JP2001231178A - Battery pack control device, module battery unit, module battery, and battery pack control method - Google Patents

Abstract

(57) [Problem] To efficiently and uniformly charge and discharge a secondary battery constituting a module battery. SOLUTION: A plurality of secondary batteries B1, B2,... B
n battery voltage detection circuit 2 for detecting each battery voltage of n
It is connected in parallel to each of the secondary batteries and is based on the charge / discharge state information of the assembled battery notified from outside of the module battery unit 10 (upper control microcomputer 101) and each battery voltage detected by the battery voltage detection circuit 2. The microcomputer 1 includes a capacity adjusting circuit 6 for adjusting the capacity of the secondary battery so that the voltage difference between the battery voltages is reduced during a halt. The voltage difference of the secondary battery during charging / discharging due to the difference in the internal resistance of the secondary battery and the charging current during charging is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery pack control device, a module battery unit, a module battery, and a battery pack control method, and more particularly to a battery pack control for controlling a battery pack in which a plurality of secondary batteries are connected in series. The present invention relates to an apparatus, a module battery unit provided with the battery pack control device, a battery module control method for controlling a module battery in which a plurality of module battery units are connected in series, and a battery pack in which a plurality of secondary batteries are connected in series.

[0002]

2. Description of the Related Art For example, in an electric vehicle or the like, an assembled battery in which a plurality of secondary batteries (unit cells) are connected in series by an amount corresponding to a required capacity is used. Since such a battery pack uses a large number of batteries, it is important to ensure reliability. That is, if any of the secondary batteries constituting the battery pack is overcharged or overdischarged, the function of the secondary battery is reduced and the function of the battery pack as a whole is also reduced.

In particular, if the voltage of the secondary battery becomes too high during charging, safety is impaired. Therefore, a voltage higher than a predetermined value is prevented from being generated on the charger side. In addition, each of the secondary batteries constituting the assembled battery has manufacturing variations, and when a secondary battery is used as the assembled battery, the charge acceptability and the discharge capacity are different due to an uneven temperature distribution. Come.

[0004] For this reason, the discharge capacity from the discharge depth of 0% (full charge) varies among the secondary batteries, and the discharge capacity of the assembled battery decreases. That is, at the time of discharging, the secondary battery having a reduced discharge capacity ends discharging quickly and enters an overdischarged state, and the overdischarged secondary battery becomes a load of another secondary battery and all secondary batteries are loaded. Before the depth of discharge of the next battery reaches 100%, the voltage drops, and the discharge of the assembled battery ends. Conversely, at the time of charging, the secondary battery which did not reach the depth of discharge of 100% at the time of discharging reaches the depth of discharge of 0% first, the voltage increases, and the charging ends.
Since the secondary battery that has been overdischarged at the time of discharging is charged without reaching the depth of discharge of 0%, the difference in discharge capacity between the secondary batteries is widened. Therefore, when charging and discharging are repeated, the over-discharged secondary battery is always insufficiently charged, so that the variation increases and the discharge capacity of the entire assembled battery decreases.

[0005] In the battery pack in which a plurality of secondary batteries are connected in series as described above, there is variation among the secondary batteries.
There is a problem that the discharge capacity of the whole assembled battery is reduced, a problem that a specific secondary battery is particularly deteriorated, and heat is generated by overcharge or overdischarge.

In order to cope with the above problem, there is a type in which a voltage detecting means is provided for each of the secondary batteries constituting the assembled battery, and the charging is terminated when the detected voltage reaches the charging end voltage. Also, a voltage detecting means and a bypass circuit for passing a charging current bypassing the secondary battery are provided in parallel for each of the secondary batteries constituting the assembled battery, and the secondary battery whose detected voltage becomes the charging end voltage is provided. On the other hand, there is a configuration in which a charging current is bypassed in a bypass circuit of the secondary battery.

[0007]

However, in the former case of the above-mentioned conventional example, charging is stopped when there is a secondary battery which has reached a charge end voltage among a plurality of secondary batteries constituting an assembled battery. However, it is not possible to eliminate the variation in the battery voltage between the secondary batteries.

In the latter example, the charging current is bypassed only by the voltage of the secondary battery. However, in practice, each secondary battery has a variation in internal resistance. In a secondary battery having a small internal resistance but a large internal resistance, the terminal voltage increases depending on the internal resistance to reach the charge end voltage, and a high charge state cannot be obtained for a battery with a small internal resistance. This causes variations in the state of charge of the secondary batteries having a large internal resistance, and hinders that the respective secondary batteries are uniformly and sufficiently charged, that is, the entire assembled battery is not fully charged.

[0009] As a method of charging a battery in which the variation occurs between the secondary batteries, a method of charging a secondary battery connected in series is known as a conventional example. According to this charging method, there is provided a means for examining the battery voltage of each secondary battery connected in series, and a bypass circuit for supplying a charging current bypassing the secondary battery is formed. No charging current flows to the secondary battery, and the other secondary battery is charged via the bypass circuit.

However, in the above-described method, the charging is stopped at each point when the charging stop voltage is reached, so that the charging stop time differs between the batteries connected in series. In addition, since a secondary battery having a high internal resistance reaches the charge stop voltage quickly, charging may be stopped quickly and the battery may not be fully charged.

The present invention focuses on the above problems, and efficiently and uniformly charges and discharges a secondary battery constituting an assembled battery.
An object of the present invention is to provide a battery pack control device, a module battery unit, a module battery, and a battery pack control method capable of reliably protecting a secondary battery from overcharge or overdischarge.

[0012]

According to a first aspect of the present invention, there is provided a battery pack control apparatus for controlling a battery pack in which a plurality of secondary batteries are connected in series. A battery voltage detecting means for detecting a battery voltage of each of the plurality of secondary batteries; and a charge of the battery pack connected to each of the plurality of secondary batteries in parallel and notified from outside the battery pack control device. Capacity adjusting means for adjusting the capacity of the secondary battery based on the discharge state information and each battery voltage detected by the battery voltage detecting means so as to reduce the voltage difference between the respective battery voltages at the time of suspension. And.

