Voltage detection device and battery management device

Abstract

To calculate a wiring resistance value with high accuracy in a voltage detection device and a battery management device which obtain the wiring resistance value between a battery and a voltage detection circuit.SOLUTION: A voltage detection device D comprises: a discharge circuit M which is connected in parallel to a battery cell c and has a discharging resistor Z and an electronic switch G; a voltage detection circuit A which detects the voltage of the battery cell c; and a control unit 2 which controls the electronic switch G. The control unit 2 can execute wiring resistance value acquisition processing of acquiring a wiring resistance value R between the voltage detection circuit A and the battery cell c, acquires an ON voltage value on the basis of a detection value obtained from the voltage detection circuit A after the elapse of a voltage stabilization period from setting of the electronic switch G into the ON state, acquires an OFF voltage value on the basis of the detection value obtained from the voltage detection circuit A by setting the electronic switch G into the OFF state, and acquires the wiring resistance value R on the basis of the ON voltage value and the OFF voltage value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a voltage detection device and a battery management device.

Background Art

[0002] Patent Document 1 discloses a management device and a power storage system for managing the states of a plurality of cells connected in series. As disclosed in Patent Document 1, the voltage of each of the plurality of cells is constantly monitored by a voltage measurement circuit. In such Patent Document 1, it is shown that a discharge circuit is used to obtain the voltage drop amount due to the wiring resistance between each cell and the voltage measurement circuit, and the cell voltage is corrected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when obtaining the wiring resistance value, the wiring resistance value is obtained based on the detected voltage value obtained by turning on the electronic switch provided in the discharge circuit and the detected voltage value obtained by turning off the electronic switch. However, immediately after the electronic switch is switched from the OFF state to the ON state, the output voltage of the battery does not stabilize. Therefore, the detected voltage value does not stabilize, and it is difficult to accurately obtain the wiring resistance value.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to accurately calculate the wiring resistance value in a voltage detection device and a battery management device for obtaining the wiring resistance value between a battery and a voltage detection circuit.

Means for Solving the Problems

[0006] The present invention employs the following configuration as a means to solve the above problems.

[0007] One aspect of the present invention is a voltage detection device comprising a discharge circuit connected in parallel to a battery and having a discharge resistor and an electronic switch, a voltage detection circuit for detecting the voltage of the battery, and a control unit for controlling the electronic switch, wherein the control unit is capable of performing a wiring resistance value acquisition process to acquire the wiring resistance value between the voltage detection circuit and the battery, and in the wiring resistance value acquisition process, the control unit sets the electronic switch to the ON state and, after the voltage stabilization period has elapsed, acquires a first detection voltage value for calculating wiring resistance based on the detection value obtained from the voltage detection circuit, sets the electronic switch to the OFF state and acquires a second detection voltage value for calculating wiring resistance based on the detection value obtained from the voltage detection circuit, and acquires the wiring resistance value based on the first detection voltage value for calculating wiring resistance and the second detection voltage value for calculating wiring resistance. [Effects of the Invention]

[0008] According to the present invention, the first detection voltage value for calculating wiring resistance is obtained by the voltage detection circuit after the voltage stabilization period has elapsed since the electronic switch of the discharge circuit was set to the ON state. Therefore, the first detection voltage value for calculating wiring resistance can be obtained while avoiding the period when the battery output voltage is unstable immediately after the electronic switch changes from the OFF state to the ON state. Accordingly, according to the present invention, it is possible to calculate the wiring resistance value with high accuracy in a voltage detection device and battery management device that determine the wiring resistance value between the battery and the voltage detection circuit. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram showing the circuit configuration of a voltage detection device according to the first embodiment of the present invention. [Figure 2] This is a timing chart for acquiring on-voltage and off-voltage values ​​in the voltage detection device according to the first embodiment of the present invention. [Figure 3]This is a schematic diagram showing, in chronological order, the changes in the state related to the control unit of the voltage detection device in the first embodiment of the present invention. [Figure 4] This graph shows an example of the relationship between temperature and the corrected wiring resistance value. [Figure 5] This is a flowchart illustrating the operation of the voltage detection device of the first embodiment of the present invention in the wiring resistance value acquisition sequence. [Figure 6] This is a flowchart for calculating wiring resistance. [Figure 7] This is a flowchart illustrating the operation of the voltage detection device of the first embodiment for determining the actual cell voltage value in a normal sequence. [Figure 8] This is a schematic diagram showing the general configuration of a battery management device in a second embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the voltage detection device and battery management device according to the present invention will be described with reference to the drawings.

[0011] (First Embodiment) Figure 1 is a circuit diagram showing the circuit configuration of the voltage detection device D of this embodiment. The voltage detection device D of this embodiment is designed to detect the battery pack B. This voltage detection device D is installed together with the battery pack B in electric vehicles, hybrid vehicles, and other electric vehicles that use a motor as a power source, and detects the voltage of the battery pack B. A temperature sensor T is also connected to the voltage detection device D to measure the temperature of the battery pack B. Note that the temperature of the battery pack B is not limited to the internal temperature of the battery pack B, but also includes the ambient temperature of the location where the battery pack B is installed. A power supply device U is also connected to the voltage detection device D to supply power.

