Battery charging device and battery charging method

Abstract

To provide a device and a method that can quickly charge a battery.SOLUTION: A battery charing device 100 in an embodiment comprises: N power supply batteries from a first power supply battery 11 to an N-th power supply battery; and a plurality of electromagnetic relays 2a to 2o. The battery charing device 100 charges a target battery B connected to each of the N power supply batteries via any one of the plurality of electromagnetic relays 2a to 2o. The battery charing device is configured so that the N power supply batteries are connected to the charged battery B in order from the first power supply battery 11 to the N-th power supply battery by the plurality of electromagnetic relays 2a to 2o. In response to an electromagnetic relay of the plurality of electromagnetic relays 2a to 2o being placed in an open state upon termination of charging of the target battery B by an n-th power supply battery of the N power supply batteries, an (n+1)th power supply battery is connected to the target battery B by any electromagnetic relay of the plurality of electromagnetic relays 2a to 2o other than one electromagnetic relay in an open state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery charging device and a battery charging method. [Background technology]

[0002] Patent Document 1 discloses a battery charging device that charges a vehicle battery using a commercial power source or a power supply device that is a charging stand. The charging device in Patent Document 1 charges the vehicle battery with a current value calculated so that charging is completed within the charging time desired by the user. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-121148 Summary of the Invention [Problem to be solved by the invention]

[0004] The charging device disclosed in Patent Document 1 may not be able to fully meet the user's demand for quick charging.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a battery charging device and a battery charging method that can quickly charge a battery to a high charging rate. [Means for solving the problem]

[0006] The battery charging device of the present invention includes N (N is an integer greater than or equal to 2) supply batteries from a first supply battery to an Nth supply battery that supply power for charging, and at least M (M is an integer that is N times 3) electromagnetic relays, and charges a battery to be charged that is connected to each of the N supply batteries via any of the plurality of electromagnetic relays, wherein the N supply batteries are connected to the battery to be charged in order from the first supply battery to the Nth supply battery via the plurality of electromagnetic relays to charge the battery to be charged, and when charging of the battery to be charged by the nth supply battery (n is a positive integer less than N) of the N supply batteries is completed, one of the plurality of electromagnetic relays is opened, and the (n+1)th supply battery is connected to the battery to be charged by any of the plurality of electromagnetic relays other than the one electromagnetic relay.

[0007] A battery charging method of the present invention uses N (N is an integer greater than or equal to 2) supply batteries from a first supply battery to an Nth supply battery that supply power for charging, and at least M (M is an integer that is N times 3) electromagnetic relays, the method including: connecting the N supply batteries in sequence from the first supply battery to the Nth supply battery using the plurality of electromagnetic relays to a chargeable battery to be charged; and charging the chargeable battery using the N supply batteries connected to the chargeable battery in sequence; and connecting the N supply batteries in sequence to the chargeable battery includes, when charging of the chargeable battery by the nth supply battery (n is a positive integer less than N) of the N supply batteries is completed, opening one of the plurality of electromagnetic relays and closing one of the plurality of electromagnetic relays, thereby connecting the (n+1)th supply battery to the chargeable battery via any of the electromagnetic relays. [Effects of the Invention]

[0008] According to the present invention, the battery can be quickly charged to a high charge rate. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a circuit diagram illustrating an example of a battery charging device according to an embodiment of the present invention; [Figure 2A] 1 is a schematic diagram showing an example of the configuration of an electromagnetic relay in a battery charging device according to an embodiment of the present invention; [Figure 2B] FIG. 2B is a diagram showing a modification of a part of the electromagnetic relay of FIG. 2A. [Figure 3] FIG. 2 is a circuit diagram showing the configuration of the battery charging device of FIG. 1 in more detail. [Figure 4] FIG. 10 is a circuit diagram schematically illustrating a modified example of a battery charging device according to an embodiment of the present invention. [Figure 5] FIG. 10 is a circuit diagram schematically illustrating an example of a battery charging device according to another embodiment of the present invention. [Figure 6] FIG. 6 is a circuit diagram schematically illustrating a modified example of the battery charging device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The battery charging device and the battery charging method of the present invention will be described below with reference to the accompanying drawings. However, the battery charging device and the battery charging method of the present invention are not limited to the following embodiments.

[0011] <Overall configuration and operation of a battery charging device according to one embodiment> Fig. 1 shows a schematic circuit diagram of a battery charging device 100, which is an example of a battery charging device according to one embodiment of the present invention. As shown in Fig. 1, the battery charging device 100 includes five power supply batteries, namely, a first power supply battery 11 to a fifth power supply battery 15, which supply power for charging. The battery charging device 100 also includes a plurality of electromagnetic relays, namely, a first electromagnetic relay 2a to a fourteenth electromagnetic relay 2n and an output electromagnetic relay 2o. In the example of Fig. 1, the battery charging device 100 charges a battery B connected to each of the five power supply batteries 11 to 15 via one of the 15 electromagnetic relays 2a to 2o.

[0012] The number of power supply batteries and electromagnetic relays included in the battery charging device 100 in FIG. 1 is merely an example of the number of power supply batteries and electromagnetic relays that may be included in the battery charging device of this embodiment. The battery charging device of this embodiment may include N power supply batteries, where N is an integer greater than or equal to 2, and M electromagnetic relays, where M is an integer greater than or equal to 3. The battery charging device of this embodiment may include at least M electromagnetic relays, and therefore may include a number greater than M. Therefore, the battery charging device of this embodiment charges a battery B connected to each of N power supply batteries, which is two or more, via either M, where M is an integer greater than or equal to 3, or M or more electromagnetic relays (hereinafter, the battery B to be charged is also referred to as the "battery to be charged" to distinguish it from the power supply batteries).

[0013] The battery to be charged B is connected between the negative pole 1n of each of the N power supply batteries (first to fifth power supply batteries 11 to 15 in the example of Figure 1) and the second terminal 22 and the fourth terminal 24 of the output electromagnetic relay 2o among the multiple electromagnetic relays (first to fourteenth electromagnetic relays 2a to 2n and output electromagnetic relay 2o in the example of Figure 1).

[0014] The battery to be charged B may be any type of secondary battery that can be used repeatedly by charging. Any type of secondary battery in any state of charge (SOC: State Of Charge, hereinafter also referred to as "charging rate") other than fully charged may be connected to the battery charging device of this embodiment and charged. As an example, the battery to be charged B may be a lead-acid battery, particularly a lead-acid battery for automobiles.

[0015] The first to fifth power supply batteries 11 to 15 (N power supply batteries) may be any batteries, but are preferably secondary batteries of the same type and rating as the battery to be charged B. Therefore, the first to fifth power supply batteries 11 to 15 may be, for example, lead storage batteries, particularly lead storage batteries for automobiles.

[0016] The battery charging device of this embodiment is configured so that N power supply batteries (first to fifth power supply batteries 11-15 in the example of FIG. 1) are connected to the chargeable battery B one by one in sequence from the first power supply battery 11 to the Nth power supply battery (fifth power supply battery 15 in the example of FIG. 1) via a plurality of electromagnetic relays (first to fourteenth electromagnetic relays 2a-2n and output electromagnetic relay 2o in the example of FIG. 1). Therefore, if each of the N power supply batteries has a higher charging rate than the charging rate of the chargeable battery B when connected to the chargeable battery B, the chargeable battery B is charged by each power supply battery in sequence. In this way, the battery charging device of this embodiment is configured so that by connecting each of the N power supply batteries one by one in sequence to the chargeable battery B, the N power supply batteries charge the chargeable battery B one by one in the order in which they are connected to the chargeable battery B.

[0017] The chargeable battery B is connected to each power supply battery in turn, and a large, unlimited charging current flows from each power supply battery in turn, causing the chargeable battery B to be charged rapidly. First, the chargeable battery B is charged by the first power supply battery 11, which is connected to the chargeable battery B first. The charging rate of the first power supply battery 11 rapidly decreases in contrast to the progress of rapid charging of the chargeable battery B (increase in charging rate). Charging of the chargeable battery B by the first power supply battery 11 ends when the charging rate of the first power supply battery 11 becomes approximately the same as the charging rate of the chargeable battery B, as it is no longer possible to flow charging current.

[0018] As described above, in the battery charging device of this embodiment, each power supply battery is connected to the chargeable battery B one by one in sequence, from the first power supply battery 11 to the N-th power supply battery (the fifth power supply battery 15 in FIG. 1 ), and the chargeable battery B is charged by each connected power supply battery. That is, when charging by the first power supply battery 11 is completed, the second power supply battery 12 is connected to the chargeable battery B, and the second power supply battery 12 charges the chargeable battery B. Thereafter, when charging by the second power supply battery 12 is completed, the third power supply battery 13 is connected to the chargeable battery B, and the third power supply battery 13 charges the chargeable battery B. Similarly, charging by the fourth power supply battery 14 and the fifth power supply battery are performed sequentially. That is, generally speaking, when charging by the n-th power supply battery of the N power supply batteries is completed, charging by the (n+1)-th power supply battery begins, where n is a positive integer less than N.

[0019] In order to sequentially charge the N power supply batteries, the battery charging device of this embodiment is configured so that one of the plurality of electromagnetic relays opens when charging of the chargeable battery B by the nth power supply battery (n is a positive integer less than N) of the N power supply batteries is completed. Furthermore, the battery charging device of this embodiment is configured so that when one electromagnetic relay opens in this way, the (n+1)th power supply battery is connected to the chargeable battery B by any of the plurality of electromagnetic relays other than the one electromagnetic relay.

[0020] As an example, when charging of the chargeable battery B by the first power supply battery 11 is completed as described above, the first electromagnetic relay 2a of the multiple electromagnetic relays 2a to 2o in the example of Fig. 1 is opened. This opening causes the third to fifth electromagnetic relays 2c to 2e to connect the second power supply battery 12 to the chargeable battery B, as will be described later. Because the second power supply battery 12 is not particularly discharged until it is connected to the chargeable battery B, it maintains a higher charging rate than the charging rate of the chargeable battery B. Therefore, the chargeable battery B is further rapidly charged by the second power supply battery 12 until it reaches a charging rate substantially equal to that of the second power supply battery 12.

[0021] After the second power supply battery 12 has finished charging the chargeable battery B, the third power supply battery 13 through the Nth power supply battery (the fifth power supply battery 15 in FIG. 1 ) are connected to the chargeable battery B one by one in the same manner, and the chargeable battery B is charged by each power supply battery, one by one. By connecting each power supply battery, which has a higher charging rate than the chargeable battery B, to the chargeable battery B one by one in the same manner and charging the chargeable battery B, the chargeable battery B can be charged stepwise to a higher charging rate. Each power supply battery charges the chargeable battery B rapidly, just like the charging by the first power supply battery 11 described above. Therefore, the battery charging device of this embodiment can quickly charge a battery such as the chargeable battery B to a high charging rate.

