JP2010246214A - Device for regulating and monitoring battery voltage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery voltage regulating and monitoring device, capable of automatically balancing voltages of multiple batteries without loss, measuring the voltage of each battery through simple circuitry, and automatically determining whether each battery has reached its end of life. <P>SOLUTION: Switches SW1 to SWn provided in correspondence with multiple series-connected batteries BT1 to BTn are changed temporally and connected in parallel with a capacitor C. Electric charges are given and received between the connected batteries and capacitor C to balance the voltages. The voltage between both the ends of the capacitor C after balancing is measured with a voltage measurement unit 1 through a switch SWK and the measured voltage is stored in a storage unit 4. At a predetermined point of time, a measured voltage Vi and a reference voltage VK for the presence of deterioration are compared with each other. When the measured voltage Vi is lower than the reference voltage VK, it is determined that the battery BTi has deteriorated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a battery voltage adjustment monitoring device, and more particularly to a battery voltage adjustment monitoring device capable of adjusting the voltage of each battery in a well-balanced manner and monitoring the correctness of each battery when variations occur in the voltage of each battery due to use. .

When a battery that outputs a constant voltage and a voltage that is relatively higher than the voltage of each battery needs to be output as a power supply voltage, a plurality of batteries are connected in cascade. When it is necessary to check the degree of consumption of such cascaded batteries, the voltage across each battery may be measured.
As a technique for measuring the voltage across the battery as described above, a differential amplifier that obtains an output voltage corresponding to the voltage across the secondary battery as the battery to be measured, and a voltage that converts the output voltage value of the differential amplifier into a frequency -A frequency converter and a microcomputer as a detection means for detecting the frequency as the voltage value of the battery to be measured. By using a voltage-frequency converter, only a single signal line is connected to the microcomputer. The structure which detects the voltage of a secondary voltage is disclosed (for example, refer patent document 1).
In addition, in order to balance the voltages of a plurality of cascade-connected batteries, both poles of one capacitor (capacitor) are connected in parallel from both poles of each battery via a switch, and both switches of each battery are connected. A battery pack balance device is disclosed in which the switch is turned on and off repeatedly at predetermined intervals so that both electrodes of each battery are sequentially connected to a capacitor in order to balance the potential difference between the electrodes of each battery. For example, see Patent Document 2).
Moreover, in order to efficiently charge the secondary batteries connected in series, the secondary batteries are connected in series and connected to each secondary battery in parallel with a main circuit having connection terminals at both ends of the series connection. A bypass circuit in which a resistor and a switch are connected in series, and a measurement control circuit that measures the voltage of each secondary battery and controls the on / off of the switch, and charging a constant current between the end terminals of the main circuit A secondary battery charging / discharging device is disclosed in which a current is supplied or a discharge current is supplied, the voltage of each secondary battery is measured, and charging / discharging of the secondary battery is adjusted (for example, Patent Document 3). reference).

JP-A-11-109005 JP 2000-166113 A Japanese Patent No. 3517844

In the battery voltage measuring device described in Patent Document 1 described above, the voltage across each battery can be easily measured. However, when there is variation in the terminal voltage of each battery, it is necessary to adjust it by recharging or the like. There is a problem that it takes time and effort to improve the voltage balance.
Moreover, in the battery pack balance device described in Patent Document 2, the voltage balance of each battery can be automatically achieved with a simple circuit configuration, but since it does not have a function of measuring voltage in the process of voltage balancing, the terminal of each battery There was a problem that the voltage could not be measured, the degree of balance could not be confirmed, and the existence of the battery life could not be known.
Moreover, the charging / discharging device of the secondary battery described in Patent Document 3 can take the voltage balance of each battery and can also measure the voltage. However, when balancing the voltage, charging the secondary battery, The balance is reduced to a low predetermined voltage by discharging through the bypass circuit, and there is a problem that power is consumed for the balance by energizing the resistor, and the bypass circuit for each battery, the voltage for each battery. There is a problem in that it requires a means of measurement and the processing becomes complicated.
The present invention has been made paying attention to the above-mentioned problems, and can automatically reduce the voltage balance of a plurality of batteries without loss, and can measure the voltage of each battery with a simple circuit configuration. An object of the present invention is to provide a battery voltage adjustment monitoring device that can automatically determine whether or not a battery has reached the end of life and can detect a defective battery at an early stage.

