WO2019093153A1

WO2019093153A1 - Cell balance control device, and cell balance control method

Info

Publication number: WO2019093153A1
Application number: PCT/JP2018/039834
Authority: WO
Inventors: 雅貴善教; 明彦柴田; 純一仲宗根
Original assignee: 株式会社村田製作所
Priority date: 2017-11-10
Filing date: 2018-10-26
Publication date: 2019-05-16

Abstract

Control units (511-51n) respectively belonging to cell balance controllers (501-50n) set dead zones for respective battery cells (111-11n) using the state of charge of each battery cell (111-11n) as a reference. Each control unit (511-51n) calculates the deviation between the state of charge of the respective battery cell thereof (111-11n) and the battery cell (111-11n) adjacent to said battery cell (111-11n), and if the deviation exceeds the dead zones, the control unit (511-51n) controls and drives a wireless power transmitter (301-30n) of the adjacent battery cell to transmit electric power from the battery cell (111-11n) with a high state of charge to the battery cell (111-11n) with a low state of charge.

Description

Cell balance control apparatus and cell balance control method

The present invention relates to a cell balance control device that equalizes the charge states of a plurality of battery cells connected in series that constitute a battery module, and a cell balance control method.

In recent years, hybrid vehicles (HVs) and plug-in hybrid vehicles (PHVs) that can effectively improve the fuel consumption rate of vehicles by using an engine and an electric motor in combination have been widely put to practical use. In addition, electric vehicles (EVs) that use only an electric motor as a power source and do not discharge exhaust gas have also been put to practical use. For example, in such hybrid vehicles and electric vehicles, a battery module in which a plurality of secondary batteries such as lithium ion batteries are connected in series is used.

Here, in order to prolong the life of the battery module and to improve the utilization efficiency of power, it is important to use it so that the variation in the state of charge of each battery cell is maintained within a predetermined range. However, variations occur in the charge state of each battery cell due to variations in internal resistance, ambient temperature, and the like. In view of the above, there has been proposed a technology for suppressing variations in the state of charge of a plurality of battery cells constituting a battery module, that is, a cell balance control device for equalizing the state of charge of each battery cell (see, for example, Patent Document 1).

In the cell balance control device described in Patent Document 1, the threshold voltage is determined based on the battery temperature detected by the temperature sensor, and the battery cell having a voltage higher than the threshold voltage is converted to a battery cell having a voltage lower than the threshold voltage. A cell balance circuit composed of a plurality of transformers and switching elements is controlled so that current flows.

JP, 2013-5678, A

According to the cell balance control device described above, it is possible to balance the voltages of the plurality of battery cells while considering the temperature of the battery. However, in order to eliminate (equalize) voltage variations of a plurality of battery cells, a loss of power occurs each time current flows from a battery cell having a voltage higher than the threshold voltage to a battery cell having a voltage lower than the threshold voltage. . Therefore, a cell balance technique capable of further reducing power loss is desired.

The present invention has been made to solve the above-mentioned problems, and in a cell balance control device for equalizing the charge states of a plurality of battery cells connected in series, which constitute a battery module, the charge states are equalized. Cell balance control apparatus capable of reducing power loss due to

A cell balance control device according to the present invention is a cell balance control device for equalizing the charge states of a plurality of battery cells connected in series, which constitutes a battery module, and a detection unit for detecting the charge state of each battery cell A power transmission unit provided for each battery cell for transmitting power between adjacent battery cells, and a control unit for driving and controlling the power transmission unit, the control unit for each of the battery cells A dead zone is provided based on the charge state of the cell, and a deviation of the charge state between each battery cell and a battery cell adjacent to the battery cell is calculated, and the battery cell having a high charge state when the deviation exceeds the dead zone. The power transmission unit of the adjacent battery cell is drive-controlled so as to transmit the power to the battery cell in the low charge state.

A cell balance control method according to the present invention comprises detecting a charge state of each battery cell in a cell balance control method for equalizing the charge states of a plurality of battery cells connected in series constituting a battery module. For each battery cell, a dead zone is provided on the basis of the charge condition of each battery cell, and the deviation of the charge condition between each battery cell and the battery cell adjacent to the battery cell is calculated. And a control step of driving and controlling a power transmission unit of an adjacent battery cell so as to transmit power from a battery cell in a high state of charge to a battery cell in a low state of charge when exceeded.

According to the cell balance control device or the cell balance control method of the present invention, a dead zone is provided for each battery cell based on the charge state of each battery cell, and the battery cell and the battery cell adjacent to the battery cell are provided. The power transfer unit of the adjacent battery cell is configured to transmit power from the battery cell with high charge state to the battery cell with low charge state when the deviation of the charge state with is calculated and the deviation exceeds the dead zone. Drive control is performed. In addition, a dead zone (hysteresis) is provided based on the charge status (for example, charge amount / charge rate, voltage value, etc.) of each battery cell, and power is transmitted only when the deviation of the charge status exceeds the dead zone. Thus, the frequency of power transmission can be reduced. As a result, it is possible to reduce the power loss due to the equalization of the charge state.

According to the present invention, in a cell balance control device for equalizing the charge states of a plurality of battery cells connected in series that constitute a battery module, it is possible to reduce power loss due to the equalization of charge states. .

It is a block diagram showing functional composition of a cell balance control device concerning an embodiment. It is a flowchart which shows the process sequence of the equalization process (1st control form) by the cell balance control apparatus which concerns on embodiment. It is a figure for demonstrating the equalization process using the dead zone which concerns on a 1st control form. It is a flowchart which shows the process sequence of the equalization process (2nd control form) by the cell balance control apparatus which concerns on embodiment. It is a flowchart which shows the process sequence of the equalization process (3rd control form) by the cell balance control apparatus which concerns on embodiment. It is a figure for demonstrating the method of pairing in the equalization process which concerns on a 3rd control form. It is a flowchart which shows the process sequence of the equalization process (4th control form) by the cell balance control apparatus which concerns on embodiment. It is a figure for demonstrating the lock state in the equalization process which concerns on a 4th control form. It is a flowchart which shows the process sequence of the equalization process (5th control form) by the cell balance control apparatus which concerns on embodiment. It is a figure for demonstrating the equalization process using the linear approximation formula which concerns on a 5th control form. It is a block diagram which shows the structure of the cell balance control apparatus which concerns on a modification. It is a block diagram showing the circuit composition of the cell balance control device concerning an embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are used for the same or corresponding parts. Further, in the respective drawings, the same elements are denoted by the same reference numerals, and duplicate explanations will be omitted.