[0022] Although not shown in Figure 1, when the battery charging device of an embodiment includes more than two power supply batteries, such as the battery charging device 100 of Figure 1, a charging prevention means is provided that prevents at least the (n+2)th to Nth power supply batteries from charging the chargeable battery B while the nth power supply battery is charging the chargeable battery B.

[0023] <Electromagnetic relay> Each of at least M electromagnetic relays included in the battery charging device of this embodiment has a first terminal 21, a second terminal 22, a third terminal 23, and a fourth terminal 24, like the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o shown in Fig. 1. Each electromagnetic relay is configured so that conduction is established between the third terminal 23 and the fourth terminal 24 by the action of a magnetic field generated by a current flowing from the first terminal 21 to the second terminal 22.

[0024] The multiple electromagnetic relays included in the battery charging device of this embodiment are not particularly limited in type, as long as they are capable of establishing electrical continuity between another pair of terminals when a current flows between them. For example, each of the multiple electromagnetic relays included in the battery charging device of this embodiment, such as the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o, may be configured as an electromagnetic contactor, or so-called a magnetic switch, provided in a starter motor used to start an internal combustion engine. For example, a magnetic switch provided in a starter motor of an automobile may be used as the multiple electromagnetic relays of the battery charging device of this embodiment.

[0025] 2A schematically shows an example of the configuration of each electromagnetic relay 2 constituting the plurality of electromagnetic relays in the battery charger of this embodiment. FIG. 2A shows an example of an electromagnetic relay 2 constituted by an electromagnetic contactor (magnetic switch) provided in the starter motor of an internal combustion engine as described above. As shown in FIG. 2A, each of the plurality of electromagnetic relays (electromagnetic relay 2) has a first terminal 21, a second terminal 22, a third terminal 23, and a fourth terminal 24. A coil 205 is provided between the first terminal 21 and the second terminal 22, and the first terminal 21 and the second terminal 22 are connected to each other via the coil 205.

[0026] The electromagnetic relay 2 further includes a housing 210 and includes a moving body 203 (first moving body) that moves due to a magnetic force generated by a current flowing through a coil 205, contacts 201 and 202 that face abutment portion 203a at one end of the moving body 203, and a spring 208. The spring 208 is interposed between an extension portion 209 of the moving body 203 and the housing 210. The contact 201 is connected to the third terminal 23, and the contact 202 is connected to the fourth terminal 24. The abutment portion 203a of the moving body 203, the contact 201, and the contact 202 are all conductive. In the example of FIG. 2A, the housing 210 is also conductive, and the second terminal 22 is provided to be electrically connected to the housing 210.

[0027] When the magnetic switch that constitutes electromagnetic relay 2 is provided in an automobile starter motor, third terminal 23 is connected directly to the automobile battery (not shown), while first terminal 21 is connected via a starter switch (not shown). Fourth terminal 24 is connected to the armature (not shown) of the starter motor, and second terminal 22 is connected to the automobile body, which serves as frame ground. However, when an automobile magnetic switch is used as electromagnetic relay 2 that constitutes the battery charging device of this embodiment, first to fourth terminals 21 to 24 of electromagnetic relay 2 are not connected to these automobile parts or locations.

[0028] When a current flows between the first terminal 21 and the second terminal 22, the coil 205 forms an electromagnet. The spring 208 biases the moving body 203 in the direction opposite to the contacts 201 and 202 so that the tip 204 of the moving body 203 is positioned at a predetermined position when no current flows through the coil 205. When a current flows from the first terminal 21 through the coil 205 to the second terminal 22, the moving body 203 is moved toward the contacts 201 and 202 while compressing the spring 208, and the abutting portion 203a of the moving body 203 comes into contact with the contacts 201 and 202. This contact establishes electrical continuity between the third terminal 23 and the fourth terminal 24. Thus, when a current flows from the first terminal 21 to the coil 205, electrical continuity is established between the two terminals of the electromagnetic relay 2, i.e., between the third terminal 23 and the fourth terminal 24, and this conduction causes the electromagnetic relay 2 to be in a closed state.

[0029] On the other hand, as described above, the moving body 203 is biased by the spring 208 in the opposite direction to the contacts 201 and 202, and therefore, when no current flows through the coil 205, the moving body 203 is separated from the contacts 201 and 202. As a result, there is no electrical continuity between the third terminal 23 and the fourth terminal 24, and the electromagnetic relay 2 is in the open state. In this way, the moving body 203 is displaced as the electromagnetic relay 2 switches between the open state and the closed state.

[0030] In the example of Fig. 2A, as described above, contactor 202 and fourth terminal 24 are connected to first terminal 21 via coil 206, similar to a magnetic switch provided in a typical automobile starter motor. However, when electromagnetic relay 2 of the battery charging device of this embodiment is configured as a magnetic switch for an automobile, a portion of the magnetic switch may be modified as shown in Fig. 2B. Fig. 2B shows an enlarged view of portion IIB of electromagnetic relay 2 of Fig. 2A after modification.

[0031] In the modification example partially shown in FIG. 2B , the wiring 207 connecting the coil 206 (and the first terminal 21) and the fourth terminal 24 (and the contact 202) is cut. This prevents the first terminal 21 and the third terminal 23 from being connected via the coil 206 and affecting the operation of the electromagnetic relay 2 when the third terminal 23 (see FIG. 2A ) and the fourth terminal 24 are electrically connected. Furthermore, in the modification illustrated in FIG. 2B , the wiring 207 extending from the coil 206 and separated from the fourth terminal 24 is connected to the housing 201. That is, the first terminal 21 and the second terminal 22 (see FIG. 2A ) are electrically connected via the coil 206. Therefore, the voltage to be applied between the first terminal 21 and the second terminal 22 to close the electromagnetic relay 2 can be reduced.

[0032] <Connections between each electromagnetic relay and between each electromagnetic relay and each power supply battery> Referring again to FIG. 1, the connections between the electromagnetic relays of the battery charging device 100 of FIG. 1 and the connections between the electromagnetic relays and the power supply batteries will be described. The battery charging device 100 of FIG. 1 includes the first through fifth power supply batteries 11 through 15, the first through fourteenth electromagnetic relays 2a through 2n, and the output electromagnetic relay 2o, as described above, as well as diodes 31 through 34 and switches 41 and 42. The switch 41 is disposed to engage with the movable body 203 of the first electromagnetic relay 2a and opens and closes in response to the displacement of the movable body 203 of the first electromagnetic relay 2a. Similarly, the switch 42 is disposed to engage with the movable body 203 of the fourth electromagnetic relay 2d and opens and closes in response to the displacement of the movable body 203 of the fourth electromagnetic relay 2d. As an example, the switches 41 and 42 are push-button switches, preferably tactile switches that are in a closed state (on state) only while pressed.

[0033] Note that in FIG. 1, the illustration within the dash-dot-dotted lines in frames L3 and L4 is partially omitted, and only the seventh electromagnetic relay 2g through the twelfth electromagnetic relay 2l are shown. However, within frame L3, like the fourth to sixth electromagnetic relays 2d through 2f within frame L2, the seventh to ninth electromagnetic relays 2g through 2i are connected to each other and to the fourth power supply battery 14. Similarly to the diode 32 within frame L2, a diode (not shown) is connected to the seventh electromagnetic relay 2g, and a switch (not shown) is provided that engages with the seventh electromagnetic relay 2g and opens and closes in response to the displacement of its moving body, similar to the switch 42. A diode (not shown) is connected to the switch, similar to the diode 34 within frame L2. Similarly, within frame L4, the tenth to twelfth electromagnetic relays 2j through 2l are connected to each other and to the fifth power supply battery 15. In addition, a diode (not shown) is connected to the 10th electromagnetic relay 2j, and a switch (not shown) is disposed which engages with the 10th electromagnetic relay 2j and opens and closes depending on the displacement of its moving body, and a diode (not shown) is connected to the switch.

[0034] Thus, the battery charging device 100 includes switches such as switch 41 and switch 42 that open and close depending on the displacement of a moving body 203 included in one of a plurality of electromagnetic relays, such as the first, fourth, seventh, and tenth electromagnetic relays 2a, 2d, 2g, and 2j.

[0035] As shown in FIG. 1 , the positive electrode 1p of the first power supply battery 11 is connected to the first terminal 21 of each of the first electromagnetic relay 2a and the second electromagnetic relay 2b, and to the third terminal 23 of the second electromagnetic relay 2b. The second terminal 22 and the fourth terminal 24 of the first electromagnetic relay 2a are connected to the first terminal 21 of the output electromagnetic relay 2o via a diode 31 so that current can flow to the first terminal 21 of the output electromagnetic relay 2o. Specifically, the second terminal 22 and the fourth terminal 24 of the first electromagnetic relay 2a are connected to the anode of the diode 31, the cathode of which is connected to the first terminal 21 of the output electromagnetic relay 2o. The third terminal 23 of the first electromagnetic relay 2a is connected to the second terminal 22 of the second electromagnetic relay 2b. The fourth terminal 24 of the second electromagnetic relay 2b is connected to the third terminal 23 of the output electromagnetic relay 2o. Meanwhile, the second terminal 22 of the third electromagnetic relay 2c is connected to the first terminal 21 of the output electromagnetic relay 2o via a switch 41 that opens and closes in response to the displacement of the moving body 203 of the first electromagnetic relay 2a so as to be electrically connected (i.e., so that current can flow to the first terminal 21 of the output electromagnetic relay 2o). Specifically, the second terminal 22 of the third electromagnetic relay 2c is connected to the anode of a diode 33 via the switch 41, and the cathode of the diode 33 is connected to the first terminal 21 of the output electromagnetic relay 2o. The negative electrodes 1n of the first to fifth power supply batteries 11 to 15 are connected to each other and to a ground potential G. The positive electrode 1p of the second power supply battery 12 is connected to the first terminal 21 and fourth terminal 24 of the third electromagnetic relay 2c, and the third terminal 23 of the third electromagnetic relay 2c is connected to the first terminal 21 of the fourth electromagnetic relay 2d.

[0036] The third terminal 23 of the third electromagnetic relay 2c is also connected to the first terminal 21 and the third terminal 23 of the fifth electromagnetic relay 2e. The second terminal 22 and the fourth terminal 24 of the fourth electromagnetic relay 2d are electrically connected to the first terminal 21 of the output electromagnetic relay 2o via a diode 32. That is, the second terminal 22 and the fourth terminal 24 of the fourth electromagnetic relay 2d are connected to the anode of the diode 32, the cathode of which is connected to the first terminal 21 of the output electromagnetic relay 2o. The third terminal 23 of the fourth electromagnetic relay 2d is connected to the second terminal 22 of the fifth electromagnetic relay 2e. The fourth terminal 24 of the fifth electromagnetic relay 2e is connected to the third terminal 23 of the output electromagnetic relay 2o. Meanwhile, the second terminal 22 of the sixth electromagnetic relay 2f is electrically connected to the first terminal 21 of the output electromagnetic relay 2o via a switch 42 that opens and closes in response to the displacement of the moving body 203 of the fourth electromagnetic relay 2d. Specifically, the second terminal 22 of the sixth electromagnetic relay 2f is connected to the anode of the diode 34 via the switch 42, and the cathode of the diode 34 is connected to the first terminal 21 of the output electromagnetic relay 2o. The first terminal 21 and the fourth terminal 24 of the sixth electromagnetic relay 2f are connected to the positive electrode 1p of the third power supply battery 13.

