JP6086487B2 - Battery state detection device - Google Patents

Description

  The present invention relates to a battery state detection device that detects the state of the battery such as the internal resistance and the degree of deterioration of the battery.

  For example, in various vehicles such as an electric vehicle (EV) that travels using an electric motor and a hybrid vehicle (HEV) that travels using both an engine and an electric motor, a lithium ion rechargeable battery is used as a power source for the electric motor. And rechargeable batteries such as nickel metal hydride batteries.

  It is known that such secondary batteries are deteriorated by repeating charging and discharging, and the chargeable capacity (current capacity, power capacity, etc.) gradually decreases. In an electric vehicle using a secondary battery, the storageable capacity is obtained by detecting the degree of deterioration of the secondary battery, and the distance that can be traveled by the secondary battery and the life of the secondary battery are calculated. doing.

  One index indicating the degree of deterioration of the secondary battery is SOH (State of Health) which is the ratio of the current chargeable capacity to the initial chargeable capacity. This SOH is known to have a correlation with the internal resistance of the secondary battery, and the SOH can be detected based on the internal resistance by obtaining the internal resistance of the secondary battery.

  The internal resistance of the secondary battery is based on, for example, a DC signal in which the voltage and current are constant or an AC signal in which the voltage and current waveforms are constant and the response to the secondary battery. Can be sought. An example of a technique for measuring the internal resistance of such a secondary battery is disclosed in Patent Document 1 and the like.

  In the method disclosed in Patent Document 1, in an assembled battery in which a plurality of secondary battery single cell batteries are combined, a single cell battery to be measured (hereinafter simply referred to as “measured battery”) is used. When a current is applied from the outside, a choke coil is provided between the unit cell adjacent to the measured battery and a shunt current flowing to the other unit cell batteries other than the measured battery is suppressed. . This eliminates the influence of other single cell batteries connected to the measured battery, measures the voltage of the measured battery before energization and the voltage of the measured battery after elapse of a predetermined time after energization, The internal resistance was calculated from the difference voltage between these voltages and the externally applied current.

JP-A-9-54147

  However, in the method disclosed in Patent Document 1, it is necessary to energize for a short time with a predetermined current by a short-time measurement circuit provided separately from the charger, that is, the current is supplied to the secondary battery separately from the charger. Therefore, there is a problem that the manufacturing cost is increased and the apparatus is enlarged.

  The present invention aims to solve this problem. That is, an object of the present invention is to provide a battery state detection device that can effectively suppress an increase in manufacturing cost and an increase in size of the device.

  In order to achieve the above object, the invention described in claim 1 is: (a) a main switch provided between a secondary battery and a load powered by the secondary battery; and (b) A sub-switch connected in parallel with the main switch and closed prior to the main switch when power supply to the load is started; (c) in parallel with the main switch and the sub-switch An inrush current limiting resistor connected in series, and (d) a charging means connected to the secondary battery via the main switch and the auxiliary switch, and for supplying a predetermined charging current to the secondary battery; (E) first switch control means for controlling the main switch so that the main switch is closed when the secondary battery is charged; and (f) during charging of the secondary battery. When the main switch is in a closed state, the current value flowing through the secondary battery is measured. 1 current value measuring means, and (g) the charging means so that a current having a predetermined first charging current value flows through the secondary battery based on the current value measured by the first current value measuring means. A battery state detection device comprising: a first charge control means for controlling the second battery, when a current that is the first charge current value flows through the secondary battery; After the voltage value is measured by the first voltage value measuring means and the first voltage value measuring means, the main switch is opened and the sub switch is closed. Second switch control means for controlling the main switch and the sub switch, and when the main switch is opened and the sub switch is closed during charging of the secondary battery, A second ampere meter for measuring a current value flowing through the secondary battery And the charging so that a current having a predetermined second charging current value different from the first charging current value flows through the secondary battery based on the current value measured by the second current value measuring means. A second charge control means for controlling the means, and a second voltage value for measuring a voltage value between both electrodes of the secondary battery immediately after a current as the second charge current value flows into the secondary battery. Based on the voltage value measured by the measuring means, the first voltage value measuring means, the voltage value measured by the second voltage value measuring means, the first charging current value, and the second charging current value. Battery state detecting means for detecting the state of the secondary battery, and the second current value measuring means is a current flowing through the secondary battery based on a voltage value between terminals of the inrush current limiting resistor. Configured to measure values Is a battery state detection device.

