Electrical storage device for a vehicle

Abstract

An electrical storage device for a vehicle, comprising a battery (3) installed in a vehicle and transferring electric power to and from a device (12) of the vehicle, a load (4) for discharging the battery (3), a control device (5) for controlling the discharging of the battery (3) via the load (4), and a power source electric power supply means for supplying power source electric power to the control device (5), wherein - the control device (5) comprises a state of charge detecting means for detecting a state of charge of the battery (3), a discharging means for discharging the battery (3) via the load (4), and a discharging stopping means for stopping the discharging of the battery (3) by the discharging means before the battery (3) is overdischarged, based on the state of charge of the battery detected by the state of charge detecting means; and - the power source electric power supply means comprises a plurality of power source electric power supply paths, each of which includes a power supply (11, 3) and a power supply line connecting the power supply (11, 3) to the control device (5), so that if an abnormality occurs in one of the paths for supplying power source electric power to the control device (5), power source electric power can be supplied to the control device (5) through another of the paths; - the power source electric power supply means includes a plurality of power supplies (11, 3); and - the plurality of power supplies (11, 3) includes a main power supply (11), an auxiliary power supply (3), and a power source switching device (6) for switching the power supply for supplying power source electric power to the control device (5) from the main power supply (11) to the auxiliary power supply (3) if an abnormality is detected in the main power supply (11). characterized in that - the auxiliary power supply (3) is the battery (3).

Description

Technical FieldThis invention relates to an electric storage device to be mounted on a vehicle, and more particularly to an electric storage device for a vehicle having a plurality of power source electric power supply paths for a control device that controls discharge of a battery.Prior ArtConventionally, vehicles have a battery for temporarily storing electric power generated from an electric generator connected to an internal combustion engine via a belt or the like. Thereby, it is possible to supply electric power necessary for the electric device in the vehicle even when the internal combustion engine does not rotate and the power generator cannot generate electric power.In addition, in recent years, vehicles have been developed in which a plurality of batteries are installed to charge the batteries by efficiently converting the energy of the vehicle into electric energy during deceleration. There is a case where the plurality of batteries include a battery for efficiently storing the electric energy of the vehicle and a battery for use in, for example, starting the vehicle.In an electric storage device for a vehicle equipped with such batteries as described above, the wiring line in or around the batteries are normally insulated so that a user, service persons, and so on cannot directly contact them. However, when the vehicle experiences a collision, the insulated portion may be damaged and there is a possibility of electric shock.In view of this, for example, JP 3 858 797 B2 provides a control device of a vehicle including an engine starting device supplied with electric power from a battery, wherein when a vehicle collision is predicted, an electric power supply to the battery is stopped and the battery is forcibly discharged to a minimum voltage necessary to start the engine by the engine starting device. Such a configuration enables the engine to be started while taking measures to prevent electric shock.Citation ListPatent LiteratureDE 10 2012 109 430 A1 discloses a system and method for discharging a vehicle battery after a vehicle damage event. The method includes determining that the vehicle has become involved in a vehicle damage event and subsequently discharging the cells in the battery to a predetermined cell voltage based on the severity of the vehicle damage event. The battery cells may be discharged with resistors already present in the vehicle battery for cell balancing purposes or discharged with resistors added for the cell discharge purpose. The voltage of the cells is monitored when they are discharged and once a respective cell voltage has reached the target voltage, a switch is opened to disconnect the resistor from the cell.US 2012 / 0 055 727 A1 describes that in the event of a vehicle collision, a control device for an in-vehicle power conversion device is supplied with a power source voltage for its operation using electric energy resulting from residual charges accumulated in smoothing capacitors provided in the power conversion device. With such a configuration, the residual charges accumulated in the smoothing capacitor provided in the power conversion device can be discharged even if a power supply is not provided to the control device from the outside of the power conversion device due to disconnection of a line.JP 2013-99 002 A discloses a vehicle power supply device including a battery for driving operation, wherein a plurality of batteries are connected to each other, and further a battery switch for connecting the battery for driving operation to a vehicle-mounted load, a control circuit for controlling the battery switch, and an electric equipment battery for supplying the operating current to a power supply line of the control circuit. The vehicle power supply device includes a temporary power supply circuit that supplies the operation power to the power supply line of the control circuit from the batteries for travel in a voltage drop state in which the supply voltage of the battery for electrical equipment falls, and maintains the control circuit in an operable state. In the voltage drop state of the battery for electric appliances, the temporary power supply circuit supplies the operating current of the power supply line of the control circuit and controls the battery switch by keeping the control circuit in the operable state.JP 2011-259 517 A discloses a converter for a vehicle that discharges residual charges of capacitors provided in the converter quickly, securely, and sufficiently when a collision or similar event occurs. To this end, a discharge regulator is provided that performs discharge control that discharges the residual charges in two capacitors when a collision of a vehicle is detected by a collision detector. An emergency