In the first aspect of the present invention, the battery voltage detecting means detects the battery voltage of each of the plurality of secondary batteries, and notifies the charge / discharge state information of the battery pack from outside the battery pack control device. You. Then, based on the notified charge / discharge state information and the respective battery voltages detected by the battery voltage detecting means, the capacity adjusting means sets the two battery voltages so as to reduce the voltage difference between the respective battery voltages at rest. The capacity of the next battery is adjusted. According to this aspect, the capacity adjusting unit reduces the voltage difference (open-circuit voltage difference) between the plurality of secondary batteries at rest caused by the difference in the internal resistance of the plurality of secondary batteries and the charging current during charging. Therefore, the battery voltages of the plurality of secondary batteries can be equalized.

In this case, when the voltage difference exceeds a preset value, a current corresponding to the capacity corresponding to the voltage difference is discharged, so that the charge capacity of the secondary battery is consumed. Can save money. Further, when each of the battery voltages detected by the battery voltage detecting means exceeds a preset set value, it may further include a cutoff signal output means for cutting off charging and discharging of the battery pack. If the battery voltage is abnormal, or if overcharging or overdischarging occurs, charging and discharging can be interrupted, so that deterioration of each rechargeable battery can be prevented. The discharge capacity can be prevented from lowering. Further, at least one of an assembled battery voltage detecting means for detecting an assembled battery voltage of the assembled battery and a battery temperature detecting means for detecting a battery temperature of at least one of the plurality of secondary batteries. The apparatus further comprises the cutoff signal output means outputs the cutoff signal when at least one of the battery pack voltage and the battery temperature exceeds a preset value, respectively. When there is a voltage abnormality in the battery or when there is a temperature abnormality in the secondary battery, it is possible to perform charging / discharging safely without deteriorating the performance of each secondary battery and the entire assembled battery. Furthermore, if the capacity adjustment of the secondary battery by the capacity adjusting means is further performed at the time of charging, the voltage difference between the secondary batteries which becomes the largest at the time of charging is reduced, and the battery voltage of the plurality of secondary batteries is reduced. It can be even more uniform. The capacity adjustment at the time of charging is performed by calculating the dischargeable capacity of each of the secondary batteries based on each battery voltage detected by the battery voltage detecting means at the end of discharging, and calculating the calculated dischargeable capacity. This is performed by the capacity adjusting means. This adjustment may be made, for example, such that the charging current corresponding to the dischargeable capacity is bypassed. At this time, if the amount of the capacity adjustment performed at the time of suspension is corrected, the capacity adjustment by the capacity adjusting means can be performed accurately. Further, the capacity adjustment at the time of charging is performed by the capacity adjusting means based on the voltage difference between the respective battery voltages detected by the battery voltage detecting means at the end of charging so that the voltage difference between the respective battery voltages becomes smaller. For example, the battery voltage of each secondary battery can be further equalized. This adjustment may be made, for example, such that when the voltage difference exceeds a preset value, a current corresponding to a capacity corresponding to the voltage difference is bypassed.

A second aspect of the present invention is a module battery unit provided with the battery pack control device of the first aspect,
As described above, the battery pack control device can efficiently and uniformly charge and discharge the battery pack, and can protect the secondary battery from an abnormal state, overcharge or overdischarge, thereby realizing an excellent module battery unit. Can be.

According to a third aspect of the present invention, there is provided a module battery in which a plurality of the module battery units according to the second aspect are connected in series, comprising state detecting means for detecting a charge / discharge state of the module battery. The charge / discharge state of the module battery detected by the detection means is notified to each of the battery pack control devices as the charge / discharge state information. The module battery of this aspect includes a state detection unit that detects a charge / discharge state of the module battery. The state detection means notifies each of the battery pack control devices of the detected charge / discharge state of the module battery as charge / discharge state information. According to this aspect, since the plurality of module battery units are connected in series, it is sufficient that the module battery has at least one state detecting means for detecting the charge / discharge state. If the charge / discharge state information is notified to the control device, each battery pack control device does not need to detect the charge / discharge state, so that each battery pack control device can be simplified.

In this case, as described above, since the module battery has a plurality of module battery units connected in series, if at least one interrupting means for interrupting charging / discharging of the module battery is provided, an interrupt signal output is provided. The charge / discharge of the module battery can be cut off when a cutoff signal is output from any of the means. Therefore, the battery pack control device of any one of the module battery units further includes a state detection unit that detects a charge / discharge state of the module battery, and the charge / discharge state detected by the state detection unit is determined by the state detection unit. Notifying the other battery pack control device as charge / discharge state information, the battery pack control device of at least one of the module battery units outputs a cutoff signal from any of the cutoff signal output means. May be provided with an interrupting means for interrupting charging and discharging of the module battery.

A fourth aspect of the present invention is a battery pack control method for controlling a battery pack in which a plurality of secondary batteries are connected in series, based on the notified charge / discharge state information. Detecting the battery voltage of each of the plurality of secondary batteries, and calculating a capacity corresponding to the voltage difference when a voltage difference between the detected battery voltages exceeds a preset value;
Discharging the current corresponding to the calculated capacity during the pause. In this case, the battery voltage of each of the plurality of secondary batteries at the end of discharge is detected based on the notified information power information, and the smallest one of the detected battery voltages at the end of discharge is detected. Calculate the dischargeable capacity of each of the other secondary batteries based on the voltage, at the time of the next charge at the end of the discharge, bypass the charge current of the other secondary battery corresponding to the calculated dischargeable capacity, Detecting a battery voltage of each of the plurality of secondary batteries at the end of charging, and when the detected voltage difference between the battery voltages at the end of charging exceeds a preset value, before completion of charging, A step of bypassing a charging current corresponding to the voltage difference may be included. Further, in the step of calculating the discharge capacity, the calculation may be performed by subtracting the capacity discharged during the pause.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a module battery to which the present invention is applied will be described with reference to the drawings.

