JP2010019653A - Battery residual capacity calculating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for calculating residual capacity, accurately and at low cost, without having to use a current detection resistance, whereas since when inserting a detection resistance necessary for calculating a battery remaining capacity between a battery and an electrical apparatus in series, defects appear, wherein the utilization time of the electrical apparatus becomes short; and in an electrical apparatus capable of replacing a battery, a microprocessor and a memory are required to be built into each battery pack, to thereby result in cost increase. <P>SOLUTION: A battery open circuit voltage is converted into a residual capacity and used as an initial value, and power consumption of an operation mode measured and stored beforehand is subjected to time integration and is added to/subtracted from the initial value. Degree of deterioration is determined by performing current integration in a separate circuit so as to avoid affecting the utilization time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a system for calculating a remaining battery capacity of a portable device driven by a battery.

As a conventional method for obtaining the remaining time or remaining capacity of a battery, a time integration method, a current integration method, and a voltage method have been proposed and actually incorporated in a device. Time accumulation methods are often used when the load is relatively constant, such as an electric shaver, and the remaining battery capacity can be determined only by the usage time. The current integration method is used in portable video cameras, etc. whose load fluctuates during use, monitors the amount of current used, subtracts it from the initial remaining capacity value when discharging, and adds it when charging it, so that it can be taken out of the battery Calculate the amount of current. In the voltage method, battery characteristic data is taken in advance and stored in a recording medium such as a ROM in the form of a table of battery voltage values versus remaining battery capacity values. During operation, the battery voltage is detected and converted to the remaining capacity by referring to the stored table. Although it is often used in cases where it is relatively difficult to accurately detect and integrate the discharge current, and when cost is a priority, the battery voltage varies greatly depending on the temperature and the size of the load, resulting in a large error.

A remaining capacity display system that uses a current integration method at the time of charging to determine that a charging voltage has been reached when the charging current decreases to a predetermined current or less when the charging current is nearly full and the remaining capacity is 100% is also common. is there. The so-called conventional current integration method is a remaining capacity display system that uses a current integration method at the time of discharging and displays 0% capacity when the discharge end voltage of the battery is reached. Therefore, it can be said that a part of the voltage method is combined even in the conventional current integration method. For degraded batteries, the conventional current integration method uses the capacity that can be discharged from the full charge to the end voltage as the true actual capacity, and is used for the next current integration to compensate when the battery capacity decreases. We are using. Alternatively, the degree of deterioration of the battery is predicted in advance based on the number of times of charging / discharging, the degree of deterioration is stored in memory, the number of times of charging / discharging is counted during use, and the capacity is corrected by multiplying the rated capacity by the degree of deterioration.

In addition, when the current flowing into and out of the battery is very small, the battery voltage can be accurately converted into the remaining capacity of the battery without being affected by the temperature and the load size. Since the amount of consumption can be accurately counted, the present inventor has proposed in Japanese Patent No. 391960 to use different methods for increasing the accuracy depending on the situation.

Also, when the battery is charged or discharged and used, the current that flows is less than the specified current value for the first time, then the current that exceeds the specified current value flows, and again falls below the specified current value for the second time. The amount of change in capacity in the voltage method in which the voltage value is converted from the voltage value to the remaining battery capacity value when the current value is equal to or less than the first and second specified current values is the amount of change in the capacity of the standard battery not including deterioration. On the other hand, the capacity value obtained by integrating the current flowing over the specified current value during the measurement by the first and second voltage methods is the actual capacity used. Therefore, in Japanese Patent No. 391960, the change in the remaining capacity of the battery obtained by the voltage method and the current accumulated value obtained by the current integrating method are compared to obtain the degree of deterioration of the battery. By reflecting the degree of deterioration obtained in this way in an equation for calculating the remaining battery capacity and correcting it, it is possible to calculate an accurate remaining capacity value taking into account the battery deterioration. In order to carry out these processes, the battery pack incorporates a microprocessor and memory. Alternatively, the microprocessor and memory of the electrical equipment body are used.
Patent No. 391960

If the open-circuit battery voltage and the current flowing into and out of the battery can be accurately detected by the prior art, it is possible to calculate a considerably accurate remaining battery capacity. However, in order to accurately detect the current flowing in and out of the battery, it is necessary to insert a high-precision detection resistor in series between the battery and the electric device and acquire the voltage generated at both ends of the detection resistor. is there. In any case, the voltage input to the electric device is reduced, and the battery power is consumed even by the detection resistor. In addition, in order to integrate the current and calculate the remaining capacity, a microprocessor and memory are required.Electric devices that can be replaced with a battery must have a microprocessor and memory for each battery pack. This is a factor of cost increase. In cellular phones driven by a single cell, the specific gravity of these factors increases, which is a fatal problem, and is a major factor that does not employ the current integration method for calculating the remaining capacity of cellular phones.