First, the configuration of the cell balance control apparatus 1 according to the embodiment will be described using FIG. 1 and FIG. 12 together. FIG. 1 is a block diagram showing a functional configuration of the cell balance control apparatus 1. FIG. 12 is a block diagram showing a circuit configuration of the cell balance control device 1.

The cell balance control device 1 includes a plurality of

battery cells

111, 112, 113,..., 11n connected in series that constitute a battery module (assembled battery) 10 (where n is limited to one digit). Cell balance control device that balances the charge state of the Here, as the state of charge (index indicating the state of charge) of the

battery cells

111, 112, 113,..., 11n, for example, using a charge amount / state of charge (SOC) or a voltage value Can. In the present embodiment, a voltage value is adopted as the state of charge of the

battery cells

111, 112, 113, ..., 11n.

The cell balance control apparatus 1 mainly includes a plurality of

voltage sensors

121, 122, 123, ..., 12n, a plurality of wireless

power transmission units

301, 302, 303, ..., 30n, a plurality of cell balance controllers 501, , And 50 n. In addition, the

cell balance controllers

501, 502, 503, ..., 50n mainly include the

control units

511, 512, 513, ..., 51n, and the

wireless communication units

521, 522, 523, ..., 52n. Is configured. Each component will be described in detail below.

The battery module 10 is mounted on, for example, a hybrid vehicle (HV) or an electric vehicle (EV), and is configured by connecting, for example, several tens to several hundreds of battery cells 111 to 11 n in series. (Ie, configured as a high voltage battery of tens to hundreds of volts).

For example, lithium ion batteries are preferably used as the battery cells 111 to 11 n. However, instead of the lithium ion battery, a chargeable / dischargeable secondary battery such as a nickel cadmium battery can also be used.

Voltage sensors 121 to 12n for detecting terminal voltages (voltage values) of the battery cells 111 to 11n are connected to the battery cells 111 to 11n, respectively. Each of the voltage sensors 121 to 12 n is electrically connected to the A / D input terminal of the corresponding cell balance controller 501 to 50 n, and a signal (voltage value) corresponding to the terminal voltage of each of the battery cells 111 to 11 n is After being A / D converted, they are read into the control units 511 to 51 n of the cell balance controllers 501 to 50 n.

In each of the battery cells 111 to 11n, wireless power transmission units 301 to 30n for transmitting power between the adjacent battery cells are disposed. As the wireless power transmission units 301 to 30n, for example, an electromagnetic induction system that transmits power using induced magnetic flux generated between the power transmission side and the power reception side, and magnetic resonance of resonators on the power transmission side and the power reception side Wireless power transmission (wireless power supply) such as magnetic resonance method for transmitting electric power, electric field coupling method for transmitting electric power using induced electric field generated between the electrode on the power transmission side and the electrode on the power transmission side arranged opposite to each other Can be used. In the present embodiment, an electric field coupling method is adopted.

The wireless power transmission units 301 to 30 n include a power transmission module that transmits power and a power transmission electrode (active electrode on the power transmission side, passive electrode), and a power reception module that receives power and a power reception electrode (active electrode on the power reception side, passive electrode). It is configured to have a pair. The power converted into alternating current by the power transmission module is transmitted to the power receiving side (adjacent battery cells 111 to 11 n) through a capacitor formed of a power transmission electrode and a power receiving electrode (power receiving electrodes of adjacent battery cells 111 to 11 n). . The power receiving module is configured to include a rectifier circuit and a voltage conversion circuit, and supplies DC power to the battery cells 111 to 11 n.

More specifically, the wireless power transmission units 301 to 30 n have flat electrodes (power transmission electrodes and power reception electrodes) disposed on both sides of the battery cells 111 to 11 n formed in a substantially rectangular parallelepiped shape. That is, between the adjacent battery cells, flat plate-like electrodes are disposed to face each other, and power is delivered using the induced electric field generated between the flat plate-like electrodes. In addition, the distance (gap) between the flat-shaped electrodes arrange | positioned so as to mutually oppose is set to several mm, for example. Further, air may be used between the electrode and the electrode, or a dielectric or the like may be interposed. In the present embodiment, air is used. The driving of each of the wireless power transmission units 301 to 30 n is controlled by the corresponding cell balance controller 501 to 50 n.

The cell balance controllers 501 to 50 n each wireless power transmission unit 301 to equalize the voltage values of the battery cells 111 to 11 n based on the detected voltage values (charging states) of the battery cells 111 to 11 n. Drive controls ~ 30n. The cell balance controllers 501 to 50n mainly include control units 511 to 51n and wireless communication units 521 to 52n.

The wireless communication units 521 to 52n transmit and receive information such as voltage values of the own cell and the other battery cells 111 to 11n with the wireless communication units 521 to 52n of the adjacent battery cells 111 to 11n. The wireless communication units 521 to 52n can use, for example, a communication method such as IrDA (Infrared Data Association), Bluetooth (registered trademark) Low Energy, Wi-Fi (registered trademark), NFC (Near Field Communication) or the like. In the present embodiment, IrDA is adopted. Information such as voltage values of the other battery cells 111 to 11 n received by the wireless communication units 521 to 52 n is output to the control units 511 to 51 n.

