JP2008054414A - Battery management device, system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery management device for making it possible to use power stored in a battery pack entirely, and to provide a battery management system and method. <P>SOLUTION: The battery management device comprises a section 31 for measuring the voltage supplied from a power supply to a battery pack, a section 32 for storing the number of secondary batteries constituting the battery pack, a section 33 for calculating a target voltage, i.e. the upper limit of charging voltage of each secondary batter, by dividing the voltage measured at the voltage measuring section 31 by the number of secondary batteries stored in the number of secondary batteries storage section 32, and voltage controllers 34a-34l provided for respective secondary batteries and supplying the voltage fed from the power supply to the battery pack to each secondary battery such that the voltage of each secondary battery becomes lower than the target voltage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery management device, a battery management system, and a battery management method, and in particular, a battery management device, a battery management system, and a battery management method for charging a plurality of secondary batteries that constitute an assembled battery by a voltage supplied from a power source. About.

When secondary batteries that can be repeatedly charged and discharged are connected in series and used as an assembled battery, if all secondary batteries have the same capacity or internal resistance, each secondary battery can be charged in a balanced manner. it can. However, in practice, there is some variation in the capacity or internal resistance of the secondary battery. Furthermore, even if the internal resistance of the secondary battery is the same in the initial stage, if charging is continued, the internal characteristics of the secondary battery change with time and the capacity of the secondary battery changes. As a result, the balance of each secondary battery is lost, and the charging voltage of the secondary battery varies, thereby reducing the life and performance of the secondary battery.
In particular, when using a lithium ion secondary battery as the secondary battery, it is important to suppress the balance of the charging voltage, and in particular, suppressing the increase in the charging voltage exceeding the regulation is a viewpoint of ensuring safety. Is regarded as the most important.

FIG. 8 is a schematic configuration diagram of a conventionally known battery management system 110. The battery management system 110 supplies a DC voltage from the DC power supply 60 to the load 80 and the battery management device 100. The battery management apparatus 100 includes a control unit 70, an assembled battery 70, and voltage adjustment units 50a to 50l. The assembled battery 70 includes twelve secondary batteries 70a, 70b, 70c, 70d,..., 70l connected in series.
In this battery management device 100, in order to suppress variations in the charging voltage of the secondary batteries 70a to 70l, a voltage adjustment unit 50 using a shunt regulator is attached to each secondary battery (see Patent Document 1).

  In addition, the voltage adjustment units 50a to 50l constantly monitor the battery voltage of the secondary batteries 70a to 70l during use, and when the battery voltage reaches a preset voltage value, the secondary batteries 1a to 50l. By bypassing the charging current to the bypass circuit in the voltage adjusting units 50a to 50l provided in parallel with 11, an increase in the battery voltage of the secondary batteries 70a to 70l is suppressed. Here, “in use” refers to a state during recovery charging after discharging the assembled battery 70 and during float charging after completion of recovery charging.

In the conventional technique, the target voltage for voltage control in the voltage adjusting units 50a to 50l is set to a constant value. For example, when a lithium ion secondary battery is used as the secondary battery, the battery voltage per lithium ion secondary battery is 4.1 (V) or 4.2 (V). Then, as the output voltage of the DC power source 60, a voltage obtained by multiplying the battery voltage of the secondary batteries 1a to 1l by the number of secondary batteries (for example, 12) constituting the assembled battery is set.
JP 2000-354335 A

However, in the conventional technique, the output voltage of the DC power supply 60 varies when a current is supplied to the load 80. For example, when the output voltage of the DC power supply 60 is 4.1 (V), the characteristics shown in FIG. 9 are obtained. In FIG. 9, the horizontal axis represents the load factor (%). In FIG. 9, the left side of the vertical axis shows the output voltage (V) of the DC power supply, and the right side of the vertical axis shows the battery voltage (V / piece) of the secondary voltage.
As shown in FIG. 9, when current is supplied to the load 80 even when the assembled battery 70 is in a fully charged state, the output voltage of the DC power supply 60 varies according to the current value of the current supplied to the load. In FIG. 9, when the load factor is 100 (%), the output voltage of the DC power supply 60 is about 48.8 (V). When the assembled battery 70 is constituted by 12 lithium ion secondary batteries connected in series and the voltage adjustment setting voltage in the voltage adjustment units 50a to 50l is 4.1 (V), recovery charge is in progress or recovery charge is completed. Thereafter, even if 10 or 11 secondary batteries reach 4.1 (V), the remaining secondary batteries may be kept at a low voltage.

