Method for thermal management of an electrochemical energy storage device of a vehicle and vehicle system

Abstract

The invention relates to a method for thermally managing an electrochemical energy accumulator of a vehicle, wherein data are received and / or determined, wherein the data include a planned or expected parking duration, environmental data of the vehicle, thermal properties of the electrochemical energy accumulator, the received and / or determined data are analyzed, and based on the analyzed data, measures for thermally managing the electrochemical energy accumulator are introduced by a control unit before, during or after parking the vehicle, wherein thermal energy is directly or indirectly removed from the electrochemical energy accumulator or supplied to the electrochemical energy accumulator by means of the measures for thermally managing the electrochemical energy accumulator via a battery cooling circuit and / or a main cooling circuit of the vehicle.

Description

Technical Field

[0001] The invention relates to a method for thermally managing an electrochemical energy storage device of a vehicle and to a vehicle system for implementing such a method. Background Art

[0002] Electrochemical energy storage devices, especially power batteries, currently used in electric vehicles or hybrid vehicles have a relatively narrow temperature range within which the power batteries can be charged and discharged with high currents. Low ambient temperatures and correspondingly cooled power batteries lead to reduced efficiency of the power batteries.

[0003] In particular, when the vehicle is parked after operation, the power battery may cool below its optimal operating temperature. Here, the average parking time of electric vehicles or hybrid vehicles before restarting is shorter than 9 hours in more than 90%. If the optimal operating temperature is lower than during this parking time, special functions such as pure electric driving, brake recuperation or energy supply to electrical appliances are usually only provided in a limited manner in hybrid vehicles in order not to affect the efficiency of the power battery. As a result, hybrid vehicles have increased CO2 emissions at low ambient temperatures.

[0004] Methods for heating the power battery during the charging process are known. However, in order to achieve this, external energy must be provided so as not to affect the capacity of the power battery. Summary of the invention

[0005] The object of the present invention is to provide a method which adjusts a traction battery of a vehicle to an operating-optimized state in an energy-efficient manner before starting the journey.

[0006] According to the invention, this object is achieved by a method having the features described below and a vehicle system having the features described below. Advantageous embodiments and improvements are described below.

[0007] In the method according to the invention for thermal management of an electrochemical energy storage device of a vehicle, data are recorded and / or determined in a step.

[0008] For this purpose, the vehicle can use a vehicle-external or vehicle-internal control unit to process the data and to store the data at least temporarily in a memory.

[0009] The data may include the planned or expected duration of the stop, environmental data of the vehicle, thermal properties of the electrochemical energy storage device, etc.

[0010] In a further step, the received and / or determined data are analyzed. Based on the analyzed data, measures for thermal management of the electrochemical energy storage device are initiated by the control unit before, during or after the vehicle stops.

[0011] The thermal management measures for the electrochemical energy storage device introduced before, during or after the vehicle is stopped preferably include directly or indirectly taking heat from the electrochemical energy storage device or inputting heat into the electrochemical energy storage device. In this case, heat can be transferred between the electrochemical energy storage device and the battery cooling circuit of the vehicle and / or between the electrochemical energy storage device and the main cooling circuit.

[0012] The corresponding measures and the time at which they are initiated are preferably dependent on the planned or expected duration of the vehicle stop, the ambient conditions and the thermal properties of the electrochemical energy storage device.

[0013] The electrochemical energy storage device can be, for example, a power battery or an auxiliary battery. In particular, the electrochemical energy storage device can be based on lithium-ion technology, lithium polymer technology, etc.

[0014] As a result, an intelligent or adaptive management method for the electrochemical energy storage device of the vehicle can be provided, by which the efficiency and driving range of the hybrid vehicle are increased.

[0015] Since more than 90% of all starting processes take place after a stop time or stop duration of less than 9 hours, thermal management measures for the electrochemical energy storage device can be implemented in such a way that optimal operating conditions, such as the operating temperature, are maintained or reestablished after the end of the stop duration.

[0016] In particular, the parking duration can be bridged by the method in optimized operating conditions with the aid of vehicle-side auxiliary devices. In this case, no electrical energy or minimal electrical energy is drawn from the electrochemical energy storage device.

[0017] This can improve the pure electric driving range of hybrid vehicles and the user acceptance of hybrid vehicles. In addition, maintaining or re-establishing optimized operating conditions reduces the CO2 emissions of the vehicle when the vehicle is restarted, thereby also improving the test results of the so-called ATCT (ambient temperature correction test).

