JP6812892B2 - Hybrid vehicle - Google Patents

Description

The present disclosure relates to a hybrid vehicle, and more specifically to a hybrid vehicle equipped with a battery including a lithium ion secondary battery.

In recent years, hybrid vehicles have become widespread. In hybrid vehicles, it is particularly required to improve fuel efficiency by efficiently using fuel. Therefore, a method for appropriately determining the operating state (operating point) of the engine and the motor has been proposed. For example, Japanese Patent Application Laid-Open No. 2001-298805 (Patent Document 1) determines the operating points of an engine and a motor based on a vehicle speed, a driving force command value for a vehicle, and an efficiency index related to fuel utilization efficiency. Disclose the hybrid vehicle.

Japanese Unexamined Patent Publication No. 2001-298805 Japanese Unexamined Patent Publication No. 2013-071622

Hybrid vehicles equipped with a lithium-ion secondary battery as a running battery are commercially available. Generally, when a lithium ion secondary battery (hereinafter, also referred to as “battery”) is charged / discharged with a large current (so-called high-rate charging / discharging), the concentration of lithium salt in the electrolytic solution (hereinafter, “salt concentration”” is used. It is known that a bias can occur. If the salt concentration is biased, the internal resistance of the battery increases, which may reduce the battery performance (charge / discharge performance). Generally, such deterioration is also referred to as "high rate deterioration".

One of the factors that cause the salt concentration to be biased by high-rate charging / discharging is that the electrode body expands due to high-rate charging / discharging, which causes the electrolytic solution inside the electrode body to be biased. The bias of the electrolytic solution caused by the high-rate charging / discharging is alleviated with the passage of time after the high-rate charging / discharging is completed. Along with this, the bias of salt concentration is gradually made uniform.

However, when the battery-equipped Ibrid vehicle is traveling on a slope or parked on a slope, the battery is tilted. Depending on the magnitude of this inclination, the electrolytic solution tends to stay below the electrode body, while the electrolytic solution tends to run short above the electrode body. As a result, the bias of the electrolyte (and the resulting bias of salt concentration) may be less likely to be uniformed compared to when the battery is horizontal.

In the hybrid vehicle disclosed in Patent Document 1, although it is disclosed that the fuel efficiency is improved by determining the operating point of the engine and the motor using the efficiency index, it is high rate that the battery tilts due to the road gradient or the like. No consideration is given to the effect on deterioration. Therefore, it may not be possible to properly protect the battery.

The present disclosure has been made to solve the above problems, and the purpose of the present disclosure is to appropriately protect the battery from high-rate deterioration while improving fuel efficiency in a hybrid vehicle equipped with a battery including a lithium ion secondary battery. It is to be.

A hybrid vehicle according to an aspect of the present disclosure uses an engine that uses fuel to generate power, a battery that includes a lithium-ion secondary battery, a detector that detects the tilt of the battery, and the power generated by the engine. It includes a rotary electric machine configured to generate electricity, a power conversion device for performing power conversion between the battery and the rotary electric machine, and a control device configured to be able to control the engine and the power conversion device. The control device determines the operating state of the engine and the rotary electric machine so that the higher the fuel utilization efficiency at the time of charging the battery, the larger the charging power to the battery. When the inclination of the battery is larger than a predetermined value, the control device calculates the concentration distribution of the lithium salt in the battery using the inclination of the battery, and corrects the operating state according to the calculated concentration distribution.

According to the above configuration, the operating state (operating point) of the engine and the rotary electric machine is corrected in consideration of the lithium salt concentration distribution (bias of lithium salt concentration) caused by the tilting of the battery. Therefore, it is possible to appropriately protect the battery while improving the fuel efficiency by using the fuel utilization efficiency.

According to the present disclosure, in a hybrid vehicle equipped with a battery including a lithium ion secondary battery, the battery can be appropriately protected while improving fuel efficiency.

