JPS61221539A - Apparatus and method for controlling battery charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control device for a battery charger that controls the charging of Nickel-Calmium battery. [Technical background of the invention] can work with.

The function of the digital mode is to increase accuracy in the control mode. In addition, measurement techniques using digital methods are rare.

Conventional charging methods for Nikka p p4 and Teri require several hours or more to fully charge with high efficiency, so the current value is controlled in various ways to supply a constant potential.

Each method has different problems. In addition, charging takes a long time, cell changes do not cause overcharging, and low capacity cells become overcharged between attempts.

-9 poles have polarity. Foss bubbles (of electrolysis) are formed on the plate. These effects raise the temperature of the battery, increasing polarization and forming bubbles until the battery overheats or ruptures. The heat generated by charging at a rapid rate and at a low rate dissipates the electrolyte, thereby causing -.

Terry reduces capacity.

To reduce such problems, the length of charging on/off cycles is controlled to reduce polarization and bubble formation.

Reduces the total charging time, which can reduce deterioration due to lower polarization and electrolysis.

Crystai Electro Co., Ltd. has developed an excellent 19Ls charger, each charging! After 4 russes, a shorter length discharge/or russ of opposite polarity is supplied to cause electrolysis. (FIG. 1) This technique allows a complete charge to be made in a few minutes per hour, as opposed to other techniques that require various hours. The effect of this method is
This type of charger, which typically exhibits a temperature increase of 0 to 7°C, is described in US Patent 3,5) 7.293
:3.5s 9,02s : 3.597.673
: 3.609.503 :3.614.582:3
．． 614.583: 3.614.58.4: and 3.
617.85).

To determine the terminal charge, measurements of battery charge are
The off-period measures the gain between discharging and charging. Some approaches take measurements at the end of battery charging.

One is to measure the battery voltage until it approaches the true value, at which time the charger will terminate charging. As shown in Figure 2a, the typical voltage during a continuing charging operation increases late in the charging cycle. For this reason, it is difficult to ensure that the battery is fully charged, even if the voltage is selected in accordance with the changes in the cells. Another approach is to charge the battery until a negative slope is detected. The problem with this approach is that the battery must not be overcharged before approaching this point, which causes the battery to heat up violently.

Another approach is to approach a certain voltage again and allow the charging period to last for a certain length before terminating. This provides a complete charge to the battery. However, this depends on an absolute value regardless of the state of the battery.

[Purpose of the invention]

In accordance with the present invention, a new and improved method is provided in which the time is determined by deriving from the actual voltage of the current, the change in the slope of the derived time, and this measurement is used to determine the charging operation of the battery with the change in slope. The purpose is to finish.

Other objects, advantages, features, and results are fully described in the following description. SUMMARY OF THE INVENTION The present invention provides a means for measuring the voltage of a battery to provide a measured voltage, and a means for measuring the voltage of a battery to provide a measured voltage. A means of determining the derived time by applying the derived voltage, and a means of determining the change in the slope of the derived voltage, typically the sign of the change in slope or the function of the change in slope.

This is a means of stopping charging at a certain point, typically when a change in sign occurs or at a predetermined running time after a change in sign occurs.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Analog Embodiment: This approach includes two approaches and uses analog techniques to determine the change in slope. Figure 3 shows battery charger 2
No and Ichimori, Teri? 0 circuit is the sample hold section (8KH) j J , J 4, "y
7 Thea 7 f J 5, aS amplifier 26, positive throw! Detector 22) Includes negative slope detection 028, arm latch 29, and dart 30.

The charger 21 charges and discharges the battery both conventionally and in the present invention.The first sample hold 23 holds the voltage, and the second one 24 compares the previously sampled voltage with the last sampled voltage. , charging rate increase, termination,
or decide to start a decline. A first derived curve is generated and the end of charging is first recognized by the detector 22 at the positive edge of the first derived curve.

