JP2022144569A - battery control system - Google Patents

Abstract

To provide a battery control system capable of suppressing the progression of deterioration of a battery with a small State of Health (SOH) in an assembled battery.SOLUTION: A battery control system 1 includes an assembled battery 2 mounted on a vehicle and including a plurality of batteries 3a to 3n arranged in series, a charge/discharge control unit 36 that controls charging and discharging of the plurality of batteries 3a to 3n, and an SOH calculation unit 34 that obtains the SOH of each of the plurality of batteries 3a to 3n. The charge/discharge control unit 36 specifies a battery with the smallest SOH from among the plurality of batteries 3a to 3n, and limits charging and discharging of the plurality of batteries 3a to 3n.SELECTED DRAWING: Figure 1

Description

The present invention relates to a battery control system that controls charging and discharging of a battery mounted on a vehicle.

A vehicle is equipped with a battery control system including an assembled battery in which a plurality of batteries are arranged. A SOH (State Of Health) of the assembled battery is required from the viewpoint of controlling charging and discharging of the assembled battery. In order to suppress deterioration of the battery, charging and discharging are restricted based on the obtained SOH of the assembled battery.

WO2013/94057

By the way, since the SOH of the assembled battery is obtained by averaging the SOH of each battery, variations in the SOH of each battery are not considered. For this reason, if charging and discharging are restricted based on the SOH of the assembled battery, it may not be possible to suppress the deterioration of batteries with small SOH.

Accordingly, the present invention has been made in view of these points, and an object of the present invention is to suppress progress of deterioration of batteries having a small SOH in the assembled battery.

In one aspect of the present invention, an assembled battery that is mounted on a vehicle and includes a plurality of batteries arranged in series, a charge/discharge control unit that controls charging and discharging of the plurality of batteries, and an SOH calculation unit that obtains each SOH (State Of Health), and the charge/discharge control unit specifies a battery with the smallest SOH among the plurality of batteries, and charges and discharges the plurality of batteries. A battery control system is provided that limits discharge.

Further, the charge/discharge control unit may limit charging and discharging of the plurality of batteries so as to suppress deterioration of the battery having the smallest SOH among the plurality of batteries.

In addition, when charging the plurality of batteries by power generation during idling of the vehicle, the charge/discharge control unit charges the plurality of batteries based on the battery having the smallest SOH among the plurality of batteries. may be restricted.

Further, the SOH calculation unit may obtain the SOH of each battery while the plurality of batteries are being charged with current of a predetermined value when the system is started.

ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that progress of deterioration of the battery with small SOH in an assembled battery can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram for demonstrating the structure of the battery control system 1 which concerns on one embodiment. FIG. 3 is a schematic diagram for explaining variations in SOH of a plurality of batteries; 4 is a flowchart for explaining an example of an operation of the battery control device 10;

<Configuration of battery control system>
A configuration of a battery control system according to one embodiment will be described with reference to FIG.

FIG. 1 is a schematic diagram for explaining the configuration of a battery control system 1 according to one embodiment. The battery control system 1 is installed, for example, in a hybrid vehicle having an engine and a motor as power sources. The battery control system 1 includes an assembled battery 2, a sensor group 5, and a battery control device 10, as shown in FIG.

The assembled battery 2 is a battery pack including a plurality of cells 3a to 3n, and is mounted on a vehicle. Batteries 3a-3n are the same battery and are arranged in series. The batteries 3a to 3n are charged by receiving power generated by the motor. Also, the batteries 3a to 3n are discharged in order to supply electric power to each part of the vehicle.

A sensor group 5 detects the state of the vehicle. The sensor group 5 includes, for example, temperature sensors that detect the temperatures of the batteries 3a to 3n and sensors that detect the travel distance of the vehicle. The sensor group 5 outputs detection results to the battery control device 10 .

The battery control device 10 controls charging and discharging of the batteries 3a to 3n of the assembled battery 2. FIG. For example, the battery control device 10 controls charging and discharging so that deterioration of the batteries 3a to 3n does not proceed. Although the details will be described later, the battery control device 10 obtains the SOH (State Of Health) of each battery in the assembled battery 2 with a constant current value, and charges and charges the batteries 3a to 3n based on the obtained SOH of each battery. Control discharge. As a result, when the SOH of some of the batteries 3a to 3n arranged in series is low, the deterioration of the entire assembled battery 2 can be suppressed by controlling the charging and discharging according to the battery with the low SOH. .