It is a figure which shows schematic the whole structure of the hybrid vehicle which concerns on embodiment of this disclosure. It is a figure which shows the structure of a battery in more detail. It is a figure for demonstrating the structure of each cell in more detail. It is a figure for demonstrating the determination method of the operating point in this embodiment. It is a figure which shows the relationship between the operating point and the charge power to a battery under the same conditions as the example shown in FIG. It is a figure for demonstrating how the electrolytic solution is biased according to the inclination of a battery. It is a figure which shows an example of the measurement result of the change rate of the internal resistance of a battery according to the inclination θx, θy of a battery. It is a figure which summarized the measurement result shown in FIG. 7B. It is a flowchart for demonstrating the operation point determination process in this embodiment. It is a flowchart for demonstrating the tilt process (S113) shown in FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

[Embodiment]
<Overall configuration of hybrid vehicle>
FIG. 1 is a diagram schematically showing an overall configuration of a hybrid vehicle according to an embodiment of the present disclosure. With reference to FIG. 1, vehicle 1 is a hybrid vehicle, which includes motor generators 10 and 20, a power splitting device 30, a drive wheel 40, an engine 50, and a power control unit (PCU) 200. A system main relay (SMR), a battery 100, an electronic control unit (ECU) 300, and a navigation device 400 are provided.

The engine 50 is an internal combustion engine that outputs power by converting the combustion energy generated when a mixture of air and fuel is burned into the kinetic energy of movers such as pistons and rotors.

The power splitting device 30 includes, for example, a planetary gear mechanism having three rotation axes of a sun gear, a carrier, and a ring gear (none of which are shown). The power dividing device 30 divides the power output from the engine 50 into a power for driving the motor generator 10 and a power for driving the drive wheels 40.

Each of the motor generators 10 and 20 is an AC rotating electric machine, for example, a three-phase AC synchronous motor in which a permanent magnet is embedded in a rotor.

The motor generator 10 is mainly used as a generator driven by the engine 50 via the power dividing device 30. The electric power generated by the motor generator 10 is supplied to the motor generator 20 or the battery 100 via the PCU 200. The motor generator 10 corresponds to the "rotary electric machine" according to the present disclosure.

The motor generator 20 mainly operates as an electric motor and drives the drive wheels 40. The motor generator 20 is driven by receiving at least one of the electric power from the battery 100 and the electric power generated by the motor generator 10, and the driving force of the motor generator 20 is transmitted to the drive shaft. On the other hand, when the vehicle is braking or the acceleration is reduced on a downhill slope, the motor generator 20 operates as a generator to generate regenerative power generation. The electric power generated by the motor generator 20 is supplied to the battery 100 via the PCU 200.

The PCU 200 executes bidirectional power conversion between the battery 100 and the motor generators 10 and 20 according to the control signal from the ECU 300. The PCU 200 is configured so that the states of the motor generators 10 and 20 can be controlled separately. For example, the motor generator 20 can be put into a power running state while the motor generator 10 is in a regenerative state (power generation state). The PCU 200 includes, for example, two inverters provided corresponding to the motor generators 10 and 20 and a converter (neither shown) that boosts the DC voltage supplied to each inverter to a voltage higher than the output voltage of the battery 100. Consists of. The PCU 200 corresponds to the "power conversion device" according to the present disclosure.

The SMR 150 is electrically connected between the battery 100 and the PCU 200. The SMR 150 is opened / closed in response to a control signal from the ECU 300. As a result, the continuity and disconnection between the battery 100 and the PCU 200 are switched.

The battery 100 includes a plurality of cells 110 (see FIG. 2), each of which is a lithium ion secondary battery. The battery 100 stores electric power for driving the motor generators 10 and 20, and supplies electric power to the motor generators 10 and 20 through the PCU 50. Further, the battery 100 is charged by receiving the generated power through the PCU 200 when the motor generators 10 and 20 generate power.

The battery 100 is provided with a voltage sensor 102, a current sensor 104, and a temperature sensor 106. The voltage sensor 102 detects the voltage VB of a plurality of cells connected in parallel in the battery 100. The current sensor 104 detects the current IB input / output to / from the battery 100. The temperature sensor 106 detects the temperature TB for each cell. Each sensor outputs the detection result to the ECU 300. A plurality of temperature sensors 106 (a number smaller than the number of cells) may be provided for the battery 100, and the temperature may be detected using a plurality of (for example, several) adjacent cells as monitoring units.