  In the invention described in claim 1, the main switch is provided between the secondary battery and a load supplied with power by the secondary battery, and is connected in series with the sub switch and the sub switch. An inrush current limiting resistor is provided in parallel with the main switch between the secondary battery and the load. Since the secondary switch is closed prior to the main switch, when power supply to the load is started, power is first supplied through the secondary switch and the inrush current limiting resistor, and then the main switch is closed and the main switch is closed. Electric power is supplied through the switch. Further, when charging the secondary battery, the first switch control means controls the main switch so that the main switch is in a closed state (hereinafter referred to as “first open / close state”), and the first switch When the current value measuring means is in the first open / close state during charging of the secondary battery, the current value flowing through the secondary battery is measured, and the first charge control means is measured by the first current value measuring means. Based on the current value, the charging means is controlled so that a current having a predetermined first charging current value flows through the secondary battery. And the 1st voltage value measurement means measures the voltage value between the both electrodes of a secondary battery, when the electric current used as the 1st charging current value is flowing into the secondary battery. A state in which the main switch is opened and the sub switch is closed after the voltage value is measured by the first voltage value measuring unit (hereinafter referred to as “second switch state”). The main switch and the sub switch are controlled so as to be. When the second current value measuring means is in the second open / close state during charging of the secondary battery, the current value flowing through the secondary battery is measured. The charging means is configured so that the second charging control means causes a current having a predetermined second charging current value different from the first charging current value to flow through the secondary battery based on the current value measured by the second current value measuring means. To control. The second voltage value measuring means measures the voltage value between both electrodes of the secondary battery immediately after the current that becomes the second charging current value flows to the secondary battery. Based on the voltage value measured by the first voltage value measuring means, the voltage value measured by the second voltage value measuring means, the first charging current value and the second charging current value, the battery state detecting means Detect the state of. The second current value measuring means is configured to measure the current value flowing through the secondary battery based on the voltage value between the terminals of the inrush current limiting resistor.

  According to the first aspect of the present invention, in the configuration for supplying power to the load by the secondary battery, the auxiliary switch and the inrush current limiting resistor are provided separately from the power supply path provided with the main switch. In the case of providing another power supply path, the inrush current is limited by using the other power supply path at the start of power supply. When charging the secondary battery, these two power supply paths are used. 2 is used to supply two different charging currents to the secondary battery, and the value of the current flowing through the secondary battery can be measured using an inrush current limiting resistor provided in advance. In other words, a current corresponding to the first charging current value is passed using the power supply path provided with the main switch, and the voltage value between both electrodes of the secondary battery at that time is measured, and the sub switch is provided. A current as the second charging current value is passed using another power supply path, and a voltage value between both electrodes of the secondary battery at that time is measured, and the secondary battery is based on these voltage value and current value. Detect the state of. And about the electric current used as the 2nd charging current value, it is produced | generated by controlling a charging means based on the electric current value measured using the inrush current limiting resistor in the said other electric power supply circuit. For this reason, the state of the secondary battery can be detected without providing a means for supplying a current to the secondary battery separately from the charging means, so that an increase in manufacturing cost and an increase in size of the apparatus can be effectively suppressed.

  In addition, as a configuration for measuring the current value flowing in the secondary battery, for example, in the case of measuring based on the magnetic field due to the current flowing in the secondary battery, the measurement accuracy becomes low when the current value is small, In the case where the current measuring means is provided in series between the secondary battery and the charging means, the measurement accuracy can be improved, but power loss or heat generation occurs in the current measuring means when power is supplied to the load. However, in the present invention, since the current value flowing through the secondary battery is measured using a pre-installed inrush current limiting resistor, it is possible to suppress degradation in measurement accuracy, power loss and heat generation. Can do.