That is, when 11 secondary batteries reach 4.1 (V), the voltage of the assembled battery 70 in which these 11 secondary batteries are connected in series is 45.1 (V) (= 4.1). (V) × 11), and the remaining battery voltage reaches only 3.7 (V) (= 48.8 (V) −45.1 (V)).
When the voltage of 10 secondary batteries has reached 4.1 (V), the voltage of the assembled battery 70 in which these 10 secondary batteries are connected in series is 41 (V) (= 4.1). (V) × 10), and the remaining two secondary batteries share 7.8 (V). Even when two secondary batteries are charged using 7.8 (V) evenly, they reach only 3.9 (V).

  The capacity of the lithium ion secondary battery largely depends on the recovery charge voltage, and is almost proportional to the voltage value. When the charge voltage is low, the capacity is low. And in discharge of a lithium ion secondary battery, it is necessary to complete | finish discharge, if a battery voltage falls to a fixed voltage from a viewpoint of protection of a secondary battery. Therefore, when the assembled battery 70 is discharged in a state where only one secondary battery having a low capacity is included in the assembled battery 70, the secondary battery having a low battery voltage and a small capacity reaches the discharge end voltage first. At this stage, the discharge of the assembled battery 70 ends, and there is a problem that the entire power stored in the assembled battery 70 cannot be used.

  This invention is made | formed in view of the said situation, The objective is to provide the battery management apparatus, battery management system, and battery management method which can use all the electric power accumulate | stored in the assembled battery. .

The present invention has been made to solve the above problems, and the invention according to claim 1 is a battery pack in which a plurality of secondary batteries are connected in series, and a voltage supplied from a power source to the battery pack. Voltage measuring means for measuring the number, secondary battery number storage means for storing the number of secondary batteries constituting the assembled battery, voltage measured by the voltage measuring means, and the secondary battery number storage means A target voltage calculating means for calculating a target voltage that is an upper limit of a charging voltage of each secondary battery based on the number of secondary batteries, and a battery voltage of each secondary battery provided for each secondary battery. The battery management apparatus further includes a voltage supply unit that supplies a voltage supplied from the power source to the assembled battery to each secondary battery so that the voltage is equal to or lower than the target voltage.
In the present invention, the voltage measuring means measures the voltage supplied from the power source to the assembled battery, the secondary battery number storage means stores the number of secondary batteries constituting the assembled battery, and the voltage measured by the voltage measuring means Based on the number of secondary batteries stored in the secondary battery number storage means, the target voltage calculation means calculates a target voltage that is the upper limit of the charging voltage of each secondary battery, and the battery voltage of each secondary battery is The voltage supply means supplies the voltage supplied from the power source to the assembled battery to each secondary battery so that the voltage is lower than the target voltage. Therefore, a voltage equal to or lower than the target voltage can be evenly supplied to each secondary battery, and variation in the charging voltage of each secondary battery can be prevented. As a result, it is possible to prevent the discharge to the load of the entire assembled battery from being stopped halfway due to the low charging voltage of any of the plurality of secondary batteries. Electric power can be used.

The invention according to claim 2 is provided for each of the secondary batteries, and bypasses the current supplied to the secondary battery when the battery voltage of the secondary battery becomes larger than the target voltage. A battery management device having a bypass means.
In the present invention, when the battery voltage of the secondary battery becomes larger than the target voltage, the current supplied to the secondary battery is bypassed. Therefore, since the secondary battery whose charging voltage has not reached the target voltage can be charged by the bypass current, each secondary battery can be charged to the target voltage evenly.

