JP2013240142A - Connection method of battery pack and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax a return current and a rush current during operation of a battery pack, in a battery pack for vehicle consisting of battery packs connected in parallel.SOLUTION: If the voltages of battery packs 101(#1) and 101(#2) are not uniform during ignition off, a current is fed between two battery packs 101 via a resistor R, by turning relays A, D on, turning relays C, B off, and turning a main relay off, thus equalizing both voltages. During ignition on, the outputs of two battery packs 101 are connected with an external load via a resistor R by turning the relays C, D on, and turning the relays A, B off. Upon elapsing a predetermined time, the outputs of two battery packs 101 are connected directly with an external load without passing through the resistor R, by turning the relays A, B on, and turning the relays C, D off. A return current between the battery packs 101 and a rush current to a load can thereby be relaxed with a simple configuration.

Description

  The present invention relates to an assembled battery for a vehicle including battery packs connected in parallel.

  A so-called hybrid car, plug-in hybrid car, hybrid vehicle, hybrid electric vehicle or the like, which is equipped with a motor (electric motor) as a power source in addition to an engine or a transport machine (hereinafter referred to as “vehicle etc.”) is practical It has become. Furthermore, an electric vehicle that does not include an engine and drives the vehicle only by a motor is being put into practical use. As a power source for driving these motors, a lithium ion battery having a small size and a large capacity has been frequently used. And in such an application, the battery pack comprised by connecting several battery cells in series may be supplied as a battery pack further connected in parallel. The voltage necessary for driving the motor of the vehicle is obtained by the series connection of the battery cells, and the necessary current capacity is obtained by the parallel connection of the battery packs.

  In the conventional assembled battery having such a configuration, when there is a potential difference between the voltages of the battery packs connected in parallel, when the main relay of the assembled battery is turned on and connected to the load, the battery having the higher voltage There is a possibility that a reflux current may be generated from the pack toward the battery pack having a lower voltage. This reflux current varies in size, affecting the charge / discharge cycle and shortening the battery life, and may cause accidents such as smoke and ignition of the assembled battery. When the vehicle travels, even if the balance is maintained by the internal resistance of each battery pack, a potential difference is generated between the batteries due to the elimination of the polarization, so that a reflux current may be generated, leading to a failure of the battery.

  As a conventional technique for preventing such a reflux current, the following technique is known (for example, the technique described in Patent Document 1). The first switch is in one of a first state in which one electrode of the first battery device is connected to the first connection line, a second state in which the first switch is not connected, and a third state in which the electrode is connected via a resistor. Switch. The second switch is one of a first state where one electrode of the second battery device is connected to the first connection line, a second state where the second switch is not connected, and a third state where the second switch is connected via a resistor. Switch to Then, the management device changes the first and second switches from the first state to the second state in response to a battery replacement start signal, and returns from the second state to the third state in response to a battery replacement end signal. The state is returned to the first state from the third state in response to an equalization end signal indicating that the equalization between the first and second battery devices has ended. With such a configuration, inrush current generated when one of the battery devices (an assembled battery or an assembled battery module) connected in parallel is replaced.

  However, this conventional technology only reduces the inrush current at the time of battery replacement, and cannot prevent the reflux current generated based on the potential difference between the battery packs that occurs during actual operation of the vehicle, for example. In addition, for example, during operation of the vehicle, when the ignition is turned on, inrush current may occur when the main relay of the assembled battery is connected to an external load such as a travel motor. A circuit to be used is also required, and the circuit scale becomes large.

JP 2011-1000066 A

  An object of the present invention is to alleviate the return current and the inrush current during operation of an assembled battery.

  An example of an embodiment is a battery pack in which a plurality of battery packs are connected in parallel, and when the ignition is off, when the voltages of the battery packs are not uniform, the battery packs are connected to each other via an inrush current prevention resistor. When the ignition is turned on, the output of the battery pack is connected to the load connected to the assembled battery via the inrush current prevention resistor when the ignition is turned on. After the predetermined time elapses, the output of the battery pack is connected to the load without going through the inrush current preventing resistor.

According to the present invention, it is possible to improve the quality of the assembled battery by reducing the reflux current and the inrush current, improve safety, and extend the life.
Further, according to the present invention, it is possible to prevent the generation of the return current between the parallel battery packs in the assembled battery and the generation of the inrush current with respect to the load connected to the outside with a small circuit scale.

It is a block diagram of the battery system by 1st Embodiment. It is a block diagram of the balance part in 1st Embodiment. It is operation | movement explanatory drawing of 1st Embodiment. It is a timing chart which shows control operation of a 1st embodiment. It is a flowchart which shows the control action before the vehicle starting of 1st Embodiment. It is a flowchart (the 1) which shows the control action at the time of the vehicle starting of 1st Embodiment. It is a flowchart (the 2) which shows the control action at the time of the vehicle starting of 1st Embodiment. It is a flowchart (the 3) which shows the control action at the time of the vehicle starting of 1st Embodiment. It is a flowchart which shows the control action at the time of driving | running | working and completion | finish of driving | running | working of 1st Embodiment. It is a block diagram of the battery system by 2nd Embodiment. It is a block diagram of the balance part in 2nd Embodiment. It is operation | movement explanatory drawing of 2nd Embodiment. It is a timing chart which shows control operation of a 2nd embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of a battery system 100 according to the first embodiment.
In FIG. 1, the battery system 100 includes a plurality of battery packs 101 configured by connecting a plurality of battery cells (for example, several tens to several hundreds) in series (two sets of # 1 and # 2 in the example of FIG. 1). It is an assembled battery for vehicles comprised by connecting in parallel.

