WO2021192428A1

WO2021192428A1 - Battery monitoring device

Info

Publication number: WO2021192428A1
Application number: PCT/JP2020/045182
Authority: WO
Inventors: 鈴木　潤; 大高工
Original assignee: 日立Astemo株式会社
Priority date: 2020-03-26
Filing date: 2020-12-04
Publication date: 2021-09-30
Also published as: CN115298923A; JPWO2021192428A1

Abstract

This battery monitoring device comprises: a plurality of voltage detection circuits which are provided corresponding to a plurality of battery modules connected in series and detect the voltages of a plurality of battery cells constituting each battery module as cell voltages; a control circuit which controls the charging state of the plurality of the battery cells by communicating with the voltage detection circuit by means of a communication method other than DG communication; and a discharging means provided corresponding to each battery cell for discharging each battery cell. The control circuit instructs the voltage detection circuit to discharge the battery cell at the end by using the discharging means in the connection relationship of each battery cell in one battery module, thereby identifying the other battery module adjacent to the battery module so as to discharge the battery cell in the connection relationship.

Description

Battery monitoring device

The present invention relates to a battery monitoring device.
The present application claims priority based on Japanese Patent Application No. 2020-055526 filed in Japan on March 26, 2020, the contents of which are incorporated herein by reference.

Patent Document 1 below discloses a voltage detection device in which a plurality of voltage detection circuits provided corresponding to each battery module of a battery are connected in series to a microcomputer by a communication line. In this voltage detection device, a plurality of voltage detection circuits and a microcomputer perform daisy communication via a communication line, so that the detection voltage of each voltage detection circuit is transmitted to the microcomputer.

Japanese Patent Application Laid-Open No. 2015-136255

By the way, in DG communication, the order of detection voltages received by a control device such as a microcomputer depends on the connection order of each voltage detection circuit. Therefore, the control device can relatively easily grasp the connection order of each voltage detection circuit, that is, the connection order of each battery module.

However, in communication methods other than DG communication, such as wireless communication, the order of detection voltages received by the control device does not have a fixed relationship with the connection order of each voltage detection circuit. Therefore, there is a problem that the control device cannot easily grasp the connection order of each battery module.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery monitoring device capable of easily grasping the connection order of a plurality of battery modules in a communication method other than DG communication.

In order to achieve the above object, the present invention has adopted the following aspects.
(1) That is, the battery monitoring device according to one aspect of the present invention is provided corresponding to each of a plurality of battery modules connected in series, and measures the voltages of the plurality of battery cells constituting each battery module. A plurality of voltage detection circuits that detect each as a voltage; a control circuit that controls the charging state of the plurality of the battery cells by communicating with the voltage detection circuit by a communication method other than daisy communication; and each of the battery cells. The control circuit comprises a discharge means provided corresponding to each of the battery cells for discharging; the control circuit connects the battery cells at the ends in the connection relationship of the battery cells in one battery module. By instructing the voltage detection circuit to discharge by the discharging means, another battery module adjacent to the battery module is specified so as to discharge the battery cell in the connection relationship.

(2) In the battery monitoring device according to (1) above, the following configuration may be adopted: each of the voltage detection circuits includes a non-volatile memory in which an identification code is stored; , The identification code is received from all the voltage detection circuits at the time of connection with each of the voltage detection circuits; based on the identification code, each of the battery modules is connected to each of the battery cells in a connection relationship. An instruction is given to discharge the battery cell at least at either end, and at that time, based on a variation in parameters detected by the voltage detection circuit of the other battery module other than the instruction for discharging. Identify other adjacent battery modules.

(3) In the battery monitoring device according to (1) or (2) above, the following configuration may be adopted: the voltage detection circuit is the voltage of the battery cell at the end of each battery module. The battery at the end of each battery module is detected when the control circuit discharges the battery cell at the end of each battery module. Other adjacent battery modules are identified based on cell voltage fluctuations.

(4) In the battery monitoring device according to (1) or (2) above, the following configuration may be adopted: the voltage detection circuit is parallel to the battery cell at the end of each battery module. The control circuit comprises a parameter variation based on the current detected by the current detector when the battery cell at the end of each battery module is discharged. , Identify other adjacent battery modules.