The target voltage calculating means may divide the voltage measured by the voltage measuring means by the number of secondary batteries stored in the secondary battery number storage means. A battery management device that calculates a voltage.
In the present invention, the target voltage is calculated by the target voltage calculating means by dividing the voltage measured by the voltage measuring means by the number of secondary batteries stored by the secondary battery number storing means. Therefore, the voltage supplied from the power source to the assembled battery can be evenly supplied to each secondary battery, and variations in the charging voltage of each secondary battery can be prevented.

  According to a fourth aspect of the present invention, there is provided the battery management device according to any one of the first to third aspects, a load connected in parallel with the battery management device, the battery management device and the load. And a power source for supplying a voltage to the battery management system.

  According to a fifth aspect of the present invention, there is provided a first step in which voltage measuring means measures a voltage supplied from a power source to an assembled battery in which a plurality of secondary batteries are connected in series, and the assembled battery is configured. A secondary battery number storage means for storing the number of secondary batteries, and a voltage measured by the voltage measurement means is divided by the number of secondary batteries stored by the secondary battery number storage means, thereby obtaining each secondary battery. A second step in which the target voltage calculation means calculates a target voltage that is an upper limit of the charging voltage of the battery, and supplies the secondary battery from the power source so that the battery voltage of each secondary battery is equal to or lower than the target voltage. And a third step in which voltage supply means provided for each of the secondary batteries supplies the secondary battery to each of the secondary batteries.

  In the present invention, since the charging voltage of any secondary battery among the plurality of secondary batteries is low, it is possible to prevent the discharge to the load of the entire assembled battery from being stopped halfway, and the assembled battery is charged Full power can be used.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a battery management device 10 according to an embodiment of the present invention. The battery management device 10 includes an assembled battery 1, a control unit 3, voltage adjustment units 5a, 5b, 5c, 5d,..., 5l, and a charging voltage detection unit 7.
The assembled battery 1 includes 12 secondary batteries 1a, 1b, 1c, 1d,..., 1l connected in series. The number of secondary batteries constituting the assembled battery 1 is not limited to twelve. Both ends of the assembled battery 1 are connected to the terminal p1 and the terminal p2 of the battery management device 10, respectively. In the present embodiment, a lithium ion secondary battery is used as the secondary battery, but a lead storage battery or the like may be used as the secondary battery.

The control unit 3 is connected to the voltage adjustment units 5 a to 5 l and the charging voltage detection unit 7. The control unit 3 will be described later with reference to FIG.
Voltage regulators 5a, 5b, 5c, 5d,..., 5l are connected to both ends of secondary batteries 1a, 1b, 1c, 1d,. Yes. The voltage adjustment unit will be described later with reference to FIG.
The charging voltage detection unit 7 is connected to the control unit 3 and outputs a voltage to be measured to the control unit 3.

FIG. 2 is a schematic configuration diagram of the battery management system 11 according to the embodiment of the present invention. In this battery management system 11, one terminal of the DC power source 2 (power source) and one terminal of the load 4 are connected to the terminal p1 of the battery management device 10 (FIG. 1). Further, the other terminal of the DC power source 2 and the other terminal of the load 4 are connected to the terminal p <b> 2 of the battery management device 10.
In the embodiment of the present invention, a connection point q1 where a wiring laid from one terminal p1 of the battery management device 10 and a wiring laid from one terminal of the load 4 are connected, and one terminal of the DC power supply 2 Between the two, a charging voltage detection unit 7 is installed.
The DC power supply 2 supplies a voltage to the battery management device 10 and the load 4. The load 4 is a communication device or the like, and is driven using power supplied from the DC power supply 2 or the battery management device 10.

