WO2023053352A1

WO2023053352A1 - Electric device

Info

Publication number: WO2023053352A1
Application number: PCT/JP2021/036162
Authority: WO
Inventors: 達哉神野; 健次柴田
Original assignee: 本田技研工業株式会社
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2023-04-06
Also published as: JPWO2023053352A1

Abstract

The electric device pertaining to the present invention comprises a battery unit, a power converter for converting an output voltage of the battery unit, a function unit for realizing a prescribed function on the basis of the voltage converted by the power converter, a current detection unit for detecting an electric current from the battery unit to the power converter, and a processor for controlling driving of the power converter, the processor causing the power converter to output an AC voltage and sequentially changing the frequency of the AC voltage, and evaluating the degree of degradation of the battery unit on the basis of a detection result from the current detection unit obtained in the band of the sequentially changed frequency.

Description

electrical equipment

The present invention mainly relates to evaluation of the degree of deterioration of battery units provided in electrical devices.

A battery unit that can be mounted on an electrical device such as a work machine or vehicle needs to be replaced depending on the degree of deterioration (see Patent Document 1).

Japanese Patent No. 5618575

Since the manner in which the battery unit is used may differ depending on the application of the electrical device in which it is mounted, a technique for more appropriately evaluating the degree of deterioration of the battery unit is generally required.

An exemplary object of the present invention is to make it possible to appropriately evaluate the degree of deterioration of a battery unit relatively easily.

A first aspect of the present invention relates to an electrical device, the electrical device comprising:
a battery unit;
an inverter that converts the output voltage of the battery unit;
a functional unit that realizes a predetermined function based on the voltage converted by the inverter;
a current detection unit that detects a current from the battery unit to the inverter;
and a processor for driving and controlling the inverter, wherein
The processor
causing the inverter to output an AC voltage and alternating the frequency of the AC voltage;
The degree of deterioration of the battery unit is evaluated based on the detection result of the current detection section obtained in the frequency band that changes in the order.

According to the present invention, the above evaluation can be appropriately realized.

It is a block diagram which shows the structural example of an electric device. 4 is a flow chart showing an example of a method for evaluating the degree of deterioration of a battery unit; FIG. 10 is a diagram showing an example of a lookup table for evaluation;

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined arbitrarily. Also, the same or similar configurations are denoted by the same reference numerals, and redundant explanations are omitted.

(System configuration)
FIG. 1 is a block diagram showing an example of the configuration of an electrical device 1 according to an embodiment. The electrical device 1 includes a battery unit 11 , a power converter 12 , a functional section 13 , a voltage detection section 14 , a current detection section 15 , a temperature detection section 16 and a processor 17 . The battery unit 11 typically outputs a DC (Direct Current) voltage. A rechargeable secondary battery such as a lithium ion battery can be used for the battery unit 11 . The battery unit 11 may simply be expressed as a battery.

The power converter 12 is configured to be able to convert the output voltage of the battery unit 11 . In this embodiment, the power converter 12 includes a plurality of transistors M1 to M4 provided in series and in parallel, and each of them individually becomes conductive or non-conductive so that the output voltage of the battery unit 11 to AC (Alternating Current) voltage. Power converter 12 may be expressed as an inverter. Known switch elements such as MOS (Metal Oxide Semiconductor) transistors and bipolar transistors may be used for the transistors M1 to M4.

The functional unit 13 realizes a predetermined function based on the voltage converted by the power converter 12. The concept of function includes the function that realizes the application of the electrical device 1, which may be the main function of the electrical device 1 or a sub-function. Such functional unit 13 is connected to power converter 12 as an internal load of electrical device 1 . Additionally, an external load (not shown) may be connectable to power converter 12 via terminal T1 for external connection.

In this embodiment, the electric device 1 is a working machine, and the function is a working function. Examples of work include lawn mowing, snow removal, farm work, and the like. Alternatively, the electrical device 1 may be a vehicle, in which case the function may be a driving function. Alternatively, the electrical device 1 may be a mobile object without wheels (eg, a ship, etc.), in which case the function may be a locomotion function or a propulsion function. That is, the concept of electrical device 1 can include any device that performs a given function based on electrical energy. From another point of view, the electrical device 1 can also be expressed as a CBU (Completely Built-Up) or the like.

