JP2007256218A - Measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the generation of a spark due to an inflow of an inrush current, and to suppress an increase in power consumption. <P>SOLUTION: The measurement device includes: a current supply part 2 supplying a measurement current Im to a battery 100 via first terminals 22a, 22b; a CPU 9 measuring internal resistance Rx of the battery 100 during a supply of the measurement current Im; and a connection detection part 3 detecting connection of the first terminals 22a, 22b and the battery 100. The current supply part 2 includes: a current source 11 supplying the measurement current Im to the battery 100; a capacitor 12 and a resistor 13 connected in series between the current source 11 and the first terminal 22a; and a switch circuit 14 configured so as to be capable of short-circuiting a section between both ends of the resistor 13. The CPU 9 measures the internal resistance Rx after short-circuiting the section between both the ends of the resistor 13 by controlling the switch circuit 14 when connection of the first terminals 22a, 22b and the battery 100 is detected by the connection detection part 3 and when a prescribed condition is satisfied. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a current supply unit that supplies a measurement current to a battery as a measurement object via a measurement terminal, and a measurement unit configured to measure an electrical parameter of the battery when the measurement current is supplied. The present invention relates to a measuring device provided.

As this type of measuring apparatus, the applicant discloses a battery measuring apparatus capable of measuring electrical parameters of a battery in Japanese Patent Laid-Open No. 9-281202. This battery measuring device includes a current source (“AC constant current source” in the same publication), an amplifier, and a detection circuit, and is configured to measure internal resistance as an electrical parameter. In this case, the current source supplies a measurement signal (AC signal) to the battery via the coupling capacitor. The amplifier amplifies the voltage drop of the measurement signal due to the internal resistance of the battery, and the detection circuit detects the voltage drop amplified by the amplifier in synchronization with the phase of the AC current source. Thereby, in this battery measuring device, the internal resistance (effective resistance) of the battery is measured (detected).
JP-A-9-281202 (page 4, FIG. 1)

  However, the battery measuring apparatus has the following problems to be improved. That is, in this type of measuring device, when a battery is connected to a current source via a coupling capacitor, the coupling capacitor in the initial state is not charged, so the current from the battery suddenly enters the coupling capacitor. Flow into. At this time, since an excessive inrush current flows at the contact point between the measurement terminal on the current source side and the battery terminal, there is a possibility that a spark resulting from the inflow of the inrush current may occur at the contact point of both terminals. In this case, for example, by providing a current limiting resistor between the measurement terminal connected to the battery and the coupling capacitor, the current value of the current flowing from the battery to the coupling capacitor is reduced, and the inrush current flows. It is possible to avoid the occurrence of sparks due to. However, in this configuration, extra power is consumed due to flowing the measurement current through the current limiting resistor, so that the power consumption of the entire measurement apparatus during measurement increases. In this case, in this type of measuring device, since it is generally assumed that the usage mode is carried around and the battery is used as the driving source of the measuring device, the power consumption can be kept low. preferable.

  In addition, since a general battery as a measurement object has a very small internal resistance, a sufficient measurement current must be supplied to the battery in order to accurately measure the internal resistance. In this case, in order to avoid the occurrence of sparks, it is necessary to increase the resistance value of the current limiting resistor to some extent. However, as the resistance value is increased, the power consumption increases.

  The present invention has been made in view of such problems to be improved, and avoids the occurrence of sparks due to inflow of inrush current and suppresses an increase in power consumption, while accurately setting the electrical parameters of the battery. The main object is to provide a measuring device that can be measured.

  In order to achieve the above object, a measuring apparatus according to claim 1 includes a current supply unit that supplies a measurement current to a battery as a measurement object via a measurement terminal, and an electric power for the battery when the measurement current is supplied. A measurement device configured to include a measurement unit that measures a physical parameter, a connection detection unit that detects connection of the measurement terminal and the battery, and a control unit, wherein the current supply unit is connected to the battery A current source for supplying the measurement current; a capacitor and a resistor connected in series between the current source and the measurement terminal; and a switch circuit configured to be short-circuited between both ends of the resistor, When the connection detection unit detects the connection between the measurement terminal and the battery and a predetermined condition is satisfied, the control unit controls the switch circuit to short-circuit both ends of the resistor. Wherein the measurement unit is measuring the electrical parameters after.

