WO2015015596A1

WO2015015596A1 - Battery system

Info

Publication number: WO2015015596A1
Application number: PCT/JP2013/070761
Authority: WO
Inventors: 孝徳山添; 裕有田; 洋平河原; 寛岩澤
Original assignee: 株式会社日立製作所
Priority date: 2013-07-31
Filing date: 2013-07-31
Publication date: 2015-02-05

Abstract

This battery system comprises the following: battery-cell groups; battery-cell management apparatuses, each of which obtains measurement results relating to the states of charge of the battery cells in a corresponding battery-cell group; and a battery-pack management apparatus that performs wireless or wired communication with the battery-cell management apparatuses. Each battery-cell management apparatus uses power supplied from the battery cells in the corresponding battery-cell group to transmit the aforementioned measurement results to the battery-pack management apparatus. On the basis of the measurement results transmitted from the battery-cell management apparatuses, the battery-pack management apparatus estimates the states of charge of the battery cells in the battery-cell groups, and on the basis of the results of said estimation, changes the amount of communication performed with the battery-cell management apparatuses.

Description

Battery system

The present invention relates to a battery system.

Currently, as global environmental problems are greatly highlighted, there is a need to reduce carbon dioxide emissions to prevent global warming. For example, a gasoline engine vehicle, which is a large source of carbon dioxide, has begun to be replaced by a hybrid electric vehicle and an electric vehicle. A large-sized secondary battery representative as a power source for a hybrid electric vehicle or an electric vehicle needs to have a high output and a large capacity. Therefore, the storage battery module constituting this is generally configured by connecting a plurality of battery cells in series and parallel.

Lithium ion batteries are widely known as large capacity secondary batteries. In handling lithium ion batteries, measures such as prevention of high voltage charging and deterioration of performance due to overdischarge are required. For this reason, a storage battery module that is mounted on a hybrid electric vehicle or an electric vehicle and that uses a lithium ion battery for each battery cell generally monitors the battery state such as voltage, current, and temperature for each battery cell. It has the function to control each battery cell according to.

As a method for realizing control of a battery cell in accordance with the battery state as described above, for example, techniques disclosed in

Patent Documents

1 and 2 below are known. In the battery cell control method by the battery control device disclosed in Patent Document 1, a discharge circuit and a switch are provided for each battery cell, and the switch is controlled to open and close according to the state of charge (SOC) of each battery cell. The SOC variation of each battery cell is adjusted. Further, in the battery cell control method by the assembled battery control means disclosed in Patent Document 2, when there is a group of battery cells whose SOC is higher than a predetermined charging state, the battery cell group is stopped when charging / discharging of the assembled battery is stopped. By continuing the operation of the single battery control means corresponding to the above, the battery cells of the battery cell group are discharged to adjust the SOC variation between the battery cell groups.

Japanese Unexamined Patent Publication No. 2012-135140 Japanese Unexamined Patent Publication No. 2012-10563

In the battery cell control method disclosed in Patent Document 1, since it is necessary to provide a discharge circuit and a switch for each battery cell in the battery control device, the battery control device may be increased in cost and reliability. There is. Further, in the battery cell control method disclosed in Patent Document 2, since the SOC variation is adjusted when charging / discharging of the assembled battery is stopped, the SOC variation cannot be adjusted in real time during charging / discharging.

A battery system according to the present invention includes a battery cell group configured by one or a plurality of battery cells, and a battery cell that is provided corresponding to the battery cell group and obtains a measurement result regarding a charge state of the battery cell of the battery cell group. And a battery pack management device that performs wireless or wired communication between the management device and the battery cell management device. In this battery system, the battery cell management device transmits the measurement result to the assembled battery management device using the power supplied from the battery cells of the battery cell group. Further, the assembled battery management device estimates the charge state of the battery cells of the battery cell group based on the measurement result transmitted from the battery cell management device, and based on the estimation result of the charge state, Change the amount of communication between them.

According to the present invention, it is possible to adjust the SOC variation of the battery cell in real time during charge / discharge without requiring a special circuit or component.

It is a figure which shows the structure of the vehicle-mounted system containing the battery system by one Embodiment of this invention. It is a figure which shows the structural example of the battery system by the 1st Embodiment of this invention. It is a figure which shows the example of a communication flow between an assembled battery management apparatus and a battery cell management apparatus. It is a figure which shows the structural example of the battery system by the 2nd Embodiment of this invention. It is a figure which shows the structural example of the battery system by the 3rd Embodiment of this invention.