In order to solve the above problem, instead of the current integration method, the power consumption in each operation mode of the electric device is measured in advance, a table is created, and the table is stored in a memory built in the electric device. When each operation mode designation means designates an operation mode, a circuit without a current detector is realized by reading power consumption corresponding to the operation mode from the memory and adding / subtracting from the remaining battery capacity. When the user does not use the electrical device or at the user's will, the circuit is switched so that almost all the current passes through the current detector. Then, the battery capacity converted from the accurate open battery voltage and the used battery capacity are measured, and the deterioration degree is calculated by the method described in the related art. If the battery data stored in the memory is not useful after replacing the battery, new battery data to be acquired using a wireless or internet connection is downloaded. As described above, the problem is solved by combining the three methods of calculating the remaining battery capacity, the method of converting the open battery voltage into the remaining capacity, the current integration method, and the time integration method.

The present invention, in an electric device driven by a battery, comprises an operation mode designation means, a microprocessor, a first memory, a second memory 2, a data transfer means, a voltage detection means, and a current detection means. First data for converting an open battery voltage acquired in advance to a remaining battery capacity is transferred and stored in a first memory using a data transfer means such as a writer. Further, the second data of power consumption or current consumption in each operation mode of the electrical device acquired in advance is transferred and stored in the second memory using a data transfer means such as a writer. When the operation mode specifying means determines the mode in which the electric device operates, and when the power consumption or current consumption of the operation mode is a small operation mode smaller than the specified value, the microprocessor uses the first data stored in the first memory. The open battery voltage detected using the voltage detecting means is converted into the remaining battery capacity to obtain the initial remaining capacity. When the power consumption or current consumption in the operation mode is larger than the specified value in the large operation mode, the power consumption or current consumption corresponding to the operation mode is multiplied by the operation time in the operation mode from the second data to calculate the initial capacity. Add / subtract from the value to find the remaining capacity. When the operation mode is a detection current in which almost all of the current flowing into and out of the battery passes through the current detection means, the detection current is integrated over time, and the remaining capacity is obtained by adding or subtracting from the initial value as the consumed capacity. Accordingly, there is a feature that three types of battery remaining capacity calculation methods, that is, a voltage method, a time integration method, and a current integration method, are switched according to the situation.

The invention according to claim 2 is a constant current circuit in which the current detection means can set the current value in advance, and has a feature that the set current value is multiplied by the operation time to obtain the consumed capacity of the battery.

In the invention of claim 3, the data transfer means has a third memory and a server, and the server stores the data stored in the third memory via the wireless communication means or the Internet. It has the feature of transferring to memory.

By accurately detecting the open battery voltage and the current flowing into and out of the battery and combining the voltage method and the current integration method, a considerably accurate remaining battery capacity can be calculated. However, since a detection resistor is inserted in series with the circuit for current detection, the voltage input to the electrical device is reduced and battery power is also consumed by the detection resistor. Therefore, instead of the current integration method, if the power consumption that has been measured and known in advance is integrated over time, the detection resistor is not required, so that the use time of the electric device can be extended. In addition, when the user does not use the electric device, switching the circuit so as to pass through the current detection means can measure the accurate battery capacity to be used, so that the accurate degree of battery deterioration can also be measured. In addition, by having a data transfer means, externally measured battery data can be written and stored in memory, and new battery data and charger data can be transferred and rewritten when the battery or charger is replaced. There is an effect that can be easily done. Then, since it is not necessary to incorporate a microprocessor or memory for each battery, there is an effect of minimizing the cost increase that occurs when a highly accurate remaining capacity system is made.

In addition, knowing the exact battery deterioration level is extremely important for calculating the remaining battery capacity and thus for battery management. By the way, when the user is not using the electric device, for example, when charging, the charger has a time zone in which a known constant current flows. According to the second aspect of the present invention, an accurate current consumption is obtained by using the time zone, and a change in the remaining capacity converted from the open battery voltage is compared, so that there is a great effect of calculating an accurate battery deterioration degree. Also in this deterioration degree calculation, the current detection resistor can be eliminated, and a circuit for acquiring the voltage between the resistors is not necessary, so that the cost reduction effect is great.

