JP7537486B2 - Battery control device and vehicle - Google Patents

Description

This disclosure relates to a battery control device and a vehicle.

In recent years, leasing companies that lease vehicles may re-lease or sell leased vehicles after the lease period expires.

If the leased vehicle is an electric vehicle (EV) equipped with a battery used for driving the vehicle, the battery's lifespan will affect the residual value. The battery's lifespan will vary depending on the battery's usage and type.

Batteries deteriorate as they are repeatedly charged and discharged. One parameter that quantifies the degree of deterioration of a battery is SOH (State of Health). SOH is, for example, the ratio of the maximum amount of power at the time of deterioration to the initial (shipped) maximum amount of power, which is taken as 100%. The maximum amount of power of a battery decreases as the battery is repeatedly charged and discharged.

For example, a battery control device has been disclosed that calculates the battery capacity value of a battery and calculates the degree of deterioration of the battery by dividing the calculated battery capacity value by an initial value of the battery capacity (see, for example, Patent Document 1).

JP 2019-105589 A

Since the battery's lifespan affects its residual value, if it were possible to grasp the degree of battery deterioration during the lease period, it would be possible to increase the battery's value by taking measures to extend its life. However, there is a problem in that there is no effective way to predict the degree of battery deterioration.

The objective of the present disclosure is to provide a battery control device and vehicle that can predict the degree of battery deterioration.

In order to achieve the above object, a battery control device according to the present disclosure includes:
an acquisition unit that acquires frequency data relating to the frequency of each of a plurality of deterioration factors that deteriorate the battery when the battery is charged;
a degradation map showing a relationship between the degradation factors and a degradation rate, which is a rate at which the battery deteriorates;
a deterioration degree prediction unit that predicts a first deterioration degree of the battery based on the frequency data and the deterioration map;
a deterioration level calculation unit that calculates a second deterioration level of the battery based on a predetermined parameter;
a correction unit that corrects the deterioration map based on the first deterioration degree and the second deterioration degree;
Equipped with
the frequency data is data on a frequency of accumulating, for a certain period of time, the power consumption when charging the battery, the state of charge of the battery, and the temperature of the battery, which are the deterioration factors;
the deterioration map indicates a correspondence relationship between the power consumption and the state of charge of the battery and a deterioration rate, and is provided corresponding to each of a plurality of temperature sections;
The correction unit corrects the deterioration map for each of the temperature sections .

The vehicle in this disclosure is equipped with the battery control device described above.

This disclosure makes it possible to predict the degree of battery deterioration.

FIG. 1 is a block diagram illustrating a functional configuration of a battery control device according to an embodiment of the present disclosure. FIG. 2 is a diagram showing an example of frequency data corresponding to battery temperature categories. FIG. 3 is a diagram showing an example of a deterioration map corresponding to temperature classifications of a battery. FIG. 4 is a diagram showing an example of the relationship between the maximum power amount of the battery and time. FIG. 5 is a flowchart showing an example of a process for correcting the degradation map.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
1 is a block diagram showing a schematic functional configuration of a battery control device according to an embodiment of the present disclosure. In this embodiment, a battery (not shown) and the control device 1 are mounted on an electric vehicle (EV). The control device 1 monitors the state of the battery, such as the voltage, current, temperature, and remaining capacity of the battery, and performs control for using the battery safely and effectively. Note that a part or the whole of the control device 1 is not limited to being mounted on an electric vehicle.

The control device 1 includes a memory unit 2 and a control unit 3. In FIG. 1, the arrows indicate the main data flows, and there may be data flows not shown in FIG. 1. In FIG. 1, each functional block indicates a functional unit configuration, not a hardware (device) unit configuration. Therefore, the functional blocks shown in FIG. 1 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus or a controller area network (CAN bus).

The storage unit 2 is a storage device such as a ROM (Read Only Memory) that stores the BIOS (Basic Input Output System) of the computer that realizes the control device 1, a RAM (Random Access Memory) that serves as the working area of the control device 1, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores the OS (Operating System), application programs, various information referenced when the application programs are executed, and a degradation map (described later).

The control unit 3 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) of the control device 1, and functions as an acquisition unit 30, a deterioration degree prediction unit 31, a deterioration degree calculation unit 32, and a correction unit 33 by executing the programs stored in the memory unit 2.

