte.
Rechargeable lithium ion battery cells are used for instance in motor vehicles, in particular in electric vehicles (EV) , in hybrid electric vehicles (HEV) and in plug-in hybrid electric vehicles (PHEV) . Battery systems comprising lithium ion battery cells are used inter alia in electric vehicles to supply a current to an electric motor for driving the electric vehicle.
Battery systems with lithium ion battery cells, in particular in motor vehicles, are operated at a wide temperature range. However, at high temperatures, for example above 60℃, the battery cells may be damaged. Hence, when battery cells reach high temperatures, current and power output must be reduced to prevent further heating. For this purpose, battery systems comprise a  management system which is capable of determining the battery temperature and the battery current. Thereat, the management system includes appropriate control software for executing an appropriate method for controlling and supervising the battery system in order to prevent overheating of the battery cells.
The document WO 2017/115091 A1 discloses a battery management system for use in charging a rechargeable battery. The battery management system comprises a controller and a temperature sensor, wherein the temperature sensor is configured to provide a temperature signal based on a temperature of the rechargeable battery, and wherein the controller is configured to control a charging current for charging the rechargeable battery based on the temperature signal. In response to the temperature signal indicating that the temperature exceeds a first threshold temperature signal value the charging current is tapered down as a function of increasing temperature.
The document US 2003/090238 A1 discloses a method and an apparatus for controlling the charge and discharge currents in a battery as a function of temperature. When a battery is charged or discharged in an environment that approaches its design operating temperature extreme, the currents are reduced to limit self-heating of the battery and thus extend the useful operating environment temperature range. A temperature sensor is coupled to a controller to sense the battery temperature. The temperature information is used to set a suitable charging or discharging current.
Disclosure of the Invention
A method for operating a battery system in an electric vehicle is proposed. The battery system serves in particular to supply a battery current to an electric motor for driving the electric vehicle. The battery system comprises at least one battery module with at least one battery cell and a management system that is capable of determining a battery temperature of the battery system and the battery current flowing through the battery system. The management system is also capable of reducing said battery current if appropriate.
Therein, the battery current is reduced when the battery temperature is between a first threshold and a second threshold and when the battery current is greater than a first limit value. Such a reduction of the battery current is also called derating.
Furthermore, the battery current is reduced by means of a control loop when the battery temperature is between the second threshold and a third threshold.
And the battery current is turned off when the battery temperature is greater than the third threshold.
Thereat, the first threshold is smaller than the second threshold, and the second threshold is smaller than the third threshold. Hence, the first threshold is smaller than the third threshold.
According to an advantageous embodiment of the invention, the control loop which is active when the battery temperature is between the second threshold and the third threshold is arranged to control the battery current such that the battery temperature reaches the second threshold which is smaller than the third threshold.
According to a preferred embodiment of the invention, the battery current is reduced according to a predefined characteristic curve when the battery temperature is between the first threshold and the second threshold.
Thereat, the predefined characteristic specifies a dependency of the reduction of the battery current from a required current. Thereat, the battery current is the current that really flows through the battery system. The required current is a  current which is required by a user or by the electric motor to fulfil a user's requirement, for example on acceleration or on going uphill.
According to an advantageous embodiment of the invention, the reduction of the battery current is zero when the required current is smaller than the first limit value. That means, there is no reduction of the battery current when the battery current is quite small, for example when the electric vehicle is running evenly on low speed. As a relatively small battery current does not cause a significant rise in temperature, a reduction of such a small battery current does not significantly lower the battery temperature.
Preferably, the dependency of the reduction of the battery current from the required current is linear when the required current is between the first limit value and a second limit value.
Further preferably, the reduction of the battery current is constant when the required current is greater than the second specific limit. That means, there is a constant reduction of the battery current by a defined percentage when the battery current is quite high, for example when the electric vehicle is going uphill or is accelerating.
Preferably, the battery system comprises a plurality of battery modules electrically connected in parallel. Thereat, each battery module preferably comprises a plurality of battery cells electrically connected in series and/or in parallel.
Furthermore, a battery system is proposed. Thereat, the battery system comprises at least one battery module with at least one battery cell. The battery system also comprises a management system which is capable of determining a battery temperature of the battery system and a battery current flowing through the battery system. The management system is also capable of reducing said battery current if appropriate.
Therein, the management system of the battery system is designed to execute the method according to the invention.
Advantages of the Invention
The method according to the invention allows reducing the temperature of the battery module, if appropriate, by means of a minimum reduction of the battery current. Thus, driving pleasure remains to a large extend also when a derating is necessary to reduce the temperature of the battery module. In particular the reduction of the battery current when the battery temperature is between the first threshold and a second threshold allows counteracting a rise in temperature at an early stage. Furthermore, the reduction of the battery current by means of the control loop allows counteracting a rise in temperature at an early stage. The method according to the invention hence is quite flexible and allows adequate reduction of the battery current.
Brief Description of the Drawings
For a better understanding of the aforementioned embodiments of the invention as well as additional embodiments thereof, reference should be made to the description of embodiments below, in conjunction with the appended drawings showing:
Figure 1 a schematic view at a battery system,
Figure 2 a schematic diagram with a predefined characteristic curve specifying a dependency of the reduction of the battery current from a required current and
Figure 3 a schematic diagram of a control loop for the reduction of the battery current.
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The drawings only provide schematic views of the invention. Like reference numerals refer to corresponding parts, elements or components throughout the figures, unless indicated otherwise.