FIG. 1 is a diagram showing a configuration of an in-vehicle system including a battery system according to an embodiment of the present invention. The in-vehicle system shown in FIG. 1 is mounted on a vehicle such as a hybrid electric vehicle or an electric vehicle, and includes a battery system 1, an inverter 2, a motor 3, a relay box 4, and a host controller 5.

The battery system 1 includes one or a plurality of battery cell groups 10 each constituted by one or a plurality of battery cells, and the battery cell management device 100 corresponds to each battery cell group 10. Is provided. Each battery cell management device 100 performs measurement (voltage, current, temperature, etc.) related to the state of charge (SOC: State of Charge) or the deterioration state (SOH: State of Health) of the battery cell group 10. Then, using the power supplied from the battery cells of the battery cell group 10, wireless (or wired) communication is performed with the assembled battery monitoring device 200, and measurement results regarding the charge state and the deterioration state of the battery cell group 10 are obtained. It transmits to the assembled battery monitoring apparatus 200. Details of communication performed at this time will be described later.

The assembled battery monitoring device 200 acquires a measurement result related to the charge state or the deterioration state of the battery cell group 10 corresponding to the battery cell management device 100 from each battery cell management device 100. Then, based on the acquired measurement result, the charged state and the deteriorated state of each battery cell group 10 are estimated, and the estimated result is transmitted to the host controller 5.

The host controller 5 controls the inverter 2 and the relay box 4 based on the estimation result of the charged state and the deteriorated state of each battery cell group 10 transmitted from the assembled battery monitoring device 200. The inverter 2 converts the DC power supplied from each battery cell group 10 into three-phase AC power when the relay box 4 is in a conductive state, and supplies the three-phase AC power to the motor 3, thereby driving the motor 3 to rotate. Generate driving force. Further, when the vehicle is braked, the battery cells of each battery cell group 10 are charged by converting the three-phase AC regenerative power generated by the motor 3 into DC power and outputting it to each battery cell group 10. The operation of the inverter 2 is controlled by the host controller 5.

(First embodiment)
FIG. 2 is a diagram showing a configuration example of the battery system 1 according to the first embodiment of the present invention. The battery system 1 shown in FIG. 2 further includes a temperature detection unit 300 and a current detection unit 400 in addition to the battery cell group 10, the battery cell management device 100, and the assembled battery monitoring device 200 shown in FIG. FIG. 2 shows an example in which n battery cell groups 10 and n battery cell management devices 100 are provided in the battery system 1. In FIG. 2, the first, second, and nth battery cell groups 10 are represented by reference numerals 10-1, 10-2, and 10-n, respectively, and the first, second, and nth provided corresponding thereto. The battery cell management devices 100 are denoted by reference numerals 100-1, 100-2, and 100-n, respectively.

The temperature detection means 300 detects the temperature of the battery system 1 and outputs the detection result to the assembled battery management apparatus 200 as the temperature of each battery cell group 10. The current detection unit 400 detects a current flowing through the battery cell group 10 connected in series, and outputs the detection result to the assembled battery management apparatus 200.

The battery cell management device 100 includes a battery control unit 20 and a communication control unit 30. The battery control unit 20 detects the voltage of each battery cell of the corresponding battery cell group 10 to acquire a measurement result regarding the charging state or the deterioration state of the battery cell group 10, and sends the measurement result to the communication control unit 30. Output. The communication control unit 30 uses the electric power supplied from the battery cells of the corresponding battery cell group 10 to display the voltage detection result of each battery cell input from the battery control unit 20 by wireless (or wired) communication. It transmits to the management apparatus 200. In the case of wired communication, each battery cell management device 100 may be individually connected to the assembled battery management device 200. Alternatively, a plurality of battery cell management devices 100 may be connected in a daisy chain, and one or both ends thereof may be connected to the assembled battery management device 200.

The assembled battery management device 200 acquires the temperature detected by the temperature detection means 300 and the current detected by the current detection means 400. Moreover, the voltage of each battery cell of the battery cell group 10 corresponding to each battery cell management apparatus 100 is acquired by performing communication with each battery cell management apparatus 100. Based on these pieces of information, the assembled battery management apparatus 200 can estimate the state of charge (SOC) and the state of deterioration (SOH) of each battery cell group 10.