It is a figure which shows schematic structure of the battery state detection apparatus of one Embodiment of this invention. It is a figure which shows the equivalent circuit of a secondary battery. It is a flowchart which shows an example of the charging process performed by the control part with which the battery state detection apparatus of FIG. 1 is provided.

  Hereinafter, a battery state detection device according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram showing a schematic configuration of a battery state detection device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an equivalent circuit of the secondary battery. FIG. 3 is a flowchart illustrating an example of a charging process executed by a control unit included in the battery state detection device of FIG.

  The battery state detection device is mounted on, for example, an electric vehicle and detects an internal resistance of the secondary battery as a state of a secondary battery included in the electric vehicle. Of course, you may apply to the apparatus, system, etc. which were equipped with secondary batteries other than an electric vehicle.

  As shown in FIG. 1, the battery state detection device (indicated by reference numeral 1 in the figure) of the present embodiment includes an assembled battery 5 mounted on an electric vehicle (not shown), a motor supplied with power by the assembled battery 5, It is provided between loads 6 such as various electronic devices, and performs charging of the assembled battery 5 and detection of internal resistance of the secondary battery B constituting the assembled battery 5.

  The assembled battery 5 is configured by connecting a plurality of secondary batteries B in series. As schematically shown in FIG. 2, these secondary batteries B have an electromotive force portion e that generates a voltage and an internal resistance r. The secondary battery B generates a voltage V between both electrodes (the positive electrode Bp and the negative electrode Bn), and this voltage V is a voltage generated by an electromotive force generated by the electromotive force unit e and a voltage generated by a current flowing through the internal resistance r. And Vr (V = Ve + Vr).

  Such an internal resistance r of the secondary battery B can be obtained by the following method.

In the secondary battery B, when the voltage between both electrodes of the secondary battery B when a predetermined charging current I1 is passed is V1, the voltage V1 is expressed by the following equation (i).
V1 = Ve + r × I1 (i)

In the secondary battery B, a predetermined charging current I2 (I2 ≠ I1) is supplied instead of the charging current I1 in a state where the voltage V1 is obtained when the charging current I1 is supplied. Here, the charging current I2 is set to a sufficiently small current value such that the voltage Ve of the secondary battery B does not change to affect the detection of the internal resistance r, and the energization time is also short. That is, the charging current I2 is referred to as “charging current” for the sake of convenience from the direction of flow, but in actuality, charging is not performed with the charging current I2. When the voltage between both electrodes of the secondary battery B when the charging current I2 is flowing is V2, the voltage V2 is expressed by the following equation (ii).
V2 = Ve + r × I2 (ii)

And from these (i) and (ii) formula, the internal resistance r of the secondary battery B is calculated | required by the following (iii) formula.
r = (V1-V2) / (I1-I2) (iii)

  The internal resistance r of the secondary battery B has a correlation with SOH (State of Health) which is a ratio of the current chargeable capacity to the initial chargeable capacity in the secondary battery B. Therefore, by measuring the internal resistance r of the secondary battery B, it is possible to grasp SOH.

  And the battery state detection apparatus of this embodiment detects the internal resistance of the secondary battery B which comprises the assembled battery 5 using the method mentioned above.

  A battery state detection device (indicated by reference numeral 1 in the figure) of the present embodiment shown in FIG. 1 includes a main switch 11, a sub switch 12, an inrush current limiting resistor 13, a charging unit 21, a first switch A current value measuring unit 22, a second current value measuring unit 23, a voltage value measuring unit 24, a multiplexer unit 25, and a control unit 30 are provided.

  The main switch 11 is composed of, for example, a relay device, and is inserted and arranged in series in a circuit portion C1 that connects the assembled battery 5 and the load 6. That is, the main switch 11 is provided between the assembled battery 5 and the load 6. The positive electrode of the assembled battery 5 is connected to the load 6 through the circuit portion C1, and the negative electrode of the assembled battery 5 is connected to the load 6 through the reference potential circuit G (ground).