(Construction) As shown in FIG. 1, a module battery 100 of the present embodiment includes a module battery unit in which a plurality of module battery units 10, 11,. A higher-level control microcomputer (hereinafter, referred to as a higher-level control microcomputer) 101 for controlling the whole, a charging / discharging current detecting circuit 102 connected in series to the uppermost module battery unit 10 and detecting a charging / discharging state of the module battery 100; And a cutoff switch 103 connected in series to the charge / discharge current detection circuit 100 to cut off the charge / discharge current.

The host control microcomputer 101 includes a CPU for performing arithmetic processing and an RO for storing a program to be executed by the CPU.
M, a RAM serving as a work area for the CPU, an input / output interface serving as a port for input / output signals with the outside, and the like.

The charge / discharge current detection circuit 102 has a built-in current sensor for measuring the charge / discharge current as a voltage value using the shunt (shunt) resistance as a sensor, and converts the voltage value across the shunt resistor measured by the current sensor into a current value. After the conversion, the signal value connected to the host control microcomputer 101 is changed to the default value -1 when the module battery unit is being charged.
The default value 1 when discharging, the default value 0 when pausing (during charging pause or discharging pause),
Each is output to the host control microcomputer 101. An FET, a relay, or the like can be used for the cutoff switch 103. According to a cutoff control signal from the host control microcomputer 101 through a signal line connected to the host control microcomputer 101,
A configuration in which the switch can be turned on (at the time of a high level signal) or off (at the time of a low level signal), and the switch can be manually released from off to on in preparation for use after charging of the module battery 100 is completed; Has become.

A signal line for outputting a state value (default value) indicating that the above-mentioned module battery 100 is being charged, discharged or paused is connected to the host control microcomputer 101 and each of the module battery units 10, 11,. When each of the secondary batteries in each of the battery modules 10, 11,...
1 is connected by a signal line for notifying an abnormal situation. The cutoff switch 103 is connected to the plus external output terminal, and the minus side of the lowest module battery unit 1m is connected to the minus external output terminal. Therefore, the module battery 100 is configured to be connectable to a load or a charger, for example, via a fuse (not shown) or the like to a positive external output terminal.

As shown in FIG. 2, the module battery unit 10 includes an assembled battery B in which a plurality of secondary batteries B1, B2,... Bn are connected in series, and an assembled battery control device for controlling the assembled battery B. 5 is comprised.

The battery pack control device 5 includes the microcomputer 1. The microcomputer 1 has a configuration similar to that of the above-described host control microcomputer 101, and includes a CPU, a ROM, a RAM, an input / output interface, and the like. Note that the ROM also stores various setting values described later.

Further, the battery pack controller 5 controls each of the secondary batteries B
, B2, ... Thermistors 71, 72, ... that are arranged in contact with the surface of Bn and measure the temperature of each secondary battery
7n. Thermistors 71, 72, ... 7n
Are connected to a battery temperature detection circuit 3 which converts a resistance (voltage) value measured by these thermistors into a temperature value and outputs it to the microcomputer 1.

Further, the battery pack control device 5 includes a battery voltage detecting circuit 2 for detecting a battery voltage of each secondary battery.
As shown in FIG. 3, this battery voltage detection circuit 2 is configured to have the same number of operational amplifier circuits as the number of secondary batteries, each including an operational amplifier IC1 and resistors R11 to R15.
The positive-phase input terminal of the operational amplifier IC1 of each operational amplifier circuit is connected to the plus terminal of each secondary battery via a resistor R12, and the negative-phase input terminal is connected to the minus terminal of each secondary battery via a resistor R11. , Output terminals are connected to the microcomputer 1. Therefore, taking the secondary battery B1 as an example, the voltage output from the output terminal of the operational amplifier IC1 is a potential difference (V1-V2) between the potential V1 of the secondary battery B1 and the potential V2 of the secondary battery B2, that is, It becomes the voltage of the secondary battery B1.

As shown in FIG. 2, the battery pack control device 5 is connected in parallel with the secondary batteries B1, B2,... Bn, adjusts the battery capacity of each secondary battery, and has the same circuit configuration. , 6n. As shown in FIG. 4, for example, the capacitance adjusting circuit 61 includes an N-channel MOS type FET Q1, an NPN type transistor Q2, and resistors R1 to R6. The drain of the FET Q1 is connected to the positive terminal of the secondary battery B1 via the resistor R1. Terminal, the source is the negative terminal of the secondary battery B1, and the transistor Q
The bases 2 are connected to the microcomputer 1 via the resistors 4 respectively. Therefore, the capacity adjustment circuit 61
When a small current (adjustment signal) of a predetermined voltage is output from
Since a current flows through the gate of the FET Q1, a current flows from the drain to the source of the FET Q1.

Further, as shown in FIG. 2, the battery pack control device 5 detects the voltage value of the module battery unit 10 and outputs the voltage value to the microcomputer 1 as a part of the battery voltage detecting circuit 4 as a part of the battery pack voltage detecting means. It has. The unit voltage detection circuit 4 includes an operational amplifier including a resistor and an operational amplifier, a filter resistor and a capacitor, a detection resistor for detecting a voltage, and the like.

(Operation) Next, the module battery 10 of the present embodiment will be described with reference to a flowchart and an operation explanation circuit diagram.
The operation of 0 will be described. When the power of the microcomputer 1 is turned on, the CPU of the microcomputer 1 initializes the work area of the RAM according to the program stored in the ROM and returns to the RO.
An initial process of reading various set values stored in M and transferring to the RAM is performed, and execution of a module battery unit control processing routine shown in FIG. 5 is started.

In step 100 of FIG. 5, each secondary battery B
The protection processing subroutine shown in FIG. 6 is executed to protect 1, B2,... Bn from abnormal voltage or the like. First, in step 102, the assembled battery voltage value output from the unit voltage detection circuit 4 is fetched, and in the next step 104, the fetched assembled battery voltage value is transferred from the ROM to the RAM work area. Voltage value stored in the RAM last time (see step 272 in FIG. 7) to detect whether the battery voltage value is larger than the battery voltage value, whether the battery pack voltage value is smaller than the battery pack voltage lower limit set value, and whether the cell is short. (The voltage set value transferred to the RAM only when this step is executed first) and the voltage change amount ΔV / Δt per time between the current detected voltage value and the calculated voltage change amount ΔV / Δt are calculated. It is determined whether or not the voltage of the battery pack is abnormal by determining whether or not the absolute value is larger than the set value of the voltage change amount. Therefore, in step 104, an affirmative determination is made that any one of the upper limit, the lower limit, and the voltage change amount ΔV / Δt is out of the set range. In the case of a negative determination, since there is no abnormality in the voltage of the entire module battery unit, each temperature value of each secondary battery output from the battery temperature detection circuit 3 is taken in the next step 106.