Thus, when the SOC of each battery cell group 10 is obtained, the assembled battery management apparatus 200 calculates the average SOC of the battery cell group 10 by calculating the average value. As a result, when there is a battery cell group 10 with an SOC that is higher than the average SOC by a predetermined specified value Δ% or more, the frequency of communication performed with the battery cell management device 100 to which the battery cell group 10 is connected is determined. It is increased more than other battery cell management devices 100. Thereby, the power consumption required for communication when transmitting the voltage detection result of the battery cell from the battery cell monitoring device 100 to the assembled battery management device 200 is increased more than that of the other battery cell monitoring devices 100. As a result, the SOC of the battery cell group 10 connected to the battery cell monitoring device 100 can be relatively lowered, and the SOC can be adjusted with the other battery cell group 10.

FIG. 3 is a diagram showing an example of a communication flow between the assembled battery management device 200 and the battery cell management devices 100-1 to 100-n. As shown in FIG. 3, the assembled battery management device 200 first transmits a command 1 as a command for reading the voltage value of the battery cell group 10-1 to the first battery cell management device 100-1. To do. Upon receiving this command 1, the battery cell management device 100-1 detects the voltage of each battery cell in the connected battery cell group 10-1, and returns the voltage value data as response 1 to the assembled battery management device 200. To do.

Next, the assembled battery management device 200 transmits a command 2 as a command for reading the voltage value of the battery cell group 10-2 to the second battery cell management device 100-2 in the same manner. Receiving this command 2, the battery cell management device 100-2 detects the voltage of each battery cell in the connected battery cell group 10-2, and returns the voltage value data as response 2 to the assembled battery management device 200. To do.

The assembled battery management device 200 repeatedly transmits the command and receives the response as described above up to the nth battery cell management device 100-n. Thereby, the voltage value of each battery cell group 10 can be acquired from each battery cell monitoring device 100 as data for calculating the SOC of each battery cell group 10.

The communication between the assembled battery management device 200 and the battery cell management devices 100-1 to 100-n using the communication flow described above can be realized by, for example, time division wireless communication using a plurality of communication slots. it can. That is, the assembled battery management device 200 and each battery cell management device 100 (battery cell management devices 100-1 to 100-n) use this communication slot assigned to each battery cell management device 100, respectively. Such time division wireless communication can be performed.

The assembled battery management apparatus 200 uses the voltage value of each battery cell group 10 acquired as described above, and the temperature and current values acquired from the temperature detection means 300 and the current detection means 400, respectively. An SOC of 10 is estimated. As a result, for example, it is assumed that the SOC of the battery cell group 10-1 is higher than the value obtained by adding the specified value Δ% to the average SOC in the first voltage recognition cycle. In such a case, as shown in FIG. 3, the assembled battery management device 200 transmits command 1 to the battery cell management device 100-1 corresponding to the battery cell group 10-1 in the next second voltage recognition cycle. By increasing the number of times, the number of times response 1 is returned from battery cell management device 100-1 is increased. As a result, the number of communication slots assigned to the battery cell management apparatus 100-1 is increased to increase the amount of communication performed with the battery cell management apparatus 100-1. As a result, the power consumption in the battery cell group 10-1 can be made larger than that in the other battery cell groups, and the SOC of the battery cell group 10-1 can be relatively lowered.

In the example described above, the assembled battery management device 200 has been described as increasing the amount of communication performed with the battery cell management device 100 corresponding to the battery cell group 10 having a high SOC. Conversely, the amount of communication performed with the battery cell management device 100 corresponding to the battery cell group 10 having a low SOC may be reduced. For example, it is assumed that the SOC of battery cell group 10-1 is lower than the value obtained by subtracting the specified value Δ% from the average SOC. In such a case, the assembled battery management device 200 does not transmit the command 1 to the battery cell management device 100-1 corresponding to the battery cell group 10-1 in the next voltage recognition cycle. As a result, the number of times the response 1 is returned from the battery cell management device 100-1 is reduced, and the number of communication slots assigned to the battery cell management device 100-1 is reduced. Reduce the amount of communication between them. As a result, the power consumption in the battery cell group 10-1 can be made smaller than that in the other battery cell groups, and the SOC of the battery cell group 10-1 can be relatively increased.

That is, the assembled battery management device 200 changes the amount of communication performed with each battery cell management device 100 based on the estimation result of the SOC of each battery cell group 10. Thereby, the dispersion | variation in SOC of each battery cell group 10 can be adjusted.