According to a first aspect of the present invention, there is provided a battery voltage adjustment monitoring device which is provided in correspondence with a plurality (n) of batteries connected in cascade, and two electrodes at one end of each battery. A plurality (n) of first two-pole double-throw switches connected to the negative and negative sides, and both ends connected to one and the other of the two poles at the other end of the two-pole double-throw switch, A capacitor (capacitor) connected in parallel to a battery corresponding to the double-throw switch being turned on, a second two-pole double-throw switch with two poles at one end connected to both ends of the capacitor, and each battery connected to the capacitor In order to switch and connect to each of the first two-pole double-throw switches, a turn-on command signal is sent to the first two-pole double-throw switches in a predetermined order. A control unit for sending a closing command signal to the two-pole double-throw switch, and the other end of the second two-pole double-throw switch And a voltage measuring unit that receives and measures the voltage across the capacitor when the second two-pole double-throw switch is turned on.
According to a second aspect of the present invention, there is provided a battery voltage regulation monitoring device according to the first aspect, wherein the second i-pole battery is connected to the n i (i = 1 to n) -th battery and the capacitor. A storage unit that stores a voltage measured by the voltage measurement unit when a throw switch is turned on, and a battery correctness evaluation unit that determines whether or not the i-th battery has deteriorated based on a voltage value stored in the storage unit. It is characterized by providing.
According to a third aspect of the present invention, there is provided the battery voltage adjustment / monitoring device according to the second aspect, wherein the battery pressure correctness evaluation means sets the first reference voltage, the first reference voltage, and the measured voltage that are set in advance. And a means for judging that the battery may be over-discharged when the measured voltage is lower than the first reference voltage.
According to a fourth aspect of the present invention, there is provided the battery voltage adjusting apparatus according to the second aspect, wherein the battery success / failure evaluation means obtains a second reference voltage set in advance, the second reference voltage, and the measured voltage. Comparing means is included, and when the measured voltage is higher than the second reference voltage, it is determined that the battery may be overcharged.
Further, in the present invention, the capacitor includes not only a general capacitor but also a capacitor having a large capacity such as a rechargeable secondary battery having a large equivalent capacity, an electric double layer capacitor, and the like.

According to the present invention, by turning on the corresponding two-pole double-throw switch between each battery and the battery, the voltage of both is made equal by moving the charge from the higher to the lower. In addition to being able to equalize the voltage and confirm the voltage during the adjustment process, it is possible to evaluate the correctness of the voltage of each battery at a predetermined timing, judge the consumption of each battery, and prevent damage or malfunction of the power battery system. Can be detected.

It is a circuit diagram explaining the schematic structure of the battery voltage adjustment monitoring apparatus which concerns on one Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the battery voltage adjustment monitoring apparatus of the embodiment. It is a timing waveform diagram which shows ON and OFF of each double pole double throw switch for demonstrating operation | movement of the battery voltage adjustment monitoring apparatus of the embodiment. It is a figure which shows the data map memorize | stored in the memory | storage part of the signal processing apparatus of the battery voltage adjustment monitoring apparatus of the embodiment.

Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a circuit diagram showing a circuit configuration of a battery voltage adjustment monitoring device according to an embodiment of the present invention.
In FIG. 1, n batteries (lithium batteries) BT1, BT2,..., BTn are connected in cascade (in series). Each of the batteries BT1, BT2,..., BTn is charged from the charging source 6 through the switch SR1, and from each battery BT1, BT2,..., BTn to the load 8 through the switch SR2. Discharged. Further, two-pole double-throw switches SW1, SW2,..., SWn are arranged corresponding to the batteries BT1, BT2,.
Two-pole terminals at one end (left side) of the two-pole double switch SW1 are individually connected to the + electrode and the − electrode of the battery BT1. The two-pole terminal at the other end (right side) of the two-pole double-throw switch SW1 is individually connected to one end and the other end of the capacitor C.
The two-pole terminal at one end of the two-pole double-throw switch SW2 is connected to the + electrode and the − electrode of the individual battery BT2. Two-pole terminals at the other end of the two-pole double-throw switch SW2 are individually connected to one end and the other end of the capacitor C.
Further, the two-pole double-throw switches SW3,..., SWn are also connected to the + and − electrodes of the batteries BT3, BT4,..., BTn, and are connected to the capacitor C in the same manner. ing.
In addition, the two-pole terminal at one end of the second two-pole double-throw switch SWK is individually connected to one end and the other end of the capacitor. Furthermore, one of the other two-pole terminals of the two-pole double-throw switch SWK is connected to ground (GND), and the other is connected to the input end of the voltage measuring unit 1.
The signal processing device 2 is arranged to control the batteries BT1,..., BTn, switches SW1,..., SWn and SWK, and the voltage measuring unit 1, and includes a control calculation unit 3, a storage unit 4, and a display unit. 5 is provided. The control operation unit 3 sends ON signals S1, S2,..., Sn to the switches SW1, SW2,..., SWn in a predetermined order, and sequentially switches the switches SW1, SW2,. Turn on. Further, a signal SK for turning on the switch SWK is sent between the signals SI, S2,..., Sn, the switch SWK is turned on, a measurement command is given to the voltage measuring unit 1, and a measured voltage is taken in.
Moreover, the memory | storage part 4 of a signal processing apparatus memorize | stores the voltage calculated by the voltage measurement part 1, and the data calculated based on this measured voltage.
Next, the operation of the battery voltage adjustment monitoring device according to this embodiment will be described with reference to the flowchart shown in FIG. 2 and the time chart shown in FIG.
When the processing operation is started, in step ST1, first, the variable I where I = 0 is incremented by one. As a result, initially I = 1. This variable I is a variable indicating how many times the switches SW1,..., SWn are sequentially switched. Next, the process proceeds to step ST2.
In step ST2, first, the variable i where i = 0 is incremented by one. As a result, i = 1 is set first. This variable i is a variable that indicates what number of switches SW1,..., SWn are turned on. Next, the process proceeds to step ST3.
In step ST3, the switch SW1 is turned on with an ON command signal S1 to turn on the switch SWi (= SW1) for T time. By turning on the switch SW1, a capacitor C is connected in parallel to the battery BT1.
Due to the connection between the battery BT1 and the capacitor C, the charge of the battery BT1 moves to the capacitor C. When the voltage of the battery BT1 and the voltage across the capacitor C become equal to each other, the charge transfer from the battery BT1 stops. Next, the process proceeds to step ST4.
In step ST4, an ON command signal SK1 is sent to the switch SWK to turn it on to turn on the switch SWK for T time. As a result, both ends of the capacitor C are connected to the input ends of the voltage measuring unit 1. Next, the process proceeds to step ST5.
In step ST5, the control calculation unit 3 issues a measurement command to the voltage measurement unit 1, and the voltage measurement unit 1 receives the measurement command, measures the voltage Vi (= V1) of the capacitor C, and the voltage storage unit 4 To remember. Subsequently, the process proceeds to step ST6.
In step ST6, the voltage difference ΔV = Vi−Vi−1 between the battery BTi and the battery BTi-1 is calculated from the voltage Vi stored this time and the already stored voltage Vi−1, and stored in the storage unit 4 as well. To do. Next, the process proceeds to step ST7.
In step ST7, it is determined whether i = n. Since i = 1 at the beginning of the operation and not i = n, the determination returns to step ST2 in step ST7. In step ST2, the variable i is incremented by 1 and i = 2. Next, the process proceeds to step ST3.