The battery 100 is further provided with a gyro sensor 108. For example, when the vehicle 1 is traveling on a slope or when the vehicle 1 is stopped on a slope, the vehicle 1 may be tilted. The gyro sensor 108 detects the inclination θ of the battery 100 from the horizontal direction. More specifically, the gyro sensor 108 has an inclination θx in the short side direction (x-axis direction) of the cell 110 (described later) with respect to the horizontal direction, and an inclination θy in the long side direction (y-axis direction) of the cell 110 with respect to the horizontal direction. Detect both. The gyro sensor 108 outputs the detection result to the ECU 300. The location where the gyro sensor 108 is installed is not limited to the battery 100, and may be installed at another location of the vehicle 1 (for example, a hill start assist system (not shown)). The gyro sensor 108 corresponds to the "detection device" according to the present disclosure.

The navigation device 400 includes a GPS (Global Positioning System) receiver (not shown) for identifying the position of the vehicle 1 based on radio waves from an artificial satellite (not shown). The navigation device 400 executes various navigation processes of the vehicle 1 by using the position information (GPS information) of the vehicle 1 specified by the GPS receiver. More specifically, the navigation device 400 superimposes the current position of the vehicle 1 on the road map around the vehicle 1 based on the GPS information of the vehicle 1 and the road map data stored in the memory (not shown). It is also displayed on the navigation screen (not shown). In addition, the navigation device 400 uses GPS information to guide a recommended route from the current value of the vehicle 1 to the destination.

The ECU 300 includes a CPU (Central Processing Unit) 302, a memory (more specifically, a ROM (Read Only Memory) and a RAM (Random Access Memory)) 304, and an input / output port (shown) for inputting / outputting various signals. ) And is included. The ECU 300 controls the engine 50 and the PCU 200 based on the signals received from each sensor and the programs and maps stored in the memory 304. As a result, the charging / discharging of the battery 100 is controlled.

FIG. 2 is a diagram showing the configuration of the battery 100 in more detail. FIG. 3 is a diagram for explaining the configuration of each cell 110 in more detail. In addition, in FIG. 2 and FIG. 3, it is assumed that the vehicle 1 is in a horizontal state (a state of traveling on a flat ground or being parked).

With reference to FIG. 2, the battery 100 includes a plurality of cells 110, a pair of end plates 120, a restraint band 130, and a plurality of bus bars 140. In FIG. 2, one end of the stacking direction (x-axis direction) of the laminated body formed by stacking the plurality of cells 110 is partially shown. A pair of end plates 120 are arranged so as to face one end of the laminated body and the other end in the stacking direction. The pair of end plates 120 are restrained by the restraint band 130 with all the cells 110 sandwiched therein. Each cell 110 has a positive electrode terminal 113 and a negative electrode terminal 114 (see FIG. 3). The positive electrode terminal 113 of a certain cell and the negative electrode terminal 114 of an adjacent cell are fastened by a bus bar 140 and electrically connected to each other. As a result, a plurality of cells 110 are connected in series.

With reference to FIG. 3, in FIG. 3, the cell 110 is shown through the interior. The cell 110 has a battery case 111 having a substantially rectangular parallelepiped shape. The short side direction (thickness direction) of the battery case 111 is the x-axis direction, the long side direction (length direction) is the y-axis direction, and the height direction is the z-axis direction. The vertical direction is the negative z-axis direction, and the horizontal direction is the xy plane direction.

The upper surface of the battery case 111 is sealed by the lid 112. One end of each of the positive electrode terminal 113 and the negative electrode terminal 114 projects outward from the lid 112. The other ends of the positive electrode terminal 113 and the negative electrode terminal 114 are connected to the internal positive electrode terminal and the internal negative electrode terminal (neither of them is shown) inside the battery case 111, respectively. The electrode body 115 is housed inside the battery case 111. The electrode body 115 is formed by laminating a positive electrode 116 and a negative electrode 117 via a separator 118 and winding the laminated body. The electrolytic solution is held in the positive electrode 116, the negative electrode 117, the separator 118, and the like.