Each of the control units 511 to 51n monitors the charge / discharge state (for example, charge amount / charge rate, voltage value, charge / discharge current, etc.) of the corresponding battery cell 111 to 11n, and the voltage of each battery cell 111 to 11n An equalization process (cell balance process) is performed to equalize the values. The control units 511 to 51 n include a CPU that performs calculations, a ROM that stores programs for causing the CPU to execute each process, a RAM that stores various data such as calculation results, and the wireless power transmission units 301 to 30 n. It is configured to have an I / F such as a driver circuit to be driven. In the control units 511 to 51n, the CPU executes the programs stored in the ROM or the like to realize the above functions.

As shown in the upper part of FIG. 3, each of the control units 511 to 51 n sets dead zones on the + side and the − side with reference to the voltage value of each of the corresponding battery cells 111 to 11 n. . In addition, in the example of FIG. 3, the case where the dead zone was provided about the battery cell 112 was shown. Here, the dead zone is set to, for example, a value (width) of ± several% (for example, ± 1%) with respect to the voltage value of the fully charged state of each of the battery cells 111 to 11 n. For example, when the voltage value in the fully charged state is 4.2 V and set to ± 1% thereof, the dead zone is set to ± 0.042 V.

Further, each of the control units 511 to 51n calculates the deviation of the state of charge between the corresponding battery cell 111 to 11n and the battery cell 111 to 11n adjacent to the corresponding battery cell 111 to 11n.

Then, when the deviation exceeds the dead zone, each of the control units 511 to 51 n starts from the battery cell having a high voltage value (battery cell 112 in the example shown in FIG. 3) to the battery cell having a low voltage value (FIG. 3) In the example, the wireless power transmission units 301 to 30n of the adjacent battery cells (the battery cell 112 and the battery cell 113 in the example shown in FIG. 3) are driven and controlled to transmit power to the battery cell 113).

Since the voltage values of the battery cells 111 to 11 n (the battery cell 112 in the example of FIG. 3) decrease along with the transmission of power during the equalization process, the dead band reference value also decreases with the decrease of the voltage value. It will decrease. Then, as shown in the lower part of FIG. 3, when the voltage difference (deviation) with the adjacent battery cells 111 to 11 n (the battery cell 113 in the example of FIG. 3) falls within the dead zone, 51 n (the control unit 512 and the control unit 513 in the example shown in FIG. 3) stop the equalization process. Then, the above equalization process is performed on all the control units 511 to 51n, that is, for all the battery cells 111 to 11n, the voltage values of the entire battery module 10 are equalized.

Next, the operation (first control mode) of the cell balance control device 1 will be described with reference to FIG. FIG. 2 is a flowchart showing the procedure of the equalization process (first control mode) by the cell balance control apparatus 1. The processing shown in FIG. 2 is repeatedly performed mainly at each of the cell balance controllers 501 to 50n at a predetermined timing.

First, in step S100, the voltage values of all the battery cells 111 to 11n detected by the voltage sensors 121 to 12n are read. Next, in step S102, it is determined whether or not the deviation between the maximum value and the minimum value of the voltage values of all the read battery cells 111 to 11n is equal to or less than a predetermined value (within the allowable range) (for example, fully charged) A determination is made as to whether it is within ± 1% of the hourly voltage value. Here, when the deviation between the maximum value and the minimum value is equal to or less than a predetermined value, the process is temporarily left. On the other hand, when the deviation between the maximum value and the minimum value is larger than a predetermined value, the process proceeds to step S104.

In step S104, a determination is made as to whether the deviation from the voltage values of the battery cells 111 to 11n on both sides is equal to or greater than a predetermined dead zone. In addition, about the setting method of a dead zone, since it is as having mentioned above, detailed description is abbreviate | omitted here. Here, when the deviation of the voltage value is equal to or greater than the dead zone, the process proceeds to step S106. On the other hand, when the deviation of the voltage value is less than the dead zone, the process proceeds to step S108.

In step S106, power is transmitted from the battery cell having a high voltage value (the battery cell 112 in the example of FIG. 3 described above) to the battery cell having a low voltage value (the battery cell 113 in the example of FIG. 3) The wireless power transmission units 301 to 30 n of the battery cells (the

battery cells

112 and 113 in the example of FIG. 3) are drive-controlled.

Subsequently, in step S108, a determination is made as to whether or not the process of step S104 and step S106 described above has been performed for all of the battery cells 111 to 11n. Here, if the process has not been executed for all the battery cells 111 to 11n, the process returns to step S104, and the above-described steps S104 to S104 are performed until the process is completed for all the battery cells 111 to 11n. The process of S108 is repeatedly performed. On the other hand, when the process is executed for all the battery cells 111 to 11 n, the process temporarily exits. Then, as described above, the present process is performed again at a predetermined timing, and the equalization process is repeatedly performed until the above-described step S102 is affirmed (that is, until the equalization is completed). As a result, the state of charge (voltage value) is equalized in the entire battery module 10. If there is a higher-level system (for example, a battery management system that manages the entire battery module 10, etc.), the information to that effect is notified to the upper-level system when equalization of the charge state is completed. It is good also as composition.

Here, simulation is performed using a model of a battery module in which six battery cells are connected in series, and equalization is made between the case where a dead zone is provided (this embodiment) and the case where a dead zone is not obtained (comparative example) The magnitude of the power loss associated with the processing was compared. As a result, when the dead zone is provided, the power loss associated with the equalization process is reduced by 62.6% as compared with the case where the dead zone is not provided.

As described above in detail, according to the present embodiment (first control mode), a dead zone is provided for each of the battery cells 111 to 11 n based on the voltage value of each of the battery cells 111 to 11 n. Deviations of voltage values between the battery cells 111 to 11n and the battery cells 111 to 11n adjacent to the battery cells 111 to 11n are calculated, and when the deviation exceeds the dead zone, the battery cells 111 to 111n having high voltage values The wireless power transmission units 301 to 30 n are drive-controlled to transmit power from 11 n to the battery cells 111 to 11 n having low voltage values. As described above, by using wireless power transmission to transfer power, it is possible to reduce wiring (wire harness) and to reduce the weight of the device. In addition, the degree of freedom in layout can be enhanced. Furthermore, since the dead zone is provided based on the voltage value of each of the battery cells 111 to 11n and the power is transmitted only when the deviation of the voltage value exceeds the dead zone, the frequency of power transmission can be reduced. As a result, it is possible to achieve both the weight reduction of the battery module 10 and the reduction of the power loss due to the equalization of the voltage value.

