JP2019169246A - Power storage device for vehicle - Google Patents

Abstract

To provide power storage means for vehicle which prevents firing of the power storage means for a vehicle on the basis of breakdown prediction of the power storage means for vehicle at the time of collision prediction of an EV, and alleviates reduction of subsequent drivable distance.SOLUTION: A power storage device for vehicle including a main circuit part constituted by connecting multiple power storage modules in series for supplying power for driving vehicle, and a discharge circuit part for outputting and discharging power individually from the multiple power storage modules further includes collision prediction means of vehicle, step-up means of the power outputted from the discharge circuit part, and a bypass part for bypassing selected one of the multiple power storage modules and connecting with a main circuit part. When the collision prediction means predicts collision of vehicle, a power storage module where breakdown is predicted is selected out of the multiple power storage modules and the discharge circuit part is made to output that power. The output power is boosted by step-up means and used for charging the power storage modules other than the selected one.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a vehicle power storage device, and more particularly to a vehicle power storage device that supplies electric power for driving an electric vehicle.

  In recent years, there has been an increasing interest in electric vehicles (EVs) that do not emit carbon dioxide or the like during travel. The EV includes a power storage device that stores electric power, and travels by driving driving wheels by rotating an electric motor with electric power for driving a vehicle supplied from the power storage device. In addition, the electric power of the power storage device activates electrical components such as a braking device, a steering device, a headlamp, and an air conditioner.

  The power storage device mounted on the EV has a large capacity so that the distance (cruising distance) that can be traveled with the electric power stored to the maximum is increased. Charging for storing electric power in the power storage device is performed mainly by supplying electric power from a commercial power source or the like when parking, and charging is performed by converting EV kinetic energy into electric energy by a regenerative brake during traveling.

  By the way, when the electric storage device of the vehicle is damaged due to the collision of the EV, the electrode plate is short-circuited inside the storage battery constituting the electric storage device and heat is generated by a short-circuit current, and the combustible electrolyte may ignite. In order to avoid this danger, as in Patent Document 1, when a collision is detected, the electric power of some of the storage batteries constituting the power storage device is discharged safely at the discharge unit so as not to ignite. Technology is known.

Special table 2015-518702 gazette

  However, since the power storage device mounted on the EV has a large capacity and takes a certain amount of time even when some of the storage batteries are discharged, there is a possibility that even if the discharge is started after a collision, it may ignite in time. Moreover, there is a possibility that the battery cannot be discharged safely due to disconnection in the power storage device due to a collision. Therefore, it is conceivable that when a collision is predicted, the power storage device is discharged before the collision. Since the discharged electric power is consumed as heat at this time, even if a minor collision or collision is avoided and the vehicle can run on its own, almost no electric power remains in the power storage device, and the travelable distance is almost Decreasing to zero and unable to run.

  An object of the present invention is to prevent a power storage device from igniting based on a prediction of a failure of the power storage device when an EV collision is predicted, and to reduce a decrease in the distance that can be traveled thereafter. Is to provide.

  According to the first aspect of the present invention, a main circuit unit configured by connecting a plurality of power storage modules in series to supply power for driving the vehicle, and the power output individually from the plurality of power storage modules are discharged. In a power storage device for a vehicle having a discharge circuit section for the purpose, a collision prediction means for predicting a collision of a vehicle, a boosting means for boosting the power output to the discharge circuit section, and the plurality of power storage modules A bypass path for bypassing the selected power storage module and connecting to the main circuit unit, and when the collision prediction means predicts a vehicle collision, damage among the plurality of power storage modules is predicted. The power storage module is selected and power is output to the discharge circuit unit, and the power is boosted by the boosting means to store the power storage modules other than the selected power storage module. It is characterized by charging a.

  According to the above configuration, when an EV collision is predicted, a power storage module that is predicted to be damaged by the collision is selected, the power is output to the discharge circuit unit, and the output power is boosted by the boosting means to predict the damage. The other power storage modules that are not used are charged. Therefore, the power of the selected power storage module can be reduced to prevent the vehicle power storage device from firing. In addition to the power stored in other non-selected power storage modules due to minor collisions or when collisions are avoided and the vehicle can run, it moves from the power storage module selected by charging to another power storage module. Since the generated electric power can also be supplied as driving electric power, it is possible to reduce the decrease in the distance that can be traveled.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, when the power storage modules other than the selected power storage module cannot be charged, the discharge circuit section is discharged.
According to the above configuration, when the other non-selected power storage module cannot be charged due to the full charge state, the power of the selected power storage module is discharged by the discharge circuit unit. Can be prevented. In addition, since the amount of discharge converted into heat can be reduced by charging, damage caused by overheating of the discharge circuit portion can be avoided even when collision prediction and collision avoidance are repeated.