FIG. 3 is a circuit diagram showing a specific configuration of the battery management device 10 according to the embodiment of the present invention. The control unit 3 includes a voltage measurement unit 31 (voltage measurement unit), a secondary battery number storage unit 32 (secondary battery number storage unit), a voltage calculation unit 33 (target voltage calculation unit), a voltage controller 34a,. 34k, 34l.
The voltage measuring unit 31 obtains the voltage Va supplied from the DC power supply 2 (see FIG. 2) output from the charging voltage detection unit 7 to the assembled battery 1 and the load 4 and outputs the voltage Va to the voltage calculation unit 33. To do.
The secondary battery number storage unit 32 stores the number N of secondary batteries constituting the assembled battery 1. In the present embodiment, since the assembled battery 1 is composed of twelve secondary batteries 1a to 1l, the secondary battery number storage unit 32 stores 12 as the number N of secondary batteries.

  The voltage calculation unit 33 is based on the voltage Va output from the voltage measurement unit 31 and the number N of secondary batteries stored in the secondary battery number storage unit 32, and the upper limit of the charging voltage of each of the secondary batteries 1a to 1l. A target voltage Vp is calculated. More specifically, the voltage calculation unit 33 divides the voltage Va measured by the voltage measurement unit 31 by the number N of secondary batteries stored in the secondary battery number storage unit 32 to thereby obtain the target voltage Vp (= Va / N) is calculated. The voltage calculation unit 33 outputs the calculated target voltage Vp to each of the voltage controllers 34a to 34l.

  The voltage controller 34k acquires the target voltage Vp from the voltage calculation unit 33 and outputs it to the voltage adjustment unit 5k, so that the battery voltage of the secondary battery 1k is equal to or lower than the target voltage Vp. 1 is supplied to the secondary battery 1k. Further, the voltage controller 34 k acquires the battery voltage of the secondary battery 1 k and a bypass current value described later from the voltage adjustment unit 5 k and outputs the acquired voltage to the control unit 3. The configuration of the voltage controllers 34a to 34j, 34l is the same as the configuration of the voltage controller 34k, and thus the description thereof is omitted.

FIG. 4 is a flowchart showing processing of the voltage calculation unit 33 according to the embodiment of the present invention.
First, the voltage calculation unit 33 acquires the voltage Va from the voltage measurement unit 31 (step S11). And the voltage calculating part 33 reads the number N of secondary batteries from the odd number 32 of secondary batteries (step S12).
Then, the voltage calculation unit 33 calculates the target voltage Vp (= Va / N) from the voltage Va and the number N of secondary voltages (step S13). Then, the voltage calculator 33 outputs the target voltage Vp calculated in step S13 to the voltage controllers 5a to 5l (step S14).
And the voltage calculating part 33 determines whether predetermined time (for example, 1 second) passed by referring the built-in timer (step S15). If the predetermined time has not elapsed ("NO" in step S15), the voltage calculation unit 33 waits until the predetermined time elapses. On the other hand, if the predetermined time has elapsed (“YES” in step S15), the process proceeds to step S11.

Next, the voltage adjustment unit 5k in FIG. 3 will be described. In addition, since the structure of the voltage adjustment parts 5a-5j and 5l is the same as that of the voltage adjustment part 5k, those description is abbreviate | omitted. The voltage adjusting unit 5k includes a bypass current control element 41, a bypass current limiting element 42, a bypass current measuring element 43, a battery voltage error amplifier 44, and a battery voltage measuring error amplifier 45.
The bypass current control element 41, the bypass current limiting element 42, and the bypass current measuring element 43 are connected in series and constitute a bypass circuit (bypass means). This bypass circuit is connected in parallel with the secondary battery 1k.

The bypass current control element 41 is an element such as a transistor, and when a control signal is received from the battery voltage error amplifier 44, a bypass current that is not used for charging the secondary battery 1k among the charging current is supplied to the bypass circuit. Control to flow.
The bypass current limiting element 42 is an element such as a fuse, and when a current larger than an allowable bypass current value that is the maximum value of the bypassable current flows in the bypass circuit, the bypass current control element 41 and the bypass current measuring element The electric current which flows between 43 is interrupted | blocked.
The bypass current measuring element 43 measures the current value of the bypass current flowing through the bypass circuit and outputs the measured value to the voltage controller 34k as the bypass current measured value.