[0012] As shown in Figure 1, the voltage detection device D includes connection wiring H (0th connection wiring H0, 1st connection wiring H1, 2nd connection wiring H2, and 3rd connection wiring H3). The voltage detection device D also includes CR filters F (0th CR filter F0, 1st CR filter F1, 2nd CR filter F2, and 3rd CR filter F3). The voltage detection device D also includes discharge resistors Z (0th discharge resistor Z0, 1st discharge resistor Z1, 2nd discharge resistor Z2, and 3rd discharge resistor Z3). The voltage detection device D also includes a voltage detection IC 1.

[0013] The voltage detection IC1 includes input terminals IN (0th input terminal IN0, 1st input terminal IN1, 2nd input terminal IN2, and 3rd input terminal IN3). The voltage detection IC1 also includes control terminals CT (0th control terminal CT0, 1st control terminal CT1, 2nd control terminal CT2, and 3rd control terminal CT3). Furthermore, the voltage detection IC1 includes voltage detection circuits A (1st voltage detection circuit A1, 2nd voltage detection circuit A2, and 3rd voltage detection circuit A3). Additionally, the voltage detection IC1 includes electronic switches G (1st electronic switch G1, 2nd electronic switch G2, and 3rd electronic switch G3). Finally, the voltage detection IC1 includes a control unit 2.

[0014] The battery pack B, which is the target of detection, will now be described. Battery pack B consists of multiple battery cells c (first battery cell c1, second battery cell c2, and third battery cell c3) connected in series, and is a secondary battery that supplies DC power, which is the output voltage (battery voltage) obtained by summing the electromotive forces of the multiple battery cells c, to an external load. Such a battery pack B is, for example, a lithium-ion battery.

[0015] Note that Figure 1 shows a configuration of battery pack B that includes three battery cells c: a first battery cell c1, a second battery cell c2, and a third battery cell c3. For convenience, however, the number of battery cells constituting battery pack B is not limited to three. Furthermore, the voltage detection circuit A and electronic switch G constituting the voltage detection IC1 are provided corresponding to the battery cells c, and therefore the number of voltage detection circuits A and electronic switches G changes according to the number of battery cells c.

[0016] The battery cells c (batteries) have a predetermined electromotive force (cell voltage) and are connected in series with each other. Among the first battery cell c1, the second battery cell c2, and the third battery cell c3, the first battery cell c1 and the third battery cell c3 are odd-numbered cells with an odd connection order. On the other hand, the second battery cell c2 is an even-numbered cell with an even connection order.

[0017] Also, each battery cell c has a predetermined internal resistance. This internal resistance exists for each electrode of the battery cell c, that is, for the plus electrode and the minus electrode, as shown in the figure, and can change according to the usage state of the battery pack B.

[0018] That is, an internal resistance r1n exists at the minus electrode of the first battery cell c1, and an internal resistance r1p exists at the plus electrode of the first battery cell c1. Also, an internal resistance r2n exists at the minus electrode of the second battery cell c2, and an internal resistance r2p exists at the plus electrode of the second battery cell c2. Further, an internal resistance r3n exists at the minus electrode of the third battery cell c3, and an internal resistance r3p exists at the plus electrode of the third battery cell c3.

[0019] Returning to the description of the voltage detection device D. The connection wiring H is provided corresponding to each electrode of the battery cell c and is an electric wire that electrically connects the voltage detection device D and the battery pack B. The 0th connection wiring H0 is an electric wire whose one end is connected to the minus electrode of the first battery cell c1 and the other end is connected to the input end of the 0th CR filter F0 of the voltage detection device D. This 0th connection wiring H0 has a 0th wiring resistance value R0 as the total value of its own internal resistance and the contact resistance at each end.

[0020] The 1st connection wiring H1 is an electric wire whose one end is connected to the plus electrode of the first battery cell c1, that is, the minus electrode of the second battery cell c2, and the other end is connected to the input end of the 1st CR filter F1 of the voltage detection device D. This 1st connection wiring H1 has a 1st wiring resistance value R1 as the total value of its own internal resistance and the contact resistance at each end.

[0021] The second connecting wire H2 is a wire in which one end is connected to the positive electrode of the second battery cell c2, that is, the negative electrode of the third battery cell c3, and the other end is connected to the input terminal of the second CR filter F2 of the voltage detection device D according to this embodiment. This second connecting wire H2 has a second wiring resistance value R2, which is the sum of its own internal resistance and the contact resistance of each end.

[0022] The third connection wire H3 is a wire in which one end is connected to the positive electrode of the third battery cell c3 and the other end is connected to the input terminal of the third CR filter F3 of the voltage detection device D. This third connection wire H3 has a third wire resistance value R3, which is the sum of its own internal resistance and the contact resistance of each end.

[0023] The CR filter F is a low-pass filter composed of a resistor and a capacitor, as shown in the figure. The input terminal of the 0th CR filter F0 is connected to the other end of the 0th connection wiring H0, and the output terminal is connected to the 0th input terminal IN0 of the voltage detection IC1. Furthermore, the input terminal of this 0th CR filter F0 is connected to GND, which is the reference potential, as shown in the figure.

[0024] Furthermore, the first CR filter F1 has its input terminal connected to the other end of the first connection wiring H1, and its output terminal connected to the first input terminal IN1 of the voltage detection IC1. The second CR filter F2 has its input terminal connected to the other end of the second connection wiring H2, and its output terminal connected to the second input terminal IN2 of the voltage detection IC1. In addition, the third CR filter F3 has its input terminal connected to the other end of the third connection wiring H3, and its output terminal connected to the third input terminal IN3 of the voltage detection IC1.