Description of Embodiments
Figure 1 shows a schematic view at a battery system 10 in an electric vehicle which is connected to a power electronic circuit 23. For example, the power electronic circuit 23 is a multilevel converter. A three-phase electric motor 25 of the electric vehicle is connected with the power electronic circuit 23 via three  phase conductors. The power electronic circuit 23 serves for supplying electrical energy to the electric motor 25.
The battery system 10 comprises a plurality of battery modules 5 that are electrically connected in parallel. Thereat, each of the battery modules 5 comprises a plurality of battery cells 2 that are electrically connected in series. The battery cells 2 also may be connected in parallel as well as in series within said battery modules 5. Presently, all of the battery modules 5 are shaped identically.
A switch 65 is arranged electrically between the battery system 10 and the power electronic circuit 23. When the switch 65 is closed, a battery current IB can flow through the battery system 10 and through the power electronic circuit 23. In that case, module currents IM are flowing through the battery module 5 of the battery system 10. Thereat, the battery current IB corresponds to the sum of the module currents IM that are flowing through the battery modules 5 that are connected in parallel.
The battery system 10 further comprises a management system 20 in particular for controlling and supervising the battery modules 5. The management system 20 is also connected to the power electronic circuit 23, for example by means of a digital bus-system. The management system 20 is also connected to the switch 65 and is capable of controlling said switch 65, in particular of opening and closing said switch 65.
The battery system 10 comprises a temperature sensor which is not shown here and which is connected to the management system 20. The management system 20 comprises appropriate circuitry to process signals from the temperature sensor and to determine a battery temperature of the battery system 10.The battery system 10 also comprises a current sensor which is not shown here and which is connected to the management system 20. The management system 20 comprises appropriate circuitry to process signals from the current sensor and to determine the battery current IB flowing through the battery system 10.
The management system 20 is capable of reducing the battery current IB flowing through the battery system 10 if appropriate. For example, the management system 20 may open the switch 65 and hence the battery current IB is turned off.
The management system 20 may also send respective commands to the power electronic circuit 23 to reduce the battery current IB.
Figure 2 shows a schematic diagram with a predefined characteristic curve specifying a dependency of a reduction factor RF of the battery current IB from a required current IR. The battery current IB is reduced according to said predefined characteristic curve when the battery temperature is between a first threshold T-Warn and a second threshold T-Der.
The reduction factor RF of the battery current IB is zero when the required current IR is smaller than a first limit value L1. The reduction factor RF of the battery current IB is a first factor F1 when the required current IR is equal to the first limit value L1. The reduction factor RF of the battery current IB is a second factor F2 when the required current IR is equal to a second limit value L2. The reduction factor RF of the battery current IB is linear between the first factor F1 and the second factor F2 when the required current IR is between the first limit value L1 and the second limit value L2. The reduction factor RF of the battery current IB is the second factor F2 when the required current IR is greater than the second limit value L2.
The battery current IB is turned off, in particular by opening the switch 65, when the battery temperature is greater than a third threshold T-Max. Thereat, the first threshold T-Warn is smaller than the second threshold T-Der, and the second threshold T-Der is smaller than the third threshold T-Max. The first threshold T-Warn is thus smaller than the third threshold T-Max.
Figure 3 shows a schematic diagram of a control loop 100 for the reduction of the battery current IB. The control loop 100 is designed as a cascade control loop which is described inter alia in "Grundkurs der Regelungstechnik" by Dr. -Ing. L. Merz and Dr. -Ing. H. Jaschek, 10 th edition, 1990, chapter 1.5.1.3 "Kaskadenregelkreis" .
The control loop 100 serves for the reduction of the battery current IB when the battery temperature is between the second threshold T-Der and the third threshold T-Max. The control loop 100 is arranged to control the battery current IB such that the battery temperature reaches the second threshold T-Der. The control loop 100 is contained within the management system 20.
The control loop 100 contains a setpoint adjuster 101 by means of which the second threshold T-Der is adjustable.
A temperature of the battery system 10 is measured by means of a temperature sensor 103. Respective signals from the temperature sensor 103 are processed by a temperature measuring converter 104 of the management system 20. Hence, the management system 20 determines the battery temperature of the battery system 10.
In a first subtraction point 111, a difference between the second threshold T-Der and the battery temperature of the battery system 10 is calculated. Said difference is fed to a first controller 121. Said first controller 121 is designed as a PID controller which is able to execute proportional, integral and differential control operations. The first controller 121 outputs a signal which represents a current value. Said current value indicates by which amount the required current IR is to be reduced.
In a driver torque request adjuster 125 the required current IR for the electric motor 25 for driving the electric vehicle is adjusted. The required current IR is calculated by means of a current calculator 105. Respective signals from the current calculator 105 are processed by a current converter 106 of the management system 20.
In a second subtraction point 112, a difference between the current value which is output by the first controller 121 and the required current IR adjusted in the driver torque request adjuster 125 is calculated. Said difference is fed to a second controller 122. Said second controller 122 is also designed as a PID controller which is able to execute proportional, integral and differential control operations. The second controller 122 outputs an actuating variable that is fed to the battery system 10 in order to control the battery current IB.
The control loop 100 shown in figure 3 deviates from the cascade control loop described in "Grundkurs der Regelungstechnik" . Said cascade control loop contains a closed inner loop and a closed outer loop.
The control loop 100 shown in figure 3 contains a closed outer loop which includes the setpoint adjuster 101, the first subtraction point 111, the first  controller 121, the temperature sensor 103, the temperature measuring converter 104 and an inner loop as described below.
The control loop 100 shown in figure 3 contains an inner loop which includes the driver torque request adjuster 125, the current calculator 105, the current converter 106, the second subtraction point 112, the second controller 122 and a model of the battery system 10. However, said inner loop of the control loop 100 is not closed.
The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings and those encompassed by the attached claims. The embodiments were chosen and described in order to explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