(Second control mode)
In the above-described embodiment (first control mode), the width of the dead zone is a fixed value (for example, ± 1% of the fully charged voltage value), but the width of the dead zone may be variable (second Control form).

In the second control mode, the cell balance controllers 501 to 50 n (control units 511 to 51 n) control the voltage values of all of the plurality of battery cells 111 to 11 n according to the degree of variation (for example, all battery cells 111 to 11 n). Of the dead band according to the deviation between the maximum value and the minimum value of the voltage value of The cell balance controllers 501 to 50 n, for example, increase the width of the dead zone when the variation of the voltage value is large, and reduce the width of the dead zone when the variation is small. The dead zone width is the temperature of the battery cells 111 to 11 n, the target equalization time, the allowable power consumption, and / or the allowable error (the above-mentioned allowable range). It may be set based on the range etc. In such a case, as the temperature of the battery cells 111 to 11n increases, the target equalization time decreases, the allowable power consumption decreases, and the tolerance increases, the width of the dead zone increases. The dead zone may be changed by any one of the plurality of cell balance controllers 501 to 50n, or it may be communicably connected to all the cell balance controllers 501 to 50n. Alternatively, a master controller may be further provided to integrally control all the cell balance controllers 501 to 50n, and the master controller may perform the configuration.

The second control mode will be described with reference to FIG. FIG. 4 is a flowchart showing the processing procedure of the equalization process according to the second control mode. The processing shown in FIG. 4 is also repeatedly executed mainly at predetermined timings by the cell balance controllers 501 to 50n.

First, in step S200, the voltage values of all the battery cells 111 to 11n detected by the voltage sensors 121 to 12n are read.

Next, in step S202, according to the degree of variation of the voltage values of all the plurality of battery cells 111 to 11n (for example, according to the deviation between the maximum value and the minimum value of the voltage values of all the battery cells 111 ) The width of the dead zone is set. For example, when the variation of the voltage value is large, the width of the dead zone is increased, and when the variation is small, the width of the dead zone is reduced.

Subsequently, in step S204, it is determined whether or not the deviation between the maximum value and the minimum value of the voltage values of all the read battery cells 111 to 11n is equal to or less than a predetermined value (for example, the voltage value in the fully charged state). A determination is made as to whether it is within ± 1%. Here, when the deviation between the maximum value and the minimum value is equal to or less than a predetermined value, the process is temporarily left. On the other hand, when the deviation between the maximum value and the minimum value is larger than the predetermined value, the process proceeds to step S206.

In step S206, it is determined whether the deviation from the voltage values of the battery cells 111 to 11n on both sides is equal to or greater than the dead zone set in step S202.
Here, if the deviation of the voltage value is equal to or greater than the dead zone, the process proceeds to step S208. On the other hand, when the deviation of the voltage value is less than the dead zone, the process proceeds to step S210.

In step S208, the wireless power transmission units 301 to 30n of the adjacent battery cells are drive-controlled so that the power is transmitted from the battery cell having a high voltage value to the battery cell having a low voltage value.

Subsequently, in step S210, a determination is made as to whether or not the process of step S206 and step S208 described above has been performed for all the battery cells 111 to 11n. Here, if the process has not been executed for all the battery cells 111 to 11n, the process returns to step S206, and the above-described steps S206 to S206 until the process for all the battery cells 111 to 11n is completed. The process of S210 is repeatedly performed. On the other hand, when the process is executed for all the battery cells 111 to 11 n, the process temporarily exits. Then, as described above, the present process is performed again at a predetermined timing, and the equalization process is repeatedly performed until the above-described step S204 is affirmed (that is, until the equalization is completed). As a result, the voltage values of the entire battery module 10 are equalized.

According to the present embodiment (second control mode), the width of the dead zone is dynamically set in accordance with the degree of the variation of the voltage values of all of the plurality of battery cells 111 to 11n. Therefore, the width of the dead zone is more appropriate according to the degree of variation of the voltage values of all the plurality of battery cells 111 to 11 n (for example, according to the maximum value and the minimum value of the voltage values of all the battery cells 111 It can be set to Therefore, for example, when the variation of the voltage value is large, the width of the dead zone is increased, and when the variation is small, the width of the dead zone is reduced to further equalize the state of charge of the plurality of battery cells 111 to 11n. It becomes possible to do efficiently.

(Third control mode)
In the above-described embodiment (first control mode), power is delivered at the same time as the battery cells 111 to 11n on both sides, but first, a pair is formed with the battery cells 111 to 11n adjacent to one side, A configuration in which power is exchanged within the pair, and then the battery cells 111 to 11n adjacent to the other side are re-paired, and power is exchanged within the pair (that is, the pairs are alternately rearranged to achieve equalization The configuration to be performed) may be adopted (third control mode).

More specifically, in the third embodiment, first, as shown in FIG. 6A, the cell balance controllers 501 to 50 n first perform the respective battery cells 111 to 11 n for the respective battery cells 111 to 11 n. And the adjacent battery cells 111 to 11 n on one side (the battery cell 111 and the battery cell 112 in the example of FIG. 6A, etc.) are paired (first combination). The cell balance controllers 501 to 50 n provide dead zones based on the voltage values of the battery cells 111 to 11 n for each pair, and are paired with the battery cells 111 to 11 n and the battery cells 111 to 11 n. The deviation of the voltage value between the battery cells 111 to 11n is calculated, and when the deviation exceeds the dead zone, the power is transmitted from the battery cells 111 to 11n having a high voltage value to the battery cells 111 to 11n having a low voltage value. As described above, the wireless power transmission units 301 to 30 n of the battery cells 111 to 11 n in a pair are driven and controlled.