For the positive electrode 116, the negative electrode 117, the separator 118, and the electrolytic solution, conventionally known configurations and materials as the positive electrode, the negative electrode, the separator, and the electrolytic solution of the lithium ion secondary battery can be used, respectively. As an example, the electrolytic solution is an organic solvent (for example, a mixed solvent of DMC (dimethyl carbonate), EMC (ethyl methyl carbonate) and EC (ethylene carbonate)), a lithium salt (for example, LiPF ₆ ), and an additive (for example, LiBOB). (Lithium bis (oxalate) borate) or Li [PF ₂ (C ₂ O ₄ ) ₂ ]).

<Determination of operating points for engine and motor generator>
In the vehicle 1 configured as described above, the operating state of the engine 50 and the motor generator 10 is determined so that the fuel consumption (= mileage of the vehicle 1 / fuel consumption by the engine 50) is optimized. Hereinafter, the operating state of the engine 50 and the motor generator 10 will be referred to as an "operating point", and a method for determining the operating point will be described with reference to FIGS. 4 and 5 (note that the details of FIGS. 4 and 5 are patented. Reference 1).

FIG. 4 is a diagram for explaining a method for determining an operating point in the present embodiment. In FIG. 4, the horizontal axis indicates the rotation speed of the engine 50 (engine rotation speed). The vertical axis shows the output torque (engine torque) from the engine 50.

In FIG. 4, “contour lines” with equal fuel consumption are shown by thin solid lines. Further, when the same engine output is obtained, the "optimal fuel consumption line" that minimizes the fuel consumption in consideration of the efficiency of the engine 50 and the motor generator 10 is shown by a thick solid line. The driving point is determined on the optimum fuel consumption line. In FIG. 4, six operating points A, N, B to E are illustrated on the optimum fuel consumption line.

At the driving point A, the vehicle 1 is driven by the motor generator 20 as much as possible (for example, the maximum power that can be discharged from the battery 100 is supplied to the motor generator 20 to drive the vehicle 1), and the shortage of the driving force is reduced from the engine 50. This is the operating point when the output of is covered.

The amount of fuel supplied to the engine 50 increases from the operating point A to the operating point E via the operating point N, and the discharge power from the battery 100 decreases accordingly, while the charging power to the battery 100 increases. Become. At the operating point N, the charging / discharging power (charging power and discharging power) of the battery 100 becomes 0. Then, the charging power to the battery 100 increases in the order of BCDE. The operating point E is an operating point when the vehicle 1 is driven by the engine 50 and the motor generator 10 is generated by the engine 50 by using the subordinate power in order to increase the charging power to the battery 100 as much as possible. ..

On the optimum fuel consumption line, the operating point is determined based on "fuel utilization efficiency E" indicating the fuel utilization efficiency by the engine 50 when the battery 100 is charged. The fuel utilization efficiency E can be determined, for example, as follows. That is, first, when the user operates the navigation device 400 to input the destination of the vehicle 1, the target value (target SOC) of the SOC of the battery 100 at that destination is set (calculated). The target value of the SOC may be a predetermined fixed value, or may be a variable value determined according to the destination, for example.

For example, if the operating point is determined so that the battery 100 is charged only when the fuel utilization efficiency E is relatively high, the charging opportunity of the battery 100 is reduced, so that the actual SOC at the destination is relatively low. On the contrary, if the operating point is determined so that the battery 100 is charged even if the fuel utilization efficiency E is low to some extent, the actual SOC at the destination becomes relatively high as the charging opportunity of the battery 100 increases. Therefore, a tentative value is set for the fuel utilization efficiency E, a change in SOC in the traveling route to the destination is predicted, and the predicted value of SOC at the destination is compared with the target value of SOC. If the predicted value of SOC at the destination is higher than the target value, the fuel utilization efficiency E is reduced from the previous value and the predicted value of SOC is recalculated. On the other hand, when the predicted value of SOC at the destination is higher than the target value, the fuel utilization efficiency E is increased from the previous value and the predicted value of SOC is recalculated. Then, the calculation of the fuel utilization efficiency E is repeated until the predicted value of SOC at the destination matches the target value (until the difference between the two becomes smaller than the predetermined value). The fuel utilization efficiency E when the predicted value of SOC matches the target value is adopted (see Patent Document 1 for details). Using the fuel utilization efficiency E calculated in this way, the operating point is determined as follows.