[0037] 1, as described above, the seventh to ninth electromagnetic relays 2g to 2i and a diode and switch (not shown) are arranged within frame L3, similar to the fourth to sixth electromagnetic relays 2d to 2f, diodes 32, 34, and switch 42 within frame L2, and are connected to one another in the same manner as within frame L2. Furthermore, the tenth to twelfth electromagnetic relays 2j to 2l and a diode and switch (not shown) are arranged within frame L4, similar to the manner in frame L2, and are connected to one another.

[0038] The wiring W connected to the third terminal 23 of the twelfth electromagnetic relay 2l is connected to the first terminal 21 of the thirteenth electromagnetic relay 2m and the first terminal 21 and third terminal 23 of the fourteenth electromagnetic relay 2n. The second terminal 22 and fourth terminal 24 of the thirteenth electromagnetic relay 2m are connected to the first terminal 21 of the output electromagnetic relay 2o. The third terminal 23 of the thirteenth electromagnetic relay 2m is connected to the second terminal 22 of the fourteenth electromagnetic relay 2n. The fourth terminal 24 of the fourteenth electromagnetic relay 2n is connected to the third terminal 23 of the output electromagnetic relay 2o.

[0039] The battery charging device 100 of FIG. 1 further includes a positive electrode connection terminal Tp and a negative electrode connection terminal Tn. The positive electrode connection terminal Tp is connected to the second terminal 22 and the fourth terminal 24 of the output electromagnetic relay 2o. Preferably, the second terminal 22 and the fourth terminal 24 of the output electromagnetic relay 2o are connected to the positive electrode connection terminal Tp by separate conductive wires, as shown in FIG. 1. This reduces the effect on the current flowing from the second terminal 22 to the positive electrode connection terminal Tp of a voltage drop caused by a large current that may flow between the fourth terminal 24 and the positive electrode connection terminal Tp when charging the battery to be charged B. The negative electrode connection terminal Tn is connected to the negative electrode In of each of the first to fifth power supply batteries 11 to 15, i.e., to ground potential G. In the example of FIG. 1, the negative electrode Bn of the battery to be charged B mounted on the vehicle V is connected to the negative electrode connection terminal Tn, and the positive electrode Bp of the battery to be charged B is connected to the positive electrode connection terminal Tp. That is, the second terminal 22 and fourth terminal 24 of the output electromagnetic relay 2o are connected to the positive electrode Bp of the battery to be charged B, and the negative electrode 1n of each of the N power supply batteries is connected to the negative electrode Bn of the battery to be charged B.

[0040] 1, the connections to the third terminal 23 and the fourth terminal 24 of each of the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o may be reversed from the connections shown in Fig. 1. That is, the circuit element connected to the third terminal 23 of each electromagnetic relay in Fig. 1 may be connected to the fourth terminal 24, and instead, the circuit element connected to the fourth terminal 24 may be connected to the third terminal 23.

[0041] <Operation of the battery charging device according to the embodiment> The operation of the battery charging device of this embodiment will be described using the battery charging device 100 of Figure 1 as an example. When a battery to be charged B is connected to the battery charging device 100, which includes first to fifth power supply batteries 11-15 with a higher charging rate than the battery to be charged B, the battery charging device 100 charges the battery to be charged. First, current flows from the first power supply battery 11 to the positive electrode Bp of the battery to be charged B through the first terminal 21 and second terminal 22 of the first electromagnetic relay 2a, the diode 31, and the first terminal 21 and second terminal 22 of the output electromagnetic relay 2o. As a result, the first electromagnetic relay 2a is closed, establishing electrical continuity between its third terminal 23 and fourth terminal 24, and also between the third terminal 23 and fourth terminal 24 of the output electromagnetic relay 2o. Furthermore, as current flows between the first terminal 21 and the second terminal 22 of the first electromagnetic relay 2a, the moving body 203 of the first electromagnetic relay 2a moves toward the inside of the first electromagnetic relay 2a, and the switch 41 becomes open (off).

[0042] Because the third terminal 23 and the fourth terminal 24 of the first electromagnetic relay 2a are conductive, current also flows from the first power supply battery 11 to the battery to be charged B via the first terminal 21 and the second terminal 22 of the second electromagnetic relay 2b and the third terminal 23 and the fourth terminal 24 of the first electromagnetic relay 2a. This causes the second electromagnetic relay 2b to close. As a result, the first power supply battery 11 and the battery to be charged B are connected only via the third and fourth terminals 23 and 24 of the second electromagnetic relay 2b and the third and fourth terminals 23 and 24 of the output electromagnetic relay 2o. This allows the first power supply battery 11 to quickly charge the battery to be charged with a large current. However, as described above, because the switch 41 is open, the third electromagnetic relay 2c does not close. Therefore, while the first power supply battery 11 is charging, the second power supply battery 12 is not connected to the battery to be charged B, and therefore the second power supply battery 12 does not charge the battery to be charged B. Furthermore, due to the action of the charging prevention means described above, charging by the third to fifth power supply batteries 13 to 15 is also prevented.

[0043] As the charging of the chargeable battery B by the first power supply battery 11 progresses, the decreasing charging rate of the first power supply battery 11 and the increasing charging rate of the chargeable battery B become approximately equal, and current stops flowing from the first power supply battery 11 to the chargeable battery B, thereby terminating charging by the first power supply battery 11. For example, if the charging rate of the first power supply battery 11 was 100% and the charging rate of the chargeable battery B was 0% before the connection of the chargeable battery B, charging by the first power supply battery 11 will terminate when the charging rates of the chargeable battery B and the first power supply battery 11 both reach approximately 50%.

[0044] Since current stops flowing from the first power supply battery 11 to the battery to be charged B, the first electromagnetic relay 2a and the second electromagnetic relay 2b are both open. However, the battery charging device 100 is configured so that when the first electromagnetic relay 2a is open and the switch 41 is closed, the second power supply battery 12 is connected to the battery to be charged B via the third electromagnetic relay 2c.

[0045] That is, as the first electromagnetic relay opens, the movable body 203 of the first electromagnetic relay 2a moves in a direction protruding from the first electromagnetic relay 2a, and is pressed by the movable body 203 to close the switch 41. Then, the second terminal 22 of the third electromagnetic relay 2c is connected to the positive electrode Bp of the battery to be charged B via the switch 41, the diode 33, and the output electromagnetic relay 2o. The first terminal 21 of the third electromagnetic relay 2c is connected to the positive electrode 1p of the second supply battery 12. Because the second supply battery 12 is not discharging while being charged by the first supply battery 11, it can have a higher state of charge than the battery to be charged B. Therefore, current flows from the second supply battery 12 to the first terminal 21 and then to the second terminal 22 of the third electromagnetic relay 2c. Therefore, the third electromagnetic relay 2c is closed, establishing electrical continuity between its third terminal 23 and fourth terminal 24, and connecting the positive electrode 1p of the second power supply battery 12 to the first terminal 21 of each of the fourth and fifth electromagnetic relays 2d and 2e. If the charging rate of the second power supply battery 12 is still higher than that of the battery to be charged B, current flows from the second power supply battery 12 to the positive electrode Bp of the battery to be charged B through the first terminal 21 and second terminal 22 of the fourth electromagnetic relay 2d, the diode 32, and the first terminal 21 and second terminal 22 of the output electromagnetic relay 2o. Therefore, the fourth electromagnetic relay 2d is closed, establishing electrical continuity between its third terminal 23 and fourth terminal, and the moving body 203 of the fourth electromagnetic relay 2d moves toward the interior of the fourth electromagnetic relay 2d, switching the switch 42 to the open (off) state.

[0046] Because the third terminal 23 and the fourth terminal 24 of the fourth electromagnetic relay 2d are conductive, current also flows from the second power supply battery 12 to the battery to be charged via the path that passes through the first terminal 21 and the second terminal 22 of the fifth electromagnetic relay 2e and the third terminal 23 and the fourth terminal 24 of the fourth electromagnetic relay 2d. This causes the fifth electromagnetic relay 2e to close. As a result, the second power supply battery 12 and the battery to be charged B are connected only via the third and fourth terminals 23 and 24 of the third electromagnetic relay 2c, the third and fourth terminals 23 and 24 of the fifth electromagnetic relay 2e, and the third and fourth terminals 23 and 24 of the output electromagnetic relay 2o, and the battery to be charged B is quickly charged by the second power supply battery 12 with a large current.

[0047] Meanwhile, as described above, because switch 42 is open, the sixth electromagnetic relay 2f is not closed. Therefore, while charging is being performed by the second power supply battery 11, the third power supply battery 13 is not connected to the chargeable battery B, and therefore charging of the chargeable battery B by the third power supply battery 13 is not performed. Furthermore, due to the action of the charging prevention means described above, charging by the fourth and fifth power supply batteries 14, 15 is also not performed. Note that current attempting to flow from the chargeable battery B, whose charging rate increases as charging by the second power supply battery 12 progresses, through the first electromagnetic relay 2a and other means to the first power supply battery 11 is prevented by diode 31.

[0048] As the charging of the chargeable battery B by the second power supply battery 12 progresses, the decreasing charging rate of the second power supply battery 12 and the increasing charging rate of the chargeable battery B become approximately equal, and current stops flowing from the second power supply battery 12 to the chargeable battery B, thereby ending charging by the second power supply battery 12. Current also stops flowing from the second power supply battery 12 through the path via the third electromagnetic relay 2c. For example, if the charging rate of the second power supply battery 12 before the connection of the chargeable battery B is 100%, and the chargeable battery B has been charged to a charging rate of 50% by the first power supply battery 11, charging by the second power supply battery 12 ends when the charging rates of the chargeable battery B and the second power supply battery 12 both reach approximately 75%.

[0049] Because current stops flowing from the second power supply battery 12 to the battery to be charged B, the fourth electromagnetic relay 2d opens and the fifth electromagnetic relay 2e also opens. However, just as the second power supply battery 12 connects to the battery to be charged B when charging by the first power supply battery 11 ends, the fourth electromagnetic relay 2d opens and the switch 42 closes, connecting the third power supply battery 13 to the battery to be charged B via the sixth electromagnetic relay 2f and so on.