Next, at step 108, it is detected whether each of the taken-in temperature values is larger than the battery temperature upper limit set value, whether each temperature value is smaller than the battery temperature lower limit set value, and a sharp temperature rise. For this reason, the previous time (step 2 in FIG. 274)
Calculate the temperature change amount ΔT / Δt per time between each temperature value stored in the RAM (the temperature set value transferred to the RAM only when this step is executed first) and each temperature value detected this time. And the calculated temperature change amount ΔT / Δt
It is determined whether or not each secondary battery has a temperature abnormality by determining whether or not the absolute value of is larger than the temperature change amount set value. Therefore, in this step, an affirmative determination is made that any one of the upper limit, the lower limit, and the temperature change amount ΔV / Δt is out of the set range. In the case of a negative determination, since there is no temperature abnormality in all the secondary batteries, the battery voltage V of each of the secondary batteries B1, B2,. stored in the RAM takes in _B, in step 112, it is determined whether the battery voltage V _B taken is smaller than the large squid whether and secondary battery lower limit voltage set value than the secondary battery voltage upper limit set value Thus, it is determined whether or not each secondary battery has a voltage abnormality.

In the case of a negative determination, since there is no abnormal voltage in the battery voltages of all the secondary batteries, in the next step 114, each battery voltage V stored in the RAM in step 110 is read.
By determining whether or not _B is greater than the overcharge set value, it is determined whether or not each secondary battery is in an overcharged state. If the determination is negative, since any of the secondary batteries also are not overcharged, at the next step 116, by determining whether the battery voltage V _B is less than the over-discharge setting value, each It is determined whether the secondary battery is in an over-discharge state. In the case of a negative judgment, there is no abnormality in the module voltage, battery temperature, and each secondary battery voltage necessary for each secondary battery protection, and each secondary battery is not in an overcharged or overdischarged state. In step 118, a low-level binary output signal is output to the host control microcomputer 101, the protection processing subroutine ends, and the routine proceeds to step 200 in FIG.

On the other hand, when the upper control microcomputer 101 is also powered on, the CPU of the upper control microcomputer 101
In accordance with a program stored in M, a work area of the RAM is initialized, a set value (default value) and the like stored in the ROM are read out, and initial processing for transferring to the RAM is performed.
The execution of the module battery control processing routine shown in FIG. 11 has started. The host control microcomputer 101 executes step 3
02, any one of the module battery units 1
It is determined whether or not a high-level signal has been output from the microcomputer 1 of 0, 11,..., 1 m, and if a negative determination is made, that is, if there is no abnormality in all the secondary batteries in the module battery 100, step Cutoff switch 10 at 304
3 to output a high level signal. As a result, when the cutoff switch 103 is off, it is turned on and the cutoff state is released, and when the cutoff switch 103 is on, it is kept on. Therefore, the module battery 100 becomes ready for use as a power source or ready for use. Is maintained.

Next, steps 104, 108, 1 in FIG.
When a positive determination is made in 12, 114, and 116, there is an abnormality in any of the assembled battery voltage, each secondary battery temperature, and each secondary battery voltage, or the battery is overcharged or overdischarged.
In step 120, a high-level signal is output to the host control microcomputer 101, the protection processing subroutine ends, and the routine proceeds to step 200. Steps 108, 112,
If it is determined in steps 114 and 116 that even one secondary battery is abnormal, the process proceeds to step 120 to protect all the secondary batteries.

The output of this high-level signal causes
Is affirmed in step 302 shown in FIG. Accordingly, in the next step 306, the host control microcomputer 101 outputs a low level signal to the cutoff switch 103, and returns to step 302. As a result, the cutoff switch 103 is turned off (cutoff state), and the module battery 10
0 is a primary unusable state as a power source. As described above, since the cutoff switch 103 can be manually released, the user of the module battery 100
Is checked, and if there is no abnormality, the state can be shifted to the usable state again. If an error occurs again,
Which module battery unit is the problem,
In addition, a service having an inspection jig capable of communicating (interacting) with the host control microcomputer 101 about which secondary battery is the object, and furthermore, the reason is the above-mentioned voltage, temperature, overcharge, overdischarge, etc. You can check at the station.

As shown in FIG. 11, in the module battery control processing routine, a default value output from the charge / discharge
In step 8, it is determined whether or not the battery is being discharged.
.. Output a default value 1 representing the discharging state to each microcomputer 1 of 1 m; if the determination in step 308 is negative, it is determined in the next step 312 whether or not charging is in progress; Then, a default value -1 indicating the state of charge is output to each microcomputer 1, and if a negative determination is made in step 312, a default value 0 indicating inactive is output to each microcomputer 1, and the process returns to step 302. For this reason, each microcomputer 1 is constantly notified from the higher-order control microcomputer 101 of charging / discharging state information indicating whether the module battery 100 is being charged, discharged, or suspended.

Next, in step 200 of FIG. 5, each of the secondary batteries B1, B
In order to adjust the capacity of Bn, a capacity adjustment subroutine shown in FIG. 7 is executed.

At step 202 in FIG. 7, a default value output from the host control microcomputer 101 is fetched and R
It is stored in the AM and it is determined whether or not the module battery unit is discharging by determining whether or not this default value is 1. If the determination is affirmative, the next step 2
In 04, the battery voltage V _B of each of the secondary batteries to determine whether less or not than the discharge termination voltage set value, it is determined whether to terminate the discharge. In the case of a negative decision,
Proceed to the next step 272. As a result, each module battery unit continues the discharging state. on the other hand,
If an affirmative determination is made in step 204, the following step 2 is performed in order to prevent the performance of the secondary battery from deteriorating due to overdischarge and to calculate the basic value of the adjustment capacity correction during charging described later.
Proceed to 10.