  A voltage measuring unit 103 (# 1 and # 2) is connected to the positive electrode side of each battery pack 101 (# 1 and # 2). Each voltage measuring unit 103 (# 1 and # 2) measures each output voltage of each battery pack 101 (# 1 and # 2), and sends it to a battery ECU (ElectrIc Control UnIt) 104 via the control line group 108. Notice. The battery ECU 104 is, for example, a microprocessor. The battery ECU 104 controls the operation of the battery system 100 by receiving, for example, information on ignition on / off from an ECU (not shown) that controls the entire vehicle via the communication terminal CA.

  Each voltage measuring unit 103 (# 1 and # 2) is connected to the balance unit 102. The balance unit 102 is controlled by the battery ECU 104 via the control line group 109, and is connected from the plus side power line 106 to the plus electrode terminal EB +. While the balance part 102 prevents the return current between the battery packs 101 (# 1 and # 2) and prevents an inrush current to a load (for example, a vehicle driving motor) connected to the positive electrode terminal EB +, Electric power generated by each battery pack 101 (# 1 and # 2) is supplied to the load.

  A main relay 105 that is a main changeover switch is connected to the negative pole side of each battery pack 101 (# 1 and # 2). The main relay 105 controls on / off of the entire battery system 100 under the control of the battery ECU 104 connected via the control line 110. The main relay 105 is connected to the negative electrode terminal EB− via the negative power line 107.

FIG. 2 is a configuration diagram of the balance unit 102 in the first embodiment of the battery system having the configuration of FIG. 1.
The first terminal of the relay A that is the first changeover switch is connected to one output terminal of the battery pack 101 of # 1 in FIG. 1 that is the first battery pack via the voltage measuring unit 103 of # 1. The Further, the second terminal of the relay A is connected to the plus electrode terminal EB + in FIG. 1 which is one external output terminal of the battery system 100 via the plus side power line 106.

The first terminal of the relay C that is the second changeover switch is connected to one output terminal of the battery pack 101 of # 1 that is the first battery pack via the voltage measuring unit 103 of # 1.
The 1st terminal of resistance R is connected to the 2nd terminal of relay C which is the 2nd change-over switch. A second terminal of the resistor R is connected to a positive electrode terminal EB + that is one external output terminal of the battery system 100 via a positive power line 106.

  The first terminal of the relay D that is the third changeover switch is connected to the second terminal of the relay C that is the second changeover switch. The second terminal of the relay D is connected to one output terminal of the # 2 battery pack 101 of FIG. 1 as the second battery pack via the # 2 voltage measurement unit 103.

  The first terminal of the relay B that is the fourth changeover switch is connected to one output terminal of the battery pack 101 of # 2 that is the second battery pack via the voltage measuring unit 103 of # 2. A second terminal of the relay B is connected to a positive electrode terminal EB + that is one external output terminal of the battery system 100 via a positive power line 106.

  In the battery system 100 of FIG. 1 including the balance unit 102 having the circuit configuration shown in FIG. 2, the battery ECU 104 controls the relays A, B, C, and D in the balance unit 102 via the control line group 109. Thus, the following control operation is executed. When the ignition is off and the voltages of the battery packs 101 of # 1 and # 2 are not equal, the battery ECU 104 uses the batteries R1 and # 2 via the resistor R (FIG. 2) in the balance unit 102. By passing a current between the packs 101, the voltages of the battery packs 101 of # 1 and # 2 are equalized. Further, when the ignition is turned on, the battery ECU 104 connects the outputs of the battery packs 101 of # 1 and # 2 to the positive electrode terminal EB + via the resistor R in the balance unit 102. Further, after a predetermined time has elapsed since the connection, the battery ECU 104 directly connects the outputs of the battery packs 101 of # 1 and # 2 to the positive electrode terminal EB + within the balance unit 102 without passing through the resistor R.

The control operation of the first embodiment will be described in detail below.
FIG. 3 is an operation explanatory diagram of the above-described first embodiment, and FIG. 4 is a timing chart showing a control operation of the first embodiment.

  The initial state when the ignition is off is a state I shown in FIG. In this state I, the relays A, B, C, D and the main relay E (105 in FIG. 1) are all off (OFF).