The battery control device 10 has a storage unit 20 and a control unit 30, as shown in FIG.
The storage unit 20 includes, for example, ROM (Read Only Memory) and RAM (Random Access Memory). The storage unit 20 stores programs and various data for the control unit 30 to execute.

The control unit 30 is, for example, a CPU (Central Processing Unit). The control unit 30 functions as a reference information acquisition unit 32 , an SOH calculation unit 34 , a charge/discharge control unit 36 and a replacement determination unit 38 by executing programs stored in the storage unit 20 .

The reference information acquisition unit 32 acquires reference information when calculating the SOH of the batteries 3a to 3n. For example, the reference information acquisition unit 32 acquires reference information from the detection results of the sensor group 5 . For example, the reference information acquisition unit 32 acquires the travel distance of the vehicle and the temperatures of the batteries 3a to 3n as the reference information.

The SOH calculator 34 calculates the SOH of the batteries 3 a to 3 n of the battery pack 2 . In this embodiment, the SOH calculator 34 obtains the SOH of each of the batteries 3a to 3n instead of the SOH of the assembled battery 2. FIG. The SOH calculator 34 obtains the SOH as the degree of deterioration of each battery, for example, from the current value and voltage value of each battery.

The SOH calculation unit 34 obtains the SOH of each battery while the plurality of batteries 3a to 3n are being charged with current of a predetermined value when the system is started. When the batteries 3a to 3n are charged with a predetermined current, the change in the actual current flowing through the batteries 3a to 3n is small and stable, so the SOH of each battery can be obtained with high accuracy. More specifically, when the actual current flowing through the batteries 3a to 3n varies greatly, the temperature rise rate of each battery tends to vary, so the SOH, which is affected by temperature, cannot be obtained with high accuracy. On the other hand, when the change in the actual current is small as in the present embodiment, the variation in temperature rise rate can be eliminated, so the SOH of each battery can be obtained with high accuracy.

The SOH calculator 34 may calculate the SOH of each battery in a state where the batteries 3a to 3n are being charged by generating power when the system is started. For example, the SOH calculation unit 34 obtains the SOH of each battery when the batteries 3a to 3n are charged with electric power generated by the motor while the vehicle is idling.

The SOH calculation unit 34 may refer to the reference information acquired by the reference information acquisition unit 32 and obtain the SOH of each battery at the timing when the deterioration of the battery is progressing. The SOH calculator 34 obtains the SOH of each battery when it is determined from the reference information that the SOH calculation condition is satisfied. For example, the SOH calculator 34 obtains the SOH of each battery when the system is started after the vehicle has traveled a predetermined distance (eg, 10000 km). This eliminates the need to obtain the SOH of each battery each time the system is started, and the SOH is obtained when there is a possibility that the battery has deteriorated.

In the above description, the SOH calculation unit 34 obtains the SOH of each battery by fixing the current value flowing through the batteries 3a to 3n. you may ask.

A charge/discharge control unit 36 controls charging and discharging of the plurality of batteries 3a to 3n. For example, the charge/discharge control unit 36 controls charging and discharging of the batteries 3a to 3n based on the SOH of each battery obtained by the SOH calculation unit 34. FIG. This makes it possible to accurately control charging and discharging of the batteries 3a to 3n based on the SOH of each battery determined with high accuracy.

The charge/discharge control unit 36 limits charging and discharging so that deterioration of the batteries 3a to 3d arranged in series does not progress. This is because when a plurality of batteries 3a to 3n are arranged in series, if the deterioration of one battery progresses, the other batteries will also deteriorate, and the assembled battery 2 cannot be used.

By the way, the SOH of the plurality of batteries 3a to 3n are not the same, and variations occur. This is because the temperature affecting the SOH changes according to the position of the battery in the assembled battery 2 in which the batteries 3a to 3n are arranged in series.

FIG. 2 is a schematic diagram for explaining variations in SOH among a plurality of batteries 3a to 3d.
For convenience of explanation, FIG. 2 shows the SOH of four batteries 3a-3d out of the plurality of batteries 3a-3n. The SOH sizes of the batteries 3a to 3d are different from each other. Specifically, the SOH of the battery 3c is the largest, and the SOH of the battery 3b is the smallest. In other words, battery 3b is the most deteriorated.