In step 210, a discharge termination processing subroutine shown in FIG. 8 is executed. In this discharge termination processing subroutine, a high level signal is output to the host control microcomputer 101 in step 212. As a result, the host control microcomputer 101 outputs a cutoff signal (low level signal) to the cutoff switch 103.
3 is off. In the next step 214 detects a battery voltage V _B of the respective secondary batteries. Next, in step 216, and the lowest battery voltage reference (battery voltage initially reaches the discharge end voltage) in the battery voltage V _B of each of the secondary batteries, the discharge to the discharge end voltage of other secondary batteries The possible discharge capacities are individually calculated, and in the next step 218, the calculation results are stored in a predetermined area of the RAM, and the discharge termination processing subroutine is terminated, and the flow proceeds to step 272.

On the other hand, if a negative determination is made in step 202 of FIG. 7, in the next step 206, it is determined whether or not the default value stored in the RAM in step 202 is -1 to determine that the battery is being charged. It is determined whether or not. In the case of a negative determination, since it is neither discharging nor charging, it is determined to be at rest (at the time of discharge pause or at the time of charge pause),
Proceed to the next step 220. On the other hand, in the case of an affirmative determination, in step 208, the RAM
Reads the battery voltage V _B of the battery stored in, by the battery voltage V _B of the battery to determine whether greater than the charging end voltage set value the process proceeds to RAM, whether the charging end Judge. Step 2 if affirmative
As in the case of a negative determination in step 06, the next step 220
Then, a capacity adjustment A processing subroutine shown in FIG. 9 is executed.

[0042] At step 222 of FIG. 9, the smallest cell voltage by reading the battery voltage _{V B} of the respective secondary batteries Vmi
As n, calculates the voltage difference _{V D} obtained by subtracting the Vmin from the battery voltage _{V B} of the battery _{(V D} = V B -Vmin), migrated voltage from the voltage difference _{V D} in the next step 224 in the RAM The difference setting value is read out, and the difference D between them is equal to the voltage difference V _D −
(Voltage difference set value) is calculated.

In the next step 226, the adjustment capacity Q (or Q ') described below is calculated only for each secondary battery having a positive difference D, and only the adjustment capacity Q' resulting from the calculation is stored in the RAM. In step 228, an adjustment time t (or t ′) corresponding to the adjustment capacity Q (or Q ′) is calculated,
In step 230, the output of the adjustment signal to the capacity adjustment circuit 6 connected in parallel to the secondary battery that needs to be adjusted is started.

As a result, the capacity adjustment circuit 6 starts the capacity adjustment. The capacity adjustment by the capacity adjustment circuit 6 is different between the last stage of charging (the same applies to the later-described charging) and the suspension of charging or the suspension of discharging. take. That is, at the end of charging,
For example, when an adjustment signal is output to the capacity adjustment circuit 61 shown in FIG. 4, as shown in FIG.
1, a charging current I flows, and when the N-channel MOSFET Q1 is turned on, a current Ia flows from the drain to the source. As a result, the current (I-Ia) flows through the secondary battery B1, and the charge amount corresponding to the current Ia is adjusted. The current Ia is determined by the resistor R1, and the adjusted capacitance Q is adjusted by the current Ia and the adjustment time t.
And the product On the other hand, when the adjustment signal is output to the capacity adjustment circuit 61 at the time of the suspension of charging or the suspension of discharging,
As shown in FIG. 1B, when the FET Q1 is turned on, FIG.
Unlike the case of 2 (A), no charging current flows in the secondary battery B1, and the secondary battery B1, the resistor R1, and the FET Q1
, The secondary battery B1 is in a discharged state. At this time, assuming that the current flowing through the closed circuit is Ib and the internal resistance of the secondary battery B1 is ignored, the resistance value of the resistor R1 is known, so that the current Ib is the battery voltage V _{B of the} secondary battery B1.
The adjustment capacitance Q ′ determined and adjusted is the product of the current Ib and the adjustment time t ′.

In step 232, it is determined whether or not the adjustment time t (or t ') calculated in step 228 has elapsed. This adjustment time t (or t ′) can be measured by an internal clock (not shown) of the microcomputer 1. If the determination is affirmative, in step 233, the adjustment signal output to the capacity adjustment circuit 6 to cancel the capacity adjustment of the secondary battery is turned off. Thereby, for example, the current Ia (or Ib) does not flow between the drain and the source of the N-channel MOSFET Q1 shown in FIG. 4 (or FIG. 12), so that the capacity adjustment circuit 61 adjusts the capacity of the secondary battery B1. Ends.

In the next step 234, the default value (0) stored in the RAM and the default value (1 or -1) before taking the default value (0) are read out to determine whether or not the charging / discharging is stopped. If not, step 236
When the determination is affirmative, in the next step 235, the adjustment capacity Q ′ stored in the RAM in step 228 is read, and the adjustment capacity Q ′ adjusted during the current charging / discharging pause is set.
Is added to the capacity adjusted during the previous charge / discharge pause, and the result is stored in the RAM. Therefore, the adjusted capacity is stored in the RAM only when the charging and discharging are stopped. Next, in step 236, it is determined whether or not there is another secondary battery that needs to be adjusted. If the determination is affirmative, the process returns to step 230 in order to continue the capacity adjustment of the secondary battery requiring another adjustment, and if the determination is negative, the process ends the capacity adjustment A processing subroutine and proceeds to step 272. move on.