  Similar to the main switch 11, the sub switch 12 is composed of a relay device or the like, and is connected in parallel with the circuit portion C1 (in parallel between the branch points indicated by P1 and P2 in the figure). The battery pack 5 and the load 6 are inserted and arranged in series in the circuit portion C2 connected to the load 6. That is, the sub switch 12 is connected in parallel with the main switch 11.

  The inrush current limiting resistor 13 is composed of a fixed resistor or the like, and is arranged in series with the circuit portion C2. That is, the inrush current limiting resistor 13 is connected in parallel with the main switch 11 and in series with the sub switch 12.

  The charging unit 21 includes, for example, a power supply device that is supplied with electric power from an external power source connected to the electric vehicle and can output a charging current having an arbitrary current value. The output is connected between the device 11 and the load 6 (point indicated by the symbol Q in the figure).

  The first current value measuring unit 22 is disposed between the branch point P1 on the load 6 side in the circuit part C1 and the point Q to which the output of the charging unit 21 in the circuit part C1 is connected. The first current value measuring unit 22 measures a current value flowing through the circuit part C1 when power is supplied from the assembled battery 5 to the load 6, and the circuit part is output when charging current is output from the charging unit 21 to the assembled battery 5. The current value flowing through C1 is measured. For this reason, when an ammeter of the type inserted in series in the circuit part C1 is used, a loss occurs due to the flow of current. Therefore, the first current value measuring unit 22 is, for example, an overhead line ammeter (clamp meter) or the like It is desirable to consist of

  The second current value measuring unit 23 is connected to both terminals of the inrush current limiting resistor 13, and measures the current value flowing through the circuit portion C2 based on the voltage value generated between the two terminals. Since the second current value measuring unit 23 measures the current value based on the voltage drop voltage value generated by the resistor, the current value can be accurately measured even when the current value is smaller than that of the overhead wire ammeter.

  The voltage value measuring unit 24 is connected to each of the plurality of secondary batteries B constituting the assembled battery 5 through the multiplexer unit 25 on a one-to-one basis, and measures a voltage value between both electrodes of the plurality of secondary batteries B. .

  The control unit 30 is composed of a microcomputer with a built-in CPU, ROM, RAM, and the like, and controls the battery state detection device 1 as a whole. The ROM stores in advance a control program for causing the CPU to function as various means such as first switch control means, first charge control means, second switch control means, second charge control means, and battery state detection means. The CPU functions as the various means by executing the control program.

  The control unit 30 is connected to the main switch 11, the sub switch 12, the charging unit 21, and the multiplexer unit 25, and transmits a control signal to the main switch 11, the sub switch 12, and the sub switch 12. Open / close control is performed, the current value output from the charging unit 21 is controlled (charging control), and connection switching between the plurality of secondary batteries B of the assembled battery 5 and the voltage value measuring unit 24 in the multiplexer unit 25 is controlled.

  The control unit 30 is connected to the first current value measuring unit 22, the second current value measuring unit 23, and the voltage value measuring unit 24, and flows through the circuit portion C1 by receiving measurement signals from these. The current value is acquired, the current value flowing through the circuit portion C2 is acquired, and the voltage value between the electrodes of the plurality of secondary batteries B of the assembled battery 5 is acquired.

  The control unit 30 is connected to an in-vehicle network (for example, CAN (Controller Area Network)), and is connected to a display device such as a terminal device for vehicle maintenance through the in-vehicle network. The control unit 30 transmits a signal indicating the internal resistance detected for the secondary battery B to the display device through the in-vehicle network, and displays the state of the assembled battery 5 such as the internal resistance based on the signal on the display device. Alternatively, the control unit 30 transmits a signal indicating the internal resistance detected for the secondary battery B to a display device such as a combination meter mounted on the vehicle through the in-vehicle network, and the internal resistance is based on the signal in the display device. The state of the secondary battery B such as may be displayed.