Moreover, in the example demonstrated above, in the assembled battery management apparatus 200, by increasing / decreasing the communication frequency (number of times) for transmitting the voltage measurement result of the battery cell group 10 from each battery cell management apparatus 100, the amount of communication is increased. Although the change has been described, the amount of communication may be changed by other methods. For example, a plurality of types of commands are prepared in the assembled battery management device 200, and the length of the response returned from each battery cell management device 100, that is, the length of the communication slot is changed according to the type of the command. To. And according to the magnitude | size of SOC of the corresponding battery cell group 10, by determining the kind of command transmitted with respect to each battery cell management apparatus 100, the voltage of the battery cell group 10 from each battery cell management apparatus 100 is determined. The communication time for transmitting the measurement result is changed. Even in this way, the assembled battery management device 200 can change the amount of communication performed with each battery cell management device 100 based on the estimation result of the SOC of each battery cell group 10. As a result, variation in SOC of each battery cell group 10 can be adjusted.

In addition, in order to change the amount of communication performed between the assembled battery management device 200 and each battery cell management device 100, the two methods described above may be used in combination. That is, the assembled battery management device 200 changes each battery cell management device 100 by changing at least one of the communication frequency and the communication time for causing each battery cell management device 100 to transmit the voltage measurement result of the battery cell group 10. The amount of communication performed between the two can be changed.

According to the first embodiment of the present invention described above, the following operational effects are obtained.

(1) The battery system 1 is provided corresponding to the battery cell group 10 constituted by one or a plurality of battery cells and the battery cell group 10, and the measurement result regarding the charge state of the battery cells of the battery cell group 10 A battery cell management device 100 to be acquired and a battery pack management device 200 that performs wireless or wired communication with the battery cell management device 100 are provided. The battery cell management device 100 transmits the measurement result to the assembled battery management device 200 using the power supplied from the battery cells of the battery cell group 10. The assembled battery management device 200 estimates the state of charge (SOC) of the battery cells of the battery cell group 10 based on the measurement result transmitted from the battery cell management device 100, and based on the estimation result of the SOC, the battery cell The amount of communication performed with the management apparatus 100 is changed. Since it did in this way, the dispersion | variation in SOC of a battery cell can be adjusted in real time during charging / discharging, without requiring a special circuit and components.

(2) The battery cell management device 100 transmits a measurement result to the assembled battery management device 200 in response to a command from the assembled battery management device 200. The assembled battery management device 200 changes the amount of communication performed with the battery cell management device 100 by changing at least one of the communication frequency and the communication time for causing the battery cell management device 100 to transmit the measurement result. . Since it did in this way, the amount of communication performed between the assembled battery management apparatus 200 and the battery cell management apparatus 100 can be changed appropriately and easily.

(3) The battery system 1 includes a plurality of battery cell groups 10 and a plurality of battery cell management devices 100 corresponding to the respective battery cell groups 10. The assembled battery management device 200 and the plurality of battery cell management devices 100 can perform time-division wireless communication using a communication slot assigned to each battery cell management device 100. In this case, the assembled battery management device 200 changes the amount of communication performed with the battery cell management device 100 by changing at least one of the number and the length of the communication slots based on the estimation result of the SOC. Since it did in this way, when performing wireless communication between the assembled battery management apparatus 200 and each battery cell management apparatus 100, the communication amount in the wireless communication can be changed appropriately and easily.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In 1st Embodiment mentioned above, the battery cell group 10 demonstrated the example comprised with the some battery cell. In this case, the SOC can be adjusted between the plurality of battery cell groups 10, but the SOC cannot be adjusted between the plurality of battery cells included in the same battery cell group 10. Therefore, in a second embodiment described below, an example in which such a problem is solved by configuring the battery cell group 10 by one battery cell will be described.

FIG. 4 is a diagram showing a configuration example of the battery system 1 according to the second embodiment of the present invention. In the battery system 1 shown in FIG. 4, each battery cell group 10 (battery cell groups 10-1 to 10-m) is configured by one battery cell as compared with the one according to the first embodiment shown in FIG. Is different. In FIG. 4, m represents the number of battery cell groups 10 (that is, the number of battery cells).

As shown in FIG. 4, in the battery system 1 of the present embodiment, the battery cell management device 100 is assigned to each battery cell. Therefore, by using the method described in the first embodiment, the amount of communication performed between each battery cell management device 100 and the battery management device 200 is set to the battery cell corresponding to each battery cell management device 100. The SOC of each battery cell can be adjusted by changing the SOC according to the SOC.