FIG. 5 is a diagram showing the relationship between the operating point and the charging power to the battery 100 under the same conditions as the example shown in FIG. In FIG. 5, the horizontal axis represents an increase amount (fuel increase amount) Δfuel of the fuel supply amount based on the fuel supply amount at the operating point A.

The vertical axis of the lower figure of FIG. 5 shows the increase amount (power difference) Δbat of the charging power to the battery 100 or the charging power to the battery 100 based on the discharging power from the battery 100 at the operating point A. Further, the curve L1 shows the relationship between the fuel increase amount Δfeel and the charging power to the battery 100.

The vertical axis of the upper figure of FIG. 5 shows the fuel utilization efficiency E, which is the ratio (= Δfeel / Δbat ) of the fuel increase amount Δfeel and the charge power increase amount Δbat. Further, the curve L2 shows the relationship between the fuel increase amount Δfuel and the fuel utilization efficiency E on the curve L1. The curves L1 and L2 can be obtained by experiments in advance for each combination condition of the vehicle speed V and the driving force.

First, the fuel utilization efficiency E is calculated by repeating the recalculation as described above. Then, the operating point is determined from the calculated fuel utilization efficiency E. In the example shown in FIG. 5, for example, when a certain fuel utilization efficiency E is obtained as B'on the curve L2, B, which is a point on the curve L1 corresponding to B', is determined as an operating point. .. Similarly, when the fuel utilization efficiency E is determined to be C'on the curve L2, C, which is a point on the curve L1 corresponding to C', is determined as the operating point. The same applies to the other fuel utilization efficiency E.

By determining the operating point by such a method, the engine 50 is driven in a state of high fuel consumption (driving on the optimum fuel consumption line), and the charging power to the battery 100 according to the fuel utilization efficiency E is determined. be able to.

<Battery tilt>
Here, when the vehicle 1 is traveling on a slope or parked on a slope, the battery 100 is tilted θx and θy. As described above, the inclination θx indicates the inclination of the cell 110 in the short side direction (x-axis direction) with respect to the horizontal direction, and the inclination θy is the inclination of the cell 110 in the long side direction (y-axis direction) with respect to the horizontal direction. Is shown . Depending on the inclinations θx and θy, the electrolytic solution inside the electrode body 115 may be biased, or the bias once generated may be alleviated.

FIG. 6 is a diagram for explaining how the electrolytic solution is biased according to the inclination of the battery 100. 6 and 7, which will be described later, schematically show a case where one of the plurality of cells 110 constituting the battery 100 is installed horizontally and a case where the inclination θy occurs.

When the battery 100 is installed horizontally as shown in FIG. 6A, the electrolytic solution flows evenly on the left side and the right side of the electrode body 115 (shown by the broken line).

On the other hand, when the battery 100 is tilted by θy as shown in FIG. 6B, the outflow amount of the electrolytic solution on the left side in the figure of the electrode body 115 is the outflow amount of the electrolytic solution on the right side in the figure. Can be larger than. Further, on the left side of the electrode body 115 in the drawing, the inflow of the electrolytic solution into the electrode body 115 may be less likely to occur than on the right side in the drawing. As a result, when the battery 100 is tilted, it becomes difficult to alleviate the bias of the lithium salt as compared with the case where the battery 100 is horizontal.