This is the expected negative edge, and the detector 28 terminates charging at the next negative edge. The biggest advantage of using this type of indication is that the charging rate is determined by the battery itself and is often not dependent on a predetermined voltage that is not adapted to the current state of the cell. This technique of comparing sampled output voltages using analog comparison is superior to other decision systems. As mentioned above, the temperature increase depends on the rate sampled and determined when full charge is reached. Although a fast sampling rate increases accuracy, this is at a disadvantage in terms of charge/mother pulse width. The actual end of charging is preferably before the onset of the negative slope of the battery voltage curve; experience has shown that more energy is delivered to the battery during the period after the first derived peak occurs. Even with normal capacity, a lot of heat is generated. Therefore, a more accurate curve defined by the change in slope, curve, and slope can be derived and generated to compare with the first one described above. Each higher order is calculated and
To sharpen changes in a specified slope.

When multiple batteries are connected like an I4, the charging characteristics and the resulting curves take on a unique appearance.

This data is stored and used to control the charging cycle.

Different systems with similar features may carry out some of the invention, so the user can use each battery type or
There is no need to reset or reset the controller in response to

In addition, when the battery or I4 is heavily discharged or significantly cold, the specific operation of the control device is exactly the same.

Digital Embodiment: The best embodiment of the controller uses an analog-to-digital converter (ADC) for coupling to the microcomputer. micro combination.

- The meter measures the z4 voltage during each measurement window. The occurrence of the first derived curve from the measured voltage is shown in a similar manner to the analog method.

DN −DN−1 Δt where DH and DN−1 are digital values indicating the battery voltage before the current measurement window, t is the measurement window r
It's an intermittent time. Therefore, the voltage change from one measurement window to the next is extremely small (3 mV)16
Fig. 4 shows the ``df digital converter'' of Pitt's ADC.

To refine the shape of this first derived curve, linear regression al uses rhythm. One way to recall the first derived curve is to best fit the equation for any data point with the slope of the actual curve.

This formula has a slope and a slope, i.e. y=mx+
b s where m is the slope and bay intercept. Therefore, we are only interested in the slope and only need to calculate m.

What is the formula that the linear regression curve fits?

Here, S is the number used for the sample, and the best value of S is 11
It is. Therefore, to convert the first derived curve, we used the following f inline.

This linear regression method involves 11 points in a row.

In fact, the first 11 samples of the battery voltage curve are not generated corresponding to the first derived curve, but this typically reveals only a small part of the entire curve and its effects is negligible and is illustrated in two plots in FIG.

As mentioned above, the microcombi uses an ADC to measure battery voltage. The operation of this ADC is illustrated in FIG. A common approach to analog-to-digital converters (A/I) is as shown in FIG.
is used, and its output is compared with the p4 y terminal 22 and the con/gulator 36. The 8-pit identification signal is generated by the microcombi 32. YESβ0 state line 32
The microcomputer will tell you if the digital value it generates is greater than the battery voltage. This is an iterative process and is usually referred to as "one successive aderoximation". Therefore, since we are dealing with relatively small changes in battery voltage, a high resolution ADC is desired.

In a preferred embodiment, the unconventional approach is
The selection is as shown in the figure. This circuit is a high ADC3
5m and low ADCJ5t), a de/transducer 38, an adder 39 and a sample and hold 40. Add a second 8-bit DAC35b to extend its full range to 2
2 times to minimize changes in the high DAC 35a and obtain fine resolution.

Then, first 8 pins, high 8 pins of the torque Φ converter) DA
CJ 5m runs and the rest is low 8bit.

The DAC 35b picks up and performs a coarse approximation of the battery voltage, essentially giving a resolution of 16 pins. However, this approach requires a high 8-bit DAC.
There is a problem that the lowest pit (LSB) changes even though the values are equal, this is not the true value, in fact, 8 pins, )
The DAC transfer is drawn as shown in FIG. In other words, the value of the D/A conversion can only be performed accurately with a low 8-pin DAC. However, if there is a measurement method, the LSB of Nagoya DAC
If the change in value can be supplied with a low DAC amount, high LSB errors can be eliminated. This error characteristic can be implemented by adding another sample hold 40blC "New Input 1 Calibration" (Figure 1.theta.) The calibration method is performed as described below.

In FIG. 10, the low 8-bit DAC 35b has a value of O,
High 8 pins) DACJ5a has a value of 1. The battery sample hold switch 40a is open during calibration. The calibration sample and hold switch 40b is momentarily closed and one input of the converter/four router 36 holds the high DAC count value of one. High DAC returns to count value 0. and low DA
C performs φ conversion and converts the lowest pitch of high DAC) LS
The B value is given to the (A) input of the 4/4 lator 36.