According to the third aspect of the present invention, since the battery data is stored in the memory of the server, new battery data can be acquired from the server when the battery is replaced. Then, the data acquired from the server can be stored by rewriting the memory built into the electrical device using the microprocessor built into the electrical device, eliminating the need for a built-in memory or microprocessor for each battery. There is a down effect.

Voltage method to convert battery voltage at minute current to remaining capacity using conversion table of open battery voltage versus remaining battery capacity stored in memory, and time to calculate remaining battery capacity by multiplying the used power by the usage time Three types of remaining battery capacity methods are used depending on the situation: the accumulation method and the current accumulation method for calculating the remaining battery capacity from the consumed battery capacity obtained by integrating the flowing current.

FIG. 1 is a block diagram showing a first embodiment of the present invention. The electric device 1 includes a battery 2, an operation mode designating unit 3, each operation mode 4, a voltage detection unit 5, a first memory 6, a second memory 7, a current detection unit 8 surrounded by a dotted line, and a microprocessor 9. have. The charger 10 can also be connected internally or externally. Furthermore, there is a data transfer means 12 having a third memory 11 outside to constitute a battery remaining capacity calculation system. The operation mode designating unit 3 selects the operation mode 4 using an input unit such as a keyboard, voice, light, etc., and inputs an instruction to the microprocessor 9. Although there are three types of operation modes 4 in FIG. 1, the gist of the present invention is the same regardless of the number of types. The voltage detection means 5 acquires the voltage of the battery 2. As shown in FIG. 2, the memory 6 stores a table for converting the open battery voltage into the remaining battery capacity. Needless to say, the finer the table, the higher the accuracy of the remaining capacity. However, the gist of the present invention does not change even if the function is not a table as shown in FIG. 2 but a function that converts the open battery voltage into the remaining battery capacity. The memory 7 stores a table of power consumption or current consumption consumed by each operation mode 4 shown in FIG. In FIG. 3, each operation mode 4 is suffixed and displayed as an operation mode 4-1 and an operation mode 4-2. The current detection means 8 is a conventional circuit in which the current detection resistor 14 is connected in series with the battery by the switch 13 and the voltage detection IC 15 detects the voltage across the current detection resistor 14 when a circuit current flows. The microprocessor 9 calculates the operation mode 4 instruction and the remaining battery capacity, and executes a program to be output to a display device or the like, thereby controlling the entire electric device 1. Although FIG. 1 shows a single microprocessor 9, even if there are a plurality of microprocessors 9, the gist of the present invention does not change. The charger 10 may be built in the electric device 1, but in FIG. 1, it is connected to the electric device 1 when charging is required. The data transfer means 12 is independent of the electric device 1 in this embodiment and is not shown in the figure, but the battery data measured by the testing machine is stored in the third memory 11 and the first memory 6 It is a writer that writes in the second memory 7.

Next, the operation flow of FIG. 4 will be described. Before carrying out the flow of FIG. 4, the data of the open battery voltage versus the remaining capacity obtained by the battery tester is stored in the third memory 11, and the data is stored in the first data using the writer 12 which is a data transfer means. It is transferred to the memory 5 and written. The power consumption in each operation mode of the electrical device 1 is also acquired in advance by a tester and stored in the third memory 11, and the data is transferred to the second memory 7 and written using the writer 12. . In FIG. 4, each step of the flow is displayed with S added before the serial number. First, when the electric device 1 is turned on (S1), the microprocessor 9 is turned on (S2). The current detection means 8 is turned off (S3) to reduce the flowing current as much as possible. Next, the voltage of the battery 2 is acquired using the voltage detection means 5 (S4). The acquired battery voltage is converted into the remaining battery capacity by referring to the data of the open circuit voltage versus the remaining capacity stored in the memory 6 and is stored in the memory built in the microprocessor 9 as the initial value Q0 of the remaining capacity ( S5). The open battery voltage of the battery 2 is generally a battery voltage in an open state in which the battery 2 is not connected to any load. However, in the present invention, if the current flowing into and out of the battery 2 is very small and not more than a specified value, The battery voltage is open. At this stage, the current flowing through the battery 2 is very small as the current for operating the microprocessor 9 and is therefore set to a predetermined value or less. It is determined whether or not the state where the current is below the specified value continues for a specified time, for example, 1 hour (S6). If it continues for more than the specified time, the open battery voltage is detected again using the voltage detection means 5 (S7). The initial value of the remaining capacity is updated with the value obtained by converting the open battery voltage into the remaining capacity with reference to the memory 6 (S8). Next, when the operation mode designating unit 3 designates the operation mode 4 by interrupting the microprocessor 9 (S9), the power consumption of the designated operation mode 4 is read from the table of FIG. 3 (S10). And it is judged whether power consumption is below a regulation value (S11). If it is equal to or less than the specified value, step 6 described above is performed. If the power consumption is equal to or higher than the specified value, the power consumption Q1 is calculated by time integration by multiplying the power consumption by the usage time (S12). The current remaining capacity Qr is calculated by adding or subtracting the consumed capacity calculated in step 12 from the remaining capacity initial value updated in step 5 or step 8 (S13). Each time the operation mode designating means 3 interrupts, the flow from step 9 is repeated, and the consumption capacity increases like Q1, Q2, and Qn. The calculation formula is expressed by formula (1).