  The above-described battery state detection device 1 has a main switch at the start of power supply in order to prevent the assembled battery 5 and the load 6 from being damaged by a large current flowing rapidly from the assembled battery 5 toward the load 6. 11 and the auxiliary switch 12 are controlled. Specifically, the battery state detection device 1 is ignited from an electronic control unit (ECU) (not shown) mounted on the vehicle in a state where both the main switch 11 and the sub switch 12 are open (power supply stop state). When the switch ON is notified, the auxiliary switch 12 is closed first. Thereby, a current flows from the assembled battery 5 to the load 6 through the inrush current limiting resistor 13 and the auxiliary switch 12. Thereafter, the main switch 11 is opened and the sub switch 12 is closed. Thereby, current flows from the assembled battery 5 to the load 6 through the main switch 11 thereafter. In this way, the current limited by the inrush current limiting resistor 13 is first supplied, and then an unrestricted current is supplied.

  Next, an example of the charging process in the control unit 30 provided in the battery state detection device 1 described above will be described with reference to the flowchart of FIG. In the following description, it is assumed that the assembled battery 5 includes a plurality of secondary batteries B [1] to B [n] (n is the number of secondary batteries B).

  When notified from an electronic control unit (ECU) (not shown) mounted on the vehicle that the external power source is connected, the control unit 30 performs the charging process of FIG. In this charging process, the internal resistance of the secondary batteries B [1] to B [n] of the assembled battery 5 is detected together with the charging operation of the assembled battery 5.

  First, the main switch 11 is closed and the sub switch 12 is opened. Specifically, the control unit 30 sends a control signal to the main switch 11 and the sub switch 12 so that the main switch 11 is closed and the sub switch 12 is opened (first switch state). Transmit (S110).

  Next, a current having a predetermined first charging current value I1 is passed through the assembled battery 5. Specifically, the control unit 30 detects a current value flowing through the circuit portion C1 (that is, the assembled battery 5) based on a measurement signal from the first current value measurement unit 22, and a predetermined first charging current. The charging unit 21 is feedback-controlled so that a current having a value I1 flows (S120). Here, since the secondary batteries B [1] to B [n] of the assembled battery 5 are connected in series, the secondary batteries B [1] to [n] also have the first charging current value. Current flows. The assembled battery 5 is charged by supplying a current having the first charging current value I1 in the first open / close state (that is, a charging operation).

  Next, the completion of charging is determined. Specifically, the control unit 30 transmits a control signal to the multiplexer unit 25 to sequentially connect the plurality of secondary batteries B [1] to B [n] to the voltage value measurement unit 24, and the voltage value The measurement unit 24 sequentially measures voltage values between both electrodes of the plurality of secondary batteries B [1] to B [n]. And the control part 30 detects the voltage value between both electrodes of several secondary battery B [1] -B [n] based on the measurement signal from the voltage value measurement part 24, and these voltage values When any one of them reaches a predetermined charging completion voltage value, it is determined that charging is completed, and the charging process is terminated (Y in S130).

  Alternatively, when it is determined that charging is not completed because none of the voltage values between the electrodes of the plurality of secondary batteries B [1] to B [n] has reached the charging completion voltage value (N in S130) Next, it is determined whether or not the detection of the internal resistances r [1] to r [n] is completed for the plurality of secondary batteries B [1] to B [n]. Specifically, the control unit 30 stores, in the RAM, information indicating that the internal resistance has been detected for the secondary battery B that has detected the internal resistance r when the internal resistance of the secondary battery B described later is detected (S200). The above determination is performed based on the information. When it is determined that the detection of the internal resistances r [1] to r [n] is completed for all the secondary batteries B [1] to B [n], the charging operation is restored (Y in S140). ).