As described above, depending on the inclinations θx and θy of the battery 100, the electrolytic solution tends to stay below the electrode body 115 (in the negative z-axis direction), while the electrolytic solution tends to run short above the electrode body 115. Situations can occur. As a result, the uniform bias of the electrolytic solution is hindered as compared with the state where the battery 100 is installed horizontally. As a result, the relaxation rate of the salt concentration bias caused by the high rate deterioration may be slowed down (the relaxation amount per unit time becomes small).

FIG. 7 is a diagram showing an example of the measurement result of the rate of change of the internal resistance of the battery 100 according to the inclinations θx and θy of the battery 100. The battery 100 was installed in each of the states shown in FIGS. 7 (A) to 7 (f), and the internal resistance of the battery 100 was measured every time a predetermined period elapsed. The measurement result is shown in FIG. 7 (B). In FIG. 7B, the horizontal axis represents the elapsed time from the initial state (for example, the state immediately after manufacturing), and the vertical axis represents the rate of change in the internal resistance of the battery 100 (hereinafter, abbreviated as “resistance change rate”). Is shown. The resistance change rate means the ratio of the internal resistance after the evaluation test to the internal resistance in the initial state.

With reference to FIG. 7A, the state (a) is a state of inclination θx = 0 ° and inclination θy = 90 °. The state (b) is a state in which the slope θx = 0 ° and the slope θy = −90 °. The state (c) is a state in which the inclination θx = 0 ° and the inclination θy = 45 °. The state (d) is a state in which the slope θx = 0 ° and the slope θy = −45 °. The state (e) is a state of inclination θx = θy = 0 °, that is, a state for control measurement. The state (f) is a state in which the slope θx = 90 ° and the slope θy = 0 °. As a method for measuring the internal resistance, various known methods can be adopted.

With reference to FIG. 7B, the resistance change rate of the state (a) and the state (b) is the largest, followed by the resistance change rate of the state (c) and the state (d), and the resistance of the state (f). The rate of change is relatively small. Further, it can be seen that the resistance change rate of the state (e) for the control measurement (the state of the slope θx = θy = 0 °) is the smallest. It can also be seen that the effect of the slope θx is relatively small.

FIG. 8 is a diagram summarizing the measurement results shown in FIG. 7 (B). In FIG. 8, the horizontal axis represents the inclination θy in the long side direction. The slope θx in the short side direction is 0 °. The vertical axis shows the rate of change in resistance after a lapse of a predetermined period (several months) from the initial state, based on the internal resistance in the initial state (e). With reference to FIG. 8, it can be seen that the larger the slope θy in the long side direction, the larger the resistance change rate. Therefore, the case where the slope θy changes will be typically described below. However, the slope θx may be considered in addition to the slope θy.

<Driving point determination process>
FIG. 9 is a flowchart for explaining the operation point determination process in the present embodiment. The process shown in this flowchart is called and executed from the main routine every time a predetermined condition is satisfied or a predetermined cycle elapses. Further, each step (hereinafter abbreviated as "S") included in the flowcharts of FIG. 9 and FIG. 10 described later is basically realized by software processing by the ECU 300, but dedicated hardware manufactured in the ECU 300. It may be realized by (electric circuit).

With reference to FIGS. 1 and 9, in S101, the ECU 300 acquires the current location of the vehicle 1 from the navigation device 400. The ECU 300 also estimates the current SOC of the battery 100. A known method can be used as the SOC estimation method.

In S102, the ECU 300 determines whether or not the destination has been set or changed by the user. The destination setting (change) may include a change in the recommended route due to the vehicle 1 deviating from the conventional recommended route or a change in road conditions. When the destination is set (changed) (YES in S102), the ECU 300 advances the process to S103. On the other hand, when the destination is not set (changed) (NO in S102), the ECU 300 skips the following processes S103 to S107 and proceeds to the process S108.

In S103, the ECU 300 acquires the search result of the recommended route to the destination from the navigation device 400. Further, the ECU 300 virtually divides the recommended route to the destination into n (n is a natural number of 2 or more) sections. Examples of this division method include a method of dividing a point having a characteristic on the route as a division point and a method of dividing the distance to the destination into n equal parts. The ECU 300 acquires the road environment such as the average gradient, the radius of curvature, and the altitude in each section from the navigation device 400. Information on these road environments may be acquired by communication with other vehicles (so-called vehicle-to-vehicle communication).