The battery voltage error amplifier 44 obtains the target voltage Vp (for example, 4.06 (V)) output from the voltage controller 34k and the battery voltage Vb of the secondary battery 1k output from the battery voltage measurement error amplifier 45. In comparison, when the battery voltage Vb is higher than the target voltage Vp, a control signal for instructing a bypass current to flow through the bypass current control element 41 is output to the bypass current control element 41.
The battery voltage measurement error amplifier 45 calculates the battery voltage of the secondary battery 1k from the difference between the positive and negative voltage values of the secondary battery 1k, and uses the battery voltage Vb as the control unit 3 and the battery voltage error amplifier 44. Output to.

  By inputting the target voltage Vp and the measured values of the voltages of the secondary batteries 1a to 1l output from the voltage controller 34k to the battery voltage error amplifier 44, the bypass current control element 41 of the bypass circuit is controlled. If the bypass current control element 41 is completely turned on, a maximum allowable current flows as the bypass current. Also, if it is completely off, no bypass current flows. Furthermore, by using the bypass current control element 41 in the amplification region (unsaturated region), the same state as the variable resistor can be obtained, and the current value of the bypass current to be bypassed can be continuously adjusted.

  Thus, in this bypass circuit, since the bypass current control element 41 can be used in the same manner as the variable resistor, even when the battery voltage Vb approaches the set target voltage Vp and the charging current becomes a minute value, this is the case. Even a very small charging current can be bypassed. With such control, by continuously bypassing the charging current with the bypass circuit according to the battery voltage value, each secondary battery can be controlled so as not to exceed the specified target voltage Vp.

In the present embodiment, since the voltage adjusting units 5a to 5l are connected in parallel to the secondary batteries 1a to 1l, the battery voltage is changed according to the battery voltage of each of the secondary batteries 1a to 1l in the assembled battery 1. In the secondary battery having a high battery voltage, bypass of the charging current proceeds, and in the secondary battery having a low battery voltage, charging by the inflow of the charging current proceeds, and in the assembled battery 1, the battery voltages of all the secondary batteries 1a to 1l are increased. Control is performed to achieve the target voltage Vp.
As a result, the battery voltage of each of the secondary batteries 1a to 1l constituting the assembled battery 1 is adjusted to become the target voltage Vp, so that the variation in the battery voltage of each of the secondary batteries 1a to 1l is reduced. It becomes possible to charge.

Next, effects when the battery management system 11 according to the embodiment of the present invention is used will be described. In the battery management system 11 according to the embodiment of the present invention, the assembled battery 1 is charged by a constant current constant voltage charging method. In the constant current constant voltage charging method, until the battery voltage of the battery pack 1 reaches a predetermined voltage (for example, 4.08 × N (V)), the battery pack 1 is charged with a constant current (for example, 1 (CA)). After charging and reaching a predetermined voltage, the assembled battery 1 is charged with a constant voltage (for example, 4.08 × N (V)).
In the battery management system 11 according to the embodiment of the present invention, the output voltage of the DC power supply 2 exhibits the same characteristics as those in FIG. That is, the optimum charging voltage per lithium ion secondary battery is 4.10 V, and when this voltage is exceeded, the voltage adjustment unit operates to suppress the voltage increase.

5 (a), 5 (b), 6 (a), and 6 (b) show the inside of the assembled battery 1 before and after reaching the fully charged state by performing recovery charging after discharging the assembled battery 1. It is the figure which showed typically the dispersion | variation in the voltage of each secondary battery 1a-1l. In these figures, the battery voltage (V) of the secondary battery is shown, and the vertical axis shows the number of secondary batteries (pieces).
FIG. 5A and FIG. 5B show the characteristics when the load factor is 100% in FIG. FIGS. 6A and 6B show the characteristics when the load factor is 50% in FIG.