Once we have this value, we store it in memory at location 1 of the table. Then, 256 calibration cycles are performed.

Cycle 2 is executed as follows. The count value 2 of the high DAC is applied to the sample and hold, and this value is input to the ←) input of the comparator 36.

The high DAC returns to state 1], the low DAC performs the last conversion,
The LSB of the high DAC changes from 1 to 2. Once we have this value, we store it in memory at location 2 of the table. This procedure is repeated until all the lowest pits of the high DAC have changed.

The calibration method is performed by adding as shown in the flowchart shown in FIG.

Once the high DAC and low DAC values are obtained, the high DAC
C performs the conversion using a table similar to that of the low DAC, as shown in Figure 12. Figure 13 shows the final φ and microcombi interfaces. connection via line and control line.

Basically, the low DAC uses a similar technique to generate the calibration table during each calibration technique.

The high DAC value uses the table index.

All low DAC tables are added starting from index O. The value of this calculation result is 8 during the period of φ conversion.
Add to Pitt's low DAC value. The calculated value is the battery voltage at 16 pins.

Give at That is, DN=ΣCB+DL Here, is the 16-pit digital value of the battery voltage,
H is the 8-pin value of the converted high DAC, G value, C is the value in the calibration table, and DX is the 8-pin value of the low DAC that is ~Φ converted.
is the default value.

Cable ID system; The circuit shown in Fig. 14 consists of - 4 pins, a normally closed temperature switch 42) an identification resistor R10% current source 43, a 4-bin connector 44 connected to the battery, a charger and a control device. .

The battery cable has passive electronic circuitry specifically designed to perform battery identification.

- For protection, the teri cable is 4.
Book Connections, Patch 17 Make two or three connections for K.

Pins 1 and 4 of connector 44 serve as power transmission conductors during charging and discharging. Pin 3 is a battery identification detection pin.

Pin 2 is the temperature cutoff (referred to as 'f'co) pin.

The pin informs the controller of the status of the battery charge TCO switch. Since the battery burner does not have a temperature cutoff switch, pin 2 is at the connector end of the cable...
Short to bin 1. Depending on the type of connection in the terminal, the TCO switch operates as a master or slave charge stop switch.

The controller automatically identifies what batteries are connected to the controller. The identification resistor RID is equal to this battery z4y and is connected between -3 and ground.

To identify the type of battery connected, the microcombi battery applies a known current to pin 3. This current generates a digitizing voltage across the identification resistor RID. The raw digital value is placed in the dimensional matrix of that type of battery, using the two-step Table 1.2 approach as shown in Figures 18 and 19.

The voltage across the cable 10 resistor, which corresponds to the raw digital value, is converted into a meter index, such as the Kustable's Cietzl index, and as shown in FIG. 9
Figure 19 shows such a parameter.

It's about Terry. An additional advantage of this table is that the same table can be used for multiple types of batteries, so the use of memory can be of great benefit.

One commercial embodiment of the invention actually accommodates 3211 type batteries. Each /42 meter table provides information about a particular meter by selecting data from the microcombi meter and the controller determines the charge, discharge times and current operation of the meter.

/4 ram tables are each 24 bytes long and stored serially in memory. The information contained in these cheats is the actual battery charging and discharging/meters. A commercial implementation actually uses 20 ramometer tables and requires 480 bytes. The double/quarter ramometer index table and the /quarter ramometer table (table 1.degree. 2) are placed on the RAM. Changes to the meter index table are rare, except when adding new cables.

However, the meter table is subject to change for optimization of charging, and different discharge currents correspond to calculated values of Ampere/hour with different charging techniques. (i.e. reflection 1+ is TC'0). Therefore, these values are stored in non-volatile RAM and can be accessed from the key code of the microcomputer, and can be changed at will by Needy.

In addition, /weighing type determination uses cables for specific purposes in the cable ID system.

These cables have 32 battery type ID numbers on the outside. When connected to such a special purpose cable, the microcomputer can operate in a special mode.