On the other hand, if a negative determination is made in step 232, it is determined in step 238 whether or not it is the end of charging. If the determination is affirmative, the process returns to step 230 to complete the charging. Next step 240
In step, the default value output from the host control microcomputer 101 is fetched, and the default value is 1 (discharge) or -1.
By determining whether or not (charging), it is determined whether or not the charging suspension state or the discharging suspension state has been forcibly terminated. When the determination is negative (default value 0), the sleep state is continuing, and the process returns to step 230 to continue the capacity adjustment, and when the determination is affirmative, in step 242, the capacity adjustment of all the secondary batteries is performed. The adjustment signal output to the capacitance adjustment circuit 6 for canceling is turned off. In the next step 244, the adjusted capacity Q ″ for each secondary battery is calculated back from the adjusted time t ″, and the capacity Q ″ adjusted during the suspension in step 246 is calculated up to the previous time. Then, the capacity adjusted during the suspension of charge / discharge is added and accumulated in the RAM, the capacity adjustment A processing subroutine is terminated, and the routine proceeds to step 272.

Next, if a negative determination is made in step 208 of FIG. 7, the process proceeds to step 250, where a capacity adjustment B processing subroutine shown in FIG. 10 is executed. Step 252
Then, the correction of the adjustment capacity is executed. The correction of the adjustment capacity is performed based on the adjustment capacity calculated from the end-of-discharge voltage stored in the RAM in step 218 or step 235 or step 2.
At 46, the adjustment is performed by subtracting the already adjusted total adjusted capacity at the time of charging / discharging suspension stored in the RAM. In the next step 254, it is determined whether or not the capacity adjustment is necessary by determining whether or not the adjusted capacity after the correction is larger than the adjusted capacity set value transferred to the RAM. When the determination is affirmative, the adjustment time is calculated in step 256, and the adjustment signal is applied in step 258 until the adjustment time elapses in step 260. Output to the capacity adjustment circuit 6 which is to be executed. As a result, the capacity adjustment of the corresponding secondary battery is executed at the time of the next charging after the suspension of charging and discharging. In step 256, the total adjustment amount stored in the RAM is cleared to 0 after calculating the adjustment time to prepare for the next correction.

In the next step 262, the adjustment signal output to the capacity adjustment circuit 6 of the secondary battery is turned off in order to cancel the capacity adjustment of the secondary battery. Next, in step 264, it is determined whether or not there is another secondary battery that needs to be adjusted. If it is necessary, the capacity adjustment is continued, and the adjustment time of the last secondary battery that needs adjustment is adjusted. When the time has elapsed, the capacity adjustment processing B subroutine ends, and the routine proceeds to step 272.

Next, in step 272 of FIG. 7, the module voltage is fetched and stored in the RAM in order to enable the calculation of the voltage change amount ΔB / Δt in step 104 described above. In order to enable the calculation of the amount of temperature change in step 108, each temperature value of each secondary battery is fetched and stored in the RAM, and the process returns to step 100.

(Test / Evaluation) Next, according to the above embodiment, the implementation of the module battery 100 having the module battery units 10, 11, 1m in which eight secondary batteries B1, B2,. Example and a comparative example provided with four module battery units (not including the battery pack control device of the present embodiment) of the conventional example in which eight secondary batteries were connected in series to confirm the effect of the example. , And charge / discharge, measure the discharge end voltage, and measure the module battery units 10, 11,... Of the present embodiment.
The effect of 1 m was confirmed. In addition, in the module battery units 10, 11,..., 1 m of the present embodiment, secondary batteries having intentionally varied voltage were used.

The measurement results of the discharge end voltage of the highest-order module battery unit 10 most susceptible to temperature, voltage and the like among the module batteries of the embodiment and the comparative example and the corresponding highest-order module battery unit of the comparative example are shown. These are shown in FIGS. 13 and 14, respectively. It should be noted that the same results were obtained for other module battery units in both the examples and comparative examples.

As shown in FIG. 13, in the module battery unit 10 of this embodiment, there was an initial voltage difference between the secondary batteries (cell 1 to cell 8), but the capacity was adjusted by the capacity adjusting circuits 61 to 68. The voltage difference is decreasing,
Even if a difference occurs, the capacity is adjusted and is about to fall within about 50 mV.

On the other hand, in the module battery unit of the comparative example, as shown in FIG. 14, the voltages were almost the same at the beginning, but the voltage difference increased as the cycle progressed. It can be seen that the secondary batteries connected in series are evenly adjusted by the unit battery control device of the battery unit 10. Therefore, the module battery units 10, 11,...
Are connected in series, the voltage of each secondary battery of the module battery 100 is adjusted uniformly.

(Operation, etc.) In this embodiment, in the capacity adjustment A processing subroutine, the unit voltage detection circuit 4
When the battery voltage of each of the secondary batteries detected in step (1) exceeds a set value and fluctuates, the charge current is bypassed by the capacity adjusting circuit 6 (see FIG. 12A), and the secondary batteries are individually charged and suspended during charging and discharging. The variation of the open-circuit voltage caused by the difference in the internal resistance and the charging current is discharged by the capacity adjusting circuit 6 to discharge the secondary batteries having a high open-circuit voltage, thereby balancing the battery voltages of the respective secondary batteries (see FIG. 12B). In addition, the battery voltage of each secondary battery can be equalized. In addition, since the capacity adjustment is performed when there is variation over the set value, it is possible to save the consumption of the capacity charged in each secondary battery.

In the discharge end processing subroutine, the secondary battery having the lowest voltage among the secondary battery voltages detected at the end of discharge (the secondary battery that first reaches the discharge end voltage) is used as a reference. Calculate the discharge capacity of each of the secondary batteries up to the discharge cutoff voltage (Step 2).
16) In the capacity adjustment B processing subroutine, the capacity of each secondary battery is adjusted during charging by bypassing the charging current at the next charging (steps 258 and 260).
The battery voltage of each secondary battery can be equalized.

Further, in the capacity adjustment B processing subroutine,
Since the correction is performed by subtracting the capacity adjusted at the time of the discharge suspension from the adjusted capacity calculated from the end-of-discharge voltage (Step 252), more accurate capacity adjustment can be performed as compared with the case where no correction is performed. Excessive adjustment can be prevented.

In the protection processing subroutine, when the voltage of the assembled battery, the temperature of each of the secondary batteries, the abnormality of the voltage of each of the secondary batteries, and the overcharge or overdischarge are detected, a cutoff signal is sent to the host control microcomputer 101. Since the output is performed to stop the charging and discharging of the module battery 100, it is possible to protect the secondary battery without deteriorating its performance.