Note that FIG. 1 shows an example in which the control device 1 is configured as a single device. However, the control device 1 may be realized by, for example, multiple processors, memory, and other computing resources. In this case, each part that configures the control unit 3 is realized by at least one of the multiple different processors executing a program.

The vehicle control unit 5 determines the vehicle's condition, which constantly changes while the vehicle is in motion, and controls each component, including the control device 1, to maintain the vehicle in an optimal condition.

The control device 1 executes control to charge a battery (not shown) with power from a charger (not shown) and also executes control to supply power from the battery to a motor for driving the vehicle. The battery deteriorates as a result of repeated charging and discharging, and the maximum amount of power of the battery decreases. The battery deteriorates according to the frequency of each of a number of deterioration factors. Here, the multiple deterioration factors include two or more of the power consumption when charging the battery, the battery's state of charge (SOC), and the battery temperature (cell temperature). Each of the multiple deterioration factors is detected by a sensor (not shown). The detection results of the sensor are transmitted to the monitoring unit 4 at a predetermined time interval.

(Acquisition unit 30)
The acquisition unit 30 acquires frequency data relating to the frequency of each of the multiple deterioration elements from the monitoring unit 4. The frequency data acquired by the acquisition unit 30 is stored in the memory unit 2. The temperature range of the battery from low to high is divided into multiple temperature regions (temperature categories). The frequency data is stored in the memory unit 2 for each battery temperature category (C1, C2, ..., Ci, ..., Cz). The low and high temperatures and the number of temperature categories are set by experiments and simulations.

Figure 2 is a diagram showing an example of frequency data corresponding to the temperature category Ci of a battery. The frequency data is arranged in a matrix in both the vertical and horizontal directions. In the horizontal direction, the SOC (%) categories are arranged from small to large in the order of A1, A2, ..., Aj, ..., Am. In the vertical direction, the power consumption (kWh) categories are arranged from small to large in the order of B1, B2, ..., Bk, ..., Bn. For example, frequency data d11 is frequency data corresponding to each of the temperature category Ci, SOC category A1, and power consumption category B1. Frequency data djk is frequency data corresponding to each of the temperature category Ci, SOC category Aj, and power consumption category Bk. Frequency data dmn is frequency data corresponding to each of the temperature category Ci, SOC category Am, and power consumption category Bn.

The frequency data (d11, ..., djk, ..., dmn) corresponding to each of the deterioration elements can be represented by the time corresponding to each of the deterioration elements when charging the battery. Note that the frequency data may be represented by the number of times corresponding to each of the deterioration elements when charging the battery.

In the following explanation, the value obtained by dividing the decrease in the maximum battery power by the frequency data (time) is referred to as the "deterioration rate."

3 is a diagram showing an example of a deterioration map corresponding to the temperature category Ci of a battery. In the deterioration map, the deterioration rates are arranged in a matrix in both the vertical and horizontal directions. In the horizontal direction, the SOC (%) categories are arranged in the order of A1, A2, ..., Aj, ..., Am from small to large, as in the above frequency data. In the vertical direction, the power consumption (kWh) categories are arranged in the order of B1, B2, ..., Bk, ..., Bn from small to large, as in the above frequency data. For example, the deterioration rate V11 is the deterioration rate corresponding to each of the temperature category Ci, the SOC category A1, and the power consumption category B1. The deterioration rate Vjk is the deterioration rate corresponding to each of the temperature category Ci, the SOC category Aj, and the power consumption category Bk. The deterioration rate Vmn is the deterioration rate corresponding to each of the temperature category Ci, the SOC category Am, and the power consumption category Bn. The deterioration map is stored in the storage unit 2.

(Deterioration degree prediction unit 31)
Next, we will explain how to predict the degree of deterioration of a battery (corresponding to the "first deterioration level" of the present disclosure) after a certain period of time has passed since the initial state (at the time of shipment). We will also explain the degree of deterioration of a battery as SOH (State Of Health). Note that the degree of deterioration of a battery is not limited to SOH, and may be something that indicates the degree of deterioration of a battery in stages. Furthermore, prediction of the degree of deterioration of a battery is performed for each vehicle.