  In this state, the battery ECU 104 in FIG. 1 receives each voltage of each battery pack 101 (# 1 and # 2) from each voltage measurement unit 103 (# 1 and # 2) in FIG. Get V1 and V2. Here, if V1 and V2 are not equal, the battery ECU 104 turns on the relays A and D in FIG. 2 in the balance unit 102 in FIG. By turning it off, the state is shifted to the state II in FIG. In FIG. 4, the high-level state of the lines corresponding to the relays A, B, C, D, and E indicates relay-on, and the low-level state indicates relay-off. As a result, in the state II of FIG. 3B, for example, if V1> V2, as shown by the thick broken line, the battery of # 1 is passed through the resistor R in FIG. 2 in the balance unit 102 in FIG. A current flows from the pack 101 toward the battery pack 101 of # 2. As a result, the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 are equalized so as to be equal. In this case, the resistor R suppresses a large current from flowing between the two battery packs 101, and an inrush current can be avoided. Here, considering the number of times the relays A and B are switched, the battery ECU 104 may make a transition to the state III shown in FIG. 3C instead of the state II shown in FIG. That is, the battery ECU 104 turns on the relays C and B in FIG. 2 and turns off the relays A and D in the balance unit 102 in FIG. Transition to III. In the state III in FIG. 3C, if V1 <V2, for example, current flows from the # 2 battery pack 101 to the # 1 battery pack 101 via the resistor R as shown by the thick broken line. . As a result, the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 are equalized so as to be equal. Also in this case, the resistor R suppresses a large current from flowing between the two battery packs 101, and an inrush current can be avoided. Considering the switching frequency of relays A and B, switching between state II in FIG. 3B and state III in FIG. It becomes possible to avoid that.

  After being equalized to V1 = V2 in the state II, for example, by the control operation described above (see FIG. 4), when the vehicle driver turns on the ignition, the battery ECU 104 turns on the ignition (IG-ON in FIG. 4). After detecting, the following control operation is executed. The battery ECU 104 turns off the relays A and B in FIG. 2 in the balance unit 102 in FIG. 1, turns on the relays C and D, and turns on the main relay E (105 in FIG. 1) via the control line group 109. As a result, the state transits to the state IV in FIG. In this state IV, the outputs of the battery packs 101 of # 1 and # 2 are connected to the plus electrode terminal EB + via the resistor R of FIG. 2 in the balance unit 102 of FIG. As a result, the resistor R suppresses an inrush current with respect to a load (such as a vehicle driving motor) connected to the plus electrode terminal EB +, and a load failure can be avoided.

  When a predetermined time has elapsed from the connection in the state IV and the storage of the capacity of the load is completed, the battery ECU 104 turns on the relays A and B in FIG. 2 in the balance unit 102 in FIG. When the relays C and D are turned off, the state transitions to the state V shown in FIG. In this state V, the outputs of the battery packs 101 of # 1 and # 2 are directly connected to the positive electrode terminal EB + via the relays A and B, not via the resistor R of FIG. Connected and the load is driven directly.

After the vehicle finishes running and the ignition is turned off (IG-OFF in FIG. 4), the state is changed again from the state I in FIG. 3 (a) to the state II in FIG. 3 (b) by eliminating the polarization. To do.
FIGS. 5 to 9 are flowcharts showing a control operation executed by the battery ECU 104 of FIG. 1 for realizing a more detailed operation of the above-described control operation. This control operation is realized, for example, as an operation in which a processor (not shown) in the battery ECU 104 executes a program stored in a memory (not shown).

First, before the vehicle is started, the battery ECU 104 executes the control operation shown in the flowchart of FIG.
Initially, the battery ECU 104 maintains the state I in FIG. 3A (step S1 in FIG. 5).

  Next, the battery ECU 104 acquires the output voltages V1 and V2 of the # 1 and # 2 battery packs 101 measured by the # 1 and # 2 voltage measuring units 103 via the control line group 108 of FIG. It is determined whether or not V1 = V2 (step S2 in FIG. 5).

If V1 = V2 and the determination in step S2 is YES, battery ECU 104 continues state I (step S3 in FIG. 5).
If V1 = V2 is not satisfied and the determination in step S2 is NO, battery ECU 104 determines whether or not the number of switching of relay A in balance unit 102 in FIG. Step S4). Each time the battery ECU 104 switches the relay A and the relay B, the battery ECU 104 increments the value indicating the number of times of switching of the relay A and the number of times of switching of the relay B held in the memory or the like in the battery ECU 104, and these values are processed in step S4. refer.

  If the number of times of switching of relay A is smaller than the number of times of switching of relay B and the determination in step S4 is NO, battery ECU 104, via control line group 109, relays A and D in FIG. Is turned on and the relays C and B are turned off to make a transition to the state II in FIG. 3B or FIG. 4 (step S5 in FIG. 5).

  On the other hand, if the number of times of switching of relay A is equal to or greater than the number of times of switching of relay B and the determination in step S4 is YES, the battery ECU 104 via the control line group 109 relays in FIG. By turning on C and B and turning off relays A and D, a transition is made to state III in FIG. 3C (step S6 in FIG. 5).