power supply is installed in a case of a converter, and supplies the discharge regulator with operation power if a power supply line that supplies the discharge regulator with the operation power from outside the case has a fault. The backup power supply is connected to a positive electrode line and a negative electrode line, and converts a power received from the positive electrode line into a voltage, and outputs the voltage to the discharge regulator.US 2005 / 0 035 656 A1 discloses a power supply apparatus and a power supply method for a vehicle, wherein a plurality of loads and a plurality of power supplies are connected to each other such that one of the loads is connected to a plurality of the power supplies and one of the plurality of power supplies is connected to a plurality of the loads. In addition, the power supplies and the loads are connected via a breaker unit to electrically disconnect the circuit under predetermined conditions, and a unidirectional conducting unit that allows current to flow in one direction and blocks current to flow in the opposite direction.SUMMARY OF THE INVENTIONTechnical ProblemNevertheless, the control device for a vehicle disclosed in JP 3 858 797 B2 does not consider abnormality of the power supply for supplying a power source electric power to the control device. For this reason, there is a problem that if an abnormality of the power supply to the control device occurs due to a vehicle collision or the like and the control device fails to operate, the discharging of the battery cannot be performed.The invention has been made to solve the above-described problem, and it is an object of the invention to provide an electric storage device for a vehicle that can stably operate a control device and is capable of performing discharging of a battery even when an abnormality of a power supply to the control device for the battery occurs.Solution of the ProblemThe aforementioned object is achieved by an electrical storage device for a vehicle having the features of claim 1.Advantageous Effects of the InventionThe electric storage device for a vehicle according to the invention can supply electric power source power via another path, and can stably operate the control device even when an abnormality occurs in a path supplying electric power source power to the control device. Therefore, it is possible to discharge the battery and stop the discharge before the battery becomes over-discharged.The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a first embodiment of the invention. FIG. 2 is a diagram showing the flow of the process in a control device in an electric storage device for a vehicle according to a first embodiment of the invention. FIG. 3 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a second embodiment of the invention. FIG. 4 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a third embodiment of the invention. FIG. 5 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a fourth embodiment of the invention. FIG. 6 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a fifth embodiment of the invention. FIG. 7 is a diagram showing the flow of the process in a control device in the electric storage device for a vehicle according to the fifth embodiment of the invention. FIG. 8 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a sixth embodiment of the invention. FIG. 9 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a seventh embodiment of the invention. FIG. 10 is a diagram showing the flow of the process in a control device in the electric storage device for a vehicle according to the seventh embodiment of the invention. FIG. 11 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to an eighth embodiment of the invention. FIG. 12 is a diagram showing the flow of the process in a control device in the electric storage device for a vehicle according to the eighth embodiment of the invention. FIG. 13 is a diagram showing the flow of the process in a control device in an electric storage device for a vehicle according to a ninth embodiment of the invention. FIG. 14 is a diagram showing an electric storage device for a vehicle according to a tenth embodiment of the invention. FIG. 15 is a diagram showing the flow of the process in a control device in an electric storage device for a vehicle according to the tenth embodiment of the invention. FIG. 16 is a diagram showing the flow of the process in a control device in an electric storage device for a vehicle according to an eleventh embodiment of the invention. FIG. 17 is a diagram showing the configuration of a power supply system of an internal combustion engine that includes an electric storage device for a vehicle according to a twelfth embodiment of the invention. FIG. 18 is a diagram showing the configuration of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a thirteenth embodiment of the invention.DESCRIPTION OF EMBODIMENTSFirst EmbodimentHereinafter, an electric storage device for a vehicle (an electric storage device for a vehicle) according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a power supply system of an internal combustion engine including the electric storage device for a vehicle according to the first embodiment. Note that in the drawings described below, the same or corresponding components are denoted by the same reference numerals.An internal combustion engine 1 of a vehicle (not shown) is connected to an electric generator 2 via a belt or the like. A battery 3 constituting the electric storage device for a vehicle (vehicle electric storage device), a load 4 for discharging, a control device 5 for the battery 3 and an auxiliary power supply 7 therefor, and a power supply switching device 6 for changing the power supply for the control device 5 are accommodated in a case 8. Note that an auxiliary battery 11 which is the main power supply for the control device 5 is disposed outside the housing 8.The load 4 for discharging the battery 3 is connected in parallel to the battery 3. The control device 5 for the battery 3 controls discharge caused by the load 4 and stops the discharge. The battery 3 is connected to the power generator 2 and also connected to an electric device 12 of the vehicle via a voltage conversion device 10, and transfers electric power therebetween.Thus, when the engine 1 rotates, the power generator 2 also rotates so that the electric power generated by the power generator 2 is charged into the battery 3 or the auxiliary battery 11, and the voltage thereof is converted by the voltage conversion device 10 so as to be consumed by the electric device 12.In FIG. 1, the voltage conversion device 10 is provided because the voltage