Thereafter, as shown in FIG. 6B, the cell balance controllers 501 to 50n display the battery cells 111 to 11n adjacent to the other battery cells 111 to 11n (the battery cells in the example of FIG. 6B). 112 and the battery cell 113, etc.) are paired (second combination) (ie, the pair is rearranged). The cell balance controllers 501 to 50 n form dead zones based on the voltage values of the battery cells 111 to 11 n for each pair, and are paired with the battery cells 111 to 11 n and the battery cells 111 to 11 n. The deviation of the voltage value between the battery cells 111 to 11n is calculated, and when the deviation exceeds the dead zone, the power is transmitted from the battery cells 111 to 11n having a high voltage value to the battery cells 111 to 11n having a low voltage value. As described above, the wireless power transmission units 301 to 30 n of the battery cells 111 to 11 n in a pair are driven and controlled. The setting (recombination) of the pair may be performed by one of the cell balance controllers 501 to 50n among the plurality of cell balance controllers 501 to 50n, and communication with all the cell balance controllers 501 to 50n is possible. The master controller may be further provided with a master controller that is connected to and integrally controls all the cell balance controllers 501 to 50n.

Next, a third control mode will be described with reference to FIG. FIG. 5 is a flowchart showing the processing procedure of the equalization processing according to the third control mode. The processing shown in FIG. 5 is also repeatedly executed mainly at predetermined timings by the cell balance controllers 501 to 50n.

First, in step S300, for each of the battery cells 111 to 11n, the battery cells 111 to 11n and the adjacent battery cells 111 to 11n on one side are set as a pair (first combination) (FIG. a) see).

Next, in step S302, the voltage values of all the battery cells 111 to 11n detected by the voltage sensors 121 to 12n are read. Next, in step S304, it is determined whether or not the deviation between the maximum value and the minimum value of the voltage values of all the read battery cells 111 to 11n is equal to or less than a predetermined value (for example, the voltage value in the fully charged state). A determination is made as to whether it is within ± 1%. Here, when the deviation between the maximum value and the minimum value is equal to or less than a predetermined value, the process is temporarily left. Then, as described above, the present process is executed again at a predetermined timing. On the other hand, when the deviation between the maximum value and the minimum value is larger than the predetermined value, the process proceeds to step S306.

In step S306, it is determined whether or not the deviation of the voltage values of the battery cells 111 to 11n is equal to or greater than a predetermined dead zone in the set pair. Here, when the deviation of the voltage value is equal to or greater than the dead zone, the process proceeds to step S308. On the other hand, when the deviation of the voltage value is less than the dead zone, the process proceeds to step S310.

In step S308, the wireless power transmission units 301 to 30n control driving so that power is transmitted from the battery cells 111 to 11n having high voltage values to the battery cells 111 to 11n having low voltage values in the set pair. Be done.

Subsequently, in step S310, a determination is made as to whether or not the process of step S306 and step S308 described above has been performed for all pairs. Here, when the process has not been executed for all the pairs, the process returns to step S306, and the above-described processes of steps S306 to S310 are repeatedly executed until the processes for all the pairs are completed. . On the other hand, when the process has been executed for all the pairs, the process proceeds to step S312.

In step S312, rearrangement of pairs is performed. That is, when a pair is formed with battery cells 111 to 11 n adjacent to one side, the pair is rearranged so that a pair is formed with battery cells 111 to 11 n adjacent to the other side ( See FIG. 6 (b)). When this process (pair rearrangement) is repeated an even number of times and the battery cells 111 to 11 n adjacent to the other side are paired, the battery cells 111 to 11 n adjacent to one side are performed. The pair is rearranged so that the pair is formed. Thereafter, the process proceeds to step S302. Then, the above-mentioned steps S302 to S312 are repeated again until the step S304 is affirmed (ie, the equalization is completed). As a result, the voltage values of the entire battery module 10 are equalized.

According to the present embodiment (third control mode), for example, even if power can not be simultaneously delivered to and from the battery cells 111 to 11n on both sides due to hardware limitations, the pair Thus, the voltage values of the battery cells 111 to 11 n can be equalized sequentially. In addition, even if a failure such as a short circuit occurs during the delivery of power between the battery cells, the influence can be suppressed only in the battery cells 111 to 11 n forming a pair, It is possible to prevent the influence (failure) from affecting the battery cells 111 to 11 n other than the pair. Therefore, it is possible to further improve the safety.

(Fourth control mode)
By the way, in the above-described embodiment (first to third control modes), as shown in FIG. 8, all battery cells 111 to 11 n while the deviation of the voltage value is within the dead zone between the adjacent battery cells. In general, when the deviation of the voltage value does not fall within the predetermined value, that is, the deviation of the voltage value between the adjacent battery cells in the battery cells 111 to 11 n in the continuous constant area (section) If the voltage value decreases monotonously while staying within the dead zone, the equalization process stops (although the variation does not fall within the whole (that is, it is not equalized)) That is, it may occur that all the wireless power transmission units 301 to 30 n stop (become so-called locked state).

Therefore, in the cell balance controllers 501 to 50n, even if the deviation between the adjacent battery cells is within the dead zone, the variation width of the state of charge of all the battery cells 111 to 11n exceeds the predetermined value. Preferably, the width of the dead zone is changed to a smaller value (fourth control mode). The dead zone in the locked state may be changed by any one of the cell balance controllers 501 to 50n among the plurality of cell balance controllers 501 to 50n, and communication with all the cell balance controllers 501 to 50n is possible. The master controller may be further provided with a master controller that is connected to and integrally controls all the cell balance controllers 501 to 50n.

The fourth control mode will be described with reference to FIG. FIG. 7 is a flowchart showing the processing procedure of the equalization processing according to the fourth control mode. The processing shown in FIG. 7 is also repeatedly executed mainly at predetermined timings by the cell balance controllers 501 to 50n.

First, in step S400, the voltage values of all the battery cells 111 to 11n detected by the voltage sensors 121 to 12n are read.