  Through the processing of step S5 or S6 described above, current flows between the battery packs 101 of # 1 and # 2 via the resistor R of FIG. 2 in the balance unit 102 of FIG. The equalization control is performed so that the output voltages V1 and V2 of the output are equal.

The battery ECU 104 determines whether or not the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 have become equal (step S7 in FIG. 5).
When V1 = V2 and the determination in step S7 becomes YES, the battery ECU 104 turns off all the relays A, B, C, and D in the balance unit 102 in FIG. Transition to the state I of (a) (step S8 in FIG. 5).

  If V1 = V2 is not yet satisfied and the determination in step S7 is NO, the battery ECU 104 determines whether or not an activation signal due to the ignition being turned on has been received (step S9 in FIG. 5). If the activation signal is not received and the determination in step S9 is NO, the battery ECU 104 continues the state II of step S5 or the state III of step S6, and the equalization process is continued. When the activation signal is received and the determination in step S9 is YES, the battery ECU 104 turns off all the relays A, B, C, and D in the balance unit 102 in FIG. Transition to the state I in (a) (step S10 in FIG. 5).

  In the above state I, when the ignition of the vehicle is turned on and the activation signal is received via the communication terminal CA of FIG. 1, the battery ECU 104 starts executing the control operation shown in the flowcharts of FIGS.

First, the battery ECU 104 turns on the main relay 105 (main relay E) via the control line 110 in FIG. 1 (step S11 in FIG. 6).
Next, the battery ECU 104 acquires the output voltages V1 and V2 of the # 1 and # 2 battery packs 101 measured by the # 1 and # 2 voltage measuring units 103 via the control line group 108 of FIG. It is determined whether or not V1 = V2 (step S12 in FIG. 6).

  If V1 = V2 and the determination in step S12 is YES, battery ECU 104 turns off relays A and B in FIG. 2 in balance unit 102 in FIG. 1 and turns on relays C and D via control line group 109. As a result, the state transits to the state IV in FIG. 3D (step S13 in FIG. 6). As a result, each output of the battery packs 101 of # 1 and # 2 is connected to the plus electrode terminal EB + via the resistor R of FIG. 2 in the balance unit 102 of FIG. Then, the supply of electric power to the load is started while the inrush current to the load (such as a vehicle driving motor) connected to the plus electrode terminal EB + is suppressed by the resistor R.

Battery ECU 104 determines whether or not a predetermined time has elapsed since connection in state IV (step S14 in FIG. 6).
If the predetermined time has not elapsed and the determination in step S14 is NO, the battery ECU 104 continues the current state IV (step S15 in FIG. 6), and repeatedly executes the determination in step S14.

  When the predetermined amount of time has elapsed from the connection by the state IV and the storage of the capacity of the load is completed and the determination in step S14 becomes YES, the battery ECU 104 passes through the control line group 109 in the balance unit 102 in FIG. Relays A and B in FIG. 2 are turned on, and relays C and D are turned off. As a result, the state transitions to the state V in FIG. 3E (step S16 in FIG. 6).

If V1 = V2 is not satisfied and the determination in step S12 is NO when the ignition is on, the battery ECU 104 determines whether or not V1> V2 is satisfied (step S17 in FIG. 7).
If V1> V2 and the determination in step S17 is YES, the battery ECU 104 turns on the relay C in FIG. 2 in the balance unit 102 in FIG. 1 via the control line group 109 (relays A, B, and D are (It remains off) (step 18 in FIG. 7). As a result, only the output of the battery pack 101 of # 1 in FIG. 1 is connected to the plus electrode terminal EB + via the resistor R in FIG. 2 in the balance unit 102 in FIG. In this way, power is supplied to the load only from the # 1 battery pack 101 having a high voltage, and as a result, the output voltage V1 of the # 1 battery pack 101 becomes the output voltage V2 of the # 2 battery pack 101. Approaching and equalizing.

The battery ECU 104 determines whether or not a certain time has elapsed (step S19 in FIG. 7).
If the predetermined time has not elapsed and the determination in step S19 is NO, the battery ECU 104 continues the current connection state (step S20 in FIG. 7), and repeatedly executes the determination in step S19.

When the predetermined time has elapsed and the determination in step S19 is YES, the battery ECU 104 determines whether or not V1 = V2 is satisfied (step S21 in FIG. 7).
If V1 = V2 and the determination in step S21 is YES, the battery ECU 104 turns off the relays A and B in FIG. 2 in the balance unit 102 in FIG. Is turned on, the state transits to the state IV in FIG. 3D (step S22 in FIG. 7). As a result, each output of the battery packs 101 of # 1 and # 2 is connected to the plus electrode terminal EB + via the resistor R of FIG. 2 in the balance unit 102 of FIG. Then, the supply of electric power to the load is started while the inrush current to the load (such as a vehicle driving motor) connected to the plus electrode terminal EB + is suppressed by the resistor R.

The battery ECU 104 determines whether or not a predetermined time has elapsed since connection in the state IV (step S23 in FIG. 7).
If the predetermined time has not elapsed and the determination in step S23 is NO, the battery ECU 104 continues the current state IV (step S24 in FIG. 7), and repeatedly executes the determination in step S23.