Accordingly, the module battery 10 of the present embodiment is
Each of the battery pack control devices 5 of 0 can efficiently charge and discharge each of the secondary batteries efficiently, and this is apparent from the evaluation of the embodiment.

Also, since only one charge / discharge current detection circuit 102 and one cutoff switch 103 are required for the module battery 100, they are controlled via the host control microcomputer 101 and can communicate with each microcomputer 1. , 1 m, and the size of the module battery 100 can be reduced.

In this embodiment, the host control microcomputer 1
01, but a charge / discharge current detection circuit is provided in one of the module battery units instead of the host control microcomputer 101 or in series with the module battery unit, and the charge / discharge state performed by the host control microcomputer 101 in the microcomputer 1 May be executed, and the microcomputer of another module battery unit may be notified of the charge / discharge state information (default value). Also, the module battery unit 10,
,... 1 m are connected in series, so that the cutoff switch 10 is installed in any one of the module battery units.
3 may be built in or connected in series, and the microcomputer 1 of this module battery unit may output a shutoff signal to the shutoff switch 103 performed by the host control microcomputer 101. The microcomputer 1 that controls the shut-off switch 103 is preferably a microcomputer other than the microcomputer 1 of the module battery unit 10 described above in order to reduce the load on the microcomputer. This eliminates the need for the host control microcomputer 101, so that the size of the module battery 100 can be further reduced.

Further, in the module battery unit 10 of the present embodiment, the thermistor 7 is arranged in contact with each of the secondary batteries in order to protect all the secondary batteries. It is sufficient that at least one battery is provided for an arbitrary secondary battery, such as being arranged every other battery.
In this case, although it is inferior from the viewpoint of secondary battery protection, there is an advantage that cost can be saved.
Further, in the present embodiment, an example has been described in which the thermistor 7 is used as a temperature sensor. However, various sensors that function as a temperature sensor other than the thermistor can be used.

In the present embodiment, an example in which a plurality of battery voltage detection circuits 2 shown in FIG. 3 are provided has been described.
The battery voltage of each secondary battery may be detected by one differential amplifier circuit by switching with a switch or the like.

Further, in this embodiment, FIG. 4 shows an example of the capacitance adjusting circuit 61 as the capacitance adjusting means. However, the present invention is not limited to the circuit configuration shown in FIG. It will be apparent to those skilled in the art that various circuit configurations are possible.

In this embodiment, the shunt resistor and the charging / discharging current detecting circuit 102 are exemplified as the state detecting means. However, those skilled in the art can also configure various other sensing circuits capable of detecting the charging / discharging state. It is clear to Further, the charge / discharge current detection circuit 10 of the present embodiment
In FIG. 2, the explanation is made using the default values for the sake of simplicity, but the present invention is not limited to such default values. Since an error due to noise or the like may occur in the voltage between both ends of the shunt resistor, it is preferable to use a charge / discharge current detection circuit that takes this error into account.

Further, in the present embodiment, as shown in FIG. 1, an example is shown in which each of the module units 10, 11,... , 1m and a communication line for performing communication between the host control microcomputer 101 and
For example, the upper control microcomputer 101, the module unit 10, the module unit 11, the module unit 1m, and the higher control microcomputer 101 may be connected in a loop in this order. In this way, the number of wires between each of the module units 10, 11,... 1m and the host control microcomputer 101 can be reduced, and the length of the wires can be shortened. Is reduced, and wiring routing is facilitated. In this case, notification of the charge / discharge state to each module unit and notification of an abnormal state to the higher-level control microcomputer are performed by communication between each module unit and the higher-level control microcomputer 101 via a communication line. Therefore, the notification of the charge / discharge state and the output of the abnormal signal may be performed by communication.

In the flowchart of the present embodiment, one mode of control by the microcomputer 1 and the host control microcomputer 101 has been described. However, the present invention is not limited to this, and various types of control are possible within the scope of the claims described above. It goes without saying that the transformation can be applied.

[0068]

As described above, according to the present invention,
The capacity adjusting means adjusts the voltage difference between the plurality of secondary batteries at rest, which is caused by the difference in internal resistance of the plurality of secondary batteries and the charging current at the time of charging, so that the plurality of secondary batteries can be adjusted. The battery voltage can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic block circuit diagram of a module battery according to an embodiment to which the present invention can be applied.

FIG. 2 is a block circuit diagram of a module battery unit of the module battery according to the embodiment.

FIG. 3 is a circuit diagram showing a battery voltage detection circuit of the battery pack control device of the embodiment.

FIG. 4 is a circuit diagram showing a capacity adjustment circuit of the battery pack control device of the embodiment.

FIG. 5 is a flowchart showing a module battery unit control processing routine of the battery pack control device of the embodiment.

FIG. 6 is a flowchart showing details of a protection processing subroutine of a module battery unit control processing routine.

FIG. 7 is a flowchart showing details of a capacity adjustment processing subroutine of a module battery unit control processing routine.

FIG. 8 is a flowchart showing details of a discharge termination processing subroutine in a capacity adjustment processing subroutine.

FIG. 9 shows a capacity adjustment A in a capacity adjustment processing subroutine.
It is a flowchart which shows the detail of a processing subroutine.

FIG. 10 is a flowchart showing details of a capacity adjustment B processing subroutine in a capacity adjustment processing subroutine.

FIG. 11 is a flowchart illustrating a module battery control processing routine of a higher-level control microcomputer.

12A is an operation explanatory circuit diagram showing an operation of the capacity adjustment of the capacity adjustment circuit at the time of charging, and FIG. 12B is an operation explanation circuit showing the operation of the capacity adjustment of the capacity adjustment circuit at the time of charging / discharging suspension; FIG.

FIG. 13 is a graph showing a measurement result of a discharge end voltage of a module battery unit of an example to which the present embodiment is applied.

FIG. 14 is a graph showing a measurement result of a discharge end voltage of a module battery unit of a comparative example.