of the battery 3 and that of the auxiliary battery 11 are assumed to be different, but when the voltage of the battery 3 and that of the auxiliary battery 11 are substantially the same potential, it may be replaced with a switch or the like. A starting device 13 for starting the engine 1 is supplied with electric power for driving from the auxiliary battery 11.The control device 5 includes a state-of-charge detection means for detecting the state of charge of the battery 3, a discharge means for discharging the battery 3 via the load 4, a discharge stop means for stopping the discharge of the battery 3 caused by the discharge means before the battery 3 is over-discharged based on the state of charge of the battery 3 detected by the state-of-charge detection means, and a power supply abnormality detection means for detecting an abnormality (abnormality) of the power supply for supplying power source electric power to the control device 5 (all not shown in the figure).The state-of-charge detection means calculates a state-of-charge value of the battery 3 based on the voltage, the charge and discharge current, and so on of the battery 3. The discharge stop means stops the discharge of the battery 3 caused by the discharge means if the state-of-charge value of the battery 3 calculated by the state-of-charge detection means is equal to or less than a predetermined value at which over-discharge occurs.When the battery 3 is over-discharged, deterioration is generally accelerated. In addition, when the over-discharged battery 3 is discharged, a short circuit occurs inside the battery 3, and there is a possibility of causing ignition or smoke emission. For this reason, the over-discharged battery 3 cannot be reused even if it has no damage resulting from an impact at the time of a vehicle collision.The battery 3 in the electric storage device for a vehicle according to the first embodiment is, for example, a lithium ion battery. The auxiliary battery 11 may be a lithium ion battery or may be another type of battery. The lithium ion battery is a secondary battery in which the positive electrode and the negative electrode located in an electrolyte solution are insulated from each other by a separator, and lithium ions are transferred back and forth between the positive and negative electrodes to perform charging and discharging.When the lithium ion battery is over-discharged, the electrolyte solution decomposes and the copper used in the negative electrode is turned into ions that dissolve in the electrolyte solution in the battery. The dissolved copper ions are recrystallized by charging, which may be a cause of an internal short circuit in which the positive electrode and the negative electrode are short-circuited. Therefore, it is desirable to stop discharging before overdischarge occurs.The electric storage device for a vehicle according to the invention is characterized by a plurality of power source electric power supply paths each including a power supply and a power supply line connecting the power supply and the control device to each other in a power source electric power supply means for supplying power source electric power to the control device 5.In the first embodiment, the plurality of power source electric power supply paths are formed by being provided with a plurality of power supplies. Specifically, the auxiliary battery 11 which is the main power supply and the auxiliary power supply 7 are provided as shown in FIG. 1. A power supply line is provided for connecting the control device 5 to each of the power supplies, the auxiliary battery 11, and the auxiliary power supply 7.When the power supply abnormality detection means of the control device 5 detects an abnormality such as a wiring break or a voltage drop in the auxiliary battery 11 which is the main power supply, the power supply abnormality detection means generates a power supply abnormality detection signal 9 and outputs the signal to the power supply switching device 6. The power supply switching device 6 to which the power supply abnormality detection signal 9 has been input switches the power supply supplying the power source electric power to the control device 5 from the auxiliary battery 11 to the auxiliary power supply 7 to operate the control device 5 by means of the auxiliary power supply 7.Although it has been described that the power supply abnormality detection signal 9 is generated by the control device 5 for the battery 3, the power supply abnormality detection signal 9 may be generated by another control device (not shown). As the power source electric power supply means for operating the control device 5, the auxiliary battery 11 is additionally used as the main power supply in FIG. 1. However, the main power supply of the control device 5 is not limited to the auxiliary battery 11.Next, the process flow of the control device 5 in the electric storage device for a vehicle according to the first embodiment will be described with reference to the flowchart of FIG. 2. The process operation of the control device 5 is periodically performed (e.g., every 10 ms).If an abnormality of the auxiliary battery 11 that is the main power supply of the control device 5 is detected (YES) in step 101 (S 101), the control device 5 first generates the power supply abnormality detection signal 9, and the process proceeds to step 102 (S 102). If no abnormality is detected in the main power supply of the control device 5 in S 101 (NO), the process ends.In S 102, the power supply switching device 6 to which the power supply abnormality detection signal 9 has been input switches the power supply for the control device 5 from the auxiliary battery 11 that is the main power supply to the auxiliary power supply 7. subsequently, the process proceeds to step 103 (S 103), and the discharging means of the control device 5 starts discharging the battery 3 via the load 4.After the discharge is started, the discharge stop means of the control device 5 determines whether or not the state-of-charge value of the battery 3 (calculated based on the voltage, the charge and discharge current, and the like of the battery 3) detected by the state-of-charge detection means is equal to or less than a predetermined value at which over-discharge occurs in step 104 (S 104).If it is determined that the state-of-charge value of the battery 3 is equal to or less than the predetermined value at which over-discharge occurs in step S 104 (YES), the process proceeds to step 105 (S 105), the discharge stopping means stops discharging of the battery 3, and the process is ended. If it is not equal to or less than the predetermined value at which overdischarge