  When a predetermined time has elapsed from the connection in the state IV and the storage of the capacity of the load is completed and the determination in step S23 is YES, the battery ECU 104 passes through the control line group 109 in the balance unit 102 in FIG. Relays A and B in FIG. 2 are turned on, and relays C and D are turned off. As a result, the state transitions to the state V in FIG. 3E (step S16 in FIG. 6).

  If V1 = V2 is not satisfied even if the determination of step S19 becomes YES after a certain time has elapsed, if the determination of step S21 is NO, the battery ECU 104 via the control line group 109 causes the balance unit 102 of FIG. 2 is turned on and relays C and B are turned off to make a transition to the state II in FIG. 3B (step S25 in FIG. 7). Thereby, a current flows between the battery packs 101 of # 1 and # 2 via the resistor R of FIG. 2 in the balance unit 102 of FIG. 1, and the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 are supplied. The equalization control is compulsorily performed so as to be equal.

  When V1 = V2 is not satisfied and the determination in step S12 in FIG. 6 is NO when ignition is on, and V1 ≦ V2 and the determination in step S17 in FIG. 7 is NO, the battery ECU 104 passes through the control line group 109. 1 is turned on (relays A, B, and C remain off) (step S26 in FIG. 8). As a result, only the output of the battery pack 101 of # 2 in FIG. 1 is connected to the plus electrode terminal EB + via the resistor R in FIG. 2 in the balance unit 102 in FIG. Thus, power is supplied to the load only from the # 2 battery pack 101 having a high voltage, and as a result, the output voltage V2 of the # 2 battery pack 101 becomes the output voltage V1 of the # 1 battery pack 101. Approaching and equalizing.

The battery ECU 104 determines whether or not a certain time has elapsed (step S27 in FIG. 8).
If the predetermined time has not elapsed and the determination in step S27 is NO, the battery ECU 104 continues the current connection state (step S28 in FIG. 8), and repeatedly executes the determination in step S27.

When the predetermined time has elapsed and the determination in step S27 is YES, the battery ECU 104 determines whether or not V1 = V2 is satisfied (step S29 in FIG. 8).
If V1 = V2 and the determination in step S29 is YES, the battery ECU 104 turns off the relays A and B in FIG. 2 in the balance unit 102 in FIG. Is turned on, the state transits to the state IV in FIG. 3D (step S30 in FIG. 8). As a result, each output of the battery packs 101 of # 1 and # 2 is connected to the plus electrode terminal EB + via the resistor R of FIG. 2 in the balance unit 102 of FIG. Then, the supply of electric power to the load is started while the inrush current to the load (such as a vehicle driving motor) connected to the plus electrode terminal EB + is suppressed by the resistor R.

Battery ECU 104 determines whether or not a predetermined time has elapsed since connection in state IV (step S31 in FIG. 8).
If the predetermined time has not elapsed and the determination in step S31 is NO, the battery ECU 104 continues the current state IV (step S32 in FIG. 8), and repeatedly executes the determination in step S31.

  When a predetermined time has elapsed from the connection in the state IV and the storage of the capacity of the load is completed and the determination in step S31 is YES, the battery ECU 104 passes through the control line group 109 in the balance unit 102 in FIG. Relays A and B in FIG. 2 are turned on, and relays C and D are turned off (step S16 in FIG. 6). Thereby, the state transits to the state V in FIG.

  If V1 = V2 is not satisfied even if the determination in step S27 is YES after a certain time has elapsed, if the determination in step S29 is NO, the battery ECU 104 via the control line group 109 causes the balance unit 102 in FIG. 2 are turned on and the relays A and D are turned off, thereby transitioning to the state III in FIG. 3C (step S33 in FIG. 8). Thereby, a current flows between the battery packs 101 of # 1 and # 2 via the resistor R of FIG. 2 in the balance unit 102 of FIG. 1, and the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 are supplied. The equalization control is compulsorily performed so as to be equal.

FIG. 9 is a flowchart showing the control operation of the battery ECU 104 when the vehicle is traveling from the control operation at the time of starting the vehicle of FIGS.
Steps S16, S25, and S33 in FIG. 9 are the same processes as the steps with the same numbers in FIGS. 6, 7, and 8, respectively.

When the state transitions to state V in step S16, the vehicle enters the traveling state as it is (step S34 in FIG. 9).
After the transition to the state II or III in step S25 or S33, the battery ECU 104 determines whether or not the output voltages V1 and V2 of the battery packs 101 of # 1 and # 2 are equal (step S35 in FIG. 9). ).

  If V1 = V2 is not satisfied and the determination in step S35 is NO, the battery ECU 104 continues the current state II or III (step S36 in FIG. 9), and repeatedly executes the determination in step S35.

  When V1 = V2 and the determination in step S35 is YES, battery ECU 104 turns on relays A and B in FIG. 2 in balance unit 102 in FIG. 1 and turns off relays C and D via control line group 109. To do. As a result, the state transits to the state V in FIG. 3E and enters the traveling state of the vehicle (step S34 in FIG. 9).