  Alternatively, when it is determined that the detection of the internal resistances r [1] to r [n] is not finished for all the secondary batteries B [1] to B [n] (N in S140), It is determined whether or not any of the secondary batteries B [1] to B [n] has a predetermined reference voltage value Vs. Specifically, the control unit 30 transmits a control signal to the multiplexer unit 25 to sequentially connect the plurality of secondary batteries B [1] to B [n] to the voltage value measurement unit 24, and the voltage value The measurement unit 24 sequentially measures voltage values between both electrodes of the plurality of secondary batteries B [1] to B [n]. And the control part 30 detects the voltage value between both electrodes of several secondary battery B [1] -B [n] based on the measurement signal from the voltage value measurement part 24, and these voltage values When it is determined that none of them is equal to the reference voltage value Vs, the charging operation is restored (N in S150). As for the reference voltage value Vs, one reference voltage value Vs may be used in common for a plurality of secondary batteries B [1] to B [n], or a plurality of reference voltage values Vs [1] to Vs [n] may be set for each of the plurality of secondary batteries B [1] to B [n].

  Alternatively, when it is determined that one of the voltage values between the electrodes of the plurality of secondary batteries B [1] to B [n] has reached the predetermined reference voltage value Vs (Y in S150), For the secondary battery B [k] (one of k = 1 to n), a voltage value between both electrodes (hereinafter referred to as “first voltage value V1”) is detected. Specifically, the control unit 30 transmits a control signal to the multiplexer unit 25 to connect the secondary battery B [k] to the voltage value measurement unit 24, and in the voltage value measurement unit 24, the secondary battery The voltage value between both electrodes of B [k] is measured. Then, the control unit 30 detects the first voltage value V1 based on the measurement signal from the voltage value measurement unit 24 (S160).

  Next, the main switch 11 is opened and the sub switch 12 is closed. Specifically, the control unit 30 sends a control signal to the main switch 11 and the sub switch 12 so that the main switch 11 is opened and the sub switch 12 is closed (second switch state). Transmit (S170).

  Next, a current having a predetermined second charging current value I2 is passed through the assembled battery 5. Specifically, the control unit 30 detects a current value flowing through the circuit portion C2 (that is, the assembled battery 5) based on a measurement signal from the second current value measurement unit 23, and a predetermined second charging current. The charging unit 21 is feedback-controlled so that a value current flows (S180). Here, since the secondary batteries B [1] to B [n] of the assembled battery 5 are connected in series, the secondary battery B [k] included therein also has a second charging current value. Flows. Here, the second charging current value I2 is set to a sufficiently small current value such that the voltage Ve in the electromotive force portion e of the secondary battery B does not change the detection of the internal resistance r, and the energization time is also set. It shall be short.

  Next, immediately after the second charging current value I2 flows out, a voltage value between both electrodes of the secondary battery B [k] (hereinafter referred to as “second voltage value V2”) is detected. Specifically, the control unit 30 transmits a control signal to the multiplexer unit 25 to connect the secondary battery B [k] to the voltage value measurement unit 24, and in the voltage value measurement unit 24, the secondary battery The voltage value between both electrodes of B [k] is measured. Then, the control unit 30 detects the second voltage value V2 based on the measurement signal from the voltage value measurement unit 24 (S190).

  Next, the internal resistance r [k] of the secondary battery B [k] is detected. Specifically, the control unit 30 uses the method described above (equations (i) to (iii)) to determine the first voltage value V1, the second voltage value V2, the first charging current value I1, and the second voltage value. Based on the charging current value I2, the internal resistance r [k] of the secondary battery B [k] is detected. Then, the control unit 30 stores the detected internal resistance r [k] in the RAM and stores information indicating that the internal resistance has been detected for the secondary battery B [k] in the RAM (S200). Then, the charging operation is restored.

  Then, when the above-described charging process is completed, the control unit 30 performs internal resistance r for the plurality of secondary batteries B [1] to [n] of the assembled battery 5 detected in the charging process through the in-vehicle network. [1] to [n] are transmitted to other devices.