occurs in S 104 (NO), the discharging is continued and the determination in step S 104 is repeated.As described above, in the electric storage device for a vehicle according to a first embodiment, the electric power source supply means for supplying electric power source to the control device 5 uses the auxiliary battery 11 as the main power supply, and further includes the auxiliary power supply 7. Therefore, even when an abnormality occurs in the auxiliary battery 11 that is the main power supply, the power supply is switched to the auxiliary power supply 7 to stably operate the control device 5 and perform discharging of the battery 3. Thus, the discharge can be stopped before the battery 3 is over-discharged.Further, when the auxiliary battery 11 which is the main power supply of the control device 5 is not abnormal, the auxiliary power supply 7 is not used, and only when the auxiliary battery 11 becomes abnormal, the auxiliary power supply 7 is used. Thereby, power consumption of the auxiliary power supply 7 can be suppressed. Therefore, since the load 4 for discharging is enclosed in the case 8, it cannot be touched by a person, so that electric shock can be prevented. In addition, since a power supply different from the battery 3 is used as the auxiliary power supply, the control device 5 can be operated even when the voltage of the battery 3 drops by discharging.Second EmbodimentFIG. 3 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a second embodiment of the invention. Similar to the foregoing first embodiment, the electric storage device for a vehicle according to the second embodiment includes a plurality of power supplies as the power source electric power supply means for operating the control device 5.The second embodiment uses the auxiliary battery 11 as the main power supply, similarly to the foregoing first embodiment, but uses the battery 3 as the auxiliary power supply. By using such a configuration, it is unnecessary to provide the auxiliary power supply 7 (see FIG. 1 ). The rest of the configuration is the same as that of the foregoing first embodiment, and therefore, the description thereof is omitted.According to the second embodiment, the need for providing an additional power supply is eliminated by using the existing battery 3 as the auxiliary power supply for the control device 5, and the number of parts can be reduced.Third EmbodimentFIG. 4 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a third embodiment of the invention. Similar to the foregoing first embodiment, the electric storage device for a vehicle according to the third embodiment includes the auxiliary battery 11 that is the main power supply and the auxiliary power supply 7 as the power source electric power supply means for operating the control device 5.In the third embodiment, each of the plurality of power supplies, that is, both the auxiliary battery 11 and the battery 7, is connected to the control device 5 via a reverse current prevention diode 14 that is reverse current prevention means. By using such a configuration, the power supply abnormality detection means can be eliminated. The rest of the configuration is the same as that of the first embodiment, and therefore, the description thereof is omitted.According to the third embodiment, the power supply abnormality detecting means becomes unnecessary in addition to the same advantageous effects as those of the foregoing first embodiment. Further, all of the plurality of power supplies (the auxiliary battery 11 and the auxiliary power supply 7) are different from the battery 3, and the battery 3 is not used as the power supply for the control device 5. Therefore, the power consumption of the battery resulting from the operation of the control device 5 can be prevented.Fourth EmbodimentFIG. 5 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a fourth embodiment of the invention. The electric storage device for a vehicle according to the fourth embodiment uses the auxiliary battery 11 as the main power supply for the control device 5 and the battery 3 as the auxiliary power supply, similarly to the foregoing second embodiment.In addition, each of the auxiliary battery 11 and the battery 3 is connected to the control device 5 via a reverse current prevention diode 14 which is the reverse current prevention means. The rest of the configuration is the same as that in the first embodiment, and therefore, the description thereof is omitted.The fourth embodiment does not need to provide an additional power supply because it uses the existing battery 3 as the auxiliary power supply for the control device 5.Fifth EmbodimentFIG. 6 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a fifth embodiment of the invention. In the electric storage device for a vehicle according to the fifth embodiment, a plurality of power source electric power supply paths are provided by providing a plurality of power supply lines for one power supply (the auxiliary battery 11) as the power source electric power supply means of the control device 5.One of the two power supply lines 15 aand 15 bis a main power supply line and the other is an auxiliary power supply line. In the description, it is assumed that the power supply line 15 ais the main power supply line. A power supply line switching device 16 switches the power supply line for supplying electric power source current to the control device 5 from the main power supply line 15 ato the auxiliary power supply line 15 bin a case where an abnormality in the main power supply line 15 ais detected. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.Next, the process flow of the control device 5 in the electric storage device for a vehicle according to the fifth embodiment will be described with reference to the flowchart of FIG. 7. The process operation of the control device 5 is periodically performed (for example, every 10 ms).If an abnormality in the main power supply line 15 ato the control device 5 is detected (YES) in step 210 (S 201), the control device 5 first generates the power supply abnormality detection signal 9, and the process proceeds to step 202 (S 202). If no abnormality is detected in the main power supply line 15 ato the control device 5 in S 201 (NO), the process is ended.In S 202, the power supply line switching device 16 to which the power supply abnormality detection signal 9 has been input switches the power supply line to the control device 5 from the main power supply line 15 ato the auxiliary power supply line 15 b. S 103 to S 105 following S 202 are the same as those in the flowchart of FIG. 2 explained in the foregoing first embodiment. Therefore, the description thereof is omitted.The electric storage device for a vehicle according to the fifth embodiment includes a plurality of power supply lines for supplying electric power source to the control device 5. Therefore, even when an abnormality occurs in the main power supply line 15 athat supplies power source electric power to the control device 5, the power supply line is switched to the auxiliary power supply line 15 bto stably operate the control device 5 and perform discharging of the battery 3. Thus, it is possible to stop the discharge before the battery 3 is over-discharged.Further, the configuration is such that the existing auxiliary battery 11 is used as the power supply of the control device 5 and power supply lines are added thereto. Therefore, it is unnecessary to provide an additional power supply.Sixth EmbodimentFIG. 