  When the traveling of the vehicle is completed, the battery ECU 104 turns off all the relays A, B, C, and D in the balance unit 102 in FIG. 1 via the control line group 109, and enters the state I in FIG. Return. Thereafter, the battery ECU 104 turns off the main relay 105 (main relay E) in FIG. 1 and returns to the processing in step S1 in FIG. 5 (step S37 in FIG. 9).

  As described above, in the battery system 100 according to the first embodiment having the configuration shown in FIGS. 1 and 2, voltage equalization is appropriately performed between the two battery packs 101 # 1 and # 2. In addition, efficient power supply can be performed while avoiding the occurrence of inrush current to each battery pack 101 and the load. As a result, it is possible to improve the quality of the battery system 100 by reducing the reflux current and the inrush current, improve safety, and extend the life. In the first embodiment, the circuit scale of the balance unit 102 in FIG. 1 may be a small circuit scale as shown in FIG. 2, and the cost of the battery system 100 can be kept low.

  FIG. 10 is a configuration diagram of a battery system according to the second embodiment. The battery system 100 of FIG. 1 is composed of two battery packs 101 of # 1 and # 2, whereas the battery system 100 ′ of FIG. 10 has three battery packs of # 1, # 2, and # 3. 101. Accordingly, the configuration of the balance unit 102 ′ in FIG. 10 is different from the configuration of the balance unit 102 in FIG. 1. Other configurations in FIG. 10 are the same as those in FIG.

FIG. 11 is a configuration diagram of the balance unit 102 ′ in the second embodiment of the battery system having the configuration of FIG.
11, the connection configuration of the relays A, B, C, D and the resistor R is the same as that of the first embodiment in FIG.

  Further, in FIG. 11, the first terminal of the relay F that is the fifth changeover switch is connected to the second terminal of the relay C that is the second changeover switch. The second terminal of the relay F is connected to one output terminal of the # 3 battery pack 101 of FIG. 10 which is the third battery pack via the # 3 voltage measuring unit 103.

  The first terminal of the relay G that is the sixth changeover switch is connected to one output terminal of the battery pack 101 of # 3 that is the third battery pack via the voltage measuring unit 103 of # 3. A second terminal of the relay G is connected to a positive electrode terminal EB + that is one external output terminal of the battery system 100 via a positive power line 106.

  In the battery system 100 ′ of FIG. 10 including the balance unit 102 ′ having the circuit configuration shown in FIG. 11, the battery ECU 104 includes relays A, B, C, D, and F in the balance unit 102 via the control line group 109. , G are controlled to execute the next control operation. When the ignition is off and the voltage of the battery pack 101 of # 1, # 2, or # 3 is not equal, the battery ECU 104 # 1 through the resistor R (FIG. 11) in the balance unit 102 By flowing a current between the battery packs 101 of # 2 or # 3, the voltages of the battery packs 101 of # 1, # 2, or # 3 are equalized. Further, when the ignition is turned on, the battery ECU 104 connects the output of the battery pack 101 of # 1, # 2, or # 3 to the positive electrode terminal EB + via the resistor R in the balance unit 102. Further, the battery ECU 104 directly outputs the output of the battery pack 101 of # 1, # 2, or # 3 directly to the positive electrode terminal EB + within the balance unit 102 without passing through the resistor R after a predetermined time has elapsed since the connection. Connecting.

The control operation of the second embodiment will be described in detail below.
FIG. 12 is a diagram for explaining the operation of the second embodiment, and FIG. 13 is a timing chart showing the control operation of the second embodiment.

  The battery ECU 104 in FIG. 10 is connected to each battery pack 101 (# 1, # 2, and # 3) via the control line group 108 from each voltage measurement unit 103 (# 1, # 2, and # 3) in FIG. ), The voltages V1, V2, and V3 are obtained. Here, when V1, V2, or V3 is not equal, the battery ECU 104 turns on, for example, the relays A and F in FIG. 11 in the balance unit 102 ′ in FIG. By turning off D, G, and B, the state is shifted to the state I in FIG. In FIG. 13, the high level state of the lines corresponding to the relays A, B, C, D, E, F, and G indicates the relay on, and the low level state indicates the relay off. As a result, in the state I of FIG. 12A, if, for example, V1> V3, as shown by the thick broken line, the resistance # 1 in the balance portion 102 ′ of FIG. A current flows from the battery pack 101 toward the # 3 battery pack 101. As a result, the output voltages V1 and V3 of the battery packs 101 of # 1 and # 3 are equalized so as to be equal. In this case, the resistor R suppresses a large current from flowing between the two battery packs 101, and an inrush current can be avoided.