Claims (10)

  1. Method for operating a battery system (10) in an electric vehicle,
    the battery system (10) comprising at least one battery module (5) with at least one battery cell (2) , and
    a management system (20) , capable of determining a battery temperature of the battery system (10) and a battery current (IB) flowing through the battery system (10) and capable of reducing said battery current (IB) , wherein
    the battery current (IB) is reduced when the battery temperature is between a first threshold (T-Warn) and a second threshold (T-Der) and when the battery current (IB) is greater than a first limit value (L1) ;
    the battery current (IB) is reduced by means of a control loop (100) when the battery temperature is between the second threshold (T-Der) and a third threshold (T-Max) ; and
    the battery current (IB) is turned off when the battery temperature is greater than the third threshold (T-Max) .
  2. Method according to claim 1, wherein
    the first threshold (T-Warn) is smaller than the second threshold (T-Der) , and the second threshold (T-Der) is smaller than the third threshold (T-Max) .
  3. Method according to one of the preceding claims, wherein
    the control loop (100) is arranged to control the battery current (IB) such that the battery temperature reaches the second threshold (T-Der) .
  4. Method according to one of the preceding claims, wherein
    the battery current (IB) is reduced according to a predefined characteristic curve when the battery temperature is between the first threshold (T-Warn) and the second threshold (T-Der) .
  5. Method according to claim 4, wherein
    the predefined characteristic curve specifies a dependency of the reduction of the battery current (IB) from a required current (IR) .
  6. Method according to claim 5, wherein
    the reduction of the battery current (IB) is zero when the required current (IR) is smaller than the first limit value (L1) .
  7. Method according to one of claims 5 to 6, wherein
    the dependency of the reduction of the battery current (IB) from the required current (IR) is linear when the required current (IR) is between the first limit value (L1) and a second limit value (L2) .
  8. Method according to claim 7, wherein
    the reduction of the battery current (IB) is constant when the required current (IR) is greater than the second specific limit.
  9. Method according to one of the preceding claims, wherein
    the battery system (10) comprises a plurality of battery modules (5) electrically connected in parallel.
  10. A battery system (10) , comprising
    at least on battery module (5) with at least one battery cell (2) , and
    a management system (20) , capable of determining a battery temperature of the battery system (10) and a battery current (IB) flowing through the battery system (10) and capable of reducing said battery current (IB) , wherein
    the management system (20) is designed to execute the method according to one of the preceding claims.
PCT/CN2018/104948 2018-09-11 2018-09-11 Method for operating battery system and battery system WO2020051756A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP18933245.5A EP3849836A4 (en) 2018-09-11 2018-09-11 Method for operating battery system and battery system
CN201880097391.XA CN112638694A (en) 2018-09-11 2018-09-11 Method for operating a battery system and battery system
PCT/CN2018/104948 WO2020051756A1 (en) 2018-09-11 2018-09-11 Method for operating battery system and battery system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2018/104948 WO2020051756A1 (en) 2018-09-11 2018-09-11 Method for operating battery system and battery system