The charge/discharge control unit 36 limits charging and discharging based on the SOH values of the batteries 3a to 3n obtained by the SOH calculation unit 34. FIG. In this embodiment, the charge/discharge control unit 36 specifies the battery with the smallest SOH among the plurality of batteries 3a-3n, and limits charging and discharging of the plurality of batteries 3a-3n. Specifically, the charge/discharge control unit 36 controls the deterioration of the battery with the smallest SOH among the plurality of batteries 3a to 3n (for example, the battery 3b in FIG. 2). limit the charging and discharging of the batteries 3a-3n. As a result, progress of deterioration of the battery with the smallest SOH can be suppressed, so progress of deterioration of the assembled battery 2 can be suppressed.

When charging the plurality of batteries 3a to 3n by power generation during idling of the vehicle, the charge/discharge control unit 36 selects the plurality of batteries 3a to 3n based on the battery with the smallest SOH among the plurality of batteries 3a to 3n. may limit the charging of As a result, it is possible to suppress deterioration of the batteries 3a to 3n during charging during idling.

The replacement determination unit 38 determines the battery replacement timing based on the SOH of each battery obtained by the SOH calculation unit 34 . For example, the replacement determination unit 38 determines that a battery whose SOH is lower than the threshold needs to be replaced. The replacement determination unit 38 may output information regarding batteries that require replacement. As a result, only the deteriorated battery can be appropriately replaced, so replacement of the entire assembled battery 2 can be prevented. That is, it is possible to prevent replacement of a battery that has not yet deteriorated.

<Example of battery control device operation>
An operation example of the battery control device 10 will be described with reference to FIG.

FIG. 3 is a flowchart for explaining an example of the operation of the battery control device 10. As shown in FIG.
First, the battery control device 10 determines whether or not the plurality of batteries 3a to 3n of the assembled battery 2 are charged or discharged (step S102).

When it is determined in step S102 that the batteries 3a to 3n are not charged or discharged (No), the battery control device 10 waits until charging or discharging is performed. On the other hand, when it is determined in step S102 that the batteries 3a to 3n are charged or discharged (Yes), the SOH calculator 34 of the battery control device 10 obtains the SOH of each of the batteries 3a to 3n (step S104).

Next, the charge/discharge control unit 36 identifies the battery with the lowest SOH among the plurality of batteries 3a to 3n (step S106). For example, in the case shown in FIG. 2, the battery control device 10 identifies battery 3b as the battery with the smallest SOH.

Next, the charge/discharge control unit 36 limits charging and discharging of the batteries 3a to 3n in accordance with the battery specified in step S106 (step S108). In other words, the charge/discharge control unit 36 can limit the deterioration of the most deteriorated battery by limiting charging and discharging in accordance with the most deteriorated battery.

<Effects of this embodiment>
The battery control system 1 of the embodiment described above obtains the SOH of each of the plurality of batteries 3a to 3n arranged in series. In addition, the battery control system 1 identifies the battery with the smallest SOH among the plurality of batteries 3a-3n, and limits charging and discharging of the plurality of batteries 3a-3n.
By limiting the charging and discharging of the plurality of batteries 3a to 3n in accordance with the specified battery, it is possible to suppress further progress of deterioration of the most deteriorated battery. As a result, it is possible to suppress the progression of deterioration of the entire assembled battery 2 in which a plurality of batteries including the battery in question are arranged in series. As a result, it is possible to prevent a battery with a large SOH from becoming unusable.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist thereof. be. For example, all or part of the device can be functionally or physically distributed and integrated in arbitrary units. In addition, new embodiments resulting from arbitrary combinations of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment caused by the combination has the effect of the original embodiment.

1 battery control system 2 assembled battery 3a to 3n battery 34 SOH calculator 36 charge/discharge controller

Claims (4)

an assembled battery mounted on a vehicle and including a plurality of batteries arranged in series;
a charge/discharge control unit that controls charging and discharging of the plurality of batteries;
an SOH calculator that calculates the SOH (State Of Health) of each of the plurality of batteries;
with
The charge/discharge control unit specifies a battery with the smallest SOH among the plurality of batteries, and limits charging and discharging of the plurality of batteries.
Battery control system. The charge/discharge control unit limits charging and discharging of the plurality of batteries so as to suppress deterioration of the battery with the smallest SOH among the plurality of batteries,
The battery control system according to claim 1. The charge/discharge control unit limits charging of the plurality of batteries based on a battery having the smallest SOH among the plurality of batteries when the plurality of batteries is charged by power generation during idling of the vehicle. do,
The battery control system according to claim 1 or 2. The SOH calculation unit calculates the SOH of each battery while the plurality of batteries are being charged with a current of a predetermined value when the system is started.
The battery control system according to any one of claims 1 to 3.

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