According to a third aspect of the present invention, in the first or second aspect of the invention, the main circuit unit and the bypass path bypass the selected power storage module and connect power storage modules other than the selected power storage module in series. And supplying electric power for driving the vehicle.
According to the above configuration, it is possible to supply vehicle driving power from other power storage modules other than the selected power storage module by separating the selected power storage module from the main circuit unit.

  According to the vehicle power storage device of the present invention, when an EV collision is predicted, the vehicle power storage device is prevented from igniting based on the prediction of the damage of the vehicle power storage device, and the reduction in the distance that can be traveled thereafter is reduced. can do.

It is a block diagram explaining the structure of the EV vehicle by embodiment of this invention. It is a principal part disassembled perspective view of the electrical storage apparatus by embodiment of this invention. It is a circuit diagram which shows one example of the electric power supply by embodiment of this invention. It is a principal part disassembled perspective view of the electrical storage part by embodiment of this invention. It is a circuit diagram which shows one example of charge by embodiment of this invention. It is a circuit diagram which shows one example of the discharge by embodiment of this invention. It is a flowchart of the ignition prevention control by embodiment of this invention.

Hereinafter, a power storage device for a vehicle according to an embodiment of the present invention will be described. First, the overall configuration of the EV will be described with reference to FIG.
The EV includes an electric motor 2 for driving the vehicle, a braking device 3, a vehicle speed sensor 4, a vehicle-mounted camera 5, various sensors including a millimeter wave radar 6 and the like, a DCDC converter 7 that adjusts the voltage of DC power supplied to these, and the like. A power storage device 10 that stores the vehicle driving power supplied to the vehicle side load 1 and a control unit (ECU 8) that controls the vehicle side load 1 and the power storage device 10 is mounted as the side load 1.

  The ECU 8 is constituted by a computer having a CPU, a memory for storing various programs, an input / output device, and the like. The ECU 8 processes signals periodically output from various sensors and outputs control signals for appropriately operating the electric motor 2, the braking device 3, the power storage device 10, and the like. The state of charge (SOC) of the power storage device 10 is managed by the ECU 8 to notify the driver of the current SOC, the travelable distance, and the like.

  The vehicle speed sensor 4 outputs the detected traveling speed data of the own vehicle to the ECU 8. The in-vehicle camera 5 outputs image data obtained by imaging the surroundings of the host vehicle to the ECU 8. Based on this image data, the ECU 8 specifies an object such as a vehicle, a pedestrian, or other object.

  The millimeter wave radar 6 detects the distance from the host vehicle to the target object and the relative speed between the host vehicle and the target object by receiving a reflected wave reflected from the target object by emitting a radio wave around the host vehicle. To the ECU 8. In addition, instead of the millimeter wave radar 6, a radar using laser light or ultrasonic waves may be used, or a combination of these may be used to detect the distance and relative speed to the object. You may comprise so that the distance and relative speed to the other vehicle which is a target object may be detected.

Next, the power storage device 10 will be described.
As shown in FIG. 2, the power storage device 10 has a support member 11 and a cover member 12 so as to ensure vibration resistance (rigidity) and water resistance (waterproofness) for disposing in the space below the floor panel of the EV vehicle. Is enclosed in a sealed manner. Then, heat generated from the power storage device 10 is transferred to the support member 11 using heat conduction or the like, and radiated from the support member 11 to the outside of the vehicle using running wind or the like. In the figure, an arrow U indicates upward, an arrow F indicates the front of the vehicle, and an arrow L indicates the left side of the vehicle.

  As shown in FIGS. 2 and 3, the power storage device 10 includes a plurality of power storage modules M1 to Mn connected in series by a plurality of bus bars 13 to supply electric power for driving an EV. Unit 20 and a discharge circuit unit 30 for individually outputting power from the plurality of power storage modules M1 to Mn. Note that the number of power storage modules mounted on the EV is appropriately set according to the specification of the EV.