  Further, in the measuring apparatus according to claim 2, in the measuring apparatus according to claim 1, the control unit controls the current source after controlling the switch circuit to short-circuit both ends of the resistor. The current value of the measurement current is increased, and then the electrical parameter is measured by the measurement unit.

  The measuring apparatus according to claim 3 is the measuring apparatus according to claim 1 or 2, wherein the control unit has a predetermined time from the time when the connection detecting unit detects the connection between the measuring terminal and the battery. When the time has elapsed, the measurement process is executed assuming that the predetermined condition is satisfied.

  In the measuring apparatus according to claim 1, when the connection between the measurement terminal and the battery is detected by the current supply unit and the predetermined condition is satisfied, the control unit controls the switch circuit to connect between both ends of the resistor. After short-circuiting, the measurement part is made to measure electrical parameters. In this case, the capacitor and the battery are connected via the resistor from when the measurement terminal and the battery are connected until the predetermined condition is satisfied. For this reason, it is possible to prevent current from flowing into the capacitor from the battery by the current limiting function of the resistor. Therefore, according to this measuring apparatus, generation | occurrence | production of the spark resulting from inflow of an electric current can be avoided. Further, when measuring the electrical parameter, by short-circuiting both ends of the resistor, it is possible to avoid unnecessary power consumption caused by flowing the measurement current through the resistor. For this reason, even if a larger measurement current is supplied to the battery in order to accurately measure the internal resistance of the battery, an increase in power consumption can be suppressed. Therefore, according to this measuring apparatus, it is possible to accurately measure the electrical parameters while avoiding the generation of sparks due to the inflow of current and suppressing the increase in power consumption.

  Further, according to the measuring apparatus of the second aspect, the control unit increases the current value of the measurement current prior to the measurement of the electrical parameter, so that even if noise is superimposed on the measurement current, for example, As a result, the electrical parameter can be measured more accurately.

  Further, in the measuring apparatus according to claim 3, by executing the measurement process when the control unit has passed a predetermined charging time from the time when the connection of the measurement terminal and the battery is detected by the connection detection unit, By prescribing a sufficient time for the capacitor to be charged by the current from the battery as the charging time, the control unit simply executes a simple process to determine whether or not the charging time has passed. As a result of determining whether or not the measurement process is appropriate, the measurement apparatus can be simply configured.

  Hereinafter, the best mode of a measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  First, the configuration of a battery tester 1 as an example of a measuring apparatus according to the present invention will be described with reference to the drawings.

  A battery tester 1 shown in FIG. 1 is an example of a measuring apparatus according to the present invention, and is an internal resistance (electrical parameters in the present invention) of a battery (an example of a battery in the present invention) 100 as a measurement object shown in FIG. Example) Rx can be measured by a four-terminal method. Specifically, as shown in the figure, the battery tester 1 includes a current supply unit 2, a connection detection unit 3, a voltage detection unit 4, a RAM 5, a ROM 6, an operation unit 7, a display unit 8, and a CPU 9. ing.

  The current supply unit 2 includes a current source 11, a capacitor 12, a resistor 13, and a switch circuit 14, and is configured to be able to output an alternating measurement current Im. In addition, the current supply unit 2 includes a pair of first terminals 22a and 22b (measurement terminals in the present invention; see FIG. 1; hereinafter referred to as “first terminals 22” when not distinguished). Connected. In this case, the current supply unit 2 supplies the measurement current Im to the battery 100 via the first terminal 22.