According to the second embodiment of the present invention described above, the battery cell group 10 is constituted by one battery cell, and the battery cell management device 100 corresponds to one battery cell constituting the battery cell group 10. Is provided. Since it did in this way, SOC can be adjusted between battery cells.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In 2nd Embodiment mentioned above, the battery cell group 10 was comprised by one battery cell, and the example which enabled adjustment of SOC between battery cells was demonstrated. On the other hand, 3rd Embodiment demonstrated below demonstrates the example which enables adjustment of SOC between battery cells, when the battery cell group 10 is comprised by the some battery cell.

FIG. 5 is a diagram showing a configuration example of the battery system 1 according to the third embodiment of the present invention. The battery system 1 shown in FIG. 5 is different from that according to the first embodiment shown in FIG. 2 in that each battery cell management device 100 (battery cell management devices 100-1 to 100-n) has a battery. The control unit 20 is different in that a selection circuit 21 is further mounted.

The selection circuit 21 includes a battery cell group connected to the battery control unit 20 for a battery cell that receives power supply when the communication control unit 30 transmits the voltage of the battery cell of the battery cell group 10 to the assembled battery management device 200. Select from 10 battery cells. Using the power supplied from the battery cell selected by the selection circuit 21, the communication control unit 30 uses the wireless (or wired) communication to determine the voltage detection result of each battery cell input from the battery control unit 20. It transmits to the management apparatus 200.

Note that the battery cell selection operation by the selection circuit 21 is preferably performed based on an instruction from the assembled battery management device 200. For example, the assembled battery management device 200 uses the selection circuit 21 based on the estimation result of the SOC of each battery cell constituting each battery cell group 10 in the command (see FIG. 3) transmitted to each battery cell management device 100. Each battery cell management apparatus 100 is instructed which battery cell to select. In response to the instruction from the assembled battery management device 200, each battery cell management device 100 operates the selection circuit 21 to transfer the corresponding battery cell from the corresponding battery cells of the battery cell group 10 to the communication control unit 30. It can be selected as a power supply source.

According to the third embodiment of the present invention described above, the battery cell group 10 includes a plurality of battery cells, and each battery cell management device 100 transmits a measurement result to the assembled battery management device 200. A selection circuit 21 is provided for selecting a battery cell to be supplied with power from a plurality of battery cells. The assembled battery management apparatus 200 instructs each battery cell management apparatus 100 to select a battery cell by the selection circuit 21 based on the estimation result of the SOC. Since it did in this way, when battery cell group 10 comprises a plurality of battery cells, SOC can be adjusted between battery cells.

The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

DESCRIPTION OF SYMBOLS 1 ... Battery system 10 ... Battery cell group 20 ... Battery control part 21 ... Selection circuit 30 ... Communication control part 100 ... Battery cell management apparatus 200 ... Battery pack management device 300 ... temperature detection means 400 ... current detection means

Claims

A battery cell group composed of one or more battery cells;
A battery cell management device that is provided corresponding to the battery cell group and acquires a measurement result relating to a charge state of the battery cell of the battery cell group;
An assembled battery management device that performs wireless or wired communication with the battery cell management device,
The battery cell management device uses the power supplied from the battery cells of the battery cell group to transmit the measurement result to the battery pack management device,
The assembled battery management device estimates a state of charge of the battery cells of the battery cell group based on the measurement result transmitted from the battery cell management device, and based on the estimation result of the state of charge, the battery cell A battery system that changes the amount of communication with the management device.
The battery system according to claim 1,
The battery cell management device transmits the measurement result to the assembled battery management device according to a command from the assembled battery management device,
The assembled battery management device changes the amount of communication performed with the battery cell management device by changing at least one of a communication frequency and a communication time for causing the battery cell management device to transmit the measurement result. Battery system to let you.
The battery system according to claim 1 or 2,
The battery system includes a plurality of the battery cell groups and a plurality of the battery cell management devices corresponding to the respective battery cell groups,
The assembled battery management device and the plurality of battery cell management devices perform time division wireless communication using a communication slot assigned to each battery cell management device,
The battery pack management device changes the amount of communication with the battery cell management device by changing at least one of the number and the length of the communication slots based on the estimation result of the state of charge. system.
The battery system according to claim 1 or 2,
The battery cell group is composed of one battery cell,
The battery cell management device is a battery system provided corresponding to one battery cell constituting the battery cell group.
The battery system according to claim 1 or 2,
The battery cell group is composed of a plurality of battery cells,
The battery cell management device includes a selection circuit that selects, from the plurality of battery cells, a battery cell that receives power supply when transmitting the measurement result to the assembled battery management device,
The battery pack management device instructs the battery cell management device to select a battery cell to be selected by the selection circuit based on the estimation result of the state of charge.