[0025] In the CR filter F, one end of the resistor is connected to the electrodes of each battery cell c, and the other end is connected to one end of the capacitor and the respective input terminal IN of the voltage detection IC1. Also in the CR filter F, one end of the capacitor is connected to the other end of the resistor and the respective input terminal IN of the voltage detection IC1, and the other end is grounded.

[0026] Such CR filters F are low-pass filters that remove noise superimposed on the voltage input from each battery cell c to each input terminal IN of the voltage detection IC1. As described above, the voltage detection device D and the battery pack B according to this embodiment are connected by connecting wiring H, and noise from the outside may enter the connecting wiring H. The four CR filters F suppress such noise from flowing into the voltage detection IC1.

[0027] Each discharge resistor Z has the same resistance value Rdis. The 0th discharge resistor Z0 has one end connected to the other end of the 0th connection wiring H0 and the input terminal of the 0th CR filter F0, and the other end connected to the 0th control terminal CT0 of the voltage detection IC1. The 1st discharge resistor Z1 has one end connected to the other end of the 1st connection wiring H1 and the input terminal of the 1st CR filter F1, and the other end connected to the 1st control terminal CT1 of the voltage detection IC1.

[0028] The second discharge resistor Z2 has one end connected to the other end of the second connection wiring H2 and the input terminal of the second CR filter F2, and the other end connected to the second control terminal CT2 of the voltage detection IC1. The third discharge resistor Z3 has one end connected to the other end of the third connection wiring H3 and the input terminal of the third CR filter F3, and the other end connected to the third control terminal CT3 of the voltage detection IC1.

[0029] The voltage detection IC1 is an integrated circuit that has at least the function of detecting the cell voltage of each battery cell c and forcibly discharging each battery cell c. Although not shown in the figure, the operation of this voltage detection IC1 is controlled by an external control device, and based on the voltage transmission command input from the control device, it transmits the actual cell voltage value Vr (described later) to the control device and forcibly discharges the battery cells c.

[0030] In this voltage detection IC1, the 0th input terminal IN0 is connected to the output terminal of the 0th CR filter F0 and the 1st input terminal of the 1st voltage detection circuit A1. The 1st input terminal IN1 is connected to the output terminal of the 1st CR filter F1, the 2nd input terminal of the 1st voltage detection circuit A1, and the 1st input terminal of the 2nd voltage detection circuit A2.

[0031] The second input terminal IN2 is connected to the output terminal of the second CR filter F2, the second input terminal of the second voltage detection circuit A2, and the first input terminal of the third voltage detection circuit A3. The third input terminal IN3 is connected to the output terminal of the third CR filter F3 and the second input terminal of the third voltage detection circuit A3.

[0032] Furthermore, the 0th control terminal CT0 is connected to the other end of the 0th discharge resistor Z0 and to one end of the 1st electronic switch G1. The 1st control terminal CT1 is connected to the other end of the 1st discharge resistor Z1, the other end of the 1st electronic switch G1, and to one end of the 2nd electronic switch G2. The 2nd control terminal CT2 is connected to the other end of the 2nd discharge resistor Z2, the other end of the 2nd electronic switch G2, and to one end of the 3rd electronic switch G3. The 3rd control terminal CT3 is connected to the other end of the 3rd discharge resistor Z3 and to the other end of the 3rd electronic switch G3.

[0033] Furthermore, the first voltage detection circuit A1 is a voltage amplification circuit in which the first input terminal is connected to the zeroth input terminal IN0 and the second input terminal is connected to the first input terminal IN1. This first voltage detection circuit A1 outputs a first detected voltage value V1 which indicates the terminal voltage between the voltage value of the zeroth input terminal IN0 and the voltage value of the first input terminal IN1.

[0034] The second voltage detection circuit A2 is a voltage amplifier circuit in which the first input terminal is connected to the first input terminal IN1 and the second input terminal is connected to the second input terminal IN2. This second voltage detection circuit A2 outputs a second detected voltage value V2 which indicates the terminal voltage between the voltage value of the first input terminal IN1 and the voltage value of the second input terminal IN2.

[0035] The third voltage detection circuit A3 is a voltage amplification circuit in which the first input terminal is connected to the second input terminal IN2 and the second input terminal is connected to the third input terminal IN3. This third voltage detection circuit A3 outputs a third detected voltage value V3 which represents the terminal voltage between the voltage value of the second input terminal IN2 and the voltage value of the third input terminal IN3.

[0036] The electronic switch G is an electronic switch that is turned ON / OFF by control of the control unit 2. The first electronic switch G1 has one end connected to the 0th control terminal CT0 and the other end connected to the first control terminal CT1. When the first electronic switch G1 is turned ON, it connects the other end of the 0th discharge resistor Z0 to the other end of the first discharge resistor Z1, thereby forcibly discharging the first battery cell c1.

[0037] The second electronic switch G2 has one end connected to the first control terminal CT1 and the other end connected to the second control terminal CT2. When the second electronic switch G2 is turned ON, it connects the other end of the first discharge resistor Z1 to the other end of the second discharge resistor Z2, thereby forcibly discharging the second battery cell c2.

[0038] The third electronic switch G3 has one end connected to the second control terminal CT2 and the other end connected to the third control terminal CT3. When this third electronic switch G3 is turned ON, it connects the other end of the second discharge resistor Z2 to the other end of the third discharge resistor Z3, thereby forcibly discharging the third battery cell c3.

