Vehicle

Abstract

A vehicle is provided. The vehicle includes an electric heater that heats a battery. A battery ECU includes a memory, intermittently restarts even in a sleep state, and performs temperature raising control of the battery using the electric heater to bring a battery temperature close to a target battery temperature. A charging ECU transmits charger information used for the battery ECU to set the target battery temperature to the battery ECU. The battery ECU stores the charger information in the memory during a period in which the battery ECU is in an active state. In a case where the battery ECU restarts, when the charging ECU is in the active state, the battery ECU sets the target battery temperature based on charger information newly acquired from the charging ECU, and when the charging ECU is in the sleep state, the battery ECU sets the target battery temperature based on the charger information stored in the memory.

Description

Technical Field

[0001] This disclosure relates to vehicles, and more particularly, to vehicles including heating devices for heating batteries. Background Technology

[0002] When a vehicle equipped with a lithium-ion secondary battery or similar battery is placed in an extremely low-temperature environment, the battery electrolyte may freeze. When the electrolyte freezes, the battery's internal resistance increases, thus increasing the energy loss during charging and discharging. Furthermore, in lithium-ion secondary batteries, metallic lithium may deposit on the surface of the negative electrode, promoting battery degradation (so-called lithium deposition). Japanese Patent Application Publication No. 2017-147032 discloses a battery system in which heat is applied externally to the battery to raise its temperature, and the battery is then used after being heated. Summary of the Invention

[0003] To prevent the electrolyte from freezing in extremely low temperatures and to bring the battery into a state suitable for charging and discharging, it is recommended to use heating devices such as electric heaters to perform "temperature control" of the battery so that the battery temperature is close to the target temperature.

[0004] When a vehicle is left in an extremely low-temperature environment for an extended period, multiple management devices, including those responsible for temperature control, enter a dormant state. The inventors have addressed situations where the target temperature for temperature control may not be properly set due to the activation or dormancy of these management devices.

[0005] This disclosure was made to solve the above-mentioned problems, and one of the purposes of this disclosure is to appropriately set the target temperature for temperature control.

[0006] One aspect of this disclosure relates to a vehicle including a battery, a heating device for heating the battery, a first management device, and a second management device. The first management device includes a memory and is intermittently restarted even in a dormant state, using the heating device to perform battery temperature control to bring the battery temperature close to a target temperature. The second management device sends information to the first management device for setting the target temperature. The first management device stores information in the memory while the first management device is in an active state. When the first management device restarts, it sets the target temperature based on newly acquired information from the second management device when the second management device is active; conversely, when the second management device is in a dormant state, it sets the target temperature based on information stored in the memory. Attached Figure Description

[0007] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description of the invention as understood in conjunction with the accompanying drawings.

[0008] Figure 1 This is a diagram illustrating an example of the overall structure of a vehicle according to an embodiment of the present disclosure.

[0009] Figure 2 This is a block diagram illustrating an example of the structure of a battery ECU.

[0010] Figure 3 This is a flowchart illustrating an example of the processing steps of a vehicle control method according to an embodiment of the present disclosure. Detailed Implementation

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0012] [Implementation Method]

[0013] (Vehicle structure)

[0014] Figure 1 This diagram illustrates an example of the overall structure of a vehicle according to an embodiment of the present disclosure. In this example, vehicle 1 is an electric vehicle (BEV). However, vehicle 1 is preferably an electric vehicle capable of being charged using electricity supplied from an external charger (not shown) (so-called external charging), such as a plug-in hybrid electric vehicle (PHEV) or a fuel cell electric vehicle (FCEV). Vehicle 1 can also be a hybrid electric vehicle (HEV) as long as it is equipped with a battery.

[0015] Vehicle 1 includes battery 10, monitoring unit 20, electric heater 30, system main relay (SMR) 40, charging relay (CHR) 50, inlet 60, power control unit (PCU) 70, motor generator (MG) 80, charging ECU (Electronic Control Unit) (second management device) 90 and battery ECU (first management device) 100.