[0050] That is, as the fourth electromagnetic relay 2d opens, the movable body 203 of the fourth electromagnetic relay 2d moves in a direction protruding from the fourth electromagnetic relay 2d, and is pressed by the movable body 203 to close the switch 42. Then, the second terminal 22 of the sixth electromagnetic relay 2f is connected to the positive electrode Bp of the battery to be charged B via the switch 42, the diode 34, and the output electromagnetic relay 2o. The first terminal 21 of the sixth electromagnetic relay 2f is connected to the positive electrode 1p of the third supply battery 13. Because the third supply battery 13 is not discharging while being charged by the first and second supply batteries 11 and 12, it can have a higher state of charge than the battery to be charged B. Therefore, current flows from the third supply battery 13 to the first terminal 21 and then to the second terminal 22 of the sixth electromagnetic relay 2f. Therefore, the sixth electromagnetic relay 2f is closed, establishing electrical continuity between its third terminal 23 and fourth terminal 24, connecting the positive electrode 1p of the third power supply battery 13 to the first terminals of the seventh and eighth electromagnetic relays 2g and 2h. If the charging rate of the third power supply battery 13 is still higher than that of the battery to be charged B, current flows from the third power supply battery 13 to the positive electrode Bp of the battery to be charged B through the seventh electromagnetic relay 2g and output electromagnetic relay 2o. Therefore, the seventh electromagnetic relay 2g is closed, and the eighth electromagnetic relay 2h is also closed. The third power supply battery 13 and the battery to be charged B are connected via the sixth electromagnetic relay 2f, the eighth electromagnetic relay 2h, and the output electromagnetic relay 2o, and the battery to be charged B is charged by the third power supply battery 13.

[0051] During charging by the third supply battery 13, charging by the fourth and fifth supply batteries 14, 15 does not occur, just as charging by the third to fifth supply batteries 13-15 does not occur during charging by the second supply battery. Furthermore, current flowing from the charge target battery B, whose charging rate increases as charging by the third supply battery 13 progresses, to the second supply battery 12 is prevented by diodes 32, 33.

[0052] As the third power supply battery 13 continues charging the chargeable battery B, the charging rate of the third power supply battery 13 decreases and the charging rate of the chargeable battery B increases. When this becomes approximately equal, charging by the third power supply battery 13 ends. Current also stops flowing from the third power supply battery 13 through the path via the sixth electromagnetic relay 2f. For example, if the charging rate of the third power supply battery 13 was 100% before the connection of the chargeable battery B, and the chargeable battery B was charged to 75% by the second power supply battery 12, charging by the third power supply battery 13 ends when the charging rates of the chargeable battery B and the third power supply battery 13 both reach approximately 87.5%.

[0053] When charging by the third supply battery 13 is completed, the fourth supply battery 14 is connected to the chargeable battery B via the ninth electromagnetic relay 2i, and charging of the chargeable battery B by the fourth supply battery 14 begins, just as when charging by the second supply battery 12 was completed and the third supply battery 13 was connected to the chargeable battery B and charging by the third supply battery 13 began. During charging by the fourth supply battery 14, charging by the fifth supply battery 15 does not occur, just as charging by the fourth and fifth supply batteries 14, 15 does not occur during charging by the third supply battery. Furthermore, current flowing from the chargeable battery B to the third supply battery 13 is prevented, just as current flow from the chargeable battery B to the second supply battery 12 was prevented during charging by the third supply battery 13.

[0054] When the charging rate of the fourth supply battery 14 and the charging rate of the chargeable battery B become approximately the same, charging by the fourth supply battery 14 ends. For example, if the charging rate of the fourth supply battery 14 before the connection of the chargeable battery B is 100%, and the chargeable battery B is charged to a charging rate of 87.5% by the third supply battery 13, charging by the fourth supply battery 14 ends when the charging rates of the chargeable battery B and the fourth supply battery 14 both reach approximately 93.75%.

[0055] When charging by the fourth supply battery 14 is completed, the fifth supply battery 15 is connected to the battery to be charged B via the twelfth electromagnetic relay 2l, and charging of the battery to be charged by the fifth supply battery 15 begins, in the same way that charging by the third supply battery 13 was completed and the fourth supply battery 14 was connected to the battery to be charged B and charging by the fourth supply battery 14 began. During charging by the fifth supply battery 15, current flowing from the battery to be charged B to the fourth supply battery 14 is prevented, in the same way that current flow from the battery to be charged B to the third supply battery 13 was prevented during charging by the fourth supply battery 14.

[0056] When the charging rate of the fifth power supply battery 15 and the charging rate of the chargeable battery B become approximately the same, charging by the fifth power supply battery 15 ends. For example, if the charging rate of the fifth power supply battery 15 before the connection of the chargeable battery B is 100% and the chargeable battery B is charged to a charging rate of 93.75% by the fourth power supply battery 14, charging by the fifth power supply battery 15 ends when the charging rates of the chargeable battery B and the fifth power supply battery 15 both become approximately 96.875%.

[0057] As described above, in the battery charging device 100, when charging by each power supply battery (the nth power supply battery) is completed, one of the multiple electromagnetic relays, such as the first electromagnetic relay 2a or the fourth electromagnetic relay 2d, is opened. Then, in the battery charging device 100, as the one electromagnetic relay is opened, a switch that opens and closes by engaging with the one electromagnetic relay, such as switches 41 and 42, is closed. The battery charging device 100 is configured such that, by closing the switch that opens and closes by engaging with the one electromagnetic relay, the power supply battery that will next charge the chargeable battery B (i.e., the (n+1)th power supply battery) is connected to the chargeable battery B by an electromagnetic relay other than the one electromagnetic relay. Because the battery charging device 100 is configured in this manner, even if the charging rate of the nth power supply battery decreases due to charging of the chargeable battery B and charging by the nth power supply battery is completed, the (n+1)th power supply battery can continue to charge the chargeable battery B to a higher charging rate.

[0058] FIG. 3 shows a specific example of the aforementioned charging prevention means in the battery charging device 100 of FIG. 1, which prevents at least the (n+2)th to Nth power supply batteries from charging the chargeable battery B while the nth power supply battery is charging the chargeable battery B. In the example shown in FIG. 3, the battery charging device 100 is provided with cutoff switches 44 and 45 as such charging prevention means. The cutoff switch 44 is arranged to engage with the moving body 203 of the second electromagnetic relay 2b and opens and closes in response to displacement of the moving body 203 of the second electromagnetic relay 2b. Similarly, the cutoff switch 45 is arranged to engage with the moving body 203 of the fifth electromagnetic relay 2e and opens and closes in response to displacement of the moving body 203 of the fifth electromagnetic relay 2e. As an example, the cutoff switches 44 and 45 are pushbutton switches, preferably tactile switches that are closed (on) only while pressed. 3, just like in FIG. 1, only the seventh electromagnetic relay 2g to the twelfth electromagnetic relay 2l are shown within frames L3 and L4. However, similar to the cutoff switch 45 within frame L2, a cutoff switch (not shown) is also disposed within frame L3, which engages with the eighth electromagnetic relay 2h and opens and closes in response to displacement of its moving body. Similarly, a cutoff switch (not shown) is also disposed within frame L4, which engages with the eleventh electromagnetic relay 2k and opens and closes in response to displacement of its moving body.

[0059] In the battery charging device 100 of FIG. 3, the second terminals 22 of the first, fourth, seventh, tenth, and thirteenth electromagnetic relays 2a, 2d, 2g, 2j, and 2m are connected to a bus wiring 7 connected to the first terminal 21 of the output electromagnetic relay 2o either directly or via diodes in a bus-connected manner. The first, fourth, seventh, tenth, and thirteenth electromagnetic relays 2a, 2d, 2g, 2j, and 2m are connected to the bus wiring 7 in this order from the side closest to the output electromagnetic relay 2o. Both ends of the cutoff switch 44 and the cutoff switch 45 are connected to the bus wiring 7. The cutoff switch 44 is interposed between the first electromagnetic relay 2a and the fourth electromagnetic relay 2d, and electrically disconnects or connects the bus wiring 7 between the first electromagnetic relay 2a and the fourth electromagnetic relay 2d. The cutoff switch 45 is interposed between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g, and electrically disconnects or connects the bus wiring 7 between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g. Similarly, a cutoff switch (not shown) engaged with the eighth electromagnetic relay 2h or the eleventh electromagnetic relay 2k electrically disconnects or connects the bus wiring 7 between the seventh electromagnetic relay 2g and the tenth electromagnetic relay 2j, or between the tenth electromagnetic relay 2j and the thirteenth electromagnetic relay 2m. Therefore, cutoff switches such as the cutoff switch 44 shown in FIG. 3 are examples of charging prevention means that prevent not only the (n+2)th to Nth power supply batteries but also the (n+1)th power supply battery from charging the chargeable battery B while the nth power supply battery is charging the chargeable battery B.

[0060] In the battery charging device 100 of FIG. 3, while the first power supply battery 11 is charging the chargeable battery B, the first electromagnetic relay 2a is closed, and therefore the second electromagnetic relay 2b is also closed. Therefore, the moving object 203 of the second electromagnetic relay 2b moves toward the inside of the second electromagnetic relay 2b, and the cutoff switch 44 is opened. This causes the bus wiring 7 to be disconnected between the connection point with the first electromagnetic relay 2a and the connection point with the fourth electromagnetic relay 2d. Therefore, even if the sixth, ninth, and twelfth electromagnetic relays 2f, 2i, and 2l are closed, the third through fifth power supply batteries 13-15 and the chargeable battery B are not connected and are electrically isolated. In other words, while the first power supply battery 11 is charging the chargeable battery B, the third through fifth power supply batteries 13-15 are prevented from charging the chargeable battery B.

[0061] While the chargeable battery B is being charged by the second power supply battery 12, the fourth electromagnetic relay 2d is closed, and therefore the fifth electromagnetic relay 2e is also closed. This causes the cutoff switch 45 to be opened, and the bus wiring 7 is disconnected between the connection point with the fourth electromagnetic relay 2d and the connection point with the seventh electromagnetic relay 2g. Therefore, even if the ninth and twelfth electromagnetic relays 2i and 2l are closed, the fourth and fifth power supply batteries 14 and 15 are not connected to the chargeable battery B and are electrically isolated. In other words, while the chargeable battery B is being charged by the second power supply battery 12, charging of the chargeable battery B by the fourth and fifth power supply batteries 14 and 15 is prevented.

[0062] Similarly, while the chargeable battery B is being charged by the third power supply battery 13, the seventh electromagnetic relay 2g is closed, so the breaker switch (not shown) that engages with the eighth electromagnetic relay 2h is opened, and the bus wiring 7 is disconnected between the connection point with the seventh electromagnetic relay 2g and the connection point with the tenth electromagnetic relay 2j. Therefore, even if the twelfth electromagnetic relay 2l is closed, the fifth power supply battery 15 and the chargeable battery B are not connected but electrically isolated, and charging of the chargeable battery B by the fifth power supply battery 15 is prevented.