  The current source 11 is composed of, for example, an AC constant current source, and is configured so that the current value of the measurement current Im can be changed according to the control of the CPU 9. The capacitor 12 has a capacitance of, for example, 150 μF and is a coupling capacitor that blocks the passage of the direct current by passing the measurement current Im, and is connected between the current source 11 and the resistor 13. The resistor 13 is a current limiting resistor having a resistance value of, for example, 30Ω, and is connected between the capacitor 12 and the first terminal 22a. In this case, the resistor 13 has a function of performing current limitation on the direct current Id (see FIG. 2) flowing from the battery 100 to the capacitor 12. The connection between the capacitor 12 and the resistor 13 is not limited to this, and the capacitor 12 and the resistor 13 may be connected in series between the current source 11 and the first terminal 22a (measurement terminal). The capacitor 12 may be connected between the one terminals 22a. The switch circuit 14 is composed of, for example, a relay, and is connected in parallel with the resistor 13 to short-circuit both ends of the resistor 13 under the control of the CPU 9.

  The connection detector 3 detects the voltage across the resistor 13 when the measurement current Im flows, and outputs a detection signal S1 to the CPU 9 when the voltage is equal to or higher than a predetermined voltage. The voltage detection unit 4 includes, for example, an amplifier circuit, an A / D conversion circuit, and the like (both not shown), and the inter-terminal voltage generated between both terminals of the battery 100 when the measurement current Im is supplied to the battery 100. Vb (see FIGS. 1 and 3) is detected and output to the CPU 9 as voltage data Dv. In addition, a pair of second terminals 23 a and 23 b (see FIG. 1; hereinafter, also referred to as “second terminal 23” when not distinguished) are connected to the voltage detection unit 4. In this case, the voltage detection unit 4 detects the inter-terminal voltage Vb of the battery 100 via the second terminal 23 according to the control of the CPU 9.

  The RAM 5 stores resistance data Dr indicating the resistance value of the internal resistance Rx of the battery 100. The ROM 6 stores charging time data Dt indicating a predetermined charging time (corresponding to a predetermined time in the present invention). Here, the charging time is defined as a time sufficient to complete the charging of the capacitor 12 with the current Id based on the time constant determined by the capacitance value of the capacitor 12 and the resistance value of the resistor 13. The operation unit 7 includes various switches such as a power switch and outputs an operation signal S2 corresponding to the operation of each switch to the CPU 9. The display unit 8 is composed of, for example, an LCD panel, and displays various images (for example, images indicated by the resistance value of the internal resistance Rx) under the control of the CPU 9.

  The CPU 9 functions as a control unit and a measurement unit in the present invention, and controls the voltage detection unit 4, the display unit 8, the current source 11, and the switch circuit 14. Specifically, the CPU 9 executes a predetermined measurement process when the connection detection unit 3 detects the connection between the first terminal 22 and the battery 100 and a predetermined condition is satisfied. In this case, the predetermined condition is that the CPU 9 has passed the charging time from the time when the connection detection unit 3 detects the connection between the first terminal 22 and the battery 100 (that is, the time when the detection signal S1 is output). As it is satisfied, the measurement process is executed. In this measurement process, the CPU 9 controls the switch circuit 14 to short-circuit both ends of the resistor 13 and at the same time the battery based on the voltage value of the inter-terminal voltage Vb indicated by the voltage data Dv and the current value of the measurement current Im. The resistance value of the internal resistance Rx of 100 is calculated (measured). Further, the CPU 9 controls the current source 11 prior to the calculation process of the internal resistance Rx at the time of executing the measurement process, and the measurement current Im that is output before the detection signal S1 is output from the connection detection unit 3. The current value is increased to a larger current value.

  Next, a method for measuring the internal resistance Rx of the battery 100 using the battery tester 1 will be described with reference to the drawings.

  First, the power switch of the operation unit 7 is operated in a state where the first terminal 22 is not connected to the battery 100. At this time, the operation unit 7 outputs an operation signal S2 corresponding to the power switch to the CPU 9. At this time, the CPU 9 controls the switch circuit 14 to the non-operating state to maintain both ends of the resistor 13 in a non-short-circuited state, and controls the current source 11 to control a predetermined current (for example, a low current as an example). A measurement current Im of 50 mA) is output. In this case, since the measurement current Im does not flow through the resistor 13, the voltage across the resistor 13 becomes less than the predetermined voltage, and as a result, the connection detection unit does not output the detection signal S1. Therefore, the CPU 9 determines that the first terminal 22 is not connected to the battery 100.