[0016] Battery 10 is a battery pack comprising multiple individual cells. Each individual cell is a secondary battery, typically a lithium-ion battery. However, the type of cell is not particularly limited. Battery 10 stores electricity for driving the electric generator 80 and supplies electricity to the electric generator 80 via PCU 70. Additionally, battery 10 is charged by receiving generated electricity via PCU 70 when the electric generator 80 is generating electricity. Battery 10 is also charged by electricity supplied from a charger (not shown).

[0017] The monitoring unit 20 includes a voltage sensor 21, a current sensor 22, and a temperature sensor 23. The voltage sensor 21 detects the voltage V of the battery 10 (more specifically, each individual cell contained in the battery). The current sensor 22 detects the current I relative to the input / output of the battery 10. The temperature sensor 23 detects the temperature T of the battery 10 (more specifically, any individual cell contained in the battery). Hereinafter, the temperature of the battery 10 detected by the temperature sensor 23 will be recorded as "battery temperature T". Each sensor outputs its detected value to the battery ECU 100.

[0018] The electric heater 30 is, for example, a PTC (Positive Temperature Coefficient) heater. The electric heater 30 receives power from a power source not shown (which could be the vehicle battery or an external charger) and heats the battery 10 according to control commands from the battery ECU 100. The electric heater 30 is equivalent to the "heating device" of this disclosure.

[0019] SMR40 is electrically connected to the power line connecting battery 10 and PCU70. SMR40 responds to control commands from battery ECU100 to switch the supply and disconnection of power between battery 10 and PCU70.

[0020] CHR50 is electrically connected to the power line connecting battery 10 and inlet 60. CHR50 responds to control commands from charging ECU90 to switch the supply and disconnection of power between battery 10 and inlet 60.

[0021] The inlet 60 is configured as a connector (not shown) capable of electrically connecting to a charging cable. The inlet 60 receives charging power supplied from a charger (not shown) via the charging cable.

[0022] PCU70 performs bidirectional power conversion between battery 10 and electric generator 80 according to control commands from driving ECU (not shown). PCU70 includes, for example, a converter that boosts the DC voltage of battery 10 and an converter (not shown) that converts the DC power from the converter into AC power to drive electric generator 80.

[0023] The electric generator 80 is an AC rotating motor, such as a three-phase AC synchronous motor with permanent magnets embedded in the rotor. The electric generator 80 is driven by power received from the battery 10. On the other hand, when the vehicle 1 brakes or when acceleration decreases on a downhill slope, the electric generator 80 operates as a generator to generate electricity regeneratively. The power generated by the electric generator 80 charges the battery 10 via the PCU 70.

[0024] The charging ECU 90 manages the external charging of the vehicle 1. The charging ECU 90 is configured to exchange "charger information" with a charger connected via inlet 60 and a charging cable when the vehicle 1 is being charged externally. The charger information includes, for example, information indicating the maximum power that can be supplied from the charger. The charging ECU 90 is equivalent to the "second management device" of this disclosure.

[0025] The battery ECU 100 manages the charging and discharging of the battery 10 in a way that protects the battery 10. Furthermore, the battery ECU 100 controls the electric heater 30 based on signals received from various sensors in the monitoring unit 20. More specifically, in extremely low-temperature environments, the battery ECU 100 uses the electric heater 30 to heat the battery 10 to bring its temperature T close to the target battery temperature Ttag, in order to prevent the electrolyte of the battery 10 from freezing and to bring the battery 10 into a state suitable for charging and discharging. This control is referred to as "temperature rise control". The battery ECU 100 is equivalent to the "first management device" of this disclosure.

[0026] (Structure of the battery ECU)

[0027] Figure 2 This is a block diagram illustrating an example of the structure of the battery ECU 100. The battery ECU 100 includes a processor 110, a memory 120, and a communication interface 130.

[0028] The processor 110 includes a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).

[0029] The memory 120 includes ROM (Read Only Memory) 121, RAM (Random Access Memory) 122, and storage device 123. RAM may include, for example, DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). Storage device 123 may include, for example, flash memory.