The plurality of power storage modules M1 to Mn have the same configuration. Hereinafter, the power storage module M1 will be described, and description of the other power storage modules M2 to Mn will be omitted.
The power storage module M1 includes a power storage unit 21 that stores power, a bypass path 22 for bypassing the power storage unit 21, a first changeover switch 23, a second changeover switch 24, a cooling unit 25, a cooling switch 26, A first discharge changeover switch 27 and a second discharge changeover switch 28 are provided.

  The first changeover switch 23 is disposed on the negative electrode side of the power storage unit 21 and switches the connection with the main circuit unit 20 to the power storage unit 21 or the bypass path 22. By switching the first changeover switch 23 to the bypass path 22, the power storage module M <b> 1 is bypassed and connected to the main circuit unit 20 so as to supply electric power for driving the vehicle from other power storage modules. The second changeover switch 24 is disposed on the positive electrode side of the power storage unit 21 in order to disconnect the power storage unit 21 from the main circuit unit 20. The first discharge changeover switch 27 is disposed on the negative electrode side of the power storage unit 21, and the second discharge changeover switch 28 is disposed on the positive electrode side of the power storage unit 21, and switches the power storage module M <b> 1 to or from the discharge circuit unit 30.

  For example, as shown in FIG. 4, the power storage unit 21 includes a plurality of (for example, twelve) storage batteries 21a having a standard voltage and having a positive electrode terminal and a negative electrode terminal disposed on the upper surface, and a separator 21b. Are arranged in a horizontal direction so as to form a rectangular parallelepiped shape, and are configured by connecting, for example, six batteries in which two storage batteries 21a are connected in parallel by a plurality of bus bars 21c. 21d and a negative electrode terminal 21e are provided. The bypass 22 is disposed on the positive terminal 21d and the negative terminal 21e via a first changeover switch 23 and a second changeover switch 24, respectively.

  A pair of end plates 21f arranged at both ends in the alignment direction, a pair of aluminum alloy binding bars 21g connecting the pair of end plates 21f, and a synthetic resin covering the upper side of the power storage unit 21 The upper plate 21h covers and integrates the power storage unit 21 including the temperature sensor harness 21i and the bypass path 22 arranged to detect the temperature at a predetermined location of the power storage unit 21. The upper plate 21h is fixed in a state where it is placed on the upper ends of the pair of end plates 21f and the pair of bind bars 21g by a plurality of clamp members (not shown), for example. The bypass path 22 may be disposed on the upper side of the upper plate 21h.

  The upper plate 21h is provided with a notch through which the positive electrode terminal 21d and the negative electrode terminal 21e are exposed and the temperature sensor harness 21i is inserted at positions corresponding to the positive electrode terminal 21d and the negative electrode terminal 21e. A heater unit 21j having a sheet-like heating device is attached in close contact with one of the pair of bind bars 21g, and warms the power storage unit 21 to a predetermined temperature range at a low temperature.

  The integrated power storage unit 21 is fastened and fixed to the support member 11 by, for example, a fastening member. The power storage unit 21 is in close contact with a metal (for example, aluminum alloy) plate-like support member 11 having excellent thermal conductivity through a cooling unit 25 that is in close contact with the lower surfaces of all the storage batteries 21a.

  The storage battery 21a is, for example, a lithium ion secondary battery that is a kind of secondary battery, and generates heat during charging / discharging, so that it is cooled by the cooling unit 25 so that it can be charged / discharged at a predetermined safe temperature (for example, 60 ° C.) or lower.

  The cooling unit 25 is a Peltier element cooling unit provided with a heat absorbing part and a heat radiating part. Heat is transferred to the support member 11 to which the heat dissipating part is in close contact. As shown in FIG. 3, switching between operation and stop of the cooling unit 25 is performed by a cooling switch 26 that switches connection or disconnection with the power storage unit 21.