[0039] Here, the 0th discharge resistor Z0, the 1st discharge resistor Z1, and the 1st electronic switch G1 are connected to the 1st battery cell c1, forming a discharge circuit M (1st discharge circuit M1) connected in parallel to the 1st battery cell c1. Furthermore, the 1st discharge resistor Z1, the 2nd discharge resistor Z2, and the 2nd electronic switch G2 are connected to the 2nd battery cell c2, forming a discharge circuit M (2nd discharge circuit M2) connected in parallel to the 2nd battery cell c2. In addition, the 2nd discharge resistor Z2, the 3rd discharge resistor Z3, and the 3rd electronic switch G3 are connected to the 3rd battery cell c3, forming a discharge circuit M (3rd discharge circuit M3) connected in parallel to the 3rd battery cell c3.

[0040] Although not shown in the diagram, each electronic switch G is connected in series with a current detection circuit that detects the current flowing through it. Specifically, the first electronic switch G1 is connected in series with the first current detection circuit, the second electronic switch G2 is connected in series with the second current detection circuit, and the third electronic switch G3 is connected in series with the third current detection circuit.

[0041] The current flowing through the first electronic switch G1 is the first discharge current I1 that flows through the first discharge resistor Z1 when the first electronic switch G1 is in the ON state. The current flowing through the second electronic switch G2 is the second discharge current I2 that flows through the second discharge resistor Z2 when the second electronic switch G2 is in the ON state. The current flowing through the third electronic switch G3 is the third discharge current I3 that flows through the third discharge resistor Z3 when the third electronic switch G3 is in the ON state.

[0042] The control unit 2 controls each electronic switch G and calculates the actual cell voltage value Vr of each battery cell c. The actual cell voltage value Vr of the first battery cell c1 is defined as the first actual cell voltage value V1r, the actual cell voltage value Vr of the second battery cell c2 is defined as the second actual cell voltage value V2r, and the actual cell voltage value Vr of the third battery cell c3 is defined as the third actual cell voltage value V3r.

[0043] The control unit 2 acquires the wiring resistance value R and calculates the actual cell voltage value Vr based on the wiring resistance value R. When acquiring the wiring resistance value R, the control unit 2 acquires the on-voltage value Va (first detection voltage value for wiring resistance calculation) of each battery cell c based on the detected voltage value Von (detection value) of the voltage detection circuit A when the electronic switch G is in the ON state. The control unit 2 also acquires the off-voltage value Vb (second detection voltage value for wiring resistance calculation) based on the detected voltage value Voff (detection value) of the voltage detection circuit A when the electronic switch G is in the OFF state.

[0044] In this embodiment, the control unit 2 uses the electronic switch G to obtain the wiring resistance value R. OFF Set to state, and detect voltage value V off For example, it acquires the detected voltage value V once. The control unit 2 then processes the acquired detected voltage value V. off of off Voltage value V b Furthermore, in obtaining the wiring resistance value R, the control unit 2 uses the electronic switch G. Major Set to state, and detect voltage value V on For example, multiple values ​​are acquired. The control unit 2 then processes these detected voltage values ​​V on Apply an averaging process to on Voltage value V a For example, the control unit 2 detects the voltage value V on When obtaining the detected voltage value V off By shortening the sampling period compared to when acquiring the same value, many detection voltage values ​​V can be obtained in a short time. on The control unit 2 obtains the detected voltage value V. on When acquiring the detected voltage value V, the sampling period is set to V. off The sampling period for obtaining the data is set to one-fifth of the sampling period used for acquisition.

[0045] Figure 2 is a timing chart for acquiring the on-voltage value Va and the off-voltage value Vb. Figure 2 shows the relationship between the cell voltage, the state of the electronic switch, the detection voltage acquisition period, and the averaging processing period. As shown in Figure 2, when the electronic switch G is in the OFF state, the detected voltage value (detected voltage value Vb) off The detected voltage value V is acquired. As shown in Figure 2, when the electronic switch G is in the OFF state, the detected voltage value is acquired only once during the period of one control cycle for acquiring the detected voltage value. The control unit 2 then receives the detected voltage value V off of off Voltage value V b Remember it as such.

[0046] When the electronic switch G is turned ON, the battery cell c connected to the discharge circuit including the electronic switch G discharges, and the cell voltage drops. As shown in Figure 2, in the period immediately after the electronic switch G changes from the OFF state to the ON state, the cell voltage continues to decrease over time and the cell voltage is unstable. Therefore, in this embodiment, the period immediately after the electronic switch G changes from the OFF state to the ON state during which the cell voltage is unstable is defined as the voltage stabilization period, and the detected voltage value (detected voltage value V) is set. on ) is not acquired. Note that not acquiring the detected voltage value here means that in addition to stopping the input of the signal from voltage detection circuit A to control unit 2, even if a signal is input from voltage detection circuit A to control unit 2 this value is not acquired. on Voltage value V a This also includes the meaning of not using it to obtain [the item].

[0047] The voltage stabilization period is stored in the control unit 2 in advance. For example, the period from when the electronic switch G changes from the OFF state to the ON state until the cell voltage stabilizes is determined by experimentation or simulation, and the voltage stabilization period is determined based on this result. For example, the voltage stabilization period is set to the duration of one cycle of a certain control cycle used by the control unit 2 to acquire the detected voltage value.