In S104, the ECU 300 sets (calculates) a target value (target SOC) of SOC at the destination based on the road environment of each section and the like.

In S105, the ECU 300 predicts the vehicle speed V and the driving force command value in each section based on the road environment in each section. For example, the vehicle speed V of each section basically uses the speed limit of the road, but at the intersection where the right or left turn is made, the deceleration due to the right or left turn is taken into consideration, or the acceleration / deceleration according to the curvature of the road. Can be predicted by considering. The driving force command value of each section is, for example, the driving force of the running resistance (air resistance + rolling resistance) according to the vehicle speed V, the driving force of the acceleration / deceleration according to the speed difference from the previous section, and the driving force. It can be predicted from the driving force for acceleration / deceleration according to the road gradient (see Patent Document 1 for details).

In S106, the ECU 300 calculates the fuel utilization efficiency E. Since the calculation method of the fuel utilization efficiency E has been described in detail in FIGS. 4 and 5, the description will not be repeated.

In S107, the ECU 300 predicts the SOC of each section based on the fuel utilization efficiency E calculated in S106, the vehicle speed V in each section predicted in S105, and the driving force command value P *. More specifically, as described above, the battery 100 is charged in each section by obtaining the operating point in each section based on the predicted values of the fuel utilization efficiency E and the vehicle speed V and the predicted value of the driving force command value P *. The discharge power can be calculated. Therefore, the SOC in each section can be predicted by time-integrating the charge / discharge power in each section with the current SOC (value estimated in S101) as the initial value.

In S108, the ECU 300 acquires the current vehicle speed V from a vehicle speed sensor (not shown).

In S109, the ECU 300 calculates the driving force command value P * from the vehicle speed V acquired in S108 and the accelerator opening degree Acc acquired by the accelerator sensor (not shown). More specifically, for example, the driving force command value P * corresponding to the vehicle speed V and the accelerator opening degree Acc can be calculated by referring to a table of driving force command values set in advance.

In S110, the ECU 300 predicts the error between the actual vehicle speed V (measured value) and the predicted value of the vehicle speed V in each section, and the actual driving force command value P * and the driving force command value P * in each section. It is determined whether or not the error from the value is larger than each predetermined value. As a method for calculating these errors, for example, the method described in Patent Document 1 can be used. When the error of at least one of the vehicle speed V and the driving force command value P * is larger than the predetermined value (YES in S110), the ECU 300 returns the process to S105. When both errors are equal to or less than a predetermined value (NO in S110), the ECU 300 advances the process to S111.

In S111, the ECU 300 determines whether or not the error between the current SOC and the predicted SOC is larger than a predetermined value in each section. When the SOC error is larger than the predetermined value (YES in S111), the ECU 300 returns the process to S106. When the prediction error is equal to or less than a predetermined value (NO in S111), the ECU 300 advances the process to S112.

In S112, the ECU 300 determines the operating point based on the fuel utilization efficiency E, the current vehicle speed V, and the driving force command value P *. Since this determination method has been described in detail in FIGS. 4 and 5, the description will not be repeated.

Further, in S113, the ECU 300 executes an "tilt process" for taking into account the tilt of the battery 100.

FIG. 10 is a flowchart for explaining the tilting process (S113) shown in FIG.

With reference to FIGS. 1 and 10, in S201, the ECU 300 acquires the inclination θy of the battery 100 from the gyro sensor 108.

In S202, the ECU 300 determines whether or not the inclination θy acquired in S201 is larger than a predetermined value. The predetermined value is a value at which the influence of the slope θy cannot be ignored, and can be obtained in advance by experiment or simulation. When the slope θy is larger than the predetermined value (YES in S202), the ECU 300 advances the process to S203.

In S203, the ECU 300 calculates the concentration distribution of the lithium salt in the battery 100 by, for example, executing a simulation based on fluid dynamics. Since a known method can be used for this simulation, detailed description will not be repeated (see, for example, Japanese Patent Application Laid-Open No. 2017-168211).