Publications (1)

Publication Number Publication Date
WO2020051756A1 true WO2020051756A1 (en) 2020-03-19

Family

ID=69776955

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/104948 WO2020051756A1 (en) 2018-09-11 2018-09-11 Method for operating battery system and battery system

Country Status (3)

Country Link
EP (1) EP3849836A4 (en)
CN (1) CN112638694A (en)
WO (1) WO2020051756A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005733A (en) * 2009-08-31 2011-04-06 联想（新加坡）私人有限公司 Battery pack and its function stopping method
JP2014050942A (en) * 2012-09-10 2014-03-20 Hitachi Koki Co Ltd Electric power tool
CN104264737A (en) * 2008-11-18 2015-01-07 住友重机械工业株式会社 Working machine
CN107107327A (en) * 2014-12-18 2017-08-29 日立工机株式会社 Electric tool

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5166596A (en) * 1991-08-29 1992-11-24 Motorola, Inc. Battery charger having variable-magnitude charging current source
JP4595829B2 (en) * 2006-02-15 2010-12-08 トヨタ自動車株式会社 Secondary battery control device and control method
DE102012103213A1 (en) * 2012-04-13 2013-10-17 Keba Ag Method for operating a charging connection device for electric vehicles
JP5917290B2 (en) * 2012-05-18 2016-05-11 住友重機械工業株式会社 Electric swivel
US9688159B2 (en) * 2015-01-12 2017-06-27 GM Global Technology Operations LLC Methods, apparatus, and systems for preventing over-temperature battery operation
US20160276843A1 (en) * 2015-03-20 2016-09-22 Ford Global Technologies, Llc Battery Charge Strategy Using Discharge Cycle
JP6361545B2 (en) * 2015-03-24 2018-07-25 株式会社豊田自動織機 Current control device
DE102015008533A1 (en) * 2015-07-02 2016-02-18 Daimler Ag Device for tempering an electric battery
GB2545280B (en) * 2015-12-30 2018-01-10 Hyperdrive Innovation Ltd Battery management system
GB201523105D0 (en) * 2015-12-30 2016-02-10 Hyperdrive Innovation Ltd Battery management system
CN106026034B (en) * 2016-06-30 2019-10-29 联想(北京)有限公司 A kind of over-current protection method and circuit of battery battery core

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104264737A (en) * 2008-11-18 2015-01-07 住友重机械工业株式会社 Working machine
CN102005733A (en) * 2009-08-31 2011-04-06 联想（新加坡）私人有限公司 Battery pack and its function stopping method
JP2014050942A (en) * 2012-09-10 2014-03-20 Hitachi Koki Co Ltd Electric power tool
CN107107327A (en) * 2014-12-18 2017-08-29 日立工机株式会社 Electric tool

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3849836A4 *

Also Published As

Publication number Publication date
EP3849836A1 (en) 2021-07-21
EP3849836A4 (en) 2022-05-04
CN112638694A (en) 2021-04-09

Similar Documents

Publication Publication Date Title
US9350177B2 (en) Equalization circuit, power supply system, and vehicle
US6781343B1 (en) Hybrid power supply device
US8803470B2 (en) Electric vehicle extended range hybrid battery pack system
US10797364B2 (en) Power supply system of vehicle
JP4768090B2 (en) Charge control circuit, battery pack, and charging system
JP6853805B2 (en) Electric vehicle
EP2983000B1 (en) Electrical storage device, electrical storage system, and electric vehicle
EP1265335A2 (en) Method and apparatus for controlling residual battery capacity of secondary battery
US20060012340A1 (en) Method of determining voltage condition of fuel cell vehicle
US20170166078A1 (en) Battery charge equalization system
US20140011057A1 (en) Hybrid electrochemical energy store
US20140015485A1 (en) Charging device for vehicle, vehicle equipped with charging device, and offset correction method for current sensor
US9914368B1 (en) Thermal management system for a hybrid vehicle
JP2003051331A (en) Fuel cell power source device
JP2010081692A (en) Power supply device for vehicle
JP2016110917A (en) Lithium ion secondary battery and battery system
US11489329B2 (en) Power supply system
JPH1155866A (en) Battery charger
CN111092463B (en) Secondary battery system and method for controlling charging of secondary battery
WO2020051756A1 (en) Method for operating battery system and battery system
CN115472937A (en) Three-stage charging method for aviation storage battery charger with temperature compensation
CN110392643B (en) Method for operating a vehicle, control unit and vehicle
KR20190028201A (en) Apparatus and method for adjusting charging or discharging voltage of battery
EP3376580B1 (en) Method for operating a battery system and battery system
KR20200112212A (en) Battery charging method for eco-friendly vehicle

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18933245

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2018933245

Country of ref document: EP

Effective date: 20210412