8 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a sixth embodiment of the invention. Similarly to the foregoing fifth embodiment, the electric storage device for a vehicle according to the sixth embodiment is provided with two power supply lines 15 aand 15 bfor power supply (the auxiliary battery 11) as the power source electric power supply means for the control device 5.In the sixth embodiment, each of the two power supply lines 15 aand 15 bis connected to the control device 5 via the reverse current prevention diode 14 which is the reverse current prevention means. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.According to the sixth embodiment, the power supply abnormality detecting means can be eliminated by using the reverse current preventing diode 14, in addition to the same advantageous effects as those of the foregoing fifth embodiment.Seventh EmbodimentFIG. 9 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a seventh embodiment of the invention. The electric storage device for a vehicle according to the seventh embodiment is provided with vehicle collision detecting means (not shown) for detecting or predicting a vehicle collision. If a collision is detected or predicted (predicted) by the vehicle collision detection means, the control device 5 performs discharging of the battery 3 caused by the discharging means. The rest of the configuration is the same as that of the foregoing first embodiment, and therefore, the description thereof is omitted.As shown in FIG. 9, a collision detection signal 17 and a collision prediction signal 18 output from the vehicle collision detection means are input to the control device 5. The collision detection signal 17 is generated by, for example, a control device for an airbag (not shown). The collision prediction signal 18 is generated by, for example, a forward scanning radar or a control device for a camera (both not shown in the figure). It is also possible to use only one of the collision detection signal 17 and the collision prediction signal 18.If a collision is detected or predicted from the collision detection signal, the control device 5 switches the main power supply to the auxiliary power supply 7 to perform discharging via the load 4 even before the power supply abnormality detection device detects an abnormality such as a wiring break in the auxiliary battery 11 which is the main power supply.Next, the process flow of the control device 5 in the electric storage device for a vehicle according to the seventh embodiment will be described with reference to the flowchart of FIG. 10. The process operation of the control device 5 is periodically performed (for example, every 10 ms).In step 301 (S 301), if a collision of the vehicle is detected or predicted (YES) by the collision detection signal 17 or the collision prediction signal 18 output from the vehicle collision detection means, the process first proceeds to step S 102, where the power supply switching device 6 switches the power supply for the control device 5 from the auxiliary battery 11 which is the main power supply to the auxiliary power supply 7.If no collision of the vehicle is detected or predicted, the process is ended in S 301. S 103 to S 105 are the same as those in the flowchart of FIG. 2 described in the foregoing first embodiment. Therefore, the description thereof is omitted.According to the seventh embodiment, there is provided the vehicle collision detecting means for detecting or predicting a collision of a vehicle. Therefore, at the time of collision of the vehicle, it is possible to perform discharging of the battery 3 and stop discharging before the state of charge of the battery 3 becomes over-discharged even before an abnormality in the power supply of the control device 5 is detected, in addition to the same advantageous effects as those of the foregoing first embodiment.Eighth EmbodimentFIG. 11 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to an eighth embodiment of the invention. The electric storage device for a vehicle according to the eighth embodiment is provided with a disconnection device 19 for disconnecting the connection between the battery 3 and the electric equipment 12 of the vehicle. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.The user can disconnect the connection between the battery 3 and the electric equipment 12 by operating the disconnect device 19. When the connection between the battery 3 and the electric equipment 12 is disconnected (cut off) from the disconnect device 19, the control device 5 additionally stops discharging of the battery 3 caused by the discharge means. In FIG. 11, the separator 19 is provided between the battery 3 and the electric device 12. When there are a plurality of batteries, the separator 19 may be provided between these batteries.Next, the process flow of the control device 5 in the electric storage device for a vehicle according to the eighth embodiment will be described with reference to the flowchart of FIG. 12. The process operation of the control device 5 is periodically performed (for example, every 10 ms).In step 401 (S 401), it is first determined whether or not the connection with the battery 3 is disconnected from the disconnect device 19. If the voltage of the battery 3 is disconnected (YES), the process proceeds to S 105, where the discharge of the battery 3 caused by the discharge means is stopped. In S 401, if the voltage of the battery 3 is not disconnected (NO), the process proceeds to S 101.S 101 to S 104 are the same as those in the flowchart of FIG. 2 explained in the foregoing first embodiment. Therefore, the description thereof is omitted. In FIG. 12, the determination as to whether or not the connection to the battery 3 is disconnected is performed in S 401 before S 101, but the determination in S 401 may be performed after S 101, S 102, and S 103.According to the eighth embodiment, a disconnecting device 19 for disconnecting the connection between the battery 3 and the electrical device 12 of the vehicle is provided. In addition to the advantageous effects such as those of the foregoing first embodiment, therefore, it is possible to prevent electric shock to the user, and it is also possible to prevent power consumption of the battery 3.Ninth EmbodimentThe configuration of an electric storage device for a vehicle according to a ninth embodiment of the invention is substantially the same as that of the foregoing first embodiment. Therefore, the description thereof will be omitted with reference to FIG. 1 again. The control device 5 of the electric storage device for a vehicle according to the ninth embodiment is provided with a battery abnormality detection means (not shown) for detecting an abnormality in the battery 3. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.The control device 5 performs abnormality detection for the battery 3 by the battery abnormality detection means after starting discharging by the discharging means. Specifically, an abnormality in the battery is detected by, for example, changes in the temperature and voltage of the battery 3. If an abnormality in the battery 3 is detected by the battery abnormality detection means, the battery 3 is discharged by the discharge means until its state of charge becomes approximately 0 (zero). If no abnormality is detected in the battery 3, the discharge of the battery 3 by the discharging means is stopped before the battery 3 becomes over-discharged.The process flow of the control device 5 in the electric storage device for a vehicle according to the ninth embodiment will be described with reference to the flowchart of FIG. 13. The process operation of the control device 5 is periodically performed (for example, every 10 ms). S 101 to S 103 and S 104 are the same as those in the flowchart of FIG. 2 explained in the foregoing first embodiment. Therefore, the description thereof is omitted.In S 103, the discharge of the battery 3 is started, and thereafter, in step 504 (S 504), it is determined by the battery abnormality detection means whether or not the battery 3 is abnormal. If it is determined in S 504 that the battery 3 is abnormal (YES), the process proceeds to step 505 (S 505), and it is determined whether or not the state of charge of the battery 3 is about 0. If the state of charge of the battery 3 is about 0 (YES), the process proceeds to S 105, where the discharging is stopped.If the state of charge of the battery 3 is not about 0 (NO), in S 505, the discharging is continued, and the determination in S 505 is repeated. On the other hand, if it is not determined that the battery 3 is abnormal in S 504 (NO), the process proceeds to S 104, where it is determined whether or not the state of charge of the battery 3 is equal to or less than a predetermined value at which overdischarge occurs. In FIG. 13, if the state of charge of the battery 3 becomes about 0 in S 505, the discharging is stopped in S 105. However, the discharging does not necessarily need to be stopped.According to the ninth embodiment, if an abnormality in the battery is detected by the battery abnormality detecting means, the battery 3 is discharged until the state of charge of the battery 3 becomes about 0 to reduce the power of the battery 3. Therefore, it is possible to prevent ignition or smoke emission at the time of internal short-circuit in the battery 3, in addition to the same advantageous effects as those of the foregoing first embodiment. If it is not determined that the battery 3 is abnormal, the discharge is further stopped before an overdischarge occurs. Therefore, overdischarge of the battery 3 can be prevented and the battery 3 can be reused.Depending on the state of an internal short circuit of the battery 3 (for example, when it is a micro short circuit), it may take time to detect the abnormality in the battery 3 because the voltage change or the temperature change in the battery 3 may be slow. However, by starting the discharge and then performing the abnormality detection in the battery 3 by the battery abnormality detection means, it is possible to discharge the battery 3 to the voltage at which electric blows can be prevented without waiting for the result of the abnormality detection.Tenth EmbodimentFIG. 14 shows an electric storage device for a vehicle according to a tenth embodiment of the invention. FIG. 14 shows only the inside of the housing 8, but the rest of the configuration is the same as that in the first embodiment (FIG. 1 ). Therefore, the description thereof is omitted.The battery of the electric storage device for a vehicle according to the tenth embodiment is a battery module in which a plurality of battery cells 31, 32, 33 are connected in series. As the load for discharging, a bypass circuit (bypass circuit) including resistors 41, 42, 43 and circuit opening / closing means 51, 52, 53 is additionally connected in parallel to each of the battery cells 31, 32, 33. The circuit opening / closing means 51, 52, 53 are opened and closed by the control device 5.Although the battery cells 31, 32, 33 are connected in series in FIG. 14, the configuration of the battery module is not limited thereto, the battery cells may be coupled in parallel, for example, or the connection may be a combination of a series and parallel connection.The battery abnormality detecting means (not shown) of the control device 5 detects an abnormality in each of the battery cells 31, 32, 33. If an abnormality in any of the battery cells 31, 32, 33 is detected by the battery abnormality detecting means, the battery cell concerned is discharged by the discharging means until its state of charge becomes approximately 0 (zero).In addition, the control device 5 performs abnormality detection for the battery cells 31, 32, 33 by the battery abnormality detection means after starting discharging by the discharging means, and if no abnormality is detected, discharging by the discharging means is stopped before being over-discharged.The process flow of the control device 5 in the electric storage device for a vehicle according to the tenth embodiment will be described with reference to the flowchart of FIG. 15. The process operation of the control device 5 is periodically performed (for example, every 10 ms). S 101 and S 102 are the same as those in the flowchart of FIG. 2 explained in the foregoing first embodiment. Therefore, the description thereof is omitted.The discharge of the battery module is started in S 103, and thereafter, in step 604 (S 604), it is determined by the battery