[0048] Once the voltage stabilization period has elapsed, the electronic switch G, as shown in Figure 2, Major In this state, the detected voltage value (detected voltage value V on ) is obtained. As shown in Figure 2, the electronic switch G Major In this state, the detected voltage value is acquired multiple times within a certain control cycle. In other words, the control unit 2 acquires the detected voltage value V on The sampling period for acquisition is the detected voltage value V off Set to a shorter sampling period than the sampling period. The control unit 2 then processes the multiple detected voltage values ​​V acquired at this time. on The average value on Voltage value V a It is stored as follows. For example, the control unit 2 stores 15 detected voltage values ​​V acquired continuously over time. on The average value on Voltage value V a The detected voltage value V at each set sampling period is as follows. on The moving average of on Voltage value V a That is also acceptable.

[0049] When the first electronic switch G1 is in the ON state, the control unit 2 acquires the first ON voltage value V1a of the first battery cell c1 based on the first detected voltage value V1on input from the first voltage detection circuit A1. Also, when the first electronic switch G1 is in the OFF state, the control unit 2 acquires the first OFF voltage value V1b of the first battery cell c1 based on the first detected voltage value V1off input from the first voltage detection circuit A1.

[0050] Furthermore, when the second electronic switch G2 is in the ON state, the control unit 2 acquires the second ON voltage value V2a of the second battery cell c2 based on the second detected voltage value V2on input from the second voltage detection circuit A2. Also, when the second electronic switch G2 is in the OFF state, the control unit 2 acquires the second OFF voltage value V2b of the second battery cell c2 based on the second detected voltage value V2off ​​input from the second voltage detection circuit A2.

[0051] Furthermore, when the third electronic switch G3 is in the ON state, the control unit 2 acquires the third ON voltage value V3a of the third battery cell c3 based on the third detected voltage value V3on input from the third voltage detection circuit A3. Also, when the third electronic switch G3 is in the OFF state, the control unit 2 acquires the third OFF voltage value V3b of the third battery cell c3 based on the third detected voltage value V3off input from the third voltage detection circuit A3.

[0052] The control unit 2 calculates the first wiring resistance value R0, the first wiring resistance value R1, the second wiring resistance value R2, and the third wiring resistance value R3 based on these first ON voltage value V1a, second ON voltage value V2a, third ON voltage value V3a, first OFF voltage value V1b, second OFF voltage value V2b, and third OFF voltage value V3b. The methods for calculating the first wiring resistance value R0, the first wiring resistance value R1, the second wiring resistance value R2, and the third wiring resistance value R3 will be explained later.

[0053] Furthermore, the control unit 2 calculates the actual cell voltage value Vr (actual battery voltage value) by excluding the voltage drop caused by the wiring resistance value R, based on the calculated wiring resistance value R. In other words, the control unit 2 calculates the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r based on the 0th wiring resistance value R0, the 1st wiring resistance value R1, the 2nd wiring resistance value R2, and the 3rd wiring resistance value R3. The methods for calculating the first actual cell voltage value V1r, the 2nd actual cell voltage value V2r, and the 3rd actual cell voltage value V3r will be explained later.

[0054] In this embodiment, the control unit 2 can perform a wiring resistance value acquisition process to calculate the wiring resistance value R as described above. In this embodiment, the control unit 2 performs this wiring resistance value acquisition process during the period when the ignition switch S installed in the vehicle is in the OFF state.

[0055] Figure 3 is a schematic diagram showing the changes in the state related to the control unit 2 in chronological order. As shown in Figure 3, when the ignition switch S is turned ON, the power start-up process is executed. In this power start-up process, the power supply U is started and power is supplied to the control unit 2. This starts up the control unit 2. Once the power start-up process is complete, the control unit 2 executes a normal sequence. This normal sequence is a process that is executed when the driver is able to operate the vehicle (for example, when the vehicle is running). In this embodiment, the control unit 2 acquires, for example, the actual cell voltage value Vr in the normal sequence. Also in this embodiment, the control unit 2 corrects, for example, the wiring resistance value R in the normal sequence.

[0056] The wiring resistance R changes with the temperature of the connecting wiring H. Specifically, as the temperature of the connecting wiring H rises, the wiring resistance R increases. The temperature of the connecting wiring H is greatly affected by the temperature of the battery pack B. Therefore, the control unit 2 corrects the wiring resistance R based on the temperature input from the temperature sensor T that measures the temperature of the battery pack B. In this embodiment, the control unit 2 corrects the wiring resistance R based on the difference between the temperature of the battery pack B during the wiring resistance acquisition process (wiring resistance acquisition sequence) and the temperature of the battery pack B when acquiring the actual cell voltage value Vr (normal sequence).

[0057] Figure 4 is a graph showing an example of the relationship between temperature and the corrected wiring resistance. In Figure 4, the horizontal axis represents temperature. The vertical axis represents the corrected wiring resistance. For example, let the reference temperature be tx, and the wiring resistance R at the reference temperature tx be Rx. Also, let the conductor resistance coefficient of the connecting wiring H be α. When the temperature changes from the reference temperature tx to temperature ty, the corrected wiring resistance Ry can be calculated using the following equation (1).