In S204, the ECU 300 reflects the slope θy acquired in S201 in the calculation result of the lithium salt concentration distribution in S203. For example, a correction coefficient corresponding to various slopes θy can be set based on the measurement result as shown in FIG. 8, and the calculation result of the lithium salt concentration distribution can be corrected by using the correction coefficient.

In S205, the ECU 300 limits the charge / discharge power of the battery 100 according to the calculation result (correction result) of the lithium salt concentration distribution in which the influence of the inclination θy is reflected in S204. More specifically, for example, the larger the deviation of the lithium salt concentration distribution, the lower the charging power upper limit value Win, which indicates the control upper limit value of the charging power to the battery 100, is set. This setting can be realized, for example, by preparing in advance as a map the correspondence between the index value indicating the bias of the concentration distribution of the lithium salt and the charging power upper limit value Win.

In S206, the ECU 300 redetermines (corrects) the operating point so that the battery 100 is charged and discharged within the range of the charge / discharge power (particularly the charging power) calculated in S205. More specifically, as an example, when the charging power upper limit value Wint is set lower than the normal time in S205, the operating point is set so that the charging power to the battery 100 does not exceed the charging power upper limit value Win. decide. For example, in the example shown in FIG. 4, the operating point is normally determined on the optimum fuel consumption line between N and E, but it is optimal when the charging power upper limit value Wint is set lower than the normal time. The range of operating points is limited to the range between N and C on the fuel consumption line.

Incidentally, the inclination θy in S202 is the case of less than the predetermined value (NO in S202), the processing of S203 ～S206 is skipped, and returned to the flowchart processing shown in FIG. Further, although not shown, the ECU 300 controls the torque of the engine 50 and the torque of the motor generators 10 and 20 so that the operating point determined in S206 (or S112 in FIG. 9) is realized.

As described above, according to the present embodiment, the engine 50 and the motor generator 10 take into consideration the inclinations θx and θy of the battery 100 (particularly, the lithium salt concentration distribution (bias of lithium salt concentration) caused by θy). Therefore, the operating point (operating state) is corrected. Therefore, the battery 100 can be appropriately protected while improving the fuel efficiency by using the fuel utilization efficiency E.

The embodiments disclosed this time should be considered as exemplary in all respects and not restrictive. The scope of the present disclosure is shown by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 vehicle, 10, 20 motor generator, 30 power divider, 40 drive wheel, 50 engine, 100 battery, 102 voltage sensor, 104 current sensor, 106 temperature sensor, 108 gyro sensor, 110 cell, 111 battery case, 112 lid , 113 positive electrode terminal, 114 negative electrode terminal, 115 electrode body, 116 positive electrode, 117 negative electrode, 118 separator, 120 end plate, 130 restraint band, 140 bus bar, 150 SMR, 200 PCU, 300 ECU, 302 CPU, 304 memory, 400 navigation apparatus.

Claims (1)

An engine that uses fuel to generate power,
A battery containing a lithium ion secondary battery and having a short side direction and a long side direction,
A detection device that detects the inclination of the battery in the long side direction with respect to the horizontal direction, and
A rotary electric machine configured to generate electricity using the power generated by the engine,
A power conversion device that performs power conversion between the battery and the rotary electric machine,
The engine and the power conversion device are configured to be controllable , and the higher the value of the amount of increase in the fuel divided by the amount of increase in the charging power when charging the battery, the larger the charging power to the battery. The engine and the control device for determining the operating state of the rotary electric machine are provided.
When the inclination of the battery in the long side direction with respect to the horizontal direction is larger than a predetermined value, the control device uses the inclination of the battery in the long side direction with respect to the horizontal direction to obtain a lithium salt in the battery. The concentration distribution is calculated, and the larger the deviation of the calculated concentration distribution, the lower the control upper limit of the charging power to the battery is set, and the operation is performed so that the battery is charged within the set charging power range. A hybrid vehicle that determines the state.

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