In step ST3, the switch SW2 is turned on with an ON command signal S2 to turn on the switch SWi (= SW2) for T time. By turning on the switch SW2, the capacitor C is connected in parallel to the battery BT2.
When the battery BT2 and the capacitor C are connected, the charge moves between the battery BT2 and the capacitor C from the higher voltage to the lower voltage, and the voltage across the battery BT1 and the capacitor C are equal to each other. Charge transfer stops. Next, the process proceeds to step ST4.
In step ST4, an ON command signal SK2 is sent to the switch SWK to turn it on for T time to turn on the switch SWK. As a result, both ends of the capacitor C are connected to the input ends of the voltage measuring unit 1. Next, the process proceeds to step ST5.
In step ST5, the control calculation unit 2 issues a measurement command to the voltage measurement unit 1, and the voltage measurement unit 1 receives the measurement command, measures the voltage Vi (= V2) of the capacitor C, and stores it in the storage unit 4. Remember. Subsequently, the process proceeds to step ST6.
In step ST6, the voltage difference ΔV = Vi−Vi−1 between the battery BTi and the battery BTi-1 is calculated from the voltage Vi stored this time and the already stored voltage Vi−1, and stored in the storage unit 4 as well. To do. Next, the process proceeds to step ST7.
In step ST7, it is determined whether i = n. Here, since i = 2 and not i = n, the determination in step ST7 is NO, and the process returns to step ST2.
As described above, the processes of steps ST2 to ST7 are repeated until i = n, the switches SW1 to SWn are sequentially turned on, and the batteries BT1 to BTn are switched and connected to the capacitor C. The electric charge is moved between the capacitors C in the direction from the larger voltage to the smaller voltage so that the voltage of each battery is made uniform.
When the switching connection to the capacitor C up to the battery BTn and the voltage measurement are completed, i = n, the determination in step ST7 is YES, and the process proceeds to step ST8.
In step ST8, the variable i is cleared (i ← 0). Subsequently, the process proceeds to step ST9. In step ST9, it is determined whether I = m. At the beginning of the processing operation, since I = 1 and not I = m, the determination is NO, and the process returns to step ST1.
In step ST1, the variable I is incremented by one. Here, I = 2. Subsequently, as in the case of I = 1 described above, the processing of steps ST2 to ST7 is executed, the switches SW1 to SWn are sequentially turned on, the batteries BT1 to BTn are switched and connected to the capacitors C, Electric charges are moved between the battery and the capacitor C in the direction from the larger voltage to the smaller voltage, and the voltage of each battery is further made uniform.
The processes in steps ST1 to ST9 described above are performed many times (= m) until the voltages of the respective batteries are balanced and equalized. When I = m, the determination in step ST9 is YES, and then the process proceeds to step ST10.
In step ST10, the determination reference voltage VK of the consumable battery (overdischarge battery) that has been set and stored in advance is compared with each battery voltage Vi to determine whether Vi ≦ VK. Usually, the determination is NO, and in this case, the process proceeds to step ST13. However, when the battery BTi is exhausted and the voltage after the balancing process is extremely small, the determination is YES, and the process proceeds to step ST11.
In step ST11, the consumption of the battery BTi is displayed on the display unit 5 of the signal processing device 2. Then, it transfers to step ST12 and outputs an overdischarge warning signal to the main controller 7.
In this process, the degree of consumption of the battery TBi, that is, the degree of overdischarge is determined. If the battery voltage is insufficient due to overdischarge, the battery is prohibited from being discharged before the overdischarge state leading to deterioration of the battery. Signal output is performed to obtain this. In main controller 7, in consideration of the discharge state, switch SR2 can be turned off by signal SC2 to stop the discharge.
Following the process of step ST12, the process proceeds to step ST13. In step ST13, the overcharged battery voltage Vh set and stored in advance is compared with each battery voltage Vi to determine whether Vi ≧ Vh. Usually, the determination is NO, and in this case, the process ends. However, if the battery BTi is in an overcharged state, the battery voltage is high, and the balance process is performed, but the voltage is still high, the process proceeds to step ST14 with a determination YES.
In step ST14, a battery BTi overcharge warning is displayed on the display unit 5 of the signal processing device 2. Then, it transfers to step ST15 and outputs an overcharge warning signal to the main controller 7. Here, the output of the over-electricity warning signal is performed in order to obtain a charge stoppage to the battery before the battery is overcharged leading to dangerous battery destruction when the battery charging voltage is large. In main controller 7, the switch SR1 can be turned off by signal SC1 in consideration of the overcharged state to stop charging.
In the above-described embodiment, the battery voltage Vi and the determination reference voltage VK are compared at a predetermined time point to determine the consumption of the battery BTi. However, as another embodiment, at the time of measuring each voltage Vi, The difference (Vi-Vi-1) between the previous voltage Vi-1 and the current measurement voltage Vi is obtained, and the amount of moving electricity C ((Vi-Vi-1)) obtained by multiplying this by the capacitance C of the capacitor C is obtained. A battery that generates a large amount of outflow as the charging progresses due to the amount of moving electricity and the amount of leaked electricity at a predetermined point in time, and a battery that generates a large amount of inflow as the discharge progresses can be considered as a decrease in capacity. It is also possible to determine the degree of consumption of the battery because the decrease in battery capacity causes the voltage to rise / fall faster than other batteries. Battery system A battery in which outflow occurs with charging and inflow occurs with discharge can be considered as an increase in internal resistance, and can be used as data for determining the deterioration of the battery BTi.
A battery with a large amount of inflow of electric charge is considered to be a leak. The occurrence of this leak leads to a decrease in the capacity of the assembled battery, and many leaks are also a safety problem. As described above, a safer battery system can be realized by finely monitoring the constituent batteries of the entire assembled battery.