abnormality detection means whether or not each of the battery cells 31, 32, 33 is abnormal. If it is determined in S 604 that any one of the battery cells 31, 32, 33 is abnormal (YES), the process proceeds to step 605 (S 605), and it is determined whether or not the state of charge of the battery cell in question is about 0. If the state of charge of the battery cell in question is about 0 (YES), the process proceeds to S 105, where the discharging is stopped.If the state of charge of the subject battery cell is not about 0 in S 605 (NO), the discharging is continued, and the determination in S 605 is repeated. On the other hand, if it is not determined that any of the battery cells 31, 32, 33 is abnormal in S 604 (NO), the process proceeds to step 606 (S 606), and it is determined whether the state of charge of each of the battery cells 31, 32, 33 is equal to or less than a predetermined value at which overdischarge occurs.If it is determined that the state-of-charge value of each of the battery cells 31, 32, 33 is equal to or less than the predetermined value in S 606 at which over-discharge occurs (YES), the process proceeds to step S 105, where the discharge stopping means stops the discharge and the process is ended. If it is not equal to or less than the predetermined value at which over-discharge occurs (NO) in S 606, the discharge is continued, and the determination in S 606 is repeated. In FIG. 15, if the state of charge of the subject battery cell becomes about 0 in S 605, the discharging is stopped in S 105. However, the discharging does not necessarily need to be stopped.The tenth embodiment can achieve the same advantageous effects as those of the first embodiment and the ninth embodiment. Further, because the existing bypass circuit can be used for equalizing the voltages of the battery cells 31, 32, 33, it is not necessary to provide an additional bypass circuit for discharging the battery cells 31, 32, 33 in the event of a vehicle collision.Eleventh EmbodimentThe configuration of an electric storage device for a vehicle according to an eleventh embodiment of the present invention is substantially the same as that of the foregoing first embodiment. Therefore, the description thereof with reference to FIG. 1 will be omitted again. In the eleventh embodiment, the control device 5 stops its operation after stopping the discharge of the battery 3 by the discharge stopping means. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.The process flow of the control device 5 in the electric storage device for a vehicle according to the eleventh embodiment will be described with reference to the flowchart of FIG. 16. The process operation of the control device 5 is periodically performed (for example, every 10 ms). S 101 to S 105 are the same as those in the flowchart of FIG. 2 explained in the foregoing first embodiment. Therefore, the description thereof is omitted.In S 105, the discharge of the battery 3 is stopped by the discharge stopping means, and thereafter, the process proceeds to step 706 (S706), and the operation of the control device 5 is stopped by the auxiliary power supply 7. It should be noted that the battery 3 used in the eleventh embodiment may be a battery module as described in the foregoing tenth embodiment.According to the eleventh embodiment, the power consumption of the auxiliary power supply 7 originating from the operation of the control device 5 can be prevented in addition to the same advantageous effects as those of the foregoing first embodiment. Further, if the auxiliary power supply 7 is a lithium ion battery, overdischarge of the lithium ion battery can be prevented. It is possible to prevent decomposition of the electrolytic solution, and it is possible to prevent the copper used for the negative electrode from being converted into ions and being dissolved in the electrolytic solution.Twelfth EmbodimentFIG. 17 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a twelfth embodiment of the invention. The electric storage device for a vehicle according to the twelfth embodiment is provided with a memory 20 which is a storage means for storing the record of the discharge of the battery 3 caused by the discharge means. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, description thereof is omitted.The memory 20 stores the record of discharge of the battery 3 due to an accident, the record of abnormality detection in the battery 3, and the like. Although the memory 20 is provided outside the control device 5 in FIG. 17, it is possible to provide the memory 20 in FIG. 5. In addition, the memory 20 may be either non-volatile or volatile.According to the twelfth embodiment, the memory 20 is provided for storing the record of discharge of the battery 3. Therefore, in addition to the advantageous effects such as those of the foregoing first embodiment, it is possible to determine whether or not the battery 3 can be reused without directly measuring the voltage or the temperature of the battery 3.Thirteenth EmbodimentFIG. 18 shows an example of a power supply system of an internal combustion engine including an electric storage device for a vehicle according to a thirteenth embodiment of the invention. The electric storage device for a vehicle according to the thirteenth embodiment is provided with external notifying means 21 for notifying an external part that the battery 3 is discharged or discharge by the discharging means is completed. The rest of the configuration is the same as that in the foregoing first embodiment, and therefore, the description thereof is omitted.The external notification means may be, for example, an LED lamp and is provided in the vehicle in order to inform the user or the rescuer about the state of charge of the battery 3. It is possible to provide two external notification means each indicating discharge in progress and completion of discharge. In order to distinguish between a discharge being performed and a termination of the discharge, it is possible to illuminate lamps of different colors or to emit different alarm sounds.The thirteenth embodiment is provided with an external notifying means 21 for notifying an external part that the battery 3 is discharged or has finished discharging. Therefore, in addition to the same advantageous effects as those of the foregoing first embodiment, the discharge state of the battery can be easily checked and electric shock can be prevented.In the present invention, the respective embodiments can be freely combined and appropriately changed or omitted within the scope of the present invention.Industrial applicabilityThe invention can be used in an electric storage device for a vehicle.