  The control unit 30 functions as first switch control means by executing the process of step S110 in the flowchart of FIG. 3, and functions as first charge control means by executing the process of step S120. It functions as a second switch control unit by executing the process, functions as a second charge control unit by executing the process of step S180, and functions as a battery state detection unit by executing the process of step S200. .

  As described above, in the battery state detection device 1 of the present embodiment, the main switch 11 is provided between the assembled battery 5 composed of a plurality of secondary batteries B and the load 6 supplied with power by the assembled battery 5. A sub-switch 12 and an inrush current limiting resistor 13 connected in series with the sub-switch 12 are provided between the assembled battery 5 and the load 6 in parallel with the main switch 11. Yes. Since the auxiliary switch 12 is closed prior to the main switch 11, when power supply to the load 6 is started, power is first supplied through the auxiliary switch 12 and the inrush current limiting resistor 13, and then the main switch 11. Is closed and electric power is supplied through the main switch 11. Further, when charging the battery pack 5, the first switch control means is configured so that the main switch 11 is closed and the sub switch 12 is opened (hereinafter referred to as "first switch state"). The main switch 11 and the sub switch 12 are controlled, and the first current value measuring unit 22 measures the current value flowing through the assembled battery 5 when the assembled battery 5 is being charged and in the first opened / closed state. The first charging control unit controls the charging unit 21 based on the current value measured by the first current value measuring unit 22 so that a current having a predetermined first charging current value I1 flows through the assembled battery 5. . Then, the voltage value measuring unit 24 is configured to detect the voltage value (first voltage) between the electrodes of the secondary battery B constituting the assembled battery 5 when a current that becomes the first charging current value I1 flows through the assembled battery 5. The value V1) is measured. After the second switch control means has measured the voltage value by the voltage value measuring unit 24, the main switch 11 is opened and the sub switch 12 is closed (hereinafter referred to as "second switch state"). The main switch 11 and the sub switch 12 are controlled so that When the second current value measurement unit 23 is in the second open / close state during charging of the assembled battery 5, the current value flowing through the assembled battery 5 is measured. Based on the current value measured by the second current value measuring unit 23, the second charge control means causes the battery pack 5 to receive a current having a predetermined second charging current value I2 different from the first charging current value I1. The charging unit 21 is controlled. Immediately after the voltage value measuring unit 24 starts flowing the current that becomes the second charging current value I2 into the assembled battery 5, the voltage value between the electrodes of the secondary battery B constituting the assembled battery 5 (second voltage value V2). ). The battery state detection means detects the state of the secondary battery B constituting the assembled battery 5 based on the first voltage value V1, the second voltage value V2, the first charging current value I1, and the second charging current value I2. . The second current value measuring unit 23 is configured to measure the current value flowing through the assembled battery 5 based on the voltage value between the terminals of the inrush current limiting resistor 13.

  That is, according to the present embodiment, in the configuration in which power is supplied to the load 6 by the assembled battery 5 including a plurality of secondary batteries B, the circuit portion C1 that is a power supply path provided with the main switch 11 and In addition, the circuit portion C2 that is another power supply path provided with the auxiliary switch 12 and the inrush current limiting resistor 13 is used to limit the inrush current by using the circuit portion C2 at the start of power supply. However, when charging the assembled battery 5, two different charging currents are supplied to the assembled battery 5 using the two circuit portions C1 and C2, and an inrush current limiting resistor provided in advance is provided. 13 can be used to measure the value of the current flowing through the assembled battery 5. That is, the circuit portion C1 provided with the main switch 11 is used to flow a current having the first charging current value I1, and the voltage value (first voltage value V1) between the electrodes of the secondary battery B at that time is supplied. Measure and pass a current that becomes the second charging current value I2 using the circuit portion C2 and measure the voltage value (second voltage value V2) between the electrodes of the secondary battery B at that time. The state of the secondary battery B is detected based on the first voltage value, the second voltage value, the first charging current value I1, and the second charging current value I2. The current that becomes the second charging current value I2 is generated by controlling the charging unit 21 based on the current value measured using the inrush current limiting resistor 13 in the circuit portion C2. . Therefore, it is possible to detect the state of the secondary battery B constituting the assembled battery 5 without providing a means for flowing current to the assembled battery 5 separately from the charging unit 21, thereby increasing the manufacturing cost and the size of the apparatus. Can be effectively suppressed.