(5) In the battery monitoring device according to any one of (1) to (4) above, the communication method may be wireless communication.

According to the above aspect of the present invention, it is possible to provide a battery monitoring device capable of easily grasping the connection order of a plurality of battery modules in a communication method other than DG communication.

It is a block diagram which shows the functional structure of the battery monitoring apparatus A which concerns on one Embodiment of this invention. It is a flowchart which shows the operation of the battery monitoring apparatus A. In the same embodiment, it is a schematic diagram which shows the fluctuation of the cell voltage when the specific battery cell Ca is forcibly discharged. In the same embodiment, it is a schematic diagram which shows the fluctuation of the cell voltage when the specific battery cell Ca is forcibly discharged.

Hereinafter, the battery monitoring device according to the embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the battery monitoring device A according to the present embodiment includes a plurality of voltage detection circuits D1 to Dn and one control circuit M, and detects the voltage of the assembled battery B to detect the voltage of the assembled battery B. Control the charging status. The battery monitoring device A controls the state of charge of the assembled battery B mounted on a vehicle such as an electric vehicle or a hybrid vehicle. In the description of this embodiment, "n" indicates a natural number.

The assembled battery B is a secondary battery mounted on the vehicle as a high-voltage power source, and can be charged and discharged freely. The assembled battery B has a plurality of battery modules J1 to Jn connected in series, and outputs a DC voltage of, for example, several hundred volts. Each of the plurality of battery modules J1 to Jn has a plurality of battery cells C connected in series, and outputs a DC voltage corresponding to the number of battery cells C. The plurality of battery cells C are single batteries, and each of them outputs a DC voltage of about several volts.

The assembled battery B outputs a high voltage (DC voltage) of, for example, several hundred volts according to the number of battery modules, that is, the number of battery cells C. The assembled battery B needs to accurately control the charge / discharge state, unlike a secondary battery that outputs a relatively low DC voltage such as a lead storage battery mounted on a general vehicle. The assembled battery B is, for example, a lithium ion battery.

The plurality of voltage detection circuits D1 to Dn are provided corresponding to each of the plurality of battery modules J1 to Jn described above. The plurality of voltage detection circuits D1 to Dn are the output voltages of the plurality of battery cells C constituting each of the battery modules J1 to Jn, that is, the inter-terminal voltage (cell voltage) between the positive terminal and the negative end of each battery cell C. ) Are detected respectively. That is, the first voltage detection circuit D1 is connected to the first battery module J1, the second voltage detection circuit D2 is connected to the second battery module J2, ..., The nth voltage detection circuit Dn is the nth battery module Jn. It is connected to the.

Each of these voltage detection circuits D1 to Dn has a wireless communication function for wireless communication with the control circuit M, and transmits the detected cell voltage to the control circuit M by a predetermined wireless communication method. That is, in the present embodiment, a wireless communication method is adopted as a communication method other than DG communication.
Each of the voltage detection circuits D1 to Dn includes discharge circuits (discharge means) CH1 to CH8 associated with each battery cell C. When each voltage detection circuit D1 to Dn receives a control command from the control circuit M, each voltage detection circuit D1 to Dn forcibly discharges each battery cell C.

A fluctuation detection circuit K is provided in each of the voltage detection circuits D1 to Dn. As shown in the figure, these fluctuation detection circuits K are provided corresponding to the battery cells C (one) at the low voltage side end, and amplify the signal for detecting the voltage (cell voltage) of the battery cells C. An amplifier for this purpose, or a current detector provided in parallel with the battery cell C. The fluctuation detection circuit K detects fluctuations in the cell voltage of the battery cells C (one) at the low voltage side end or fluctuations in the cell current flowing through the battery cells C.

An individual identification number is assigned to each of the plurality of voltage detection circuits D1 to Dn. This individual identification number is an identification code uniquely set in advance for each of the voltage detection circuits D1 to Dn, and is stored in advance in the non-volatile memory provided in each voltage detection circuits D1 to Dn. .. Each voltage detection circuit D1 to Dn is a communication node (CMU node) in wireless communication with the control circuit M, and by performing wireless communication with the control circuit M using an individual identification number, the control circuit M can be used. Let them identify themselves (individuals).