Although the details will be described later, the voltage detection unit 14 is configured to detect the output voltage of the power converter 12 . A known voltmeter can be used for the voltage detection unit 14 . Also, the current detection unit 15 is configured to detect the current from the battery unit 11 to the power converter 12 . A known ammeter can be used for the current detector 15 . Also, the temperature detection unit 16 is configured to detect the temperature of the battery unit 11 . A known temperature sensor can be used for the temperature detection unit 16 .

The processor 17 functions as a system controller (or simply a controller) that controls the entire system of the electric device 1, and drives and controls each of the elements included in the electric device 1. Although the details will be described later, the processor 17 sends a sinusoidal control signal to each of the plurality of transistors M1 to M4 by means of, for example, the driver 18, thereby driving and controlling the power converter 12. FIG.

The processor 17 includes a CPU (Central Processing Unit) 171 , a memory 172 and a communication interface 173 . The functions of the processor 17 described here are realized by the CPU 171 developing a predetermined program on the memory 172 and executing it. The concept of the memory 172 can include RAM (Random Access Memory) as well as ROM (Read Only Memory). The program may be read from ROM or via communication interface 173 .

The processor 17 may be composed of a semiconductor device such as an ASIC (Application Specific Integrated Circuit), that is, the functions of the processor 17 may be realized by either hardware or software.

(Regarding the evaluation of the degree of deterioration of the battery unit)
FIG. 2 is a flow chart showing an example of a method for evaluating the degree of deterioration of the battery unit 11. As shown in FIG. Each step of this flow chart is mainly executed by the processor 17 . The outline is to evaluate the degree of deterioration of the battery unit 11 based on the output current of the battery unit 11 while changing the frequency of the AC voltage output by the power converter 12 .

In step S1010 (hereinafter simply referred to as “S1010”; the same applies to other steps described later), the plurality of transistors M1 and the like are controlled to cause the power converter 12 to output an AC voltage. Altering (sweeping) the frequency of the AC voltage. Accordingly, the battery unit 11 outputs AC current to the power converter 12 while changing the frequency. In addition, the frequency may be changed from one of the low frequency and the high frequency to the other, or may be changed so as to reciprocate.

In S1020, the detection results of the voltage detection unit 14 and the current detection unit 15 are acquired for the frequency bands that are sequentially changed in S1010. The voltage detection unit 14 detects the AC voltage output by the power converter 12 while changing the frequency in S<b>1010 described above, and outputs the result to the controller 17 . The current detection unit 15 detects the AC current output by the battery unit 11 while changing the frequency in S1010 and outputs the result to the controller 17 .

Here, as shown in FIG. 1, while the frequency of the AC voltage output by the power converter 12 is changed in order, the current waveform from the battery unit 11 to the power converter 12 fluctuates, and the current value is the current It can be detected by the detection unit 15 . Along with this, the voltage waveform output by the power converter 12 fluctuates, and the voltage value can be detected by the voltage detection unit 14 .

In S1030, the degree of deterioration of the battery unit 11 is evaluated based on the AC voltage (detection result of the voltage detection unit 14) whose frequency changes and the AC current (detection result of the current detection unit 15) therebetween, and the degree of deterioration is evaluated. If satisfies the criteria, this flow chart ends, and if not, the process advances to S1040. The details of the evaluation method will be described later.

In S1040, when it is determined that the degree of deterioration of the battery unit 11 does not satisfy the standard, it is notified that the battery unit 11 needs to be replaced, and this flowchart ends. This notification may be made to the user via a predetermined notification unit (for example, display panel, LED light source, sound source, etc.) that may be provided in the electrical device 1 .

Here, when the battery unit 11 is repeatedly charged and discharged, the battery unit 11 deteriorates. For example, due to denaturation of the electrolyte contained in the battery unit 11, the charging ability and discharging ability may decrease. The degree can be evaluated based on whether the internal impedance of the battery unit 11 (resistance component, reactance component and capacitance component at a certain frequency) satisfies a standard. In the following description, the evaluation of the degree of deterioration of the battery unit 11 may simply be expressed as "evaluation".