  After being equalized to V1 = V3 in the state I, for example, by the above-described control operation (see FIG. 13), the battery ECU 104 performs the relay of FIG. 11 in the balance unit 102 ′ of FIG. After C is turned on, relay A is turned off, and relay B is turned on (relay F remains on), thereby causing a transition to state II in FIG. 12B or FIG. As a result, in the state II of FIG. 12B, if, for example, V1 = V3> V2, as indicated by the thick broken line, the resistor R in FIG. 11 in the balance unit 102 ′ in FIG. A current flows from the battery pack 101 of # 1 and # 3 toward the battery pack 101 of # 2. As a result, the output voltages V1, V3, and V2 of the battery packs 101 of # 1, # 3, and # 2 are equalized. In this case, the resistor R suppresses a large current from flowing between the three battery packs 101, and an inrush current can be avoided.

  After the control operation described above has been equalized to V1 = V3 = V2 in the state II, for example (see FIG. 13), when the vehicle driver turns on the ignition, the battery ECU 104 turns on the ignition (IG- in FIG. 13). ON) is detected, the following control operation is executed. The battery ECU 104 turns on the relay D in FIG. 11 in the balance unit 102 ′ in FIG. 10 via the control line group 109, then turns off the relay B, and turns on the main relay E (105 in FIG. 10). (Relays C and F remain on), the state transitions to state III of FIG. 12 (c) or FIG. In this state III, the outputs of the battery packs 101 of # 1, # 2, and # 3 are connected to the plus electrode terminal EB + via the resistor R of FIG. 11 in the balance section 102 ′ of FIG. As a result, the resistor R suppresses an inrush current with respect to a load (such as a vehicle driving motor) connected to the plus electrode terminal EB +, and a load failure can be avoided.

  When a predetermined time has elapsed from the connection in the state III and the storage of the capacity of the load is completed, the battery ECU 104 performs relays A, B, and B in FIG. 11 in the balance unit 102 ′ in FIG. 10 via the control line group 109. By turning on and G and turning off relays C, D, and F, the state transits to the state IV shown in FIG. 12 (d) or FIG. In this state IV, the outputs of the battery packs 101 of # 1, # 2, and # 3 are connected to the relays A, B, and G without passing through the resistor R of FIG. And directly connected to the positive electrode terminal EB +, and the load is directly driven.

After the vehicle finishes running and the ignition is turned off (IG-OFF in FIG. 13), the state is changed again to the state II in FIG.
As described above, in the second embodiment, even when there are three battery packs 101, # 1, # 2, and # 3, as in the case of the first embodiment, # 1, # 2, And # 3, the voltage is appropriately equalized, and efficient power supply can be performed while the occurrence of inrush current to each battery pack 101 and the load is avoided. It becomes possible.

  As described above, in the battery system in which two battery packs are connected in parallel in the first embodiment and three battery packs in the second embodiment, the configuration for preventing the return current during the operation of the assembled battery is disclosed. Even in the case of two or more parallel circuits, it is possible to configure a balance unit with a small circuit scale based on the same idea.

DESCRIPTION OF SYMBOLS 100,100 'Battery system 101 Battery pack 102,102' Balance part 103 Voltage measurement part 104 Battery ECU (electric control unit)
105, E Main relay 106 Positive side power line 107 Negative side power line 108, 109 Control line group 110 Control line EB + Positive electrode terminal EB− Negative electrode terminal A, B, C, D, F, G Relay R Resistance

Claims (9)