Two such modes are the power supply mode and the discharge booster mode. A variation of the power supply mode is in FIG. 14 and connects to various loads at pins 1 and 4 as in FIG. 15. In the power supply mode, the microcombi first checks which power supply cable is attached by looking for the cable ID pin 3 as described above. If one is connected, it and the other power supply cable lines become active. It is also possible that the power supply cable is not set to a value in the manner of power supply.

A variation of the discharge booster mode of FIG. 14 is shown in FIG. 16, and the discharge booster 48 is used by the user when a particular discharge power level exceeds the allowable discharge range of the charger 21 itself. If this is the case, the microcomputer will tell which channel the discharge cable is connected to. When connected, it activates and causes the internal discharge current to equal the value that caused this channel to generate the discharge current requested by the user. A discharge booster, conventionally known as an electronic load, can be used as a constant current load and can be used for a variety of purposes, including t4y test. A typical discharge booster includes a variable resistor that sinks the booster's predetermined current.

In the configuration shown in FIG. 16, this variable resistor can be removed and
The resistor RfD2 is not connected, and the resistor RfD2 operates as a current setting resistor. The discharge booster applies a current to resistor R4D2 to generate a voltage across the terminals of the resistor, which voltage indicates what current is flowing through the booster.

And at the end of the connector, the control device operates with different levels of discharge current outside of its own power capacity, and indicates what amount of current the discharge booster is operating with.
The cable ID resistor RfD1 tells the control device what discharge booster current is connected, and in the cable at the end of the discharge booster, the identification resistor R4D2 tells what discharge current the discharge booster is operating with. .

Currently, three discharge cables are offered, 2.4 and 6 ania.

A booster can be connected to any channel, and the controller is capable of using multiple boosters.

This can be done by adding current capacity in parallel. Currently, the barware discharge limit is 14 amps.

Determining Different Charging Modes Using the /45 Meter Table; Because the cable ID system uses a /45 meter table, it is possible to charge or discharge batteries other than two or four meter meters. This means that all charging and discharging amounts are A
This is because it can be analyzed using a / ram table.

According to this fact, the control device can be reformed by itself by directing acid etc. from the constant current charging mode of Nilacad, silver lead and rechargeable lithium batteries, and most of the battery charge/discharge configurations are h Compatible with all battery types.

Such flexibility would not be possible without the use of the /4 lameter Tedel, and this table is due to the cable ID system.

In each charging mode (constant voltage or constant current), various operations are possible depending on the analysis of the meter table. constant current motor
It includes the following features:

Reflective charging using first derived interruption Reflective charging using negative slope interruption Charging of interruption by TCO Charging cut off by time Charging interruption by voltage operation Constant voltage mode includes the following functions:

Charging current that is interrupted by time Charging that is interrupted by operation Since it is possible to know whether the battery is connected or not, the following conditions can be displayed and indicated to the user: ・Battery with reverse polarity ・Abnormal temperature of YAC battery! Battery t' is short-circuited, and battery t' is short-circuited. , the connector 49 is connected in series between the positive output of the power supply section and the cable. During the charging and discharging cycles, this connector is closed by the microcomputer. Before starting a charge/discharge cycle, the microcomputer quickly checks (a) the pins before the contacts make contact. If this voltage becomes negative, the charge/discharge cycle is aborted and the contacts remain open, giving a false indication of reverse polarity.

For batteries that include such a temperature cut-off switch, the controller can check for abnormally high temperatures in the battery prior to and during the charge/discharge cycle. If this switch is open, the controller will hold the current cycle and wait for the battery to cool. During this time, a hold or high temperature error indication will occur.

Open, shorted or degraded I4. Teri i4 Tsukuwa Mitsuru/
Detected by test procedures before or during the discharge cycle. Since the controller knows what type of I4 meter is connected to a given channel, it stores it in the I4 meter and compares it with the ratio value during the test procedure. This test is described below.

The contents contained in the I4 parameter table for the battery are the numerical values of the cell parameters.

Multiply this value by the VOLS per meter of the cell to obtain the normal battery voltage.

Before performing a charge/discharge cycle, the controller measures the battery voltage. If this voltage is zero or abnormally low, the battery is considered open, many cells are shorted, all cells are shorted, or the battery is completely discharged. This will be discussed below.