Figure 4 is a diagram showing an example of the relationship between the maximum power capacity of the battery and time. In Figure 4, the horizontal axis indicates time, and the vertical axis indicates the maximum power capacity (kWh). As described above, frequency data is stored in the memory unit 2 for each battery temperature category (C1, C2, ..., Ci, ..., Cz). The memory unit 2 accumulates frequency data from the initial state (at the time of shipment) until a certain period of time has passed.

Figure 4 shows the decrease in maximum power consumption Ba, which is the difference between the initial maximum power consumption (at the time of shipment) and the maximum power consumption after a certain period (accumulation period) has elapsed since the initial time (at the time of shipment). SOH is shown as the maximum power consumption after a certain period has elapsed relative to the initial maximum power consumption.

The deterioration prediction unit 31 predicts the deterioration level of the battery based on the frequency data and the deterioration map.

Specifically, the deterioration prediction unit 31 predicts the amount of decrease in the maximum power amount of the battery in a specified temperature range based on the frequency data in the specified temperature range and the deterioration map. Specifically, the deterioration prediction unit 31 multiplies the deterioration rate in the deterioration map by the frequency data (time). The multiplied value becomes the amount of decrease.

In this way, the deterioration prediction unit 31 predicts the amount of decrease in the maximum power amount of the battery for each temperature category based on the frequency data for each temperature category and the deterioration map. Next, the deterioration prediction unit 31 sums up the amount of decrease in the maximum power amount of the battery for each temperature category. The value obtained by subtracting the sum of the decrease amounts from the initial maximum power amount becomes the maximum power amount at the time of deterioration. Note that the initial maximum power amount is stored in the memory unit 2. The value obtained by dividing the maximum power amount at the time of deterioration by the initial maximum power amount becomes the SOH.

(Deterioration degree calculation unit 32)
Next, we will explain how to calculate the deterioration level of the battery (corresponding to the "second deterioration level" of the present disclosure) after a certain period of time has passed since the initial state (time of shipment). The deterioration level calculation unit 32 calculates the deterioration level of the battery based on predetermined parameters. Note that the method of calculating the deterioration level of the battery uses a publicly known method, such as the calculation method described in Patent Document 1, and therefore the description thereof will be omitted.

(Correction unit 33)
The correction unit 33 corrects the deterioration map based on the difference between the deterioration degree predicted by the deterioration degree prediction unit 31 and the deterioration degree calculated by the deterioration degree calculation unit 32. Note that the correction unit 33 may correct the deterioration map based on the magnitude relationship (e.g., ratio) between the deterioration degree predicted by the deterioration degree prediction unit 31 and the deterioration degree calculated by the deterioration degree calculation unit 32.

Next, an example of the correction of the deterioration map will be described. FIG. 4 shows the decrease amount Bb, which is the difference between the initial (shipped) maximum power amount of the battery and the maximum power amount of the battery calculated by the deterioration degree calculation unit 32. The correction unit 33 corrects the deterioration map for each temperature category by dividing the decrease amount Bb by the decrease amount Ba and multiplying the divided value (correction value) by the deterioration rate in the deterioration map for each temperature category. Therefore, the deterioration rate in the deterioration map is faster when the correction value is greater than "1" and is slower when the correction value is less than "1". By correcting the deterioration map, the deterioration rate of the battery can be grasped more accurately, and the life (remaining value) of the battery can be predicted more accurately.

Next, the deterioration map correction process will be described with reference to FIG. 5. FIG. 5 is a flowchart showing an example of the deterioration map correction process. This flow is started by the user performing an input operation after a certain period of time has elapsed since the initial setting (at the time of shipment). Note that the process shown in this flow is executed by each function of the control unit 3 of the control device 1, but here it will be described as being executed by the CPU.

First, in step S100, the CPU acquires frequency data for each of multiple temperature categories from the memory unit 2.

Next, in step S110, the CPU predicts the degree of battery deterioration based on the frequency data for each temperature category and the deterioration map.

Next, in step S120, the CPU calculates the degree of battery deterioration.

Next, in step S130, the CPU calculates the difference between the predicted battery degradation level and the calculated degradation level.

Next, in step S140, the CPU corrects the degradation map. After that, this flow ends.

The battery control device 1 in the above embodiment includes an acquisition unit 30 that acquires frequency data related to the frequency of each of a plurality of degradation factors that degrade the battery when the battery is charged, a degradation map that indicates the relationship between the degradation factors and a degradation rate that is the rate at which the battery deteriorates, a degradation prediction unit 31 that predicts a first degradation level of the battery based on the frequency data and the degradation map, a degradation calculation unit 32 that calculates a second degradation level of the battery based on predetermined parameters, and a correction unit 33 that corrects the degradation map based on the first degradation level and the second degradation level.