  As shown in FIGS. 2 and 3, the discharge circuit unit 30 includes a discharge resistor 31 for consuming the power output to the discharge circuit unit 30 and dissipating it as heat. In addition, a discharge / charge changeover switch 32 is disposed in the discharge circuit unit 30 to switch the supply destination of the electric power output to the discharge circuit unit 30 to the discharge resistor 31 and the charging DCDC converter 33 (boosting means). A switch such as the first changeover switch 23 mounted on the power storage device 10 is configured by a mechanical relay or a semiconductor element that can accept a large current of, for example, 100 A or more that flows instantaneously, and the positive terminal 21 d or the negative terminal of the power storage unit 21. It is arranged in the vicinity of 21e. The discharging resistor 31 and the charging DCDC converter 33 may not be covered with the cover member 12 for air cooling.

  The ECU 8 functionally predicts a collision between the own vehicle and an object such as another vehicle or object based on detection data of various sensors such as image data of the in-vehicle camera 5 and measurement data of the millimeter wave radar 6. Predictive means are provided. The ECU 8 and the power storage device 10 constitute a power storage device for a vehicle, and ignition prevention control including a collision determination step, a charging step, and a discharging step is performed.

  FIG. 3 shows an example of the state of power supply of the power storage device 10 during traveling including when the vehicle is stopped such as waiting for a signal. In the collision determination step, the ECU 8 may collide during the traveling based on the image data around the host vehicle, the measurement data such as the distance to the object and the relative speed, the traveling speed data of the host vehicle, and the data of the traveling direction. A certain object is identified, and it is determined whether or not it will collide in the near future (for example, after 10 seconds). If it is determined that there is a collision, the shape, size, and relative speed of the target object are specified based on the same data, the collision site in the host vehicle is predicted, and any power storage is performed by the collision. Determine if the module is damaged.

  For example, as shown in FIG. 5, the charging step selects the power storage modules M1 and M2 in which a collision is predicted and the power storage module is predicted to be damaged due to the collision, and the power of the power storage modules M1 and M2 is not selected. By charging the power storage modules M3 to Mn, the power of the selected power storage modules M1 and M2 is reduced. In some cases, only one power storage module or three or more power storage modules are selected.

  In the discharging step, when the other power storage modules M3 to Mn other than the selected power storage modules M1 and M2 are in a fully charged state, for example, further charging cannot be performed, and power remains in the selected power storage modules M1 and M2. In addition, as shown in FIG. 6, the electric power of the selected power storage modules M1 and M2 is reduced by discharging the electric power by the discharge circuit unit 30.

The ignition prevention control of the above vehicle power storage device will be described based on the flowchart of FIG. Si (i = 1, 2,...) In the figure represents a step.
In S1, collision prediction data such as image data of the in-vehicle camera 5, measurement data of the millimeter wave radar 6, and traveling speed of the host vehicle are acquired.

  In S2, based on the acquired collision prediction data, for example, it is determined whether or not the host vehicle collides with the object after 10 seconds. If the collision is predicted and the determination is Yes, the process proceeds to S3. If the collision is not predicted and the determination is No, the process returns to S1.

  In S3, it is determined whether any power storage module of the vehicle power storage device is damaged due to the predicted collision. If the determination is Yes, the process proceeds to S4, and if the determination is No, the process returns to S1. S1 to S3 so far are the collision determination steps.

  Next, in S4, for example, the power storage modules M1 and M2 are selected as the power storage modules predicted to be damaged, and the power storage unit 21 is disconnected from the main circuit unit 20 by switching the first and second changeover switches 23 and 24, respectively. The bypass path 22 is connected to the main circuit unit 20 so as to bypass the power storage unit 21, and the process proceeds to S5. The power storage modules M3 to Mn other than the selected power storage modules M1 and M2 maintain the state of being connected in series and supply driving power to the vehicle-side load 1 (see FIG. 5). This enables a collision avoidance operation and travel after the charging step or discharging step.

  In S5, the first and second discharge changeover switches 27 and 28 of the power storage modules M1 and M2 are switched so that the selected power storage modules M1 and M2 are connected to the discharge circuit unit 30 and output power, and the process proceeds to S6. Proceed (see FIG. 5).

  In S6, the charge / discharge changeover switch 32 is set so as to charge the power storage modules M3 to Mn other than the selected power storage modules M1 and M2 by boosting the power output from the selected power storage modules M1 and M2 by the DCDC converter 33 for charging. Switch to the charging DCDC converter 33 side and proceed to S7 (see FIG. 5). The boosted electric power can be supplied to the vehicle-side load 1.