In an assembled battery in which a plurality of battery packs are connected in parallel,
When the ignition is off and the voltages of the battery packs are not uniform, the currents of the battery packs are equalized by flowing a current between the battery packs through an inrush current prevention resistor.
When turning on the ignition, the output of the battery pack is connected to a load connected to the assembled battery via the inrush current prevention resistor,
After a predetermined time has elapsed since the connection, the output of the battery pack is connected to the load without going through the inrush current prevention resistor.
A method for connecting a battery pack, comprising: When turning on the ignition,
When the voltages of the battery packs are equal, the outputs of all the battery packs are connected to the load via the inrush current prevention resistor, and after the predetermined time has elapsed from the connection, all the batteries Connect the output of the pack to the load without going through the inrush current prevention resistor,
If the voltage of each battery pack is not equal, the output of the battery pack having a high voltage is connected to the load via the inrush current prevention resistor,
After the predetermined time has elapsed since the connection,
When the voltages of the battery packs are equal, the outputs of all the battery packs are connected to the load via the inrush current preventing resistors, and after the predetermined time has passed since the connection. , Connect the output of all the battery packs to the load without going through the inrush current prevention resistor,
When the voltage of each battery pack is not equal, the output of the battery pack having a high voltage is connected to the load without passing through the inrush current prevention resistor, and after the connection, When the voltages are equalized, connect the outputs of all the battery packs to the load without going through the inrush current prevention resistors.
The assembled battery connection method according to claim 1, further comprising: An assembled battery in which the first and second battery packs are connected in parallel,
A first changeover switch having a first terminal connected to one output terminal of the first battery pack and a second terminal connected to one external output terminal of the assembled battery;
A second changeover switch having a first terminal connected to one output terminal of the first battery pack;
A resistor having a first terminal connected to a second terminal of the second changeover switch and a second terminal connected to the one external output terminal;
A third changeover switch having a first terminal connected to a second terminal of the second changeover switch and a second terminal connected to an output terminal of the second battery pack;
A fourth changeover switch having a first terminal connected to one output terminal of the second battery pack and a second terminal connected to the one external output terminal;
A main changeover switch for controlling on or off of the entire assembled battery;
An assembled battery comprising: When the ignition is off and the voltages of the first and second battery packs are not equal, the first and second battery packs are caused to flow by passing a current between the first and second battery packs via the resistor. Equalize the voltage of the second battery pack,
When turning on the ignition, the output of the first or second battery pack is connected to the one external output terminal via the resistor,
After a predetermined time has elapsed since the connection, the output of the first or second battery pack is connected to the one external output terminal without passing through the resistor.
The assembled battery according to claim 3, wherein the first, second, third, or fourth changeover switch is controlled as described above. If the output voltage of the first and second battery packs is not equal when the ignition is off and the main changeover switch is off, the first and third changeover switches are turned on and the second and second changeover switches are turned on. By turning off the fourth changeover switch, or turning on the second and fourth changeover switches and turning off the first and third changeover switches, the first and second changeover switches are connected via the resistors. Current between two battery packs to equalize the output voltages of the first and second battery packs,
The assembled battery according to claim 4. If the output voltage of the first and second battery packs is not equal when the ignition is off and the main changeover switch is off, the number of times the first changeover switch is changed is the fourth changeover switch. Is smaller than the number of switching times, the first and third switching switches are turned on, the second and fourth switching switches are turned off, and the number of switching times of the first switching switch is the fourth switching number. If the number of switching of the changeover switch is equal to or greater than the number of changeovers, the second and fourth changeover switches are turned on and the first and third changeover switches are turned off;
The assembled battery according to claim 5. When turning on the ignition,
When the voltages of the first and second battery packs are equal, the first and fourth changeover switches are turned off, the second and third changeover switches are turned on, the main changeover switch is turned on and an ignition is performed. By turning on, each output of the first and second battery packs is connected to the one external output terminal via the resistor, and after the predetermined time has elapsed from the connection, the first and fourth battery packs are connected. By turning on the changeover switch and turning off the second and third changeover switches, each output of the first and second battery packs is connected to the one external output terminal without passing through the resistor,
When the voltages of the battery packs are not uniform, the first and fourth change-over switches are turned off, and the switch connected to the battery pack having the higher voltage among the second or third change-over switches. By turning on only the switch, the output of the battery pack having the higher voltage is connected to the load via the resistor,
After the predetermined time has elapsed since the connection,
When the voltages of the first and second battery packs are equal, the first and fourth changeover switches are turned off, the second and third changeover switches are turned on, and the main changeover switch is turned on. By turning on and turning on the ignition, each output of the first and second battery packs is connected to the one external output terminal via the resistor, and after the predetermined time has passed since the connection, By turning on the first and fourth changeover switches and turning off the second and third changeover switches, the outputs of the first and second battery packs can be output to the one external output terminal without passing through the resistors. Connected to
When the voltages of the battery packs are not equal, the second and third change-over switches are turned off and connected to the battery pack with the higher voltage of the first or fourth change-over switches. By turning on only the changeover switch, the output of the battery pack having the higher voltage is connected to the load without passing through the resistor, and the voltage of the first and second battery packs is connected after the connection. Are equalized, the first and fourth change-over switches are turned on and the second and third change-over switches are turned off, whereby the outputs of the first and second battery packs are connected via the resistors. Without connecting to the one external output terminal,
The assembled battery according to any one of claims 4 to 6, wherein: An assembled battery in which the first, second, and third battery packs are connected in parallel,
A first changeover switch having a first terminal connected to one output terminal of the first battery pack and a second terminal connected to one external output terminal of the assembled battery;
A second changeover switch having a first terminal connected to one output terminal of the first battery pack;
A resistor having a first terminal connected to a second terminal of the second changeover switch and a second terminal connected to the one external output terminal;
A third changeover switch having a first terminal connected to a second terminal of the second changeover switch and a second terminal connected to an output terminal of the second battery pack;
A fourth changeover switch having a first terminal connected to one output terminal of the second battery pack and a second terminal connected to the one external output terminal;
A fifth changeover switch having a first terminal connected to a second terminal of the second changeover switch and a second terminal connected to one output terminal of the third battery pack;
A sixth changeover switch having a first terminal connected to one output terminal of the third battery pack and a second terminal connected to the one external output terminal;
A main changeover switch for controlling on or off of the entire assembled battery;
An assembled battery comprising: If the voltage of the first, second, or third battery pack is not equal when the ignition is off, a current is passed between the first, second, or third battery pack through the resistor. To equalize the voltage of the first, second, or third battery pack,
When turning on the ignition, the output of the first, second, or third battery pack is connected to the one external output terminal via the resistor,
After a predetermined time has elapsed since the connection, the output of the first, second, or third battery pack is connected to the one external output terminal without passing through the resistor.
The assembled battery according to claim 8, wherein the first, second, third, fourth, fifth, or sixth changeover switch is controlled as described above.