FIG. 5A shows a case where a voltage of 48.8 (V) is output from the DC power supply 2 operated at a load factor of 100%. The voltage calculation unit 33 of the battery management apparatus 10 sets 4.06 (V), which is a value obtained by dividing this 48.8 (V) by the number of secondary batteries N (= 12), to the target voltage Vp.
As a result, as shown in FIG. 5A, the battery voltage of each of the secondary batteries 1a to 1l is a value around 4.06 (V). On the other hand, in the conventional battery management apparatus 100 (see FIG. 8), when the target voltage is still set to 4.1 (V), as shown in FIG. If the secondary battery reaches 4.1 (V), the battery voltages of the remaining two secondary batteries remain at 3.9 (V).
This is because when the output voltage of the DC power supply 2 is stable at 48.8 (V), the output current does not increase with a constant value corresponding to this voltage.

FIGS. 6A and 6B show characteristics when the load factor of the DC power supply is reduced to 50%. Since the output voltage of the DC power supply 2 is 48.96 (V), the target voltage Vp of the secondary battery is 4.08 (V) (= 49.96 (V) / 12 pieces). As a result, as shown in FIG. 6A, the battery voltage distribution of each secondary battery is centered on 4.08 (V).
On the other hand, in the conventional battery management apparatus 100 (see FIG. 8), even if many secondary batteries become 4.1 (V) as shown in FIG. The voltage remains low. This is because, as described above, the output of the DC power supply 2 is stable at 48.96 (V), and the output current remains at a constant value corresponding to this voltage.

As described above, the battery management apparatus 10 according to the embodiment of the present invention manages the output voltage Va of the DC power source 2 when managing the battery voltage in the voltage adjusting units 5a to 5l of the secondary batteries 1a to 1l connected in series. Each secondary battery is charged with a value obtained by dividing the voltage Va by the number N of secondary batteries as a target voltage Vp.
As a result, even if the output voltage Va of the DC power supply 2 fluctuates during the recovery charge, the battery voltage can be adjusted following the change. Thereby, it can suppress that the dispersion | variation in battery voltage generate | occur | produces and it can prevent producing a secondary battery with insufficient charge.

  In addition, you may provide the function which protects the secondary batteries 1a-1l from the overcharge and overdischarge in the control part 3 of the battery management apparatus 10 by embodiment of this invention. For example, a switch is provided between the secondary battery 1l and the terminal p2 in FIG. 2, and the battery voltage of each of the secondary batteries 1a to 1l is measured, and the battery voltage is equal to or higher than the overcharge voltage or lower than the overdischarge voltage. In this case, the switch may be opened.

For example, when using a lithium ion secondary battery as the secondary battery, if the battery voltage reaches 4.2 (V) to 4.5 (V), the lithium ion secondary battery may break down. When a battery voltage higher than the overcharge voltage is detected by at least one secondary battery, the switch is opened to ensure the safety of the assembled battery 1. In addition, when the secondary battery is discharged, the voltage of each secondary battery is measured in the same manner, and the battery voltage of 2.5 (V) or less, which is an overdischarge voltage, is at least one secondary battery. If it is detected, the switch is opened.
Such a switch control circuit can be realized by providing an OR circuit in the control unit 3. The OR circuit compares the overcharge voltage or overdischarge voltage with the measured voltage Vb and switches the switch open signal when an overcharge voltage or overdischarge voltage that is a switch open condition is detected. Output to.

  In the embodiment of the present invention, as illustrated in FIG. 2, the case where the load 4 and one battery management device 10 are connected in parallel has been described. However, the present invention is not limited to this. As shown in FIG. 7, the load 4 and the plurality of battery management devices 10 may be connected in parallel. With the configuration shown in FIG. 7, the battery management device 10 can be added to the DC power supply 2 in consideration of the current flowing through the load 2 and the capacity of the assembled battery 1. Since the assembled battery 1 is provided for each battery management apparatus 10, each assembled battery 1 can be controlled independently.