Close the contacts for a short period of time (10 amps for 30 m)
sec) Give a charge/yarus. Next, observe the f-voltage. If the voltage is abnormally low at the end of the 4th period of charging, it is the fault of the short-circuited cell, and if the voltage is 0, there is a short circuit. If the voltage is sufficiently higher than the normal battery voltage as specified in the Yarameter table, it is an open battery, a dead battery, or a deteriorated battery.

However, I4. If the battery voltage is close to the normal battery voltage calculated from the parameter table, then the abnormally low voltage measured before the charging start is due to -Cutteri/4
This is because Tsuku was severely discharged.

Even if the voltage measured before the application of the charging pulse is within the normal voltage range of 9° due to the I4 meter table, the test method will
Use until final completion.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a control device and method for a battery charger, which is capable of charging to full charge in a short time with little temperature rise by charging using charging pulses.

[Brief explanation of drawings]

Figures 1 and 19 are diagrams explaining the present invention. Figure 1 is a timing diagram explaining charging of the P4Y battery by charge/discharge/mother pulse. Figure 2a is a diagram of the battery voltage during discharging. FIG. 2b is an enlarged view of a part of FIG. 2a showing changes over time and the first derived voltage; FIG. Fig. 3 is a professional diagram of a charger using the analog control device of the present invention, Fig. 4 is an enlarged view of the battery voltage of the type shown in Figs. 2a and 2b, and Fig. 5 is a diagram without using linear regression. FIG. 6 is a block diagram of the charger using the digital control device of the present invention; FIG. 7 is a block diagram of the analog-to-digital converter shown in FIG. 6; Figure 7 is a diagram showing the operation of the analog-to-digital converter, Figure 9 is a schematic diagram of the two analog-to-digital converters shown in Figure 7, and Figure 1O is a diagram showing the operation of the two analog-to-digital converters shown in Figure 7. A block diagram of another similar embodiment of the present invention, FIG. 11 is a flowchart showing the operation of the element shown in FIG. 10, FIG. 12 is a diagram showing an element conversion table related to FIG. 10, and FIG. 10 shows the internal connections of the elements shown in Figure 10,
Figure 14 shows the electrical configuration of the battery cable, Figure 15 shows the electrical configuration of the cable that supplies power to the load, and Figure 16 shows the electrical configuration of the cable used for discharge booster operation. FIG. 17 is a diagram showing the electrical configuration of the control device for erroneous detection, and FIGS. 18 and 19 are diagrams showing the arrangement of the table that stores the battery charge/discharge/countermeasure meter. 21... Charger, 22... Pavteri, 23.24.
...Sample hold circuit, 25...Buffer amplifier, 26...Differential amplifier, 21.28...Slope detection, 29...Arm? latch. Applicant's agent Patent attorney Takehiko SuzueFIG, 2
b FIG, 4 4/12 FIG, 5 22 DAC input (-h UNDON FIG, 9 FIG, +2 0-": s-1-+J Hi DAC/IL S
B'h? -1'LIC"""'i× Tomi HiDA
To C ← = HiDAC^4L%LoDACI%d: I method 15 t ratio f1o m11 10 / +2 FIG, 14 lG15 +I/12 FIG, old FIG, 17 FIG, old FIG, 19 Procedural amendment ( (Method) 2) Name of the invention: Battery charger control device and method 3, relationship with the amended case Name of patent applicant: Christie Electric Corporation,
4. Agent address: 17 Mori Building, 1-26-5 Toranomon, Minato-ku, Tokyo March 25, 1986 6. Subject to amendment

Claims (24)