In general, the evaluation results of the degree of deterioration can fluctuate depending on the environment. For example, depending on the frequency band of the AC voltage converted and output by the power converter 12, the battery unit 11 may be usable, or the use should be avoided (when the battery unit 11 needs to be replaced). ) is also available. Also, depending on the temperature of the battery unit 11, the battery unit 11 may be usable or should be refrained from being used. Therefore, evaluation may be required to be carried out from multiple perspectives.

As an example, the internal impedance of the battery unit 11 may be calculated to determine whether the battery unit 11 needs to be replaced.

FIG. 3 shows an example of the lookup table Tb1 that is referenced during evaluation. The allowable output power (unit [W (watt)]) of the battery unit 11 can be set in the lookup table Tb1 corresponding to each internal impedance. Lookup table Tb1 includes a plurality of lookup tables corresponding to a predetermined temperature range (for example, -40 to +160 [°C]), from which one corresponding to the detection result of temperature detection unit 16 is selected. It should be referred to as According to the lookup table Tb1, it is possible to determine whether the battery unit 11 can be used based on the power required to drive the function unit 13, for example.

According to this aspect, the evaluation may be performed in a manner suitable for the application of the electrical device 1, that is, the lookup table Tb1 may be set individually. Moreover, according to this aspect, the evaluation is not performed based only on the internal impedance calculated as described above. Therefore, it is possible to specify or estimate the environment (temperature, frequency, etc.) in which the use of the battery unit 11 should be restricted, and the details of the deterioration, for example. Note that the lookup table Tb1 may be expressed as a reference table, a reference map, or the like.

Alternatively/incidentally, evaluation may be performed individually for each of a plurality of frequencies in the frequency band to be evaluated. For example, when the frequency determined to limit the use of the battery unit 11 is higher than the reference (such as when the use of the battery unit 11 should be limited in a band above a predetermined frequency), It may be determined that replacement is required. During such arithmetic processing, correction based on the detection result of the temperature detection unit 16 may be performed.

As another example, the evaluation can be performed based on the internal impedance of the battery unit 11 that can be calculated by Fourier transforming the detection result of the current detection unit 15 . As a result, it is possible to uniformly determine whether the battery unit 11 needs to be replaced based on the internal impedance of the battery unit 11 in the frequency band to be evaluated (for example, several [Hz (hertz)] to several [MHz (megahertz)]). Become. Correction based on the detection result of the temperature detection unit 16 may be performed during such arithmetic processing as well.

As still another example, depending on the degree of deterioration of the battery unit 11, the phase difference between the AC voltage output by the power converter 12 and the AC current detected by the current detection unit 15 may change to an initial value (for example, replacement of the battery unit 11). It is also conceivable that it will fluctuate from the phase difference immediately after). Therefore, the evaluation may be made based on the phase difference between the AC voltage output by the power converter 12 and the AC current detected by the current detector 15 . Alternatively/incidentally, the phase difference between the control mode of the plurality of transistors M1 to M4 and the AC voltage (or AC current) may fluctuate from the initial value. Therefore, as yet another example, the evaluation may be further based on the phase difference with the control signal of the power converter 12 . Also in these cases, correction may be performed based on the detection result of the temperature detection unit 16 .

According to this embodiment, evaluation of the degree of deterioration of the battery unit 11 can be relatively easily and multifaceted, and the evaluation can be performed by the electric device 1 itself without using an external device for evaluation. is possible. Therefore, according to this embodiment, it can be said that the usability of the electric device 1 is also improved.

(others)
Although the names of individual elements described in the above embodiments are expressed based on primary functions in this specification, they may be expressed based on secondary functions. Therefore, the present invention is not strictly limited to those expressions (the expressions can be replaced with similar expressions). In a similar vein, the expression "unit" is used to refer to "component, piece", "member", "structure", "assembly", "circuit". circuit, module)”, “means”, etc., or may be omitted.