With the above configuration, the degree of battery deterioration is predicted based on the corrected deterioration map, making it possible to accurately predict the degree of battery deterioration.

In addition, in the battery control device 1 in the above embodiment, the frequency data is data related to the frequency of accumulated data over a certain period of time regarding the power consumption when charging the battery as degradation factors, the charging state of the battery, and the temperature of the battery. Since the degree of degradation is predicted based on the frequency data related to the degradation factors that affect the degradation of the battery, it is possible to accurately predict the degree of degradation of the battery.

In addition, in the battery control device 1 in the above embodiment, frequency data is accumulated for each of a plurality of temperature divisions, and the correction unit 33 does not need to correct the deterioration map for a temperature division if frequency data for the temperature division is not accumulated. This makes it possible to more accurately predict the degree of deterioration of the battery, since frequency data that has not affected the deterioration of the battery is not used to correct the deterioration map.

In addition, in the battery control device 1 in the above embodiment, the correction unit 33 corrects the degradation map when the difference between the first degradation level and the second degradation level exceeds a predetermined range. This makes it possible to prevent unnecessary correction of the degradation map from being performed, since the degradation map is not corrected when the difference does not exceed the predetermined range.

In the above embodiment, the deterioration level of the battery (corresponding to the "first deterioration level" of the present disclosure) is predicted after a certain period of time has elapsed since the initial state (at the time of shipment), and the deterioration map (initial deterioration map) is corrected based on the difference between the predicted deterioration level and the calculated deterioration level. However, the present disclosure is not limited to this, and the correction unit 33 may periodically correct the deterioration map. Since the deterioration level of the battery is predicted based on the deterioration map that is periodically corrected, it becomes possible to periodically correct the prediction accuracy of the deterioration level. In the case of periodically predicting the deterioration level of the battery, for example, when predicting the deterioration level for the second time, the deterioration may be predicted based on the frequency data accumulated in the period between the first and second times, and the deterioration map corrected for the first time.

In addition, the above embodiments are merely examples of concrete ways of implementing the present disclosure, and the technical scope of the present disclosure should not be interpreted in a limiting manner based on them.

In other words, the present disclosure can be implemented in various forms without departing from its essence or main characteristics.

This disclosure is suitable for use in electric vehicles equipped with a battery control device that is required to predict the degree of battery deterioration.

Reference Signs List 1 Control device 2 Storage unit 3 Control unit 4 Monitoring unit 5 Vehicle control unit 30 Acquisition unit 31 Deterioration degree prediction unit 32 Deterioration degree calculation unit 33 Correction unit

Claims (5)

an acquisition unit that acquires frequency data relating to the frequency of each of a plurality of deterioration factors that deteriorate the battery when the battery is charged;
a degradation map showing a relationship between the degradation factors and a degradation rate, which is a rate at which the battery deteriorates;
a deterioration degree prediction unit that predicts a first deterioration degree of the battery based on the frequency data and the deterioration map;
a deterioration level calculation unit that calculates a second deterioration level of the battery based on a predetermined parameter;
a correction unit that corrects the deterioration map based on the first deterioration degree and the second deterioration degree;
Equipped with
the frequency data is data on a frequency of accumulating, for a certain period of time, the power consumption when charging the battery, the state of charge of the battery, and the temperature of the battery, which are the deterioration factors;
the deterioration map indicates a correspondence relationship between the power consumption and the state of charge of the battery and a deterioration rate, and is provided corresponding to each of a plurality of temperature sections;
The correction unit corrects the deterioration map for each of the temperature sections .
Battery control device. The frequency data is accumulated according to each of a plurality of temperature sections,
the correction unit does not correct the deterioration map for the temperature division when the frequency data for the temperature division is not stored.
The battery control device according to claim 1 . The correction unit periodically corrects the deterioration map.
The battery control device according to claim 1 . the correction unit corrects the deterioration map when a difference between the first deterioration level and the second deterioration level exceeds a predetermined range.
The battery control device according to claim 1 . A vehicle comprising the battery control device according to claim 1 .