Claims

An electric storage device for a vehicle, comprising a battery (3) installed in a vehicle and transferring electric power to and from a facility (12) of the vehicle, a load (4) for discharging the battery (3), a control device (5) for controlling discharge of the battery (3) via the load (4) and a power source electric power supply means for supplying power source electric power to the control device (5), wherein the control device (5) comprises a charge state detection means for detecting a charge state of the battery (3), a discharge means for discharging the battery (3) via the load (4), and a discharge stop means for stopping discharge of the battery (3) by the discharge means before the battery (3) is over-discharged, based on the state of charge of the battery detected by the state of charge detecting means; and the power source electric power supply means has a plurality of power source electric power supply paths each including a power supply (11, 3) and a power supply line connecting the power supply (11, 3) to the control device (5), so that if an abnormality occurs in one of the paths for supplying power source electric power to the control device (5), power source electric power can be supplied to the control device (5) through another of the paths; the power source electric power supply means includes a plurality of power supplies (11, 3); and the plurality of power supplies (11, 3) include a main power supply (11), an auxiliary power supply (3), and a power source switching device (6) for switching the power supply to supply power source electric power to the control device (5) from the main power supply (11) to the auxiliary power supply (3) if an abnormality is detected in the main power supply (11), characterized in that the auxiliary power supply (3) is the battery (3).The electric storage device for a vehicle according to claim 1, characterized in that each of the plurality of power supplies (11, 3) is connected to the control device (5) via a reverse current prevention means (14).The electric storage device for a vehicle according to any one of claims 1 or 2, characterized byfurther including vehicle collision detecting means for detecting (17) or predicting (18) a collision of the vehicle, so that if a collision is detected or predicted by the vehicle collision detecting means, the control device (5) performs discharging of the battery (3) by the discharging means.An electric storage apparatus for a vehicle according to any one of claims 1 to 3, characterized byfurther including a disconnection device (19) for disconnecting a connection between the battery (3) and the device (12) to stop discharging of the battery (3) caused by the discharging means if the connection between the battery (3) and the device (12) is disconnected from the disconnection device (19).The electric storage device for a vehicle according to any one of claims 1 to 4, characterized in that the control device (5) includes battery abnormality detection means for detecting an abnormality in the battery (3) so that if an abnormality in the battery (3) is detected by the battery abnormality detection means, the battery is discharged by the discharge means until its state of charge becomes approximately 0 (zero).The electric storage device for a vehicle according to claim 5, characterized in that the battery (3) is a battery module having a plurality of battery cells (31, 32, 33) connected in series or in parallel, the battery abnormality detection means detects an abnormality in each of the battery cells (31, 32, 33), and if an abnormality in the battery cells (31, 32, 33) is detected by the battery abnormality detection means, an affected one of the battery cells is discharged by the discharge means until its state of charge becomes approximately 0 (zero).The electric storage device for a vehicle according to claim 5 or 6, characterized in that the control device (5) performs the abnormality detection of the battery (3) by the battery abnormality detection means after starting the discharge by the discharge means.The electric storage device for a vehicle according to any one of claims 1 to 7, characterized in that the control device (5) stops its operation after stopping discharge of the battery (3) caused by the discharge stopping means.An electric storage device for a vehicle according to any one of claims 1 to 8, characterized byfurther comprising storage means (20) for storing a record of discharge of said battery (3) caused by said discharge means.The electric storage device for a vehicle according to any one of claims 1 to 9, characterized byfurther including external notifying means (21) for notifying to an external part that the battery (3) is discharged or discharge by the discharging means is completed.The electric storage device for a vehicle according to any one of claims 1 to 10, characterized in that a lithium ion battery is used as the battery (3).

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