Next, in step S402, according to the degree of variation of the voltage values of all the plurality of battery cells 111 to 11n (for example, according to the deviation between the maximum value and the minimum value of the voltage values of all the battery cells 111 ) The width of the dead zone is set. For example, when the degree of variation is large, the width of the dead zone is increased, and when the degree of variation is small, the width of the dead zone is reduced.

Subsequently, in step S404, it is determined whether or not the deviation between the maximum value and the minimum value of the voltage values of all the read battery cells 111 to 11n is equal to or less than a predetermined value (for example, the voltage value in the fully charged state). A determination is made as to whether it is within ± 1%. Here, when the deviation of the voltage value between the maximum value and the minimum value is equal to or less than a predetermined value, the process is temporarily left. On the other hand, when the deviation between the maximum value and the minimum value is larger than the predetermined value, the process proceeds to step S406.

In step S406, it is determined whether the deviation of the voltage values of the battery cells 111 to 11n on both sides is equal to or greater than the set dead zone. Here, when the deviation of the voltage value is equal to or greater than the dead zone, the process proceeds to step S408. On the other hand, when the deviation of the voltage value is less than the dead zone, the process proceeds to step S410.

In step S408, the wireless power transmission units 301 to 30n of the adjacent battery cells 111 to 11n control driving so that power is transmitted from the battery cells 111 to 11n having high voltage values to the battery cells 111 to 11n having low voltage values. Be done.

Subsequently, in step S410, a determination is made as to whether or not the process of step S406 and step S408 described above has been performed for all the battery cells 111 to 11n. Here, if the process has not been executed for all the battery cells 111 to 11n, the process returns to step S406, and the above-described steps S406 to S406 are performed until the process is completed for all the battery cells 111 to 11n. The process of S410 is repeatedly performed. On the other hand, when the process is executed for all the battery cells 111 to 11n, the process proceeds to step S412.

In step S412, a determination is made as to whether power transfer has taken place (ie, is locked or not). Here, when the power transfer is not performed (when in the locked state), the process proceeds to step S414, and the value of the dead zone width is smaller than the value set in step S402 ( For example, zero) is set. Then, the process proceeds to step S406, and the above-described processes of steps S406 to S414 are performed until power transfer is performed again (that is, until the locked state is cancelled). On the other hand, when the power transfer is performed (ie, when the lock state is not set), the process is temporarily left. Then, as described above, the present process is executed again at a predetermined timing. As a result, the state of charge of the entire battery module 10 is equalized.

According to the present embodiment (the fourth control mode), although the deviation of the voltage value between the adjacent battery cells falls within the dead zone, the variation width of the state of charge of all the battery cells 111 to 11 n is If the predetermined value is exceeded, the width of the dead zone is reduced (eg, to zero). Therefore, canceling the lock state described above, that is, preventing the equalization process from being stopped even though the variation as a whole is not settled (that is, not equalized). It is possible to reliably equalize the voltage values of the battery cells 111 to 11 n.

(Fifth control mode)
In the fourth control mode described above, when the locked state is obtained, the value of the dead zone is reduced (for example, made zero), but a linear approximation formula is obtained for the voltage values of all the battery cells 111 to 11n. The power may be delivered so that the slope of the approximate expression becomes zero (fifth control mode).

More specifically, in the fifth embodiment, the variation width of the voltage values of all the battery cells 111 to 11n exceeds a predetermined value, even though the deviation is within the dead zone between the adjacent battery cells. In the case of being in the locked state (ie, in the locked state), the cell balance controllers 501 to 50 n first determine the average value of the voltage values of all the battery cells 111 to 11 n, as shown in FIG. Next, the cell balance controllers 501 to 50n obtain linear approximation formulas for the voltage values of all the battery cells 111 to 11n. More specifically, the plurality of battery cells 111 to 11 n are arranged along the horizontal axis (that is, the horizontal axis is an array of battery cells 111 to 11 n), and the vertical axis is the voltage value of each of the battery cells 111 to 11 n As a formula, a linear approximation formula for variation in voltage value is obtained.

Then, the cell balance controllers 501 to 50 n are battery cells positioned on the side where the inclination of the linear approximation formula decreases from the battery cells 111 to 11 n regardless of the dead zone for the battery cells 111 to 11 n whose voltage value exceeds the average value. The wireless power transmission units 301 to 30 n are drive-controlled to transmit power to 111 to 11 n (that is, the inclination of the linear approximation formula approaches zero). Therefore, power is transferred to the adjacent battery cells 111 to 11 n until the voltage values of the battery cells 111 to 11 n whose voltage value exceeds the average value match the average value. In the meantime, even if the voltage values of the adjacent battery cells 111 to 11 n exceed the average value, the power transfer is continuously performed.

Note that acquisition of the linear approximation formula in the locked state may be performed by any one of the plurality of cell balance controllers 501 to 50n, or all the cell balance controllers 501 to 50n may be used. A master controller connected communicably and integrally controlling all the cell balance controllers 501 to 50 n may be further provided, and the master controller may perform the configuration.

Next, a fifth control mode will be described with reference to FIG. FIG. 9 is a flowchart showing the procedure of the equalization process according to the fifth control mode. The processing shown in FIG. 9 is also repeatedly executed mainly at predetermined timings by the cell balance controllers 501 to 50n.

First, in step S500, the voltage values of all the battery cells 111 to 11n detected by the voltage sensors 121 to 12n are read.

Next, in step S502, it is determined whether or not the deviation between the maximum value and the minimum value of the voltage values of all the read battery cells 111 to 11n is equal to or less than a predetermined value (for example, the voltage value in the fully charged state). A determination is made as to whether it is within ± 1%. Here, when the deviation between the maximum value and the minimum value is equal to or less than a predetermined value, the process is temporarily left. On the other hand, when the deviation between the maximum value and the minimum value is larger than the predetermined value, the process proceeds to step S504.

In step S504, it is determined whether the deviation from the voltage values of the battery cells 111 to 11n on both sides is equal to or more than the set dead zone. Here, when the deviation of the voltage value is equal to or larger than the dead zone, the process proceeds to step S506. On the other hand, when the deviation of the voltage value is less than the dead zone, the process proceeds to step S508.