[Explanation of symbols]

1 Microcomputer (part of battery temperature detecting means, part of assembled battery voltage detecting means, part of capacity adjusting means, cut-off signal output means) 2 Battery voltage detecting circuit (part of battery voltage detecting means) 3 Battery temperature detecting Circuit (part of battery temperature detecting means) 4 Unit voltage detecting circuit (part of assembled battery voltage detecting means) 5 Battery pack control device 10, 11, 1m Module battery unit 61, 62, 6n Capacity adjusting circuit (capacity adjusting means) 71, 72, 7n Thermistor (part of battery temperature detecting means) 100 Module battery 101 Host control microcomputer (part of state detecting means, part of interrupting means) 102 Charge / discharge current detecting circuit (state detecting means) 103) Cutoff switch (part of cutoff means) B1, B2, Bn secondary battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/48 301 H01M 10/48 301 H02J 7/00 302 H02J 7/00 302C F-term (Reference) 2G016 CA03 CB11 CB12 CB31 CC01 CC03 CC04 CC13 CC27 CD04 CD06 CD14 5G003 AA01 BA03 CA11 CB01 CC04 DA12 GA01 GC05 5H030 AA03 AA04 AA06 AS20 BB01 BB21 DD08 FF22 FF43 FF44 5H040 AA40 NN05

Claims (17)

[Claims] 1. A battery pack control device for controlling a battery pack in which a plurality of secondary batteries are connected in series, comprising: battery voltage detecting means for detecting a battery voltage of each of the plurality of secondary batteries; Connected to each of the secondary batteries in parallel, based on the battery voltage detected by the battery voltage detection means and the charge / discharge state information of the battery pack notified from outside the battery pack control device, A battery pack control device comprising: a capacity adjusting unit that adjusts the capacity of the secondary battery so as to reduce the voltage difference between the battery voltages during a halt. 2. The capacity adjustment by the capacity adjusting means, wherein, when the voltage difference exceeds a preset value, a current corresponding to a capacity corresponding to the voltage difference is discharged. 2. The battery pack control device according to 1. 3. A shut-off signal output for outputting a shut-off signal for shutting off charging / discharging of the battery pack when each battery voltage detected by the battery voltage detecting means exceeds a preset value. 3. The battery pack control device according to claim 1, further comprising means. 4. An assembled battery voltage detecting means for detecting an assembled battery voltage of the assembled battery and a battery temperature detecting means for detecting a battery temperature of at least one of the plurality of secondary batteries. And the cutoff signal output means outputs the cutoff signal when at least one of the battery pack voltage and the battery temperature exceeds a preset value. The battery pack control device according to claim 3. 5. The battery pack control device according to claim 1, wherein the capacity adjustment of the secondary battery by the capacity adjustment unit is further performed during charging. 6. The capacity adjustment at the time of charging includes calculating a dischargeable capacity of each of the secondary batteries based on each battery voltage detected by the battery voltage detecting means at the end of discharging,
6. The battery pack control device according to claim 5, wherein the calculated dischargeable capacity is adjusted by the capacity adjusting means. 7. The battery pack control device according to claim 6, wherein the adjustment by the capacity adjusting unit bypasses a charging current corresponding to the dischargeable capacity. 8. The battery pack control device according to claim 5, wherein the capacity adjustment at the time of charging is corrected by the capacity adjustment performed during the pause. 9. The battery according to claim 1, wherein the capacity adjustment during charging is performed such that the voltage difference between the respective battery voltages is reduced based on the voltage difference between the respective battery voltages detected by the battery voltage detecting means at the end of charging. 9. The battery pack control device according to claim 6, wherein the capacity is adjusted by the capacity adjusting unit. 10. The adjustment by the capacitance adjusting means, when the voltage difference exceeds a preset value, bypasses a current corresponding to the capacitance corresponding to the voltage difference. The battery pack control device according to item 1. 11. The method according to claim 1, wherein
A module battery unit provided with the battery pack control device according to the above section. 12. A module battery in which a plurality of module battery units according to claim 11 are connected in series, comprising a state detecting means for detecting a charge / discharge state of the module battery, wherein the module battery detected by the state detecting means is provided. A charge / discharge state of the module battery is notified to each of the battery pack control devices as the charge / discharge state information. 13. The method according to claim 3, wherein
In a module battery in which a plurality of module battery units provided with the battery pack control device according to the paragraph are connected in series,
A module battery, comprising: shutoff means for interrupting charge / discharge of the module battery, wherein the charge / discharge of the module battery is interrupted when an interrupt signal is output from any of the shutoff signal output means. 14. The method according to claim 3, wherein
A module battery in which a plurality of module battery units each including the battery pack control device according to item 1 are connected in series, wherein the battery pack control device of any one of the module battery units is configured to charge the module battery. Further comprising a state detection means for detecting a discharge state, notifying the charge / discharge state detected by the state detection means to another battery pack control device as the charge / discharge state information, and at least one of the module battery units The battery module control device of one module battery unit has a shutoff means for shutting off charging and discharging of the module battery when a shutoff signal is output from any of the shutoff signal output means. 15. A battery pack control method for controlling a battery pack in which a plurality of rechargeable batteries are connected in series, wherein the plurality of rechargeable batteries at rest are inactive based on the notified charge / discharge state information. When the voltage difference between the detected battery voltages exceeds a preset set value, a capacity corresponding to the voltage difference is calculated. A method for controlling a battery pack including discharging a current corresponding to a capacity. 16. A battery voltage of each of the plurality of secondary batteries at the end of discharge is detected based on the notified information information, and a minimum voltage among the detected battery voltages at the end of discharge is detected. Calculating the dischargeable capacity of each of the other secondary batteries based on the battery voltage, at the time of the next charge at the end of the discharge, bypassing the charge current of the other secondary battery corresponding to the calculated dischargeable capacity. Detecting the battery voltage of each of the plurality of secondary batteries at the end of charging, and when the voltage difference between the detected battery voltages at the end of charging exceeds a preset value, before charging is completed. The method according to claim 15, further comprising the step of bypassing a charging current corresponding to the voltage difference. 17. The battery pack control method according to claim 16, wherein, in the step of calculating the dischargeable capacity, the capacity is calculated by subtracting a capacity discharged during the pause.