[0018] Due to the thermal management measures taken in advance or continuously during the parking period, the electric driving range of the hybrid vehicle is not limited or is only minimally limited.

[0019] Furthermore, the method improves driving comfort by not limiting or compromising the driving functions of the vehicle. The availability of the hybrid function can be reproduced here, since the battery availability is also significantly increased.

[0020] The method enables continuous use of the electrochemical energy store within its optimal operating parameters, thereby reducing aging of the electrochemical energy store.

[0021] Preferably, in order to implement measures for thermal management of the electrochemical energy storage device, thermal energy is taken from the electrochemical energy storage device or thermal energy is supplied to the electrochemical energy storage device via a battery cooling circuit. This measure allows normal operation of the vehicle to be achieved, during which the battery cooling circuit used is used directly for supplying and taking away thermal energy.

[0022] Preferably, in order to implement measures for thermal management of the electrochemical energy storage device, thermal energy is taken from the electrochemical energy storage device or thermal energy is input into the electrochemical energy storage device via a main cooling circuit of the vehicle. Here, the main cooling circuit can be directly or indirectly connected to the electrochemical energy storage device.

[0023] A main cooling circuit that can be directly thermally coupled to the electrochemical energy store allows the coolant of the main cooling circuit to bypass a heat exchanger that is integrated into the electrochemical energy store or arranged on the electrochemical energy store. This can be done in parallel or in series with the battery cooling circuit.

[0024] The primary cooling circuit of a vehicle or a hybrid vehicle can in particular take over the function of cooling the power unit of the vehicle's internal combustion engine and thus act as a heat source or heat sink.

[0025] In this case, the coolant in the main cooling circuit and / or in the battery cooling circuit can be used as a heat source or heat sink for the electrochemical energy storage device.

[0026] Furthermore, other components thermally coupled to the coolant of the main cooling circuit and / or the battery cooling circuit, such as cooling bodies, evaporators, power electronics, internal combustion engines, charge air coolers, turbochargers, electrical consumers, etc., can be used as heat sources or heat sinks for the electrochemical energy storage device.

[0027] According to another embodiment, in order to transfer thermal energy from the main cooling circuit to the electrochemical energy storage device, thermal energy is transferred between the main cooling circuit and the battery cooling circuit via a heat exchanger and / or a heat storage device. Preferably, the thermal energy transferred to the battery cooling circuit is supplied to the electrochemical energy storage device. This measure makes it possible to achieve an indirect thermal coupling between the electrochemical energy storage device and the main cooling circuit.

[0028] The heat exchanger can thermally couple the coolant of the main cooling circuit with the coolant of the battery cooling circuit, thereby enabling temperature compensation. The heat exchanger can preferably be switched on as required by an electromechanical valve.

[0029] The heat accumulator can, for example, comprise a solid or liquid material with a high specific heat capacity in order to act as a thermal buffer. Depending on the configuration, the heat accumulator can be designed as a latent heat accumulator.

[0030] The measures of the method make it possible to fully utilize the cost-free engine waste heat, in particular by introducing the power plant waste heat directly into the electrochemical energy accumulator or by storing the power plant waste heat in a heat accumulator and subsequently introducing the thermal energy into the electrochemical energy accumulator.

[0031] According to another embodiment, before or while the vehicle is parked, thermal management measures for the electrochemical accumulator are introduced in the form of introducing heat energy into the electrochemical accumulator, taking into account the thermal cooling curve of the electrochemical accumulator and taking into account the parking duration of the vehicle. The electrochemical accumulator is heated briefly in such a way that after the vehicle parking duration has expired, the temperature does not fall below a predefined operating temperature of the electrochemical accumulator.

[0032] This measure allows the electrochemical energy store to be preheated even before the start of the parking period, so that after the parking period has ended, the temperature of the electrochemical energy store is still in its optimal operating range. This is equivalent to approaching the minimum possible operating temperature from a higher temperature.

[0033] Preheating may be performed once before or while the vehicle is parked, or multiple times over the course of the parking duration.