[0063] 3 may be interposed between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g, rather than between the first electromagnetic relay 2a and the fourth electromagnetic relay 2d, to electrically disconnect or connect the bus wiring 7 between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g. Furthermore, the interrupter switch 45 may be interposed between the seventh electromagnetic relay 2g and the tenth electromagnetic relay 2j, rather than between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g, to electrically disconnect or connect the bus wiring 7 between the seventh electromagnetic relay 2g and the tenth electromagnetic relay 2j. Similarly, a not-shown interrupter switch that engages with the eighth electromagnetic relay 2h may be interposed between the tenth electromagnetic relay 2j and the thirteenth electromagnetic relay 2m, rather than between the seventh electromagnetic relay 2g and the tenth electromagnetic relay 2j, to electrically disconnect or connect the bus wiring 7 between the tenth electromagnetic relay 2j and the thirteenth electromagnetic relay 2m. In this case, each of the cutoff switches such as cutoff switches 44, 45 prevents the (n+2)th to Nth power supply batteries from charging the chargeable battery B while the nth power supply battery is charging the chargeable battery B. As described above, charging of the chargeable battery B by the (n+1)th power supply battery while the nth power supply battery is charging the chargeable battery B is prevented by any of the third, sixth, ninth, and twelfth electromagnetic relays 2c, 2f, 2i, and 2l being in the open state.

[0064] 3, charging prevention means such as cutoff switches 44 and 45 prevent the (n+1)th to Nth supply batteries from charging the chargeable battery B while the nth supply battery is charging the chargeable battery B. The battery charging apparatus of the embodiment may include, as such charging prevention means, a cutoff switch that is opened by an electromagnetic relay that is closed while the nth supply battery is charging the chargeable battery B, thereby electrically isolating at least the (n+2)th to Nth supply batteries from the chargeable battery B. Note that, as described above, if the battery charging apparatus of the embodiment includes only two supply batteries, charging prevention means such as cutoff switches 44 and 45 that prevent at least the (n+2)th to Nth supply batteries from charging the chargeable battery B while the nth supply battery is charging the chargeable battery B may not be provided.

[0065] FIG. 4 is a schematic circuit diagram illustrating a battery charging device 100a, which is a modified example of the battery charging device 100 shown in FIGS. 1 and 3. The battery charging device 100a does not include the third, sixth, ninth, twelfth, and thirteenth electromagnetic relays 2c, 2f, 2i, 2l, and 2m that are included in the battery charging device 100 shown in FIG. 1 and other figures. In addition, the battery charging device 100a does not include the diodes 33 and 34 and the diodes (not shown) that are similarly arranged within boxes L3 and L4 in FIG. 1 and that are included in the battery charging device 100 shown in FIG. 1 and other figures. That is, the positive electrode 1p of the second power supply battery 12 is directly connected to the first terminal 21 of the fourth electromagnetic relay 2d and the first and third terminals 21 and 23 of the fifth electromagnetic relay 2e. Although not shown, the positive electrode 1p of the third power supply battery 13 is directly connected to the first terminal of the seventh electromagnetic relay 2g and the first and third terminals of the eighth electromagnetic relay 2h, the positive electrode 1p of the fourth power supply battery 14 is directly connected to the first terminal of the tenth electromagnetic relay 2j and the first and third terminals of the eleventh electromagnetic relay 2k, and the positive electrode 1p of the fifth power supply battery 15 is directly connected to the first terminal 21 and the third terminal 23 of the fourteenth electromagnetic relay 2n.

[0066] 3, the switch 41 that engages with the moving body 203 of the first electromagnetic relay 21 is connected to the bus wiring 7 so as to be interposed between the first electromagnetic relay 2a and the fourth electromagnetic relay 2d. Therefore, the switch 41 electrically disconnects the bus wiring 7 between the connection point with the first electromagnetic relay 2a and the connection point with the fourth electromagnetic relay 2d when the first electromagnetic relay 2a is in a closed state, and conducts the bus wiring 7 when the first electromagnetic relay 2a is in an open state. Furthermore, the switch 42 that engages with the moving body 203 of the fourth electromagnetic relay 2d is connected to the bus wiring 7 so as to be interposed between the fourth electromagnetic relay 2d and the seventh electromagnetic relay 2g, similar to the disconnecting switch 45 of FIG. 3, therefore, the switch 42 electrically disconnects the bus wiring 7 between the connection point with the fourth electromagnetic relay 2d and the connection point with the seventh electromagnetic relay 2g when the fourth electromagnetic relay 2d is in a closed state, and conducts the bus wiring 7 when the fourth electromagnetic relay 2d is in an open state.

[0067] Although not shown, a switch that engages with the moving body of the seventh electromagnetic relay 2g is also provided within frame L3, and is connected to the bus wiring 7 so as to be interposed between the seventh electromagnetic relay 2g and the tenth electromagnetic relay 2j. The bus wiring 7 is electrically disconnected between the connection point with the seventh electromagnetic relay 2g and the connection point with the tenth electromagnetic relay 2j when the seventh electromagnetic relay 2g is in a closed state, and is conductive when the seventh electromagnetic relay 2g is in an open state. Similarly, a switch that engages with the moving body of the tenth electromagnetic relay 2j is also provided within frame L4, and is connected to the bus wiring 7 so as to be interposed between the tenth electromagnetic relay 2j and the fourteenth electromagnetic relay 2n. The bus wiring 7 is electrically disconnected between the connection point with the tenth electromagnetic relay 2j and the fourteenth electromagnetic relay 2n when the tenth electromagnetic relay 2j is in a closed state, and is conductive when the tenth electromagnetic relay 2j is in an open state.

[0068] 4, while the first power supply battery 11 is charging the chargeable battery B, the first electromagnetic relay 2a is closed and the switch 41 is open. As a result, the bus line 7 is disconnected between the connection point with the first electromagnetic relay 2a and the connection point with the fourth electromagnetic relay 2d. Therefore, the second to fifth power supply batteries 12 to 15 are not connected to the chargeable battery B and are electrically isolated. In other words, while the first power supply battery 11 is charging the chargeable battery B, the second to fifth power supply batteries 12 to 15 are prevented from charging the chargeable battery B.

[0069] While the chargeable battery B is being charged by the second power supply battery 12, the fourth electromagnetic relay 2d is closed, and therefore the switch 42 is open. As a result, the bus line 7 is disconnected between the connection point with the fourth electromagnetic relay 2d and the connection point with the seventh electromagnetic relay 2g. Therefore, the third to fifth power supply batteries 13-15 and the chargeable battery B are not connected and are electrically isolated. In other words, while the chargeable battery B is being charged by the second power supply battery 12, charging of the chargeable battery B by the third to fifth power supply batteries 13-15 is prevented.

[0070] Similarly, while the third power supply battery 13 is charging the chargeable battery B, the seventh electromagnetic relay 2g is closed, so the switch (not shown) engaging with the seventh electromagnetic relay 2g is open, and the bus line 7 is disconnected between the connection point with the seventh electromagnetic relay 2g and the connection point with the tenth electromagnetic relay 2j. As a result, the fourth power supply battery 14 and the fifth power supply battery 15 are not connected to the chargeable battery B and are electrically isolated, preventing the fourth power supply battery 14 and the fifth power supply battery 15 from charging the chargeable battery B. Also, while the fourth power supply battery 14 is charging the chargeable battery B, the tenth electromagnetic relay 2j is closed, so the switch (not shown) engaging with the tenth electromagnetic relay 2j is open, and the bus line 7 is disconnected between the connection point with the tenth electromagnetic relay 2j and the fourteenth electromagnetic relay 2n. As a result, charging of the chargeable battery B by the fifth power supply battery 15 is prevented.

[0071] 4, when charging of the chargeable battery B by the first power supply battery 11 is completed, the first electromagnetic relay 2a is opened, the switch 41 is closed, and the second power supply battery 12 is connected to the chargeable battery B via the fourth electromagnetic relay 2d and the fifth electromagnetic relay 2e. When charging of the chargeable battery B by the second power supply battery 12 is completed, the fourth electromagnetic relay 2d is opened, and the switch 42 is closed, and the third power supply battery 13 is connected to the chargeable battery B via the seventh electromagnetic relay 2g and the eighth electromagnetic relay 2h. Similarly, when charging of the chargeable battery B by the third power supply battery 13 is completed, the seventh electromagnetic relay 2g is opened, and the fourth power supply battery 14 is connected to the chargeable battery B via the tenth electromagnetic relay 2j and the eleventh electromagnetic relay 2k. When charging of the battery to be charged by the fourth power supply battery 14 is completed, the tenth electromagnetic relay 2j is opened, and the fifth power supply battery 15 is connected to the battery to be charged B via the fourteenth electromagnetic relay 2n.

[0072] That is, in the battery charging device 100a, when charging of the chargeable battery B by the nth power supply battery is completed, one of the electromagnetic relays is opened, and the (n+1)th power supply battery is connected to the chargeable battery B by one of the electromagnetic relays other than the opened relay. Thus, the power supply batteries are connected to the chargeable battery B one by one in sequence, and the chargeable battery B is charged by each power supply battery. Therefore, as described above, the chargeable battery B can be charged stepwise and quickly to a higher charging rate. The battery charging device 100a of this modified example includes 10 (N times 2) electromagnetic relays for N=5 power supply batteries. The battery charging device of the embodiment may include 2N times or more electromagnetic relays (N is the number of power supply batteries and is an integer equal to or greater than 2), as in the example of FIG. 4.

[0073] <Battery charging device according to another embodiment> Next, a battery charging device according to another embodiment of the present invention will be described. FIG. 5 shows a battery charging device 101, which is an example of a battery charging device according to another embodiment. Although the illustration within frame L5 is omitted in FIG. 5, the first to fourteenth electromagnetic relays 2a to 2n, diodes such as diodes 31 to 34, and switches such as switches 41, 42, 44, and 45 are arranged within frame L5, similar to the two-dot chain line frame L5 in FIGS. 1 and 3. These components are connected to each other in the same manner as in FIG. 1 or 3. The electromagnetic relays, diodes, and switches may be arranged within frame L5 in FIG. 5, similar to the two-dot chain line frame L5 in FIG. 4, and these components may be connected to each other in the same manner as in FIG. 4. The components not shown within frame L5 in FIG. 5 function and operate similarly to the components shown within frame L5 in FIG. 1, 3, or 4, and therefore repeated description of these components will be omitted.

[0074] As shown in FIG. 5, in addition to the components of the battery charging device 100 in FIG. 1, the battery charging device 101 further includes a connector 5, a connector electromagnetic relay 2p connected to the connector 5, and a switch 40. The positive terminal 5p and negative terminal 5n of the connector 5 are connected to the positive terminal Cp and negative terminal Cn of the output plug of the external charger C, respectively. In the example of FIG. 5, three connectors 5 are provided and connected in parallel with each other. Note that the battery charging device of this embodiment may include any number of connectors 5, one or more, to which external chargers are connected.

[0075] 2A, similar to the output electromagnetic relay 2o, etc. That is, the connector electromagnetic relay 2p has a first terminal 21, a second terminal 22, a third terminal 23, and a fourth terminal 24, and is configured so that when a current flows from the first terminal 21 to the second terminal 22, conduction occurs between the third terminal 23 and the fourth terminal 24. As an example, the connector electromagnetic relay 2p may be an electromagnetic contactor (a so-called magnetic switch) provided in a starter motor used to start an internal combustion engine, such as a magnetic switch provided in a starter motor of an automobile.