BT1, BT2, ..., BTn batteries
SW1, SW2,..., SWn Two-pole double-throw switch SWK Second two-pole double-throw switch C Capacitor 1 Voltage measurement unit 2 Signal processing unit 3 Control unit 4 Storage unit 5 Display unit 6 Charging source 7 Main control unit 8 load

Claims (4)

A plurality (n) of batteries connected in cascade;
A plurality of (n) first two-pole double-throw switches provided corresponding to each of the batteries, the two poles at one end being connected to the positive side and the negative side of each battery;
A battery having both ends connected to one and the other of the two poles at the other end of the two-pole double-throw switch, and connected in parallel to the corresponding battery when each two-pole double-throw switch is ON;
A second double-pole double-throw switch in which two poles at one end are connected to both ends of the capacitor;
In order to switch and connect each battery to the capacitor in a predetermined sequence, a turn-in command signal is sent to each first double-pole double-throw switch in a predetermined sequence. A control unit that sends a closing command signal to the second two-pole double-throw switch in-between;
A voltage measuring unit having an input connected to the other two poles of the second two-pole double-throw switch, and receiving and measuring the voltage across the capacitor when the second two-pole double-throw switch is ON;
A battery voltage adjustment monitoring device comprising:     A storage unit for storing a voltage measured by the voltage measurement unit by turning on a second two-pole double-throw switch following the connection of the n i (i = 1 to n) -th battery and the capacitor; The battery voltage adjustment monitoring apparatus according to claim 1, further comprising: a battery correctness evaluation unit that determines whether or not the i-th battery has deteriorated based on a voltage value stored in the storage unit.     The battery correctness evaluation means includes means for comparing a first reference voltage set in advance with the measured voltage, and the battery may be overdischarged when the measured voltage is lower than the first reference voltage. The battery voltage adjustment monitoring apparatus according to claim 2, wherein the battery voltage adjustment monitoring apparatus is determined to be present.     The battery correctness evaluation means includes means for comparing a second reference voltage set in advance with the second reference voltage and the measured voltage, and the battery is measured when the measured voltage is higher than the second reference voltage. The battery voltage adjustment monitoring device according to claim 2, wherein the battery voltage is determined to be in an overcharged state.

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