  Next, as shown in FIG. 1, when the first terminals 22 a and 22 b and the second terminals 23 a and 23 b are connected to the battery 100, the measurement current Im becomes the current source 11 as shown by the broken line in FIG. 2. 1, the capacitor 12, the resistor 13, the first terminal 22 a, the battery 100, the first terminal 22 b, and the other output terminal of the current source 11. For this reason, as a result that the voltage across the resistor 13 becomes equal to or higher than the predetermined voltage, the connection detection unit 3 outputs the detection signal S1 to the CPU 9. Next, the CPU 9 determines that the first terminal 22 is connected to the battery 100, reads the charging time data Dt from the ROM 6, and starts counting the charging time indicated by the charging time data Dt.

  On the other hand, at this time, as indicated by a one-dot chain line in FIG. 2, a direct current Id based on the electromotive force Vx of the battery 100 is supplied from the first terminal 22a, the resistor 13, the capacitor 12, the current source 11, and the first terminal 22b. Flows through the current path. In this case, the current Id flowing into the capacitor 12 is limited by the resistor 13. Therefore, in this battery tester 1, the occurrence of sparks due to the inflow of the current Id from the battery 100 is avoided.

  Next, when the above charging time has elapsed, charging of the capacitor 12 with the current Id is completed, and the inflow of the current Id into the current supply unit 2 is restricted. Further, the CPU 9 executes the measurement process on the assumption that the predetermined condition is satisfied when the charging time has elapsed. In this case, since a sufficient time for the capacitor 12 to be charged by the current Id is specified in advance as the charging time, the CPU 9 only performs a simple process for determining whether or not the charging time has elapsed. Therefore, it is possible to determine whether the measurement process is appropriate.

  In the measurement process, the CPU 9 controls the switch circuit 14 to short-circuit both ends of the resistor 13. At this time, as indicated by a broken line in FIG. 3, the measurement current Im includes one output terminal of the current source 11, the capacitor 12, the switch circuit 14, the first terminal 22 a, the battery 100, the first terminal 22 b, and the current source. 11 is supplied to the battery 100 through a current path including the other output terminal.

  Next, the CPU 9 controls the current source 11 to adjust the current value of the measurement current Im so as to be a predetermined current value (for example, 150 mA as an example of a large current) larger than the initial current value (in this case, 50 mA). increase. In this case, by increasing the measurement current Im during the measurement process, for example, even if noise is superimposed on the measurement current Im, the S / N ratio at the time of measurement can be maintained large. Subsequently, the CPU 9 controls the voltage detection unit 4 to output voltage data Dv. The voltage value of the inter-terminal voltage Vb indicated by the voltage data Dv and the current value of the measurement current Im (in this case, 150 mA) are output. Based on this, the resistance value of the internal resistance Rx of the battery 100 is calculated. Next, the CPU 9 stores the resistance data Dr indicating the resistance value of the internal resistance Rx in the RAM 5 and controls the display unit 8 to display an image indicating the resistance value of the internal resistance Rx, thereby ending this measurement process. .

  Thus, in this battery tester 1, the CPU 9 controls the switch circuit 14 to detect resistance when the connection between the first terminal 22 and the battery 100 is detected by the current supply unit 2 and a predetermined condition is satisfied. After both ends of 13 are short-circuited, the internal resistance Rx is measured. In this case, the capacitor 12 and the battery 100 are connected via the resistor 13 from the time when the first terminal 22 and the battery 100 are connected until the predetermined condition is satisfied. For this reason, it is possible to prevent the current Id from flowing into the capacitor 12 from the battery 100 by the current limiting function of the resistor 13. Therefore, according to this battery tester 1, it is possible to avoid the occurrence of a spark due to the inflow of the current Id. Further, when measuring the internal resistance Rx, by short-circuiting both ends of the resistor 13, it is possible to avoid unnecessary power consumption due to the measurement current Im flowing through the resistor 13. For this reason, even if a larger measurement current Im is supplied to the battery 100 in order to accurately measure the internal resistance of the battery 100, an increase in power consumption can be suppressed. Therefore, according to the battery tester 1, it is possible to accurately measure the internal resistance Rx while avoiding the generation of a spark due to the inflow of the current Id and suppressing an increase in power consumption.