[0058] Ry = Rx{1 + α(ty - tx)} (1)

[0059] For example, let the reference temperature tx be 20°C, the temperature ty be 0°C, and the wiring resistance Rx at the reference temperature be 100mΩ. Also, let the conductor resistance coefficient α of the connecting wiring H be 0.00393. In this case, the corrected wiring resistance Ry is 92.14mΩ from equation (1). Furthermore, as shown in Figure 4, the corrected wiring resistance Ry when the temperature ty is -40°C is 76.42mΩ, the corrected wiring resistance Ry when the temperature ty is -20°C is 84.28mΩ, the corrected wiring resistance Ry when the temperature ty is 40°C is 107.86mΩ, the corrected wiring resistance Ry when the temperature ty is 60°C is 115.72mΩ, and the corrected wiring resistance Ry when the temperature ty is 80°C is 123.58mΩ.

[0060] For example, the control unit 2 stores in advance a calculation formula that shows the relationship between the above difference and the correction value, and determines the correction value based on this calculation formula. For example, if the connecting wiring H is formed of a conductor, the amount of change in the wiring resistance value R due to temperature change can be calculated as the value obtained by multiplying the conductor temperature resistance coefficient α by the above difference. Therefore, the control unit 2 corrects the wiring resistance value R by adding the value obtained by multiplying the conductor temperature resistance coefficient α by the above difference (correction value) to the wiring resistance value R before correction.

[0061] Furthermore, if the difference between the temperature of battery pack B at the time of the previous correction of the wiring resistance value R and the current temperature of battery pack B exceeds a predetermined threshold (recorrection threshold ta), the control unit 2 corrects the wiring resistance value R again. In other words, during the normal sequence, if the temperature of battery pack B changes by more than the recorrection threshold ta, the control unit 2 corrects the wiring resistance value R again.

[0062] Furthermore, as shown in Figure 3, when the ignition switch is turned from the ON state to the OFF state, the wiring resistance value acquisition sequence is executed. In other words, the wiring resistance value acquisition sequence is executed when the driver is not operating the vehicle. In this wiring resistance value acquisition sequence, the control unit 2 executes the wiring resistance value acquisition process. The control unit 2 acquires the wiring resistance value R by calculating and storing the wiring resistance value R in the wiring resistance value acquisition process. Once this wiring resistance value acquisition sequence is completed, the power shutdown process is executed. In this power shutdown process, the shutdown process of the control unit 2 is executed, and the power supply from the power supply unit U to the control unit 2 is stopped.

[0063] Please note that the process of acquiring wiring resistance values ​​may take some time. For this reason, it is preferable to perform the wiring resistance value acquisition process when the driver is not operating the vehicle (when the ignition switch is OFF). However, it is also possible to perform the wiring resistance value acquisition process when the ignition switch is ON. For example, in cases where a general user does not operate the vehicle, such as at a dealership, it is possible to perform the wiring resistance value acquisition process when the ignition switch is ON.

[0064] Next, the operation of the voltage detection device D according to this embodiment will be explained in detail with reference to the flowcharts in Figures 5 to 7.

[0065] Figure 5 is a flowchart illustrating the operation of the voltage detection device D in the wiring resistance value acquisition sequence. When the ignition switch is turned off (step S1a), the control unit 2 acquires the temperature of the battery pack B (battery pack temperature t1) from the temperature sensor T (step S1b). Subsequently, the control unit 2 determines whether the battery pack temperature t1 acquired in step S1b is within the normal range (step S1c). The normal range here refers to the range in which the temperature of the battery pack B may change during normal use, for example, from about -40°C to about 80°C.

[0066] If the control unit 2 determines in step S1c that the battery pack temperature t1 is outside the normal range, it determines that the temperature sensor T is abnormal (step S1d). If the control unit 2 determines that the temperature sensor T is abnormal, it outputs a temperature sensor abnormality signal to the outside indicating that the temperature sensor T is abnormal, and proceeds to step S1e.

[0067] If the control unit 2 determines in step S1c that the battery pack temperature t1 is within the normal range, it executes the wiring resistance calculation process (step S1e). Figure 6 is a flowchart of the wiring resistance calculation process. As shown in Figure 6, when the wiring resistance calculation process is started, the control unit 2 obtains the off-voltage value Vb (step S2a).

[0068] When the control unit 2 obtains the off-voltage value Vb, it sets the first electronic switch G1, the second electronic switch G2, and the third electronic switch G3 all to the OFF state, obtains the first detected voltage value V1off from the first voltage detection circuit A1, the second detected voltage value V2off ​​from the second voltage detection circuit A2, and the third detected voltage value V3off from the third voltage detection circuit A3.

[0069] Next, the control unit 2 sets one of the electronic switches G to the ON state (step S2b). Then, the control unit 2 determines whether or not the voltage stabilization period has elapsed (step S2c). If the control unit 2 determines that the voltage stabilization period has not elapsed, it repeats step S2b. On the other hand, if the control unit 2 determines that the voltage stabilization period has elapsed, it obtains the ON voltage value Va (step S2d).

[0070] When the control unit 2 acquires the ON voltage value Va, for example, it sets the first electronic switch G1 to the ON state and the second electronic switch G2 and the third electronic switch G3 to the OFF state, shortening the sampling period and acquiring the first detected voltage value V1on multiple times. By setting the first electronic switch G1 to the ON state and the second electronic switch G2 and the third electronic switch G3 to the OFF state, the first discharge current I1 flows through the closed circuit connecting the first battery cell c1 and the first electronic switch G1. The control unit 2 calculates the average value of the multiple first detected voltage values ​​V1on and acquires this average value as the first ON voltage value V1a. In step S2d, the control unit 2 also acquires the second off voltage value V2b and the third off voltage value V3b during the period when the first electronic switch G1 is in the ON state.