The control circuit M is a microcomputer that controls the charging state of the assembled battery B, that is, a plurality of battery cells C by communicating with each of the voltage detection circuits D1 to Dn (CMU node) by the above-mentioned predetermined wireless communication method. .. That is, the control circuit M detects the charged state of the assembled battery B, that is, each battery cell C, based on the cell voltage received from the voltage detection circuits D1 to Dn (CMU node) via wireless communication. Further, the control circuit M controls the charging state of the assembled battery B by transmitting a control command generated based on the detection result to each voltage detection circuits D1 to Dn (CMU node) via wireless communication. ..

The control circuit M includes a non-volatile memory in which a control program and various control data are stored, a calculation unit that executes calculations based on the control program, a volatile memory that temporarily stores the calculation results of the calculation unit, and voltage detection. A communication unit or the like that performs wireless communication with circuits D1 to Dn (CMU node) is provided.

The control circuit M acquires the above-mentioned individual identification number from each of the voltage detection circuits D1 to Dn (CMU node), and is individually connected to each voltage detection circuit D1 to Dn (CMU node) based on the individual identification number. Wireless communication is performed. Although not shown, the control circuit M is connected to the upper control system of the vehicle by wired communication.

The control circuit M can perform wireless communication that identifies (identifies) an individual of each voltage detection circuit D1 to Dn (CMU node) by using the individual identification number as described above. However, the control circuit M stores control data indicating individual identification numbers of the voltage detection circuits D1 to Dn (CMU node) before performing wireless communication with the voltage detection circuits D1 to Dn (CMU node). Not. Further, the control circuit M does not store control data indicating the connection positions of the voltage detection circuits D1 to Dn (CMU nodes) with respect to the battery modules J1 to Jn.

That is, the control circuit M has an individual identification number (first individual identification number) of the first voltage detection circuit D1 (CMU node) and an individual identification number (second individual identification number) of the second voltage detection circuit D2 (CMU node). , ..., The individual identification number (nth individual identification number) of the nth voltage detection circuit Dn (CMU node) is not recognized at the initial stage.
Further, in the control circuit M, the first voltage detection circuit D1 (CMU node) is connected to the first battery module J1, and the second voltage detection circuit D2 (CMU node) is connected to the second battery module J2. The connection position such as is not recognized.

Therefore, the control circuit M initially determines which battery module J1 to Jn the cell voltage acquired from each voltage detection circuit D1 to Dn (CMU node) is related to among the plurality of battery modules J1 to Jn connected in series. I can't recognize it. It is indispensable for the control circuit M to recognize the individual identification number and the connection position in order to control the charge / discharge state of the assembled battery B.

Next, the operation of the battery monitoring device A for recognizing the connection position will be described with reference to the flowchart of FIG.

When the ignition switch (IG) of the vehicle changes from the "OFF" state to the "ON" state, this state change is notified from the upper control system to the control circuit M. When the control circuit M recognizes this "IG ON" (step S1), it determines whether or not the connection positions of the battery modules J1 to Jn with respect to the voltage detection circuits D1 to Dn have been recognized (step S2). ..

That is, since the process of FIG. 2 is executed even at the time of "IG ON" in the past, the control data (connection position data) indicating the connection position described above is stored in the non-volatile memory of the control circuit M. On the other hand, at the time of "IG ON" for the first time, the process of FIG. 2 is not executed.

Due to such circumstances, the control circuit M confirms whether or not the connection position data is stored in the non-volatile memory, and if the connection position data is stored, the determination in step S2 is set to "Yes". If the connection position data is not stored, the determination in step S2 is set to "No". Then, when the determination in step S2 is "Yes", the control circuit M ends all the processing. On the other hand, when the determination in step S2 is "No", it is determined whether or not the pairing instruction is received from the upper control system (step S3).

The determination in step S3 is "Yes" when the control circuit M has already received the pairing instruction from the host control system and is stored in the non-volatile memory, and when the pairing instruction is not stored in the non-volatile memory. Is "No".
If the determination in step S3 is "Yes", the process proceeds to step S4, and the control circuit M receives a pairing instruction (BMU pairing instruction) from the host control system. Then, the control circuit M transmits a request for acquiring the individual identification number to all the voltage detection circuits D1 to Dn (all CMU nodes) (step S5). On the other hand, if the determination in step S3 is "No", the determination in step 3 is performed again.