  Further, according to the battery tester 1, the CPU 9 increases the current value of the measurement current Im prior to the measurement of the internal resistance Rx, so that, for example, even if noise is superimposed on the measurement current Im, As a result of maintaining a large S / N ratio, the internal resistance Rx can be measured more accurately.

  In the battery tester 1, the CPU 9 performs a measurement process when a predetermined charging time has elapsed since the connection detection unit 3 detected the connection between the first terminal 22 and the battery 100, thereby By setting a sufficient time for charging of the capacitor 12 by Id as the charging time, the measurement process starts only by executing a simple process in which the CPU 9 determines whether or not the charging time has elapsed. As a result, the battery tester 1 can be easily configured.

  In addition, this invention is not limited to said structure. For example, although the example in which the present invention is applied to the battery tester 1 that measures the internal resistance Rx has been described above, the present invention can be applied to a measuring device that can measure various electrical parameters such as voltage, current, and temperature. In addition, these various parameters can be applied to a measuring apparatus capable of measuring two or more types. Moreover, although the battery tester 1 that measures the internal resistance Rx by the four-terminal method has been described as an example, the battery tester 1 can be applied to a measuring device that measures various electrical parameters by the two-terminal method.

  Moreover, although the structure which short-circuits between the both ends of the resistor 13 using the switch circuit 14 was demonstrated, this invention is not limited to this. For example, it is possible to adopt a configuration in which a resistor having a resistance value smaller than that of the resistor 13 is connected in parallel to the resistor 13 when the switch circuit 14 is in an ON state. Even in this configuration, the power consumption caused by the measurement current Im flowing through the resistor 13 can be suppressed in the same manner as the above configuration.

  In addition, although the configuration in which the measurement process is executed when the predetermined condition is satisfied when the charging time has elapsed is described above, the present invention is not limited to this. For example, it is possible to adopt a configuration in which the CPU 9 performs a measurement process on the assumption that a predetermined condition is satisfied when the direct current Id is measured and the current value of the current Id falls below a predetermined reference value. it can.

1 is a configuration diagram showing a configuration of a battery tester 1. FIG. It is a circuit diagram which shows the electric current path | route of the electric current Id and measurement current Im which flow when the switch circuit 14 is an OFF state. FIG. 6 is a circuit diagram showing a current path of a measurement current Im that flows when a switch circuit is in an ON state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery tester 2 Current supply part 3 Connection detection part 4 Voltage detection part 9 CPU
DESCRIPTION OF SYMBOLS 11 Current source 12 Capacitor 13 Resistance 14 Switch circuit 22a, 22b 1st terminal 23a, 23b 2nd terminal 100 Battery Dt Charging time data Im Measurement current Id Current Rx Internal resistance

Claims (3)

A current supply unit that supplies a measurement current to a battery as a measurement object via a measurement terminal, a measurement unit that measures electrical parameters of the battery at the time of supply of the measurement current, the measurement terminal, and the measurement unit A measurement device configured to include a connection detection unit that detects battery connection and a control unit,
The current supply unit includes a current source that supplies the measurement current to the battery, a capacitor and a resistor connected in series between the current source and the measurement terminal, and a short circuit between both ends of the resistor. Switch circuit,
After the control unit detects a connection between the measurement terminal and the battery and the predetermined condition is satisfied by the connection detection unit, the control unit controls the switch circuit to short-circuit both ends of the resistor. A measurement apparatus that causes the measurement unit to measure the electrical parameter.   The control unit controls the switch circuit to short-circuit both ends of the resistor, and then controls the current source to increase the current value of the measurement current, and thereafter, the electrical current is supplied to the measurement unit. The measuring apparatus according to claim 1, wherein the measuring parameter is measured.   The control unit executes the measurement process on the assumption that the predetermined condition is satisfied when a predetermined time elapses from the time when the connection between the measurement terminal and the battery is detected by the connection detection unit. Item 3. The measuring device according to item 1 or 2.

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