In step S506, the wireless power transmission units 301 to 30n of the adjacent battery cells 111 to 11n control driving so that power is transmitted from the battery cells 111 to 11n having high voltage values to the battery cells 111 to 11n having low voltage values. Be done. Thereafter, the process proceeds to step S508.

In step S508, a determination is made as to whether or not the process of step S504 and step S506 described above has been performed for all of the battery cells 111 to 11n. Here, if the process has not been executed for all the battery cells 111 to 11n, the process returns to step S504, and the above-described steps S504 to S504 are performed until the process is completed for all the battery cells 111 to 11n. The process of S508 is repeatedly performed. On the other hand, when the process is executed for all the battery cells 111 to 11n, the process proceeds to step S510.

In step S510, a determination is made as to whether power transfer has taken place (ie, is it in a locked state). Here, when the movement of the power is performed (when not in the locked state), the process is temporarily left out. Then, as described above, the present process is executed again at a predetermined timing. On the other hand, when the power transfer has not been performed (when in the locked state), the process proceeds to step S512.

In step S512, the average value of the voltage values of all the battery cells 111 to 11n is obtained. Then, in step S514, a linear approximation formula is obtained for the voltage values of all the battery cells 111 to 11n.

Subsequently, in step S516, it is determined whether or not the voltage values of the battery cells 111 to 11n are equal to or greater than the average value. Here, when the voltage values of the battery cells 111 to 11n are equal to or more than the average value, the process proceeds to step S518. On the other hand, when the voltage values of the battery cells 111 to 11n are less than the average value, the process proceeds to step S520.

In step S518, for the battery cells 111 to 11n whose voltage value exceeds the average value, regardless of the dead zone, the battery cells 111 to 11n are positioned adjacent to the battery cell 111 on the side where the inclination of the linear approximation formula decreases. The wireless power transmission units 301 to 30 n are drive-controlled so that power is transmitted to 11 n (that is, the slope of the linear approximation formula becomes zero). Thereafter, the process proceeds to step S520.

In step S520, a determination is made as to whether or not the process of step S516 and step S518 described above has been performed for all of the battery cells 111-11n. Here, if the process has not been executed for all the battery cells 111 to 11n, the process returns to step S516, and the above-described steps S516 to S516 are performed until the process is completed for all the battery cells 111 to 11n. The process of S520 is repeatedly performed. On the other hand, when the process is executed for all the battery cells 111 to 11 n, the process is temporarily left out. Then, as described above, the present process is executed again at a predetermined timing. As a result, the state of charge of the entire battery module 10 is equalized.

According to the present embodiment (fifth control mode), the variation width of the voltage values of all the battery cells 111 to 11 n is in spite of the fact that the deviation of the voltage value is within the dead zone between the adjacent battery cells. If it exceeds the predetermined value, the average value of the voltage values of all the battery cells 111 to 11 n is determined, and a linear approximation formula for the voltage values of all the battery cells 111 to 11 n is determined. For battery cells 111 to 11n exceeding the value, regardless of the dead zone, power is transmitted from the battery cells 111 to 11n to the battery cells 111 to 11n located (adjacent) on the side where the inclination of the linear approximation formula decreases The wireless power transmission units 301 to 30 n are driven and controlled (ie, the inclination of the linear approximation formula becomes zero). Therefore, canceling the lock state described above, that is, preventing the equalization process from being stopped even though the variation as a whole is not settled (that is, not equalized). As a result, the battery cells 111 to 11 n can be reliably equalized.

The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment (first to fifth control modes), and various modifications are possible. For example, in the above embodiment, the voltage value is used as an index indicating the charge state of the battery cells 111 to 11n, but instead of the voltage value, for example, charge and discharge currents are integrated to estimate SOC (current integration method) The SOC may be used as an indicator that indicates the state of charge. Moreover, although the case where the cell balance control apparatus 1 was equipped with the one battery module 10 was made into the example and demonstrated in the said embodiment, multiple battery modules 10 may be connected in parallel.

In the above embodiment, when the deviation of the voltage values of the adjacent battery cells 111 to 11n falls within the dead zone, the delivery (equalization processing) of the power is stopped, but the deviation of the voltage values of the adjacent battery cells 111 to 11n When it enters the dead zone, a predetermined constant amount of power may be delivered. Further, for example, the tendency of variation in voltage values of the battery modules 10 (battery cells 111 to 11 n) may be learned, and the dead zone may be corrected (variable) using the learning result. In this way, individual differences and aging deterioration of the battery module 10 can be absorbed.

In the above embodiment, the widths of the dead zone provided on the + side and the dead zone provided on the − side are the same, but the widths of the dead zone provided on the + side and the dead zone provided on the − side may be different. Further, the width of the dead zone or the detected voltage value may be corrected according to the temperature of the battery cells 111 to 11 n or the like.

In the above embodiment, wireless communication is used for communication among the cell balance controllers 501 to 50n (wireless communication units 521 to 52n), but for example, CAN (Controller Area Network), UART (Universal Asynchronous Receiver / Transmitter), Wired communication such as SPI (Serial Peripheral Interface) may be employed. However, it is preferable to use wireless communication from the viewpoint of weight reduction of the device, freedom of configuration, and the like. In the above embodiment, communication is performed between adjacent cell balance controllers 501 to 50n (wireless communication units 521 to 52n). However, communication may be performed between any cell balance controllers 501 to 50n. .

In the above embodiment (second to fifth control modes), one of the plurality of cell balance controllers 501 to 50n has the master function, but as shown in FIG. Alternatively, the master controller 70 may be configured to be communicably connected to all the cell balance controllers 501 to 50n and collectively control all the cell balance controllers 501 to 50n.

Although the power is transmitted wirelessly in the above embodiment, the power may be transmitted by wire. The present invention can be suitably applied to, for example, a BMS (battery management system).