[0076] The switch 40 is disposed so as to engage with the moving body 203 of the output electromagnetic relay 2o, and opens and closes according to the displacement of the moving body 203 of the output electromagnetic relay 2o. As an example, the switch 40 is a push button switch, similar to the switches 41 and 42 in Fig. 1, and is preferably a tactile switch that is closed only while being pressed.

[0077] The first terminal 21 of the connector electromagnetic relay 2p is connected to the positive electrode 5p of the connector 5 via the switch 40, and the third terminal 23 is connected directly to the positive electrode 5p of the connector 5. Meanwhile, the second terminal 22 and the fourth terminal 24 of the connector electromagnetic relay 2p are connected to the positive electrode connection terminal Tp, as are the second terminal 22 and the fourth terminal 24 of the output electromagnetic relay 2o. Preferably, the second terminal 22 and the fourth terminal 24 of the connector electromagnetic relay 2p are connected to the positive electrode connection terminal Tp by separate conductive wires, as shown in FIG. 5 . This reduces the effect on the current flowing from the second terminal 22 to the positive electrode connection terminal Tp of a voltage drop caused by a large current that may flow between the fourth terminal 24 and the positive electrode connection terminal Tp when the chargeable battery B is being charged by the external charger C. More preferably, as shown in FIG. 5, the second terminal 22 of the output electromagnetic relay 2o and the second terminal 22 of the connector electromagnetic relay 2p are also connected to the positive electrode connection terminal Tp by separate conductive wires, as shown in FIG. 5.

[0078] The connector electromagnetic relay 2p in the example of Fig. 5 includes a moving body (second moving body) 211 that displaces as the connector electromagnetic relay 2p switches between an open state and a closed state, similar to the output electromagnetic relay 2o. In the battery charging device 101 of Fig. 5, the moving body 211 moves toward the inside of the connector electromagnetic relay 2p when a current flows from the first terminal 21 to the second terminal 22 of the connector electromagnetic relay 2p. On the other hand, when no current flows from the first terminal 21 to the second terminal 22, the moving body 211 is configured to protrude toward the outside from the connector electromagnetic relay 2p as shown by arrow A in Fig. 5.

[0079] The first terminal 21 of the connector electromagnetic relay 2p is also connected to a conductor 61 that is connected to the moving object 211 and moves together with the moving object 211. That is, the positive electrode 5p of the connector 5 is also connected to the conductor 61 via the switch 40. The negative electrode 5n of the connector 5 is connected to the ground potential G and is electrically connected directly to the negative electrodes 1n of the first to fifth power supply batteries 11 to 15. In this embodiment, the positive electrodes 1p of the N power supply batteries (the first to fifth power supply batteries 11 to 15 in FIG. 5 ) are individually connected to conductors 62 that are respectively disposed near the conductor 61. The conductors 62 are positioned so as to come into contact with the conductor 61 when no current flows from the first terminal 21 to the second terminal 22 of the connector electromagnetic relay 2p, that is, when the conductor 61 moves together with the moving object 211 in the direction away from the connector electromagnetic relay 2p as indicated by the arrow A.

[0080] In the battery charging device 101 of FIG. 5, while the first through fifth power supply batteries 11 through 15 are charging the chargeable battery B, a current flows between the first terminal 21 and the second terminal 22 of the output electromagnetic relay 2o, causing the output electromagnetic relay 2o to be closed. This causes the switch 40 to be open, separating the first terminal 21 of the connector electromagnetic relay 2p from the positive terminal 5p of the connector 5. Because the connector electromagnetic relay 2p is open, the chargeable battery B will not be charged by the charger C, even if the charger C is connected to the connector 5. Furthermore, because the connector electromagnetic relay 2p is open, the conductors 61 and 62 are in contact, but the open switch 40 separates the connector 5 from the conductor 61. Therefore, even if the charger C is connected to the connector 5, the first through fifth power supply batteries 11 through 15 will not be charged by the charger C.

[0081] Then, when charging of the battery to be charged by the first to fifth power supply batteries 11 to 15 is completed, current no longer flows between the first terminal 21 and the second terminal 22 of the output electromagnetic relay 2o, and the output electromagnetic relay 2o enters an open state. That is, the movable body 203 of the output electromagnetic relay 2o moves in a direction protruding from the output electromagnetic relay 2o. As a result, the switch 40 is pressed by the movable body 203 of the output electromagnetic relay 2o and enters a closed state, connecting the first terminal 21 of the connector electromagnetic relay 2p to the positive electrode 5p of the connector 5. Current flows from the charger C through the first terminal 21 and second terminal 22 of the connector electromagnetic relay 2p to the battery to be charged B, and the connector electromagnetic relay 2p enters a closed state.

[0082] That is, the third terminal 23 and the fourth terminal 24 of the connector electromagnetic relay 2p are electrically connected, and the charger C and the battery to be charged B are connected via the third terminal 23 and the fourth terminal 24 of the connector electromagnetic relay 2p. Therefore, the battery to be charged 5B, which has been charged by the first to fifth power supply batteries 11 to 15, is further charged by the charger C.

[0083] In this manner, in this embodiment, when charging of the chargeable battery B by the N power supply batteries (first to fifth power supply batteries 11 to 15 in the example of FIG. 5) is completed, the connector electromagnetic relay 2p connects the connector 5 to the chargeable battery B. Therefore, after charging by the N power supply batteries, charging by the charger C may automatically begin for the chargeable battery B that has not been fully charged. Therefore, the chargeable battery B that has not been fully charged can be further charged, thereby further increasing its charging rate.

[0084] Furthermore, in the battery charging device 101, when the output electromagnetic relay 2o is opened, the switch 40 is closed, electrically connecting the conductor 61 to the positive electrode 5p of the connector 5. However, while current flows between the first terminal 21 and the second terminal 22 of the connector electromagnetic relay 2p, the moving body 211 of the connector electromagnetic relay 2p moves toward the inside of the connector electromagnetic relay 2p, separating the conductor 61 from each of the conductors 62, as shown in FIG. 5. This also electrically separates the positive electrode Cp of the connector C from the positive electrodes 1p of the first to fifth power supply batteries 11 to 15. Therefore, even if a charger C is connected to the connector 5, the first to fifth power supply batteries 11 to 15 are not charged by the charger C.

[0085] Then, when the battery to be charged B reaches a fully charged state, for example, and charging by the charger C ends, current stops flowing between the first terminal 21 and the second terminal 22 of the connector electromagnetic relay 2p. Because the connector electromagnetic relay 2p opens, the moving body 211 protrudes in the direction of arrow A in FIG. 5. The conductor 61 also moves with the moving body 211 and abuts against each conductor 62. Therefore, the positive electrodes 1p of each of the first to fifth power supply batteries 11 to 15 are connected to the positive electrode Cp of the charger C via the conductors 62, 61, switch 40, and connector 5. Therefore, each power supply battery after charging the battery to be charged B is charged by the charger C.

[0086] 5 is configured so that when current stops flowing from the connector 5 to the chargeable battery B, the connector electromagnetic relay 2p opens and the connector 5 and each of the N power supply batteries are electrically connected by the contact between the conductor 61 and the conductor 62 caused by the displacement of the mobile object 211. Therefore, after the charging of the chargeable battery B by the N power supply batteries is completed and the final charging of the chargeable battery B by an external charger such as charger C is also completed, charging of the N power supply batteries by the external charger can be automatically started. In other words, the N power supply batteries whose charging rates have decreased due to the charging of the chargeable battery B can be recharged, and their respective charging rates can be restored, preferably to a fully charged state.

[0087] In the battery charging device 101 of FIG. 5, while the chargeable battery B is being charged by N power supply batteries (first to fifth power supply batteries 11-15 in the example of FIG. 5), the positive electrodes 1p of the power supply batteries are connected to each other via the conductors 62 and 61. Therefore, as described above, it may not be possible to connect power supply batteries having a higher charging rate than the chargeable battery B one by one to the chargeable battery B and charge the chargeable battery B to a higher charging rate in stages as intended. Therefore, while charging is being performed by the N power supply batteries, it is preferable to manually or automatically separate the positive electrodes 1p of the power supply batteries from each other. For example, each power supply battery may be connected to each conductor 62 via a connector (not shown), and the connector may be separated when each power supply battery starts charging the chargeable battery B and connected when each power supply battery finishes charging.

[0088] 5 may be coupled to the conductor 61 in such a manner that only the action caused by the displacement of the moving body 203 when the output electromagnetic relay 2o is in the closed state is transmitted to the conductor 61 (i.e., in such a manner that the displacement of the conductor 61 when the connector electromagnetic relay 2p is in the closed state does not act on the moving body 203). For example, the end of a hook-like part such as a hook may be attached to the moving body 203 of the output electromagnetic relay 2o on the side opposite to the hook portion, and the hook portion of the part may be hooked onto the surface of the conductor 61 facing the conductor 62. By engaging the moving body 203 of the output electromagnetic relay 2o with the conductor 61 in this manner, when the output electromagnetic relay 2o is in the closed state, i.e., while the chargeable battery B is being charged by each power supply battery, the conductor 61 can be separated from each conductor 62 by the displacement of the moving body 203 toward the inside of the output electromagnetic relay 2o. That is, by separating the conductor 61 from each of the conductors 62, the positive electrodes 1p of the power supply batteries can be separated from each other. On the other hand, even if the conductor 61 is displaced in a direction away from the conductor 62 when the connector electromagnetic relay 2p is closed, the displacement does not act on the movable body 203 of the output electromagnetic relay 2o. Therefore, the displacement of the conductor 61 does not interfere with the movement of the movable body 203 to close the switch 40.

[0089] FIG. 6 shows a modified example of the battery charging device 101 of FIG. 5 , which has a means for isolating the positive electrodes 1p of the power supply batteries from each other during charging by the power supply batteries, different from the above example. The battery charging device 101 of the example of FIG. 6 includes an electromagnetic relay 2r for the power supply battery, a switch 43, and a diode 35 in addition to the components included in the battery charging device 101 of FIG. 5 . In FIG. 6 , components similar to those included in the battery charging device 101 of FIG. 5 are assigned the same reference numerals as in FIG. 5 , and redundant descriptions of those components will be omitted. Note that, in the example of FIG. 6 , the second terminal 22 and the fourth terminal 24 of the connector electromagnetic relay 2p are preferably connected to the positive electrode connection terminal Tp by separate conductive wires, as shown in FIG. 6 .

[0090] 2A, the electromagnetic relay 2r for the power supply battery has the same structure as the output electromagnetic relay 2o. That is, the electromagnetic relay 2r for the power supply battery has a first terminal 21, a second terminal 22, a third terminal 23, and a fourth terminal 24, and is configured so that when a current flows from the first terminal 21 to the second terminal 22, conduction occurs between the third terminal 23 and the fourth terminal 24. As an example, the electromagnetic relay 2r for the power supply battery may be an electromagnetic contactor (a so-called magnetic switch) provided in a starter motor used to start an internal combustion engine, such as a magnetic switch provided in a starter motor of an automobile.