After step S5, the process proceeds to step S6. In step S6, when the control circuit M receives the individual identification number from all the voltage detection circuits D1 to Dn (all CMU nodes), the control circuit M determines “Yes” and proceeds to step S7. On the other hand, if the determination in step S6 is "No", the determination in step 6 is performed again.
In step S7, one of the voltage detection circuits D1 to Dn (CMU node) is individually selected, and the discharge circuit corresponding to the specific battery cell C is provided for the selected voltage detection circuit (CMU node). By operating the battery cell C, the specific battery cell C is forcibly discharged.

The specific battery cell C is a battery cell C (one) at the high voltage side end in the connection relationship of the plurality of battery cells C in each battery module J1 to Jn. For example, when the second voltage detection circuit D2 (second CMU node) is individually selected, the control circuit M is a battery located at the high voltage side end in the second battery module J2 connected to the second voltage detection circuit D2. The cell C, that is, the battery cell C located on the highest potential side of the plurality of battery cells C connected in series is forcibly discharged as the specific battery cell C.

Due to such forced discharge of the specific battery cell C, the battery cells C adjacent to the specific battery cell C in the connection relationship of the plurality of battery modules J1 to Jn constituting the assembled battery B, that is, the plurality of battery cells C. The cell voltage or cell current of (adjacent battery cell) fluctuates from the original cell voltage or cell current.

As shown in FIG. 3A, for example, when the battery cell Ca at the high voltage side end of the second battery module J2 is forcibly discharged as a specific battery cell C in the second voltage detection circuit D2 (second CMU node), this The cell voltage or cell current of the battery cell C at the low voltage side end of the first battery module J1 (another battery module) adjacent to the high voltage side of the battery cell Ca changes.

Following step S7, the process proceeds to step S8. In step S8, the control circuit M is connected in one battery module connected to one voltage detection circuit (CMU node) individually selected from the voltage detection circuits D1 to Dn (CMU node) in this way. When the battery cell C at the end is discharged, it is determined whether or not the cell voltage or cell current fluctuates in the battery cell C at the end on the high voltage side based on the detection result of the fluctuation detection circuit K.
Then, when the fluctuation of the voltage or the cell current occurs (step S8: Yes), the control circuit M proceeds to step S9. In step S9, another battery module (adjacent node) adjacent to the changed battery cell C is recognized. After step S9, the process proceeds to step S11.

Here, as shown in FIG. 3B, when the battery cell C at the high voltage side end of the first battery module J1 connected to the first voltage detection circuit D1 (first CMU node) is forcibly discharged, the height is said to be high. There is no other battery module adjacent to the high voltage side of the battery cell C at the end of the voltage side. Therefore, in this case, the cell voltage or cell current of the battery cell C does not fluctuate with respect to the other battery modules. That is, in this case, the determination in step S8 is "No".

In such a case, the process proceeds from step S8 to step S10.
In step S10, the control circuit M assigns one voltage detection circuit (CMU node) to the highest level node, that is, the battery module located at the highest level in the connection position among the plurality of battery modules J1 to Jn in the assembled battery B. Recognize that it is a connected MCU node.

Then, when the processing up to step S10 is completed for one voltage detection circuit (CMU node) individually selected in step S7, the control circuit M proceeds to step S11. In step S11, it is determined whether or not the processes up to step S10 have been completed for all of the plurality of battery modules J1 to Jn. If the result is "No" in step S11, the process returns to step S7. On the other hand, if "Yes" in step S11, the process ends.
The control circuit M specifies the positional relationship of all the battery modules J1 to Jn constituting the assembled battery B by repeating the processes of steps S7 to S10 for all the battery modules J1 to Jn (all CMU nodes).

According to the present embodiment, among the plurality of battery modules J1 to Jn constituting the assembled battery B, the battery cell C at the end of the connection relationship of the battery cell C in one battery module is forcibly discharged to discharge the battery cell C. It is possible to identify another battery module adjacent to one battery module in the connection relationship. Therefore, according to the present embodiment, it is possible to easily grasp the connection order of the plurality of battery modules J1 to Jn in a wireless communication method other than DG communication.