[Claims] (1) means for measuring the voltage of the battery; means for determining time from the voltage measured by this means; means for determining the charging slope from the voltage; and means for stopping charging as a function of the change in the slope. A control device for a battery charger, comprising: (2) A control device for a battery charger according to claim 1, wherein the determining means is an analog means. (3) A control device for a battery charger according to claim 1, wherein the determining means is digital means. (4) In the battery charger control device according to claim 1, the determining means determines the time from an initially given time. (5) The battery charger control device according to claim 4, wherein the determining means determines the change in slope based on a change in the sign of the slope. (6) The battery charger control device according to claim 1, wherein the means for stopping charging stops the charger when a change in slope is detected. (7) The battery charger control device according to claim 1, wherein the means for stopping charging stops the charger at a predetermined time after the determined change in the slope. (8) a differential amplifier having first and second inputs and an output; a first sample and hold circuit that provides an output to one input of the differential amplifier and connects the input to the voltage of the battery; a second sample-and-hold circuit that takes the output of the first sample-and-hold circuit as an input and supplies the output to the other input of the differential amplifier; a second sample-and-hold circuit that has first and second inputs and an output; a first slope detector which takes the output of the differential amplifier as input and provides an output when the first sign of the slope is detected; a second slope detector that provides an output connected to the input of the AND gate when an opposite sign is detected; and a second slope detector that connects the output of the first slope detector to the input and connects the output to the other input of the AND gate. A control device for a battery charger, comprising: a latch circuit that provides a latch circuit to a battery charger; (9) means for measuring the voltage of the battery; an analog-to-digital converter for converting the measured analog voltage into a digital voltage; and a calculation means for calculating time from the digital voltage and determining a change in slope using this time. and means for stopping charging as a function of the change in slope. (10) A comparator having first and second inputs;
a first digital-to-analog converter having an output connected to one input of the comparator; a first digital-to-analog converter having an output connected to one input of the first digital-to-analog converter; input the output of the second digital-to-analog converter,
Battery charging comprising an analog-to-digital converter consisting of a voltage divider circuit whose output is connected to the other input of the adder circuit, and a sample and hold circuit whose input is supplied with battery voltage and whose output is connected to the other input of the comparator. device control device. (11) The device according to claim 9, comprising: a resistor equal to a battery; means for supplying a known current to the resistor; means for measuring the voltage generated across the resistor by the current; and the measured voltage. A control device for a battery charger, comprising: means for making the voltage equal to a predetermined battery. (12) In the item described in claim 11,
A control device for a battery charger, wherein the means for proportionalizing comprises: a memory; means for converting the value of the measured voltage; and means for examining the value equal to a battery in the memory. (13) The device according to claim 9, further comprising: a first resistor equal to a battery; a known current source; and a first resistor connected to the current source via the first resistor.
and first circuit means for outputting a first voltage across terminals of a resistor. (14) In the item described in claim 13, the parameter table stored in the memory; and the index table stored in the memory, the index table having an index proportional to a voltage value and a parameter table, and means for selecting a parameter table as a function of a first voltage across terminals of a resistor. (15) In the thing described in claim 13,
A control device for a battery charger comprising: a second discharge current resistor and a second circuit means connected to a second resistor of a current source of the battery discharge booster for use with a battery discharge booster. (16) Measuring the voltage of the battery, determining the time from the measured voltage given by the voltage extraction, determining the change in the slope of the voltage extraction, and charging using the function of the slope change. A method for controlling a battery charger, the steps comprising: stopping the battery charger; (17) In the method according to claim 16,
A method of controlling a battery charger comprising determining a first time. (18) In the method according to claim 17,
A method of controlling a battery charger comprising determining a change in the sign of a slope. (19) In the method according to claim 16,
A method of controlling a battery charger including stopping charging when a change in slope is detected. (20) In the method according to claim 16,
A method of controlling a battery charger, comprising: stopping charging at a predetermined time after a determined change in slope. (21) In the method according to claim 16,
A method of controlling a battery charger comprising measuring the voltage developed across the terminals of the resistor from a known current with a resistor operating with the battery and making it proportional to the measured voltage of a particular battery. (22) In the method according to claim 21,
A method for controlling a battery charger, wherein the proportionalizing step comprises: examining a table in memory in relation to the number of measured voltages; (23) In the method according to claim 16,
A method of controlling a battery charger comprising: determining the polarity of a battery terminal; comparing the polarity with a desired polarity; and blocking charging of the battery when the polarity differs from the desired polarity. (24) In the method according to claim 16,
including measuring the battery voltage, comparing the measured voltage with the voltage in the table, charging the battery for the above-mentioned period of time, measuring the voltage of the battery again, and comparing the table of voltages indicated in the battery status with the second measured voltage. Compare battery charger control methods.