[0091] In the example of Fig. 6, the moving body 211 of the electromagnetic relay 2p for connector is not connected to the conductor 61 as in Fig. 5, but is engaged with the switch 43. That is, the switch 43 opens and closes by the displacement of the moving body 211 of the electromagnetic relay 2p for connector. When the electromagnetic relay 2p for connector is in the open state, the switch 43 is closed by the displacement of the moving body 211 protruding outward from the electromagnetic relay 2p for connector, and when the electromagnetic relay 2p for connector is in the closed state, the switch 43 is opened by the displacement of the moving body 211 toward the inside of the electromagnetic relay 2p for connector. As an example, the switch 43 is a push button switch, similar to the switch 40, and is preferably a tactile switch that is closed only while it is pressed.

[0092] The first terminal 21 of the electromagnetic relay 2r for the power supply battery is connected to the positive pole 5p of the connector 5 via the switches 43 and 40, together with the third terminal 23. When the switches 40 and 43 are closed, the first terminal 21 and the third terminal 23 of the electromagnetic relay 2r for the power supply battery are electrically connected to the positive pole 5p of the connector 5. The second terminal 22 of the electromagnetic relay 2r for the power supply battery is connected to the ground potential G, and the fourth terminal 24 is connected to the conductor 61.

[0093] Like the output electromagnetic relay 2o, the power supply battery electromagnetic relay 2r includes a moving body (third moving body) 212 that displaces as the power supply battery electromagnetic relay 2r switches between an open state and a closed state. In the battery charging device 101 shown in FIG. 6, a conductor 61 is connected to the moving body 212 of the power supply battery electromagnetic relay 2r. The conductor 61 moves together with the moving body 212. When a current flows from the first terminal 21 to the second terminal 22 of the power supply battery electromagnetic relay 2r, i.e., when the power supply battery electromagnetic relay 2r is closed, the moving body 212 moves toward the inside of the power supply battery electromagnetic relay 2r, as shown by arrow A in FIG. 6. On the other hand, when no current flows from the first terminal 21 to the second terminal 22, i.e., when the power supply battery electromagnetic relay 2r is open, the moving body 212 is configured to protrude toward the outside from the power supply battery electromagnetic relay 2r. The conductor 61 is displaced in accordance with the behavior of the moving body 212 .

[0094] 6, each conductor 62 individually connected to the positive electrode 1p of each of the N power supply batteries (first to fifth power supply batteries 11 to 15 in FIG. 6) is positioned so that the conductor 62 comes into contact with the conductor 61 when the conductor 61 moves in the direction indicated by arrow A toward the power supply battery electromagnetic relay 2r. That is, when a current flows from the first terminal 21 to the second terminal 22 of the power supply battery electromagnetic relay 2r, the power supply battery electromagnetic relay 2r is closed and the conductors 61 and 62 come into contact with each other. Therefore, when both the switch 40 and the switch 43 are closed and a current flows from the positive electrode 5p of the connector 5 through the first terminal 21 and the second terminal 22 of the power supply battery electromagnetic relay 2r to ground potential G, the positive electrode 5p of the connector 5 is electrically connected to the positive electrode 1p of each of the first to fifth power supply batteries 11 to 15.

[0095] 6, while the chargeable battery B is being charged by the first to fifth power supply batteries 11 to 15, the output electromagnetic relay 2o is closed and the switch 40 is open, so no current flows to the first terminal 21 of either the connector electromagnetic relay 2p or the power supply battery electromagnetic relay 2r. Therefore, because both the connector electromagnetic relay 2p and the power supply battery electromagnetic relay 2r are open, the positive electrode 5p of the connector 5 is not connected to the chargeable battery B, nor is it connected to the positive electrodes 1p of each of the first to fifth power supply batteries 11 to 15. Note that at this time, a current (reverse flow) that could flow from the chargeable battery B to the power supply battery electromagnetic relay 2r via the second terminal 22 and first terminal 21 of the connector electromagnetic relay 2p is prevented by the diode 35.

[0096] When charging of the chargeable battery B by the first to fifth power supply batteries 11 to 15 is completed, as described above, the output electromagnetic relay 2o opens, causing the switch 40 to close, and the connector electromagnetic relay 2p closes, connecting the positive terminal 5p of the connector 5 to the chargeable battery B. The chargeable battery B is finally charged by the charger C. Meanwhile, the displacement of the moving body 211 of the connector electromagnetic relay 2p, which is now closed, causes the switch 43 to open. Therefore, the power supply battery electromagnetic relay 2r does not close, and the positive terminal 5p of the connector 5 remains separated from the positive terminals 1p of the first to fifth power supply batteries 11 to 15.

[0097] Then, when charging of the chargeable battery B by the charger C is completed, as described above, the connector electromagnetic relay 2p enters an open state, and the moving object 211 protrudes outward from the connector electromagnetic relay 2p. This causes the switch 43 to close, and current flows from the positive terminal 5p of the connector 5 to the first and second terminals 21 and 22 of the power supply battery electromagnetic relay 2r and to ground potential G. This causes the power supply battery electromagnetic relay 2r to close, and the conductors 61 and 62 come into contact. As a result, the positive terminal 5p of the connector 5 is electrically connected to the positive terminals 1p of the first through fifth power supply batteries 11 through 15 via the switch 40, the switch 43, the third and fourth terminals 23 and 24 of the power supply battery electromagnetic relay 2r, the conductors 61 and 62, and the conductors 61 and 62. Therefore, the first through fifth power supply batteries 11 through 15 are charged by the charger C.

[0098] In this way, in the battery charging device 101 of the example of Figure 6, while the first to fifth power supply batteries 11 to 15 are charging the chargeable battery B, the positive electrodes 1p of each power supply battery can be separated from each other, and then, after charging of the chargeable battery B by the charger C is completed, the connectors 5 and each power supply battery can be automatically connected, and each power supply battery can be charged by the charger C.

[0099] <How to charge the battery> Next, a battery charging method according to an embodiment of the present invention will be described with reference to FIG. 1 again. The battery charging method according to this embodiment is a method for charging a target battery using N (N is an integer equal to or greater than 2) power supply batteries, from the first power supply battery 11 to the fifth power supply battery 15 shown in FIG. 1 , and at least M (M is an integer equal to N times 3) electromagnetic relays. For example, a plurality of electromagnetic relays, such as the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o shown in FIG. 1 , are used in the battery charging method according to this embodiment. The battery charging method according to this embodiment will be described below using the battery charging device 100 shown in FIG. 1 as an example. Note that the battery charging method according to this embodiment may be implemented using the battery charging device 100 shown in FIG. 1 or 3 or the battery charging device 101 shown in FIG. 5 or 6 as described below, but is not limited to using the battery charging device 100 or the battery charging device 101.

[0100] The battery charging method of this embodiment includes connecting N power supply batteries, from the first power supply battery 11 to the Nth power supply battery (the fifth power supply battery 15 in the battery charging device 100), one by one to a battery to be charged (the battery to be charged B in FIG. 1 ) using a plurality of electromagnetic relays, such as the first through fourteenth electromagnetic relays 2a through 2n and the output electromagnetic relay 2o. The battery charging method of this embodiment also includes charging the battery to be charged B using the N power supply batteries (the first through fifth power supply batteries 11 through 15 in the battery charging device 100) connected to the battery to be charged, one by one, in sequence. As described above in the explanation of the operation of the battery charging device 100, when charging the battery to be charged B using the first through fifth power supply batteries 11 through 15, the first power supply battery 11 is first connected to the battery to be charged B via the second electromagnetic relay 2b and the like, and the first power supply battery 11 charges the battery to be charged. While the first power supply battery 11 is charging the chargeable battery B, charging by the second to fifth power supply batteries 12 to 15 is prevented by using charging prevention means such as switches 44 and 45 (see FIG. 3) described with reference to FIG. 3.

[0101] When the charging rate of the first power supply battery 11 and the charging rate of the chargeable battery B become substantially the same, charging by the first power supply battery 11 is terminated. Then, by opening the first electromagnetic relay 2a and closing the third electromagnetic relay 2c and the fifth electromagnetic relay 2e, the second power supply battery 12 is connected to the chargeable battery B via the third electromagnetic relay 2c, the fifth electromagnetic relay 2e, and the output electromagnetic relay 2o. This connection starts charging the chargeable battery B by the second power supply battery 12. While the chargeable battery B is being charged by the second power supply battery 12, charging by the third to fifth power supply batteries 13-15 is prevented by a charging prevention means such as a switch 45 (see FIG. 3).

[0102] Thereafter, when the charging rate of the second supply battery 12 and the charging rate of the battery to be charged B become substantially the same, charging by the second supply battery 12 is terminated. Then, the fourth electromagnetic relay 2d is opened and the sixth electromagnetic relay 2f and the eighth electromagnetic relay 2h are closed, thereby connecting the third supply battery 13 to the battery to be charged B via the sixth electromagnetic relay 2f, the eighth electromagnetic relay 2h, and the output electromagnetic relay 2o. This connection starts charging the battery to be charged B by the third supply battery 13. While the battery to be charged B is being charged by the third supply battery 13, charging by the fourth and fifth supply batteries 14, 15 is prevented by a charging prevention means, such as a switch (not shown), described with reference to FIG. 3.

[0103] Similarly, when charging by the third power supply battery 13 is completed, the seventh electromagnetic relay 2g is opened and the ninth electromagnetic relay 2i and the eleventh electromagnetic relay 2k are closed, thereby connecting the fourth power supply battery 14 to the battery B to be charged via the ninth electromagnetic relay 2i, the eleventh electromagnetic relay 2k, etc. Then, charging of the battery B to be charged by the fourth power supply battery 14 begins. Furthermore, when charging by the fourth power supply battery 14 is completed, the tenth electromagnetic relay 2j is opened and the twelfth electromagnetic relay 2l and the fourteenth electromagnetic relay 2n are closed, thereby connecting the fifth power supply battery 15 to the battery B to be charged via the twelfth electromagnetic relay 2l, the fourteenth electromagnetic relay 2n, etc. Then, charging of the battery B to be charged by the fifth power supply battery 15 begins.

[0104] In the battery charging method of this embodiment, connecting N power supply batteries in sequence to the chargeable battery B to be charged thus includes opening one of the plurality of electromagnetic relays (in the battery charging device 100, the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o) when charging of the chargeable battery B by the nth power supply battery among the N power supply batteries is completed. Note that n is a positive integer less than N. In the battery charging device 100 of FIGS. 1 and 3, examples of one electromagnetic relay are the first, fourth, seventh, and tenth electromagnetic relays 2a, 2d, 2g, and 2j.