[0071] Furthermore, the control unit 2 also performs steps S2b, S2c, and S2d for each of the second electronic switch G2 and the third electronic switch G3. In other words, the control unit 2 sets the second electronic switch G2 to the ON state and the first electronic switch G1 and the third electronic switch G3 to the OFF state, shortening the sampling period and acquiring the second detected voltage value V2on multiple times. By setting the second electronic switch G2 to the ON state and the first electronic switch G1 and the third electronic switch G3 to the OFF state, the second discharge current I2 flows through the closed circuit connecting the second battery cell c2 and the second electronic switch G2. The control unit 2 calculates the average value of the multiple second detected voltage values ​​V2on and acquires this average value as the second ON voltage value V2a. In step S2d, the control unit 2 also acquires the first OFF voltage value V1b and the third OFF voltage value V3b during the period when the second electronic switch G2 is in the ON state.

[0072] Furthermore, the control unit 2 sets the third electronic switch G3 to the ON state and the first electronic switch G1 and the second electronic switch G2 to the OFF state, shortening the sampling period and acquiring the third detected voltage value V3on multiple times. By setting the third electronic switch G3 to the ON state and the first electronic switch G1 and the second electronic switch G2 to the OFF state, the third discharge current I3 flows through the closed circuit connecting the third battery cell c3 and the third electronic switch G3. The control unit 2 calculates the average value of the multiple third detected voltage values ​​V3on and acquires this average value as the third ON voltage value V3a. In step S2d, the control unit 2 also acquires the first OFF voltage value V1b and the third OFF voltage value V3b during the period when the third electronic switch G3 is in the ON state.

[0073] Furthermore, the control unit 2 may acquire the detected voltage value Von by alternately setting the second electronic switch G2 (even switch) corresponding to the second battery cell c2, which is an even cell, and the first electronic switch G1 and the third electronic switch G3 (odd switches) corresponding to the first battery cell c1 and the third battery cell c3, which are odd cells, to either the ON or OFF state.

[0074] Next, the control unit 2 calculates the wiring resistance value R (step S2e). Here, the wiring resistance value R is calculated based on the off-voltage value Vb obtained in step S2a and the on-voltage value Va obtained in step S2d. The method for calculating the wiring resistance value R using the on-voltage value Va and the off-voltage value Vb is not particularly limited.

[0075] The following describes an example of how to calculate the wiring resistance R using the on-voltage value Va and the off-voltage value Vb.

[0076] For example, when the second electronic switch G2 is set to the ON state and the first electronic switch G1 and the third electronic switch G3 are set to the OFF state, the second discharge current I2 flows through the closed circuit connecting the second battery cell c2 and the second electronic switch G2. In this state, the following two equations (2) and (3) hold true for this closed circuit. V2b = I2·(R1+R2)+V2a (2) I2 = V2b / (R1 + R2 + 2Rdis) (3)

[0077] Furthermore, regarding the first wiring resistance R1 and the second wiring resistance R2 that constitute the closed circuit through which the second discharge current I2 flows, the following equation (4) is obtained based on the two equations (2) and (3) above. (R1+R2)=-2Rdis·(V2a-V2b) / V2a (4)

[0078] On the other hand, in the state of step S2d, the third off-voltage value V3b is the voltage rise when the second discharge current I2 flows through the second wiring resistor R2 relative to the cell voltage of the third battery cell c3. Therefore, the following relationships (5) and (6) using the second discharge current I2 hold. Based on these two equations (5) and (6), the following equation (7) relating to the second wiring resistance value R2 is obtained.

[0079] V3b = V3a - I2·R2 (5) I2·R2=V3b-V3a (6) R2 = (V3b - V3a) / I2 (7)

[0080] Then, the control unit 2 calculates the second wiring resistance value R2 in the second connection wiring H2 based on equation (7) above. In other words, the control unit 2 determines the second wiring resistance value R2 by substituting the third off voltage value V3b obtained in step S2a and the third on voltage value V3a obtained in step S2d into equation (7), and also by substituting the second discharge current I2 obtained by the third current detection circuit into equation (7).

[0081] Furthermore, in the state of step S2d, the first off-voltage value V1b is the voltage rise when the second discharge current I2 flows through the first wiring resistor R1 relative to the cell voltage of the first battery cell c1. Therefore, the following relationships (8) and (9) hold. Based on these two equations (8) and (9), the following equation (10) relating to the first wiring resistance value R1 is obtained.

[0082] V1b = V1a - I2·R1 (8) I2·R1=V1b-V1a (9) R1 = (V1b - V1a) / I2 (10)

[0083] Then, the control unit 2 calculates the first wiring resistance value R1 in the first connection wiring H1 based on equation (10) above. Specifically, the control unit 2 determines the first wiring resistance value R1 by substituting the first off-voltage value V1b obtained in step S2a and the first on-voltage value V1a obtained in step S2d into equation (10), and also by substituting the second discharge current I2 obtained by the second current detection circuit into equation (10).