[0034] According to another specific embodiment, after the vehicle is parked, measures for thermal management of the electrochemical energy accumulator are introduced in the form of introducing heat energy into the electrochemical energy accumulator, taking into account the thermal cooling curve of the electrochemical energy accumulator and taking into account the parking duration of the vehicle. Preferably, a management duration is determined, which ends before the parking duration has expired and is shorter than the parking duration, and the measures for thermal management are carried out during the management duration. As a result, thermal energy can be drawn from the main cooling circuit or the heat accumulator during the parking duration in order to increase the temperature of the electrochemical energy accumulator to an optimal level during the management duration.

[0035] Similarly, the method can be applied to overheated electrochemical energy storage devices. In particular, the temperature of the electrochemical energy storage device can be reduced to an optimal operating level by dissipating the heat energy.

[0036] The control period can be determined with the aid of Fourier's law or the heat conduction equation. In this case, the control period corresponds to the period required to heat the electrochemical energy storage device from the expected or measured actual temperature to the target temperature or the optimum operating temperature. Preferably, the thermal energy present in the vehicle's main cooling circuit and / or the battery cooling circuit at the start of the control period can be determined or estimated in order to enable a particularly precise determination of the control period. The control period can be determined by an algorithm or a simulation.

[0037] According to another embodiment, in order to provide thermal energy, the coolant of the battery cooling circuit and / or the main cooling circuit of the vehicle is heated by absorbing brake recuperation energy in the form of thermal energy and / or by absorbing thermal energy from at least one load of the vehicle. This measure can be used to manage the electrochemical energy storage device by using the electrical energy and / or thermal energy generated during braking. For example, the electrical energy recuperated by braking can be converted into thermal energy in a brake resistor and output to the battery cooling circuit.

[0038] According to another specific embodiment, data about the planned or expected parking duration are received by manual input or determined by a self-learning system, for example a pre-trained neural network. In this case, typical parking durations of drivers of hybrid vehicles can be analyzed historically in order to estimate the expected parking duration. In addition, various parameters or various data of the electrochemical energy storage device, the main cooling circuit and the battery cooling circuit can be collected and analyzed in order to determine the management duration.

[0039] The data can be received, determined and evaluated by a control unit inside or outside the vehicle.

[0040] Based on the received data, it can be decided when to initiate measures for thermal management of the electrical energy storage device. In addition, the duration of the measures or the management duration can be determined.

[0041] According to another aspect of the present invention, a vehicle system is provided. The vehicle system can preferably be arranged for a vehicle or integrated in a vehicle, the vehicle being designed as a hybrid vehicle and having a main cooling circuit and a battery cooling circuit. In addition, the vehicle has at least one electrochemical energy accumulator, which is thermally coupled to the battery cooling circuit and directly or indirectly thermally coupled to the main cooling circuit. The main cooling circuit is preferably thermally coupled to an internal combustion engine of the vehicle. Here, the internal combustion engine can be configured as a drive device or as a generator for energy supply. The vehicle is configured to implement the method according to the present invention.

[0042] The method can also be used to raise at least one electrochemical energy storage device of the vehicle to an optimal operating level after the vehicle stops and at low ambient temperatures. In particular, waste heat from the internal combustion engine of the vehicle's main cooling circuit can be used for thermal management of the electrochemical energy storage device. In this case, the electrochemical energy storage device can be heated to a maximum or increased operating temperature at least temporarily in order to provide a sufficiently hot electrochemical energy storage device even after the duration of the stop in order to immediately start operating the hybrid function of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention is schematically illustrated with the aid of embodiments in the drawings and will be further described with reference to the drawings. The present invention shows:

[0044] Figure 1 A vehicle system according to a first embodiment of the present invention is shown.

[0045] Figure 2 A vehicle system according to a second embodiment of the present invention is shown, and

[0046] Figure 3 A vehicle system according to a third embodiment of the present invention is shown.

[0047] List of reference numerals:

[0048] 1. Vehicle System

[0049] 2 Main cooling circuit

[0050] 4 Battery cooling circuit

[0051] 6Electrochemical accumulator

[0052] 8 Internal combustion engine

[0053] 10 Control unit

[0054] 12 Heat storage

[0055] 14 Heat Exchanger DETAILED DESCRIPTION

[0056] The invention will now be explained with reference to the accompanying drawings by means of exemplary embodiments. Identical components are denoted by the same reference numerals.

[0057] Figure 1 A vehicle system 1 according to a first embodiment of the invention is shown. The vehicle system 1 has a main cooling circuit 2 and a battery cooling circuit 4.