DESCRIPTION OF SYMBOLS 1 Cell balance control apparatus 10

Battery module

111, 112, 113, ..., 11

n Battery cell

121, 122, 123, ..., 12

n Voltage sensor

301, 302, 303, ..., 30 n Wireless electric

power transmission part

501 , 502, 503, ..., 50 n

cell balance controllers

511, 512, 513, ..., 51

n control units

521, 522, 523, ..., 52 n wireless communication units

Claims

In a cell balance control device for equalizing the charge states of a plurality of battery cells connected in series, which constitute a battery module,
A detection unit that detects the charge state of each battery cell;
A power transfer unit provided for each of the battery cells for transmitting power between adjacent battery cells;
A control unit that drives and controls the power transmission unit;
The control unit is configured to control each of the battery cells
While providing a dead zone based on the charge condition of each battery cell,
Calculating the deviation of the state of charge between each of the battery cells and the battery cells adjacent to the battery cell;
A cell characterized by driving and controlling a power transmission unit of an adjacent battery cell so as to transmit power from a battery cell with a high state of charge to a battery cell with a low state of charge when the deviation exceeds the dead zone. Balance control device.
The cell balance control device according to claim 1, wherein the dead zone is set in advance based on a predetermined ratio with respect to a fully charged state of the battery cell.
The cell balance control device according to claim 1, wherein the control unit sets the width of the dead zone in accordance with the degree of variation in the state of charge of all of the plurality of battery cells.
The control unit is configured to control each of the battery cells
The respective battery cells and one adjacent battery cell are paired, and a dead zone is provided for each pair based on the charge state of each battery cell, and each battery cell and the battery cell are paired A battery cell paired to calculate a deviation of the charge state from the battery cell and transmit power from the battery cell with high charge state to the battery cell with low charge state when the deviation exceeds the dead zone Drive control of the power
Thereafter, each battery cell and the other adjacent battery cell are paired, and a dead zone is provided for each pair based on the charge state of each battery cell, and each battery cell and the battery cell are paired The deviation of the charge condition with the battery cell is calculated, and when the deviation exceeds the dead zone, the battery cell is paired to transmit power from the battery cell with high charge condition to the battery cell with low charge condition. The cell balance control device according to any one of claims 1 to 3, which controls driving of a power transmission unit of a battery cell.
The control unit is configured to, in a case where the variation width of the state of charge of all the battery cells exceeds a predetermined value, although the deviation is within the dead zone among all the adjacent battery cells. The cell balance control device according to any one of claims 1 to 4, wherein the width of the dead zone is reduced.
The control unit is configured to perform all of the plurality of adjacent battery cells in the case where the variation width of the state of charge of all the battery cells exceeds a predetermined value although the deviation is within the dead zone. The average value of the state of charge of the battery cell is determined, and a linear approximation formula for the state of charge of all the battery cells is obtained, and for the battery cell whose state of charge exceeds the average value, regardless of the dead zone, from the battery cell The cell balance according to any one of claims 1 to 4, wherein the power transmission unit is drive-controlled to transmit power to a battery cell positioned on the side where the slope of the linear approximation formula decreases. Control device.
The cell balance control device according to any one of claims 1 to 6, wherein the power transmission unit is a wireless power transmission unit that wirelessly transmits power.
The wireless power transmission unit has flat plate electrodes disposed facing each other between the battery cells, and transmits power using an induced electric field generated between the electrodes. The cell balance control apparatus according to 7.
In a cell balance control method for equalizing the charge states of a plurality of battery cells connected in series, which constitute a battery module,
A detection step of detecting a charge state of each battery cell;
For each of the battery cells,
While providing a dead zone based on the charge condition of each battery cell,
Calculating the deviation of the state of charge between each of the battery cells and the battery cells adjacent to the battery cell;
A control step of driving and controlling a power transmission unit of an adjacent battery cell to transmit power from the battery cell with high charge state to the battery cell with low charge state when the deviation exceeds the dead zone;
A cell balance control method comprising:
10. The cell balance control method according to claim 9, wherein the dead zone is preset based on a predetermined ratio with respect to a fully charged state of the battery cell.
10. The cell balance control method according to claim 9, wherein in the control step, the width of the dead zone is set in accordance with the degree of variation in the state of charge of all of the plurality of battery cells.
In the control step, for each of the battery cells,
The respective battery cells and one adjacent battery cell are paired, and a dead zone is provided for each pair based on the charge state of each battery cell, and each battery cell and the battery cell are paired A battery cell paired to calculate a deviation of the charge state from the battery cell and transmit power from the battery cell with high charge state to the battery cell with low charge state when the deviation exceeds the dead zone Drive control of the power
Thereafter, each battery cell and the other adjacent battery cell are paired, and a dead zone is provided for each pair based on the charge state of each battery cell, and each battery cell and the battery cell are paired The deviation of the charge condition with the battery cell is calculated, and when the deviation exceeds the dead zone, the battery cell is paired to transmit power from the battery cell with high charge condition to the battery cell with low charge condition. The cell balance control method according to any one of claims 9 to 11, wherein drive control of the power transmission unit of the battery cell is performed.
In the control step, even if the deviation is within the dead zone between all adjacent battery cells, if the variation width of the state of charge of all the battery cells exceeds a predetermined value, The cell balance control method according to any one of claims 9 to 12, wherein the width of the dead zone is reduced.
In the control step, in the case where the variation width of the state of charge of all the battery cells exceeds a predetermined value, although the deviation is within the dead zone among all the adjacent battery cells. The average value of the state of charge of the battery cell is determined, and a linear approximation formula for the state of charge of all the battery cells is obtained, and for the battery cell whose state of charge exceeds the average value, regardless of the dead zone, from the battery cell The cell balance according to any one of claims 9 to 12, wherein the power transmission unit is drive-controlled to transmit power to a battery cell positioned on the side where the inclination of the linear approximation formula decreases. Control method.
The cell balance control method according to any one of claims 9 to 14, wherein the power transmission unit is a wireless power transmission unit that wirelessly transmits power.
The wireless power transmission unit has flat plate electrodes disposed facing each other between the battery cells, and transmits power using an induced electric field generated between the electrodes. The cell balance control method as described in 15.