    Qr = Q0− (Q1 + Q2 +... + Qn) (1)

Qn becomes -Qn at the time of charging and is added to Q0, and is the capacity stored in the battery 2, but in the present invention, both are explained as the consumed capacity. The table of FIG. 3 shows the operation mode vs. power consumption. However, since the current consumption is obtained by dividing the power consumption by the battery voltage, it is generally easy to convert the battery capacity into ampere hours. Even if power consumption and current consumption or battery capacity and battery power are used in the same meaning in the description, the gist of the invention does not change.

Next, the deterioration degree calculation mode is set manually or automatically during a non-use time zone when the user is not using the electric device 1 (S14). First, it is determined whether or not the power consumption in the operation mode 4 is not more than a specified value and not less than a specified time (S15). If the specified value or less is equal to or longer than the specified time, the open battery voltage is converted into the remaining capacity and the initial value is updated to obtain Qf0 (S16). If the specified time has not been reached, wait until it reaches. When the designated time is reached, the current detection means 8 is turned on (S17). In this embodiment, the switch 13 is switched to DC resistance, and any one of the operation modes 4 is selected as a load (S18), the consumed battery capacity is counted by current integration, and the consumed battery capacity Qa is measured (S19). . Next, the operation mode 4 is turned off to stop the current flowing through the battery (S20). The state where the current is stopped continues for a predetermined time or longer (S-21). An open battery voltage is acquired using the voltage detection means 5 (S22). The open battery voltage is converted into the remaining capacity Qr0 from the table of FIG. 2 (S23). The battery deterioration degree α is calculated by subtracting Qr0 from Qf0 and dividing by Qa (S24). The calculation formula is expressed by formula (2).

    α = (Qf0−Qr0) / Qa (2)

Qf0 means the first remaining capacity initial value when f is a front mark. Qr0 means the second remaining capacity initial value when r is a mark of the rear. Qa means a battery capacity for deterioration calculation when a is an age mark. That is, Qf0 and Qr0 are obtained from the table of FIG. 2 measured under the condition that the battery is not deteriorated, and Qa is the current battery capacity including the deterioration, so that the deterioration degree α can be calculated.

Then, the remaining capacity initial value Q0 is updated with the value of Qr0 (S25). Thereafter, until an interrupt (S9) for specifying the operation mode 4 is received during that time, an open battery voltage is intermittently acquired at a time interval t (S26) (S27) and converted to a remaining capacity, and the initial remaining capacity is obtained. The value is updated (S28) and a loop is entered (S29).

Thus, since it is well known that the obtained remaining capacity Qr and the battery deterioration degree α are used for various battery management, the description thereof will be omitted.

A second embodiment of claim 2 will be described with reference to FIG. 1 in a configuration in which a constant current circuit 16 and a power plug 17 incorporated in a charger are added to the first embodiment. Almost all chargers for secondary batteries that are charged and used repeatedly have a constant current circuit 16, and there is a constant current charging period. Therefore, in the present invention, the constant current circuit 16 is used as current detection means. That is, when the constant current circuit 16 operates, the current detection means 8 is on and vice versa. The current detected by the current detection 16 is a known value set in the charger 10 in advance. Then, when the current detecting means 8 is replaced with the constant current circuit 16 in the flowchart of FIG. However, if the deterioration degree calculation mode is entered at the time of charging, in order to acquire the open battery voltage, a standby time until the battery voltage settles is required, and therefore the charging time becomes long. Since it is not necessary to frequently acquire the battery deterioration level, it is not usually necessary to switch to the deterioration mode. If you feel that the accuracy of the remaining capacity display has deteriorated, you can select the deterioration level calculation mode by user selection. Is the method.