[0058] Furthermore, the vehicle system 1 has at least one electrochemical energy store 6 . The electrochemical energy store 6 is thermally coupled to the battery cooling circuit 4 and directly or indirectly to the main cooling circuit 2 .

[0059] The main cooling circuit 2 is preferably thermally coupled to an internal combustion engine 8 of the vehicle. In this case, the internal combustion engine 8 is designed as a drive machine, for example.

[0060] The electrochemical energy storage device 6 is designed as a power battery and is based on lithium-ion technology in the exemplary embodiment shown. In this case, the electrochemical energy storage device 6 can be designed as a battery system or a battery module having a plurality of battery cells.

[0061] Instead of the internal combustion engine 8 , any load that generates heat can also be thermally connected to the main cooling circuit 2 or the battery cooling circuit 4 in order to provide thermal energy for the electrochemical energy storage device 6 .

[0062] Figure 1Normal operation of the vehicle is shown, in which the temperature of the electrochemical energy store 6 lies in an exemplary optimum temperature range of 30° C. to 50° C. In this case, the thermal management of the electrochemical energy store 6 is completely assumed by the battery cooling circuit 4 .

[0063] When the vehicle is stopped, measures are taken so that, at the subsequent restart, optimal operating conditions in the form of a so-called “comfort temperature” are present for the electrochemical energy store 6 . For this purpose, a large amount of information and data is acquired and evaluated by the control unit 10 .

[0064] Preferably, the predicted or estimated parking duration of the vehicle, the parking duration manually input by the driver, environmental data (such as expected ambient temperature from weather data information) and thermal properties of the electrochemical energy storage device 6 are received and analyzed by the control unit 10 .

[0065] The predicted parking duration of the vehicle can be determined by a self-learning system, such as a neural network. The thermal behavior of the electrochemical energy storage device 6 can take into account the entire battery system including the corresponding battery cells in the assembled state and in the housing. In this way, a cooling curve that depends on the ambient temperature and the temperature of the electrochemical energy storage device 6 can be created or used.

[0066] If the vehicle is parked, the method according to the invention can determine whether measures for thermal management of electrochemical energy storage device 6 have been initiated while the vehicle is parked or after the vehicle has been parked. This function can be implemented by control unit 10 of vehicle system 1 .

[0067] In particular, the measures can be taken sufficiently in time before an expected or planned vehicle start in order to manage electrochemical energy store 6 using thermal energy in such a way that it is in an optimal temperature range independently of the duration of the stop and independently of the ambient conditions when the vehicle is started.

[0068] The heat input takes place via the low-temperature battery cooling circuit 4. For example, this measure can be taken immediately when the vehicle is parked if the parking duration falls below a predetermined threshold value.

[0069] If the parking duration exceeds a predetermined threshold value, a management duration can be determined, which serves as a basis for initiating measures for thermal management after the vehicle has been parked.

[0070] In this case, the starting time for initiating the measure can be determined by subtracting the management duration from the determined parking duration.

[0071] For example, to initiate the measures when the vehicle is parked or during parking, the heat capacity of the electrochemical energy storage device 6 is used together with the introduced cooling medium (which has a different temperature in each case) and the combined temperature is calculated. This combined temperature is adjusted so that the maximum temperature is not exceeded.

[0072] Alternatively, the thermal energy is introduced from the heat storage device 12 into the electrochemical energy storage device 6 only after the vehicle has stopped, shortly before the vehicle is started, or after the parking period has ended. Figure 2 A vehicle system 1 according to a second embodiment of the present invention is shown in FIG.

[0073] The heat accumulator 12 can form an indirect thermal coupling between the main cooling circuit 2 and the battery cooling circuit 4 .

[0074] Optionally, part of the cooling medium of the battery cooling circuit 4 can also be further heated during driving by excess brake recuperation and heating elements. Shortly after the vehicle stops, this cooling medium is then introduced into the battery system or used to heat the electrochemical energy storage device 6.

[0075] In order to carry out thermal management when or after the vehicle is parked or before starting the vehicle, thermal energy can be taken from the heat storage device 12 and supplied to the electrochemical energy storage device 6 .

[0076] During vehicle operation, heat storage device 12 is supplied by main cooling circuit 2 and / or by battery cooling circuit 4 . When necessary, for example when the temperature in electrochemical energy storage device 6 is below 30° C., thermal energy can be taken from heat storage device 12 as a measure for thermal management.