  In the embodiment of the present invention, as shown in FIG. 2, the case where the charging voltage detection unit 7 is installed between the connection point q <b> 1 and one terminal of the DC power supply 2 has been described. The configuration is not limited. For example, the charging voltage detection unit 7 may be installed between one terminal p1 of the battery management device 10 and the intersection point q1.

  In the embodiment described above, the function of the voltage measurement unit 31, the secondary battery number storage unit 32, the voltage calculation unit 33, the voltage controller 34 in FIG. 3 or a program for realizing a part of these functions is a computer. The battery management apparatus 10 may be controlled by recording the program on a readable recording medium, reading the program recorded on the recording medium into a computer system, and executing the program. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

1 is a schematic configuration diagram of a battery management device 10 according to an embodiment of the present invention. 1 is a schematic configuration diagram of a battery management system 11 according to an embodiment of the present invention. It is a circuit diagram which shows the specific structure of the battery management apparatus 10 by embodiment of this invention. It is a flowchart which shows the process of the voltage calculating part 33 by embodiment of this invention. FIG. 3 is a diagram schematically showing voltage variations of secondary batteries 1a to 1l in the assembled battery 1; FIG. 3 is a diagram schematically showing voltage variations of secondary batteries 1a to 1l in the assembled battery 1; It is a schematic block diagram which shows another example of the battery management system 11 by embodiment of this invention. It is a schematic block diagram of the battery management system 110 known conventionally. It is a figure which shows the output characteristic of the DC power supply 60 known conventionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Assembly battery, 1a-1l ... Secondary battery, 2 ... DC power supply, 3 ... Control part, 5 ... Voltage adjustment part, 7 ... Charge voltage detection part, 10 * Battery management device 11 Battery management system 31 Voltage measurement unit 32 Secondary battery number storage unit 33 Voltage calculation unit 34 Voltage controller 41 .... Bypass current control element, 42 ... Bypass current limiting element, 43 ... Bypass current measuring element, 44 ... Battery voltage error amplifier, 45 ... Battery voltage measuring error amplifier

Claims (5)

An assembled battery in which a plurality of secondary batteries are connected in series;
Voltage measuring means for measuring the voltage supplied from the power source to the assembled battery;
Secondary battery number storage means for storing the number of secondary batteries constituting the assembled battery;
Target voltage calculation means for calculating a target voltage that is the upper limit of the charging voltage of each secondary battery based on the voltage measured by the voltage measurement means and the number of secondary batteries stored by the secondary battery number storage means. When,
A voltage supply means that is provided for each secondary battery, and supplies a voltage supplied from the power source to the assembled battery to each secondary battery so that the battery voltage of each secondary battery is equal to or lower than the target voltage;
A battery management device comprising:   A battery provided for each of the secondary batteries, and having a bypass means for bypassing a current supplied to the secondary battery when the battery voltage of the secondary battery becomes larger than the target voltage. Management device. The target voltage calculation means includes
The battery management apparatus, wherein the target voltage is calculated by dividing the voltage measured by the voltage measuring means by the number of secondary batteries stored by the secondary battery number storage means. The battery management device according to any one of claims 1 to 3,
A load connected in parallel with the battery management device;
A power supply for supplying voltage to the battery management device and the load;
A battery management system comprising: A first step in which voltage measuring means measures a voltage supplied from a power source to an assembled battery in which a plurality of secondary batteries are connected in series;
Secondary battery number storage means for storing the number of secondary batteries constituting the assembled battery;
By dividing the voltage measured by the voltage measuring means by the number of secondary batteries stored by the secondary battery number storage means, the target voltage calculating means obtains the target voltage that is the upper limit of the charging voltage of each secondary battery. A second step of calculating;
The voltage supply means provided for each secondary battery supplies the voltage supplied to each secondary battery from the power source to each secondary battery so that the battery voltage of each secondary battery is equal to or lower than the target voltage. A third step,
The battery management method characterized by having.

Images