  Further, as a configuration for measuring the current value flowing through the assembled battery 5, for example, in the case of measuring based on the magnetic field due to the current flowing through the assembled battery 5, the measurement accuracy becomes low when the current value is small, In the case where the current measuring unit is provided in series between the assembled battery 5 and the charging unit 21, the measurement accuracy can be improved, but power loss or heat generation occurs in the current measuring unit when power is supplied to the load. However, in this embodiment, since the current value flowing through the assembled battery 5 is measured using the inrush current limiting resistor 13 provided in advance, a decrease in measurement accuracy, power loss, and heat generation are caused. Can be suppressed.

  While the present invention has been described with reference to the preferred embodiments, the battery state detection device of the present invention is not limited to the configurations of these embodiments.

  For example, in the above-described embodiment, the configuration is such that the internal resistance r of the secondary battery B is detected as the state of the secondary battery B, but is not limited thereto, and the internal resistance r of the secondary battery B By utilizing the fact that the SOH of the secondary battery B has a correlation, the SOH may be further detected from the internal resistance r.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are included in the scope of the present invention as long as the configuration of the battery state detection device of the present invention is provided.

DESCRIPTION OF SYMBOLS 1 Battery state detection apparatus 5 Assembled battery 6 Load 11 Main switch 12 Sub switch 13 Inrush current limiting resistor 21 Charging part (charging means)
22 1st electric current value measurement part (1st electric current value measurement means)
23 Second current value measuring unit (second current value measuring means)
24 Voltage value measuring unit (first voltage value measuring means, second voltage value measuring means)
25 multiplexer unit 30 control unit (first switch control means, first charge control means, second switch control means, second charge control means, battery state detection means)
B Secondary battery I1 First charging current value I2 Second charging current value V1 First voltage value V2 Second voltage value

Claims (1)

(A) a main switch provided between a secondary battery and a load powered by the secondary battery; and (b) connected to the main switch in parallel to start supplying power to the load. A sub-switch that is closed prior to the main switch, (c) an inrush current limiting resistor connected in parallel with the main switch and in series with the sub-switch, and (d) the main switch Charging means connected to the secondary battery via the switch and the auxiliary switch, and for supplying a predetermined charging current to the secondary battery; and (e) the main switch is closed when the secondary battery is charged. First switch control means for controlling the main switch so as to be in a closed state, and (f) when the main switch is closed during charging of the secondary battery, the current flows to the secondary battery A first current value measuring means for measuring a current value; and (g) the first current value measuring means. And a first charge control means for controlling the charging means so that a current having a predetermined first charging current value flows through the secondary battery based on the measured current value. Because
First voltage value measuring means for measuring a voltage value between both electrodes of the secondary battery when a current that is the first charging current value flows through the secondary battery;
After the voltage value is measured by the first voltage value measuring means, the main switch and the sub switch are controlled so that the main switch is opened and the sub switch is closed. Second switch control means;
A second current value measuring means for measuring a current value flowing through the secondary battery when the main switch is opened and the sub switch is closed during charging of the secondary battery;
Based on the current value measured by the second current value measuring means, the charging means is controlled such that a current having a predetermined second charging current value different from the first charging current value flows through the secondary battery. Second charge control means for performing,
A second voltage value measuring means for measuring a voltage value between both electrodes of the secondary battery immediately after a current as the second charging current value flows into the secondary battery;
Based on the voltage value measured by the first voltage value measuring means, the voltage value measured by the second voltage value measuring means, the first charging current value, and the second charging current value, the secondary Battery state detection means for detecting the state of the battery,
The battery state detection device, wherein the second current value measuring means is configured to measure a current value flowing through the secondary battery based on a voltage value between terminals of the inrush current limiting resistor. .

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