[0077] Preferably, enough thermal energy is stored in heat storage device 12 that electrochemical energy storage device 6 can be heated to at least 30° C. for starting the vehicle.

[0078] The heat accumulator 12 may comprise, for example, a solid or liquid material having a high specific heat capacity in order to act as a thermal buffer. Depending on the configuration, the heat accumulator may be configured as a latent heat accumulator.

[0079] Figure 3 A vehicle system 1 according to a third exemplary embodiment of the invention is shown. A further measure for thermal management of the electrochemical energy storage device 6 is described. After the vehicle has been stopped, within the scope of a management operation, thermal energy can be transferred from the main cooling circuit 2 into the battery cooling circuit 4 and thus to the electrochemical energy storage device 6. To achieve this indirect heat transfer, a heat exchanger 14 is provided which thermally couples the main cooling circuit 2 to the battery cooling circuit 4.

[0080] So much heat is introduced into electrochemical energy storage device 6 that, during the subsequent vehicle start, a temperature of approximately 30° C. is still present in electrochemical energy storage device 6 .

[0081] Measures for thermal management of the electrochemical energy storage device 6 can be initiated by the control unit 10. In this case, the start time of the measures, the duration of the management of the measures and the type of the measures are determined by the control unit 10 based on the received data. The control unit 10 can be configured as a pre-trained neural network. In this case, the control unit 10 can act as a self-learning unit and, in particular, automatically estimate the parking duration of the vehicle in order to be able to initiate thermal management in a timely manner.

Claims

1. A method for thermal management of an electrochemical energy storage device (6) of a vehicle by means of a control unit (10), wherein: - receiving and / or determining data, wherein the data include: a planned or expected stop duration, environmental data of the vehicle and / or thermal properties of the electrochemical energy storage device (6), - analyzing the received and / or determined data and, based on the analyzed data, initiating measures for thermal management of the electrochemical energy storage device (6) before, during or after the vehicle stops, wherein thermal energy is directly or indirectly removed from the electrochemical energy storage device (6) or supplied to the electrochemical energy storage device (6) by means of the thermal management measures for the electrochemical energy storage device (6) via a battery cooling circuit (4) and / or a main cooling circuit (2) of the vehicle, After the vehicle is parked, measures for thermal management of the electrochemical energy accumulator (6) are introduced in the form of introducing heat energy into the electrochemical energy accumulator (6) taking into account the thermodynamic cooling curve of the electrochemical energy accumulator (6) and taking into account the parking duration of the vehicle, wherein a management duration is determined, which ends before the parking duration is completed and is shorter than the parking duration, and during which the measures for thermal management are carried out.

2. The method according to claim 1, characterized in that: In order to transfer thermal energy from a main cooling circuit (2) to an electrochemical energy accumulator (6), thermal energy is transferred between the main cooling circuit (2) and a battery cooling circuit (4) via a heat exchanger (14) and / or via a heat accumulator (12), and the thermal energy transferred into the battery cooling circuit (4) is supplied to the electrochemical energy accumulator (6).

3. The method according to claim 1 or 2, characterized in that: Before or when the vehicle is parked, thermal management measures for the electrochemical energy accumulator (6) are introduced in the form of introducing heat energy into the electrochemical energy accumulator (6) taking into account the thermodynamic cooling curve of the electrochemical energy accumulator (6) and taking into account the parking duration of the vehicle, wherein the electrochemical energy accumulator is heated for a short time such that the temperature of the electrochemical energy accumulator (6) does not fall below a predefined operating temperature after the vehicle parking duration has expired.

4. The method according to claim 1 or 2, characterized in that: To provide thermal energy, a coolant in a battery cooling circuit (4) and / or a main cooling circuit (2) of the vehicle is heated by absorbing brake recuperation energy in the form of thermal energy and / or by absorbing thermal energy from at least one load (8) of the vehicle.

5. The method according to claim 1 or 2, characterized in that: The data regarding the planned or estimated parking duration is received by manual input or is determined by a self-learning system.

6. The method according to claim 5, characterized in that The self-learning system includes a pre-trained neural network.

7. A vehicle system (1) comprising a main cooling circuit (2) and a battery cooling circuit (4) and at least one electrochemical energy storage device (6) which is thermally coupled to the battery cooling circuit (4) and directly or indirectly thermally coupled to the main cooling circuit (2), wherein: The vehicle system (1) is configured to carry out the method according to any one of claims 1 to 6.

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