[0105] Furthermore, connecting the N power supply batteries in sequence to the chargeable battery B to be charged includes connecting the (n+1)th power supply battery to the chargeable battery B by opening one electromagnetic relay and closing any of the electromagnetic relays other than the one electromagnetic relay among the plurality of electromagnetic relays. At this time, the (n+1)th power supply battery is connected to the chargeable battery B via any of the electromagnetic relays that is closed. In the battery charging device 100 of FIG. 1, examples of electromagnetic relays that are closed when one electromagnetic relay is opened include the third, sixth, ninth, and twelfth electromagnetic relays 2c, 2f, 2i, and 2l.

[0106] In the battery charging method of this embodiment, each power supply battery is connected to the battery to be charged B one by one in turn to charge the battery B, so that the battery to be charged B can be quickly charged to a higher charging rate.

[0107] Each of the multiple electromagnetic relays (e.g., the first to fourteenth electromagnetic relays 2a to 2n in the battery charging device 100) used in the battery charging method of the embodiment may include a moving object 203 that moves as the multiple electromagnetic relays switch between an open state and a closed state. In this case, connecting the (n+1)th power supply battery to the battery to be charged may include closing a switch (e.g., switch 41 in FIG. 1) that engages with the moving object 203 and is included in one electromagnetic relay (e.g., the first electromagnetic relay 2a in FIG. 1) that is opened when charging of the nth power supply battery ends, by the movement of the moving object 203. Then, by closing a switch such as switch 41, electromagnetic relays other than the one electromagnetic relay that is opened when charging of the nth power supply battery ends may be closed, thereby connecting the (n+1)th power supply battery to the battery to be charged.

[0108] In this way, by using a switch such as switch 41 that closes in conjunction with an electromagnetic relay that opens when charging by the nth power supply battery is completed, charging by the (n+1)th power supply battery can be started upon completion of charging by the nth power supply battery, and the battery to be charged B can be further charged to a higher charging rate.

[0109] In the battery charging method of this embodiment, each of the plurality of electromagnetic relays such as the first to fourteenth electromagnetic relays 2a to 2n and the output electromagnetic relay 2o may be an electromagnetic contactor (so-called magnet switch) provided in a starter motor of an internal combustion engine of an automobile, etc. A moving body provided in the electromagnetic contactor of the starter motor and moving in response to the opening and closing of the electromagnetic contactor may function as the moving body 203 included in the first electromagnetic relay 2a in Fig. 1 and may be useful for connecting the N power supply batteries to the battery to be charged B one by one in sequence. [Explanation of symbols]

[0110] 100, 101 Battery charging device 11~15 1st to 5th power supply batteries 1p positive electrode 1n negative electrode 2. Electromagnetic relay 2a~2n 1st to 14th electromagnetic relays 2o Output electromagnetic relay Electromagnetic relay for 2p connector 2r Electromagnetic relay for power supply battery 21~24 Terminals 1~4 203, 211 Mobile 205, 206 coils 40~42 Switch 44, 45 Isolation switch 5 Connectors 61, 62 Conductors B. Rechargeable battery C External charger

Claims

1. N (N is an integer equal to or greater than 2) power supply batteries from a first power supply battery to an Nth power supply battery that supply power for charging; a plurality of electromagnetic relays, at least M in number (M being an integer that is N times 3); Contains a battery charging device that charges batteries to be charged that are connected to the N power supply batteries via any of the plurality of electromagnetic relays, a first electromagnetic relay and a second electromagnetic relay among the plurality of electromagnetic relays are directly connected to a positive electrode of the first power supply battery, and are also connected to a positive electrode of the battery to be charged via an output electromagnetic relay among the plurality of electromagnetic relays; the ((3×n)+1)th electromagnetic relay (n is a positive integer less than N) and the ((3×n)+2)th electromagnetic relay among the plurality of electromagnetic relays are configured to be connected to a positive electrode of the (n+1)th power supply battery among the N power supply batteries via the (3×n)th electromagnetic relay among the plurality of electromagnetic relays, and to be connected to a positive electrode of the battery to be charged via the output electromagnetic relay; the battery charging device is configured so that the N power supply batteries are connected to the battery to be charged in order from the first power supply battery to the Nth power supply battery by the plurality of electromagnetic relays to charge the battery to be charged, The battery charging device is configured such that when charging of the chargeable battery by the nth supply battery among the N supply batteries is completed, the (3×(n-1)+1)th electromagnetic relay among the plurality of electromagnetic relays opens, thereby connecting the (n+1)th supply battery to the chargeable battery by the ((3×n)+1)th electromagnetic relay and the ((3×n)+2)th electromagnetic relay among the plurality of electromagnetic relays.

2. 2. The battery charging device according to claim 1, further comprising a cut-off switch that electrically isolates at least the (n+2)th to Nth power supply batteries of the N power supply batteries from the charged battery by opening a (3×(n−1)+2)th electromagnetic relay of the plurality of electromagnetic relays that is in a closed state while the nth power supply battery is charging the charged battery.

3. N (N is an integer equal to or greater than 2) power supply batteries from a first power supply battery to an Nth power supply battery that supply power for charging; a plurality of electromagnetic relays, at least M in number (M being an integer equal to N times 2); Contains a battery charging device that charges batteries to be charged that are connected to the N power supply batteries via any of the plurality of electromagnetic relays, the plurality of electromagnetic relays include (N-1) pairs of electromagnetic relays and an output electromagnetic relay connected to the positive electrode of the battery to be charged, a positive electrode of each of the first to (N-1)th supply batteries among the N supply batteries is directly connected to a different pair of electromagnetic relays among the (N-1) pairs of electromagnetic relays, and is also connected to a positive electrode of the battery to be charged via the output electromagnetic relay; an N-th power supply battery of the N power supply batteries is directly connected to one of the plurality of electromagnetic relays other than the (N-1) pairs of electromagnetic relays and the output electromagnetic relay, and is connected to the positive electrode of the battery to be charged via the output electromagnetic relay; the battery charging device is configured so that the N power supply batteries are connected to the battery to be charged in order from the first power supply battery to the Nth power supply battery by the plurality of electromagnetic relays to charge the battery to be charged, When charging of the chargeable battery by an nth supply battery (n is a positive integer less than N) of the N supply batteries is completed, a pair of electromagnetic relays among the plurality of electromagnetic relays directly connected to the nth supply battery are opened, thereby connecting the (n+1)th supply battery to the chargeable battery via a pair of electromagnetic relays among the plurality of electromagnetic relays directly connected to the (n+1)th supply battery.

4. 4. The battery charging device according to claim 1, wherein each of said plurality of electromagnetic relays is formed of an electromagnetic contactor used in a starter motor.

5. each of the plurality of electromagnetic relays includes a moving body that is displaced in accordance with switching between an open state and a closed state of the respective plurality of electromagnetic relays; the battery charging device further includes a switch that is included in a first electromagnetic relay of the plurality of electromagnetic relays and that opens and closes in response to displacement of the moving object; 5. The battery charging device according to claim 4, wherein a second supply battery among the N supply batteries is connected to the battery to be charged when the first electromagnetic relay is in the open state and the switch is in the closed state.

6. each of the plurality of electromagnetic relays includes a moving body that is displaced in accordance with switching between an open state and a closed state of the respective plurality of electromagnetic relays; the battery charging device further includes a switch included in the first electromagnetic relay that opens and closes in response to displacement of the moving object; Each of the plurality of electromagnetic relays includes a first terminal and a second terminal connected to each other via a coil, and two terminals that are electrically connected to each other when a current flows from the first terminal to the coil, and is in a closed state when the two terminals are electrically connected to each other; the positive electrode of the first power supply battery is connected to the first terminal of each of the first electromagnetic relay and the second electromagnetic relay, and to one of the two terminals of the second electromagnetic relay; the second terminal and one of the two terminals of the first electromagnetic relay are electrically connected to the first terminal of the output electromagnetic relay; the other of the two terminals of the first electromagnetic relay is connected to the second terminal of the second electromagnetic relay; the other of the two terminals of the second electromagnetic relay is connected to one of the two terminals of the output electromagnetic relay; the second terminal of a third electromagnetic relay among the plurality of electromagnetic relays is electrically connected to the first terminal of the output electromagnetic relay via the switch included in the first electromagnetic relay, which is opened or closed in response to displacement of the moving body; a positive electrode of a second power supply battery among the N power supply batteries is connected to the first terminal and one of the two terminals of the third electromagnetic relay; the battery to be charged is connected between the second terminal and the other of the two terminals of the output electromagnetic relay and the negative electrodes of the N power supply batteries, 2. The battery charging device according to claim 1, wherein the second power supply battery is connected to the battery to be charged via the third electromagnetic relay when the first electromagnetic relay is in an open state and the switch is in a closed state.

7. The device further includes a connector to which an external charger is connected, and an electromagnetic relay for the connector connected to the connector, 4. The battery charging device according to claim 1, wherein when charging of the battery to be charged by the N power supply batteries is completed, the connector electromagnetic relay connects the connector to the battery to be charged.

8. The electromagnetic relay for a connector is an electromagnetic contactor used in a starter motor, the electromagnetic relay for the connector includes a moving body that is displaced in accordance with switching between an open state and a closed state of the electromagnetic relay for the connector, 8. The battery charging device according to claim 7, wherein when current stops flowing from the connector to the battery to be charged, the connector electromagnetic relay opens, and the connector and each of the N power supply batteries are electrically connected by abutment between a conductor electrically connected to the connector and a conductor connected to the positive electrode of each of the N power supply batteries based on displacement of the moving body.

9. A battery charging method using N (N is an integer of 2 or more) power supply batteries from a first power supply battery to an Nth power supply battery, which supply power for charging, and at least M (M is an integer that is N times 3) electromagnetic relays, using the plurality of electromagnetic relays to sequentially connect the N power supply batteries to a battery to be charged, from the first power supply battery to the Nth power supply battery; Charging the battery to be charged using the N power supply batteries connected to the battery to be charged in sequence; The step of sequentially connecting the N power supply batteries to the battery to be charged comprises: connecting a positive electrode of the first power supply battery to a positive electrode of the battery to be charged via a first electromagnetic relay and a second electromagnetic relay among the plurality of electromagnetic relays and an output electromagnetic relay among the plurality of electromagnetic relays; connecting a positive electrode of the (n+1)th power supply battery among the N power supply batteries to a positive electrode of the battery to be charged via the ((3×n)+1)th electromagnetic relay (n is a positive integer less than N) and the ((3×n)+2)th electromagnetic relay among the plurality of electromagnetic relays, the (3×n)th electromagnetic relay among the plurality of electromagnetic relays, and the output electromagnetic relay; a (3×n)+2) electromagnetic relay among the plurality of electromagnetic relays to close the ((3×n)+1)-th electromagnetic relay and the ((3×n)+2)-th electromagnetic relay among the plurality of electromagnetic relays, thereby connecting the (n+1)-th electromagnetic relay to the battery to be charged via the ((3×n)+1)-th electromagnetic relay and the ((3×n)+2)-th electromagnetic relay, when charging of the battery to be charged by the n-th supply battery among the N supply batteries is completed.

10. 10. The battery charging method according to claim 9, wherein an electromagnetic contactor used in a starter motor is used as each of the plurality of electromagnetic relays.

Images