[0030] The communication interface 130 is configured to send and receive signals with other constituent devices (monitoring unit 20, electric heater 30, and charging ECU 90).

[0031] The memory 120 stores system programs, including the operating system (OS), and control programs for controlling the components of the vehicle 1. The processor 110 performs various processes by reading the system programs and control programs and expanding them in the memory 120.

[0032] (Temperature control)

[0033] When vehicle 1 is left in an extremely low temperature environment for an extended period, the battery ECU 100 enters a dormant state. Even in dormant mode, the battery ECU 100 intermittently restarts to perform temperature control under specified conditions. As a result, the battery temperature T approaches the target battery temperature Ttag for temperature control.

[0034] The battery ECU 100 obtains information from the charging ECU 90 for setting the target battery temperature Ttag. As a specific example, the battery ECU 100 obtains charger information from the charging ECU 90, which includes information indicating the maximum power that can be supplied to the vehicle 1 from the charger (not shown), and sets the target battery temperature Ttag based on the charger information. For example, the higher the maximum power that the battery ECU 100 can supply from the charger, the higher the target battery temperature Ttag is set. By raising the battery 10 to the maximum possible temperature before external charging, based on the maximum power, the internal resistance of the battery 10 decreases, enabling high-power charging. Therefore, the time required for external charging can be shortened.

[0035] However, if vehicle 1 is left in an extremely low temperature environment for an extended period of time, not only the battery ECU 100 but also the charging ECU 90 will enter a dormant state. As a result, the battery ECU 100 will be unable to obtain charger information from the charging ECU 90, which may lead to a situation where the battery ECU 100 is unable to properly set the target battery temperature Ttag.

[0036] Therefore, in this embodiment, the battery ECU 100 distinguishes the destination for obtaining charger information based on whether the charging ECU 90 is in an active state. When the charging ECU 90 is active, the battery ECU 100 obtains the latest charger information from the charging ECU 90. On the other hand, when the charging ECU 90 is not active (when the charging ECU 90 is in a dormant state), the battery ECU 100 reads the previous (last) charger information pre-stored in the memory 120. Thus, the battery ECU 100 can obtain charger information regardless of whether the charging ECU 90 is active, and therefore the target battery temperature Ttag can be set appropriately.

[0037] (Processing flow)

[0038] Figure 3 This is a flowchart illustrating an example of the processing steps of a vehicle control method according to an embodiment of the present disclosure. The processing shown in this flowchart is executed when predetermined conditions are met (e.g., each predetermined cycle). Each step is implemented by software processing based on the battery ECU 100, but may also be implemented by hardware (circuit) configured within the battery ECU 100. Hereinafter, the steps will be abbreviated as S. It is assumed that the battery ECU 100 is in a dormant state at the start of a series of processes.

[0039] In S1, the battery ECU100 determines whether the preset restart time has arrived. If the restart time has arrived (yes in S1), the battery ECU100 transitions from the dormant state to the start state (S2).

[0040] In S3, the battery ECU100 determines whether the setting conditions for the target battery temperature Ttag are met. For example, if the battery temperature T is lower than the specified temperature, the setting conditions for the target battery temperature Ttag are met. Alternatively, if a specified time has elapsed since the last setting of the target battery temperature Ttag, the setting conditions for the target battery temperature Ttag are met.

[0041] In step S4, the battery ECU 100 determines whether the charging ECU 90 is in an active state. For example, if a signal that should be sent from the charging ECU 90 is received before a specified period has elapsed, the battery ECU 100 determines that the charging ECU 90 is in an active state. In other words, if the signal is not received before the specified period has elapsed, the battery ECU 100 determines that the charging ECU 90 is not in an active state (it is in a dormant state).

[0042] When the charging ECU 90 is in the active state (yes in S4), the battery ECU 100 obtains the latest charger information through communication with the charging ECU 90 (S5). Then, the battery ECU 100 sets the target battery temperature Ttag based on the latest charger information (specifically, information indicating the maximum power that can be supplied from the charger) (S6). As mentioned above, the higher the maximum power that can be supplied from the charger, the higher the target battery temperature Ttag will be set by the battery ECU 100. Furthermore, the battery ECU 100 stores the charger information obtained in S5 in the memory 120 (e.g., SRAM) (S7). After that, the battery ECU 100 initiates processing in S10.