(Summary of embodiment)
Some features of the embodiments are summarized as follows:
A first aspect relates to an electrical device (eg, 1), the electrical device includes a battery unit (eg, 11), a power converter (eg, 12) for converting the output voltage of the battery unit, and A function unit (for example, 13) that realizes a predetermined function based on the converted voltage, a current detection unit (for example, 15) that detects current flowing from the battery unit to the power converter, and driving the power converter. and a processor (e.g. 17) for controlling, the processor causing the power converter to output an AC voltage and alternating the frequency of the AC voltage to obtain in the alternating frequency band. and evaluating the degree of deterioration of the battery unit based on the detection result of the current detection unit. According to the first aspect, it is possible to evaluate the degree of deterioration of the battery unit relatively easily and multifacetedly.

In a second aspect, the detection result of the current detection unit is an AC current, and the processor detects AC current based on the phase difference between the AC voltage output by the power converter and the AC current detected by the current detection unit. The evaluation is performed. According to the second aspect, it is possible to more appropriately evaluate the degree of deterioration of the battery unit.

In a third aspect, the processor performs Fourier transform on the detection result of the current detection section to calculate the internal impedance of the battery unit, and performs the evaluation based on the calculation result. According to the third aspect, it is possible to more simply evaluate the degree of deterioration of the battery unit.

A fourth aspect is characterized in that the processor refers to a predetermined lookup table (for example, Tb1) when performing the evaluation. According to the fourth aspect, it is possible to more appropriately evaluate the degree of deterioration of the battery unit.

In a fifth aspect, a temperature detection unit (for example, 16) that detects the temperature of the battery unit is further provided, the lookup table is one of a plurality of lookup tables, and the processor detects a temperature of the plurality of lookup tables. One of the up-tables corresponding to the detection result of the temperature detection unit is selected and referred to. According to the fifth aspect, it is possible to more appropriately evaluate the degree of deterioration of the battery unit.

A sixth aspect is characterized in that the processor notifies that replacement of the battery unit is necessary based on the result of the evaluation. According to the sixth aspect, it becomes possible for the user to replace the battery unit.

A seventh aspect is characterized in that the electric device is a vehicle, and the functional unit implements a driving function. According to the seventh aspect, the above-described evaluation method can be adopted in a typical vehicle.

An eighth aspect is characterized in that the electric device is a working machine, and the functional unit realizes a working function. According to the eighth aspect, the above-described evaluation method can be adopted in a typical working machine.

The invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the invention.

Claims

a battery unit;
a power converter that converts the output voltage of the battery unit;
a functional unit that realizes a predetermined function based on the voltage converted by the power converter;
a current detection unit that detects a current from the battery unit to the power converter;
and a processor for driving and controlling the power converter,
The processor
causing the power converter to output an AC voltage and alternating the frequency of the AC voltage;
An electric device, wherein the degree of deterioration of the battery unit is evaluated based on the detection result of the current detection section obtained in the frequency band that changes in the order.
A detection result of the current detection unit is an AC current,
The electric device according to claim 1, wherein the processor performs the evaluation based on a phase difference between the AC voltage output by the power converter and the AC current detected by the current detector.
3. The processor according to claim 1, wherein the processor calculates the internal impedance of the battery unit by Fourier transforming the detection result of the current detection unit, and performs the evaluation based on the calculation result. electrical equipment.
4. The electrical device according to any one of claims 1 to 3, wherein said processor refers to a predetermined lookup table in making said evaluation.
Further comprising a temperature detection unit that detects the temperature of the battery unit,
the lookup table is one of a plurality of lookup tables;
5. The electric device according to claim 4, wherein the processor selects and refers to one corresponding to the detection result of the temperature detection unit from the plurality of lookup tables.
The electrical device according to any one of claims 1 to 5, wherein the processor notifies that the battery unit needs to be replaced based on the result of the evaluation.
The electric device according to any one of claims 1 to 6, wherein the electric device is a vehicle, and the functional unit realizes a running function.
The electrical device according to any one of claims 1 to 6, wherein the electrical device is a work machine, and the functional unit implements a work function.