  In S7, it is determined whether or not the SOC of the selected power storage modules M1 and M2 is greater than 0%. If the determination is Yes, the process proceeds to S8. If the determination is No, there is no possibility of ignition due to the short-circuit current of the power storage modules M1 and M2 that are predicted to be damaged, so the ignition prevention control is terminated and the process returns.

  In S8, it is determined whether or not the SOCs of the other power storage modules M3 to Mn other than the selected power storage modules M1 and M2 are 100% (fully charged state). If the determination is Yes, the process proceeds to S9, and if the determination is No, the process returns to S7. S4 to S8 so far are charging steps.

  In S9, since the other power storage modules M3 to Mn cannot be charged, the discharging / charging changeover switch 32 is switched to the discharging resistor 31 side to discharge so that the power stored in the selected power storage modules M1 and M2 disappears. The preventive control is terminated (see FIG. 6). This S9 is a discharge step. Note that the first and second discharge changeover switches 27 and 28 and the cooling switch 26 may be disconnected when the selected power storage module has been discharged.

Next, functions and effects of the present invention will be described.
The own vehicle that is an EV periodically performs a prediction of a collision with an object during traveling, that is, the collision determination step. When a collision of the host vehicle is predicted, the storage module constituting the vehicle storage device is determined to be damaged, and when the damage is predicted, the storage module predicted to be damaged is selected.

  Since the selected power storage module may be damaged by a collision and ignite, the power stored in the selected power storage module is reduced to prevent this ignition. At this time, in order to transfer the power of the selected power storage module to another power storage module that is not predicted to be damaged, charging of the other power storage module with the power of the selected power storage module, that is, the above charging step is executed. Further, when the power of the selected power storage module remains even when another power storage module is fully charged by the charging step, the power is discharged by the discharging step.

  Therefore, it can prevent that the selected electrical storage module is ignited by the short circuit current by collision. In addition, the selected power storage module can be disconnected from the main circuit unit 20 and power for driving the vehicle can be supplied from the other power storage module, and the power moved from the selected power storage module to the other power storage module can also be used as the power for driving the vehicle. Since the collision can be avoided or when the collision is mild and the host vehicle can subsequently travel, the decrease in the distance that can be traveled can be reduced. In addition, since the electric power converted into heat can be reduced by charging other power storage modules, even when the collision prediction and collision avoidance are repeated, the discharge resistor 31 in the discharge circuit unit 30 is damaged due to overheating. Can be avoided.

  In addition, those skilled in the art can implement the present invention by adding various modifications to the above embodiment without departing from the spirit of the present invention, and the present invention includes such modifications.

1: Vehicle power storage device 4: Vehicle speed sensor 5: In-vehicle camera 6: Millimeter wave radar 8: ECU
DESCRIPTION OF SYMBOLS 10: Vehicle side load 11: Support member 20: Main circuit part 21: Power storage part 21a: Storage battery 22: Bypass path 23: 1st changeover switch 24: 2nd changeover switch 25: Cooling unit 26: Cooling switch 27: 1st discharge Changeover switch 28: Second discharge changeover switch 30: Discharge circuit unit 31: Discharge resistor 32: Discharge charge changeover switch 33: Charge DCDC converter M1-Mn: Power storage module

Claims (3)

A main circuit unit configured by connecting a plurality of power storage modules in series to supply power for driving the vehicle, and a discharge circuit unit for discharging the power output individually from the plurality of power storage modules In the vehicle power storage device,
Collision prediction means for predicting a collision of a vehicle, boosting means for boosting the electric power output to the discharge circuit section, and bypassing the selected power storage module among the plurality of power storage modules to the main circuit section It further includes a bypass for connecting,
When the collision predicting unit predicts a vehicle collision, the power storage module that is predicted to be damaged among the plurality of power storage modules is selected and power is output to the discharge circuit unit. The vehicle power storage device is characterized in that the power storage module other than the selected power storage module is charged by boosting the power storage device.   The power storage device for a vehicle according to claim 1, wherein when the power storage module other than the selected power storage module cannot be charged, the discharge circuit unit is discharged.   The main circuit unit and the bypass path bypass the selected power storage module, and supply power for driving the vehicle by connecting power storage modules other than the selected power storage module in series. Item 3. The vehicle power storage device according to Item 1 or 2.