[0043] If the charging ECU 90 is not in the active state (not in S4), the battery ECU 100 reads the previous charger information stored in the memory 120 (S8). Then, the battery ECU 100 sets the target battery temperature Ttag based on the previous charger information (specifically, information indicating the maximum power that can be supplied from the charger) (S9). Similar to S6, the higher the maximum power that can be supplied from the charger, the higher the target battery temperature Ttag will be set by the battery ECU 100. Afterward, the battery ECU 100 proceeds to S10.

[0044] In S10, the battery ECU 100 estimates the outside temperature. For example, the battery ECU 100 estimates the outside temperature based on the time variation of the battery temperature T. More specifically, the battery ECU 100 estimates the outside temperature based on the aforementioned three parameters (T(n-1), T(n), Δt) by referring to a mapping that defines the relationship between the previous battery temperature T(n-1), the current battery temperature T(n), their time difference Δt, and the outside temperature. Alternatively, the battery ECU 100 may obtain a measured value of the outside temperature from an outside temperature sensor not shown in the figure. The battery ECU 100 may also obtain the measured value of the outside temperature (meteorological information) through communication with the outside environment.

[0045] In S11, the battery ECU 100 sets the next start-up time. More specifically, the lower the estimated outside temperature in S10, the earlier the battery ECU 100 sets the next start-up time. In other words, the lower the outside temperature, the shorter the time from when the battery ECU 100 transitions to sleep mode until the next restart.

[0046] In S12, the battery ECU100 transitions from the startup state to the sleep state. This concludes the series of processes.

[0047] As described above, in this embodiment, even when the charging ECU 90 is in a dormant state during the restart of the battery ECU 100, the battery ECU 100 can still set the target battery temperature Ttag for temperature control by reading the charger information stored in the memory 120. On the other hand, when the charging ECU 90 is also in an active state during the restart of the battery ECU 100, the battery ECU 100 can set the target battery temperature Ttag based on the latest charger information obtained from the charging ECU 90.

[0048] Furthermore, the battery ECU 100 sets the target battery temperature Ttag for temperature control based on the charger's maximum power supply (i.e., charging performance). Thus, for example, in the case of a fast charger, by setting the target battery temperature Ttag higher to allow the battery 10 to heat up sufficiently, the time required for external charging can be shortened.

[0049] Furthermore, the lower the external temperature, the shorter the time it takes for the battery ECU 100 to transition from a dormant state to a restart. This more reliably prevents the electrolyte in the battery 10 from freezing during the period when the battery ECU 100 is in a dormant state.

[0050] Embodiments of the present invention have been described, but should be considered as illustrative rather than restrictive in all respects. The scope of the invention is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A vehicle, comprising: Battery; A heating device is used to heat the battery; A first management device, including a memory, intermittently restarts even in a dormant state, and uses the heating device to perform temperature control of the battery to bring the battery temperature close to a target temperature; and The second management device sends information to the first management device for setting the target temperature. The first management device stores the information in the memory while the first management device is in the activated state. If the first management device is restarted When the second management device is in an active state, the first management device sets the target temperature based on the information newly obtained from the second management device. On the other hand, when the second management device is in a dormant state, the first management device sets the target temperature based on the information stored in the memory.

2. The vehicle according to claim 1, wherein, The vehicle is configured to be charged by power supplied from an external charger. The first management device is a battery control device that manages the charging and discharging of the battery. The second management device is a charging control device that controls the supply of power from the charger to the vehicle.

3. The vehicle according to claim 2, wherein, The information refers to the maximum power that can be supplied from the charger.

4. The vehicle according to claim 3, wherein, The higher the maximum power, the higher the target temperature will be set by the first management device.

5. The vehicle according to any one of claims 1 to 4, wherein, The lower the external temperature, the shorter the time it takes for the first management device to transition from a sleep state to a restart state.

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