In the third embodiment, the data transfer means 12 of FIG. 1 is a server having a third third memory 11, and the first data or the second data is transmitted to the first memory or the second data through wireless communication or the Internet. It is a means for transferring to the second memory.

The operation is that if the electrical device 1 is a mobile phone, the data stored in the memory 11 can be transferred wirelessly from the data transfer means 12. Further, if the electric device 1 is a notebook computer, it can be transferred through the Internet. Many rechargeable secondary battery packs for the electrical device 1 can be replaced. If the battery pack does not contain a microprocessor or memory, the reliability of the remaining battery capacity data when the battery is changed Will be lost. For example, the table data in FIG. 2 differs between a battery pack with a short usage time and a long pack. In addition, even if the manufacturer provides batteries with different battery performance after the sale of electrical equipment, battery data will not match if the battery pack does not contain a microprocessor or memory, so the reliability of remaining capacity calculation is not Lost. Further, the power consumption of each operation mode 4 of the electrical device 1 can be connected to a new optional device, or if it is a mobile phone, it is necessary to change the power consumption just by opening a base station nearby. In such a case, according to the third embodiment of the invention of claim 3, the user of the electric device 1 connects the electric device 1 to the server 12, downloads the new data of FIG. 2 or FIG. It can be updated and stored in the memory 6 or the second memory 7.

The calculation of the remaining battery capacity is said to be most accurate by the conventional current integration method. The drawback is that the accuracy of the initial value is insufficient. In view of this, the present inventor in Japanese Patent No. 391960 converts the open battery voltage obtained when the current flowing through the battery is minimized and the battery voltage has settled over time to the remaining battery capacity by converting the initial value to the initial value. Invented to value. The battery degradation level can be calculated by combining the current integration method and the open battery voltage method. However, in the current integration method, a precise direct current resistor is inserted in series in the electric device circuit, and thus a negative factor that shortens the usage time of the electric device occurs. Furthermore, in a device in which the battery pack can be replaced, it is necessary to incorporate a microprocessor and a memory for each battery pack, which increases the cost. In the present invention, all these negative factors are eliminated while maintaining the remaining capacity calculation accuracy, so that many battery-powered portable devices such as mobile phones that have not been able to omit the remaining capacity display accuracy so far have been used. The possibility of being used and becoming a highly accurate battery management system is great.

It is a circuit block diagram of the present invention. First data table. Second data table. The flowchart which shows the effect | action of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric equipment 2 Battery 3 Operation mode designation | designated means 5 Voltage detection means 6 1st memory 7 2nd memory 8 Current detection means 9 Microprocessor 10 Charger 12 Data transfer means 16 Constant current circuit

Claims (3)

In an electric device driven by a rechargeable battery that is charged and used repeatedly, it is composed of an operation mode designation means, a microprocessor, a first memory, a second memory, a data transfer means, a voltage detection means, and a current detection means. The acquired first data, that is, the data for converting the open battery voltage to the remaining battery capacity is transferred and stored in the first memory using the data transfer means, and the second data acquired in advance, that is, the data Power consumption or current consumption in each operation mode of the electrical equipment is transferred and stored in the second memory using the data transfer means, and the operation mode designating means operates with power consumption or current consumption smaller than a specified value. When the mode is designated, the microprocessor detects the voltage using the first data stored in the first memory. When the open battery voltage is converted into a battery remaining capacity to obtain an initial value of the remaining capacity, and the operation mode in which the power consumption or current consumption in the operation mode is greater than a specified value, the operation mode is changed from the second data to the operation mode. The corresponding power consumption or current consumption is multiplied by the operation time of the operation mode to calculate the consumption capacity, and the remaining capacity is obtained by adding or subtracting from the initial value, and almost all of the current flowing in and out of the battery is passed through the current detection means. A battery remaining capacity calculation system in which, when the operation mode that is a detected current passing through is designated, the detected current is accumulated over time to add or subtract from the initial value as the consumed current to obtain a remaining capacity. 2. The battery remaining capacity calculation system according to claim 1, wherein the current detection means is a constant current circuit built in the battery, a charger, or the electric device. The data transfer means has a third memory and a server, and transfers and stores the first data or the second data to the first memory or the second memory through wireless communication or the Internet. Item 1. A battery remaining capacity calculation system according to item 1.

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