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, in the connection relationship of a plurality of battery cells C in the battery module, the battery cell C (one) at the high voltage side end is set as a specific battery cell C, but this is the only one in the present invention. Not limited to. In the connection relationship of a plurality of battery cells C in the battery module, instead of using the battery cell C (one) at the high voltage side end as a specific battery cell C, the connection of the plurality of battery cells C in the battery module. In relation to this, the battery cell C (1 piece) at the low voltage side end may be used as the specific battery cell C.

In this case, the cell voltage or cell current of the battery cell C at the high voltage side end of the other battery module adjacent to the low voltage side of the specific battery cell C changes. The control circuit M can identify another battery module adjacent to the low voltage side based on the fluctuation of the cell voltage or the cell current of the battery cell C at the high voltage side end.

(2) Further, in the connection relationship of the plurality of battery cells C in the battery module, instead of using the battery cell C (one) at the high voltage side end as a specific battery cell C, a plurality of batteries in the battery module. In the connection relationship of the cells C, the battery cells C (two) at the high voltage side end and the low voltage side end may be designated as the specific battery cells C.

In this case, the cell voltage or cell current of the battery cell C at the low voltage side end of the other battery module adjacent to the high voltage side and the high voltage side end of the other battery module adjacent to the low voltage side. The cell voltage or cell current of the battery cell C fluctuates. The control circuit M can simultaneously identify two other battery modules adjacent to the high voltage side and the low voltage side based on the fluctuation of the cell voltage or the cell current of the two other battery modules. ..

(3) In the above embodiment, based on the fluctuation of the cell voltage or the cell current detected when the battery cell C at the end is discharged in the connection relationship of the plurality of battery cells C in each battery module J1 to Jn. Other battery modules have been identified, but the invention is not limited to this. For example, other battery modules may be identified based on fluctuations in the internal impedance of the battery cell C in place of fluctuations in cell voltage or cell current, or in addition to fluctuations in cell voltage or cell current.

(4) In the above embodiment, a wireless communication method is adopted as a communication method other than DG communication, but the present invention is not limited to this. For example, a network communication method such as CAN may be adopted.

A Battery monitoring device B group battery C Battery cell CH1 to CH8 Discharge circuit (discharge means)
D1 to Dn voltage detection circuit J1 to Jn battery module M control circuit K fluctuation detection circuit

Claims

A plurality of voltage detection circuits provided corresponding to each of a plurality of battery modules connected in series and detecting the voltages of the plurality of battery cells constituting each battery module as cell voltages;
With a control circuit that controls the charging state of a plurality of the battery cells by communicating with the voltage detection circuit by a communication method other than DG communication;
With the discharging means provided corresponding to each battery cell for discharging each battery cell;
With
By instructing the voltage detection circuit that the control circuit discharges the battery cells at the ends by the discharging means in the connection relationship of the battery cells in one battery module.
A battery monitoring device comprising identifying another battery module adjacent to the battery module so as to discharge the battery cell in the connection relationship.
Each of the voltage detection circuits has a non-volatile memory in which the identification code is stored;
When the control circuit is connected to each of the voltage detection circuits, the control circuit receives the identification code from all the voltage detection circuits;
Based on the identification code, each of the battery modules is instructed to discharge the battery cells at least at both ends in the connection relationship of the battery cells, and at that time, the discharge instruction is given. The other adjacent battery module is identified based on the variation of the parameters detected by the voltage detection circuit of the other battery module other than the above.
The battery monitoring device according to claim 1.
The voltage detection circuit comprises an amplifier at the end of each battery module that amplifies a signal that detects the voltage of the battery cell;
Other adjacent batteries based on fluctuations in the voltage of the battery cell at the end of each battery module detected when the control circuit discharges the battery cell at the end of each battery module. Identify the battery module;
The battery monitoring device according to claim 1 or 2.
The voltage detection circuit comprises a current detector provided in parallel with the battery cell at the end of each battery module;
The control circuit identifies other adjacent battery modules by varying parameters based on the current detected by the current detector when the battery cells at the ends of each battery module are discharged;
The battery monitoring device according to claim 1 or 2.
The battery monitoring device according to any one of claims 1 to 4, wherein the communication method is wireless communication.