[0084] Furthermore, the following equation (11) holds true for the resistance value R0 of the 0th wiring and the resistance value R1 of the 1st wiring. Also, the following equation (12) holds true for the resistance value R2 of the 2nd wiring and the resistance value R3 of the 3rd wiring. (R0+R1)=-2Rdis·(V1a-V1b) / V1a (11) (R2+R3)=-2Rdis·(V3a-V3b) / V3a (12)

[0085] The control unit 2 calculates the resistance value R0 of the 0th wiring based on equations (10) and (11) above. The control unit 2 also calculates the resistance value R3 of the 3rd wiring based on equations (7) and (12) above. In this example, the resistance values ​​were calculated in the order of 2nd wiring resistance R2 → 1st wiring resistance R1 → 0th wiring resistance R0 → 3rd wiring resistance R3, but the order does not matter, and any wiring resistance value can be used as the reference.

[0086] In this embodiment, since the battery pack B has only three battery cells, the first wiring resistance value R1, the second wiring resistance value R2, and the third wiring resistance value R3 can be obtained by closing the second electronic switch G2 in step S1c. However, in the case of a battery pack containing more battery cells, the wiring resistance value R can be calculated using the on-voltage value Va and off-voltage value Vb obtained by closing the other electronic switches G in step S1c.

[0087] Returning to Figure 5, once the wiring resistance calculation process is complete, the control unit 2 saves the battery pack temperature t1 obtained in step S1b and the wiring resistance value R calculated in step S1e (step S1f). Once the wiring resistance value R is saved in this way, the wiring resistance acquisition sequence ends, and the power-off process is executed as shown in Figure 2.

[0088] Figure 7 is a flowchart illustrating the operation of the voltage detection device D for determining the actual cell voltage value Vr in a normal sequence. When the ignition switch is turned ON (step S3a), the control unit 2 reads out the battery pack temperature t1 and the wiring resistance value R saved in step S1f (step S3b).

[0089] Next, the control unit 2 determines whether the battery pack temperature t1 read in step S3b is within the normal range (step S3c). The normal range here refers to the range in which the temperature of battery pack B may change during normal use, for example, from about -40°C to about 80°C.

[0090] If the control unit 2 determines in step S3c that the battery pack temperature t1 is outside the normal range, it determines that the temperature sensor T is abnormal (step S3d). When the control unit 2 determines that the temperature sensor T is abnormal, it outputs a temperature sensor abnormality signal to the outside indicating that the temperature sensor T is abnormal, and proceeds to step S3g. However, since it is still necessary to manage the battery pack B even when the temperature sensor T is abnormal, when the control unit 2 proceeds to step S3g, it sets the current battery pack temperature t2 to a temporary value, for example, within the normal range.

[0091] If the control unit 2 determines in step S3c that the battery pack temperature t1 is within the normal range, it obtains the current temperature of the battery pack B (battery pack temperature t2) from the temperature sensor T (step S3e). Subsequently, the control unit 2 determines whether the battery pack temperature t2 obtained in step S3e is within the normal range (step S3f). The normal range here refers to the range in which the temperature of the battery pack B may change during normal use, for example, from about -40°C to about 80°C.

[0092] If the control unit 2 determines in step S3e that the battery pack temperature t1 is outside the normal range, it proceeds to step S3d. If the control unit 2 determines in step S3g that the battery pack temperature t1 is within the normal range, it performs temperature correction on the wiring resistance value R (step S3g). Here, as described above, the control unit 2 corrects the wiring resistance value R based on the difference between the temperature of battery pack B during the wiring resistance value acquisition process (wiring resistance value acquisition sequence) (battery pack temperature t1) and the temperature of battery pack B when acquiring the actual cell voltage value Vr (normal sequence) (battery pack temperature t2). For example, the control unit 2 calculates the above difference, determines the correction value from a calculation formula showing the relationship between the difference and the correction value, and corrects the wiring resistance value R based on the correction value. The control unit 2 corrects the 0th wiring resistance value R0, the 1st wiring resistance value R1, the 2nd wiring resistance value R2, and the 3rd wiring resistance value R3, respectively.

[0093] Next, the control unit 2 acquires the actual cell voltage value Vr based on the wiring resistance value R corrected in step S3g (step S3h). Here, the control unit 2 acquires the true detected voltage, i.e., the actual cell voltage value Vr (first actual cell voltage value V1r, second actual cell voltage value V2r, and third actual cell voltage value V3r), excluding the voltage drop caused by the wiring resistance value R, based on the following equations (13) to (15).

[0094] V1r=V1a+(R0+R1+2Rdis)·I1 (13) V2r=V2a+(R1+R2+2Rdis)·I2 (14) V3r=V3a+(R2+R3+2Rdis)·I3 (15)

[0095] Each closed circuit connected to each battery cell c has two input terminals of a CR filter connected to it. These CR filters F are low-pass filters and each has a time constant, so the voltage at each terminal IN of the input terminal changes over time after the state of the electronic switch G is set to ON or OFF.

[0096] In other words, the voltage at each terminal of the input terminal IN will be lower than the true terminal voltage, and will also be different depending on the elapsed time after the state of the electronic switch G was set. This change in the voltage at each terminal of the input terminal IN means that there is an error in the actual cell voltage value Vr depending on the timing after the state of the electronic switch G was set.

[0097] Taking these circumstances into consideration, in the voltage detection device D according to this embodiment, the control unit 2 corrects the actual cell voltage value Vr based on correction characteristics stored in advance (step S3i). For example, the control unit 2 determines the correction amount for the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r by multiplying the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r, respectively, by a correction coefficient a for each of the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r. Then, the control unit 2 completes the correction processing for the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r by adding each correction amount to the first actual cell voltage value V1r, the second actual cell voltage value V2r, and the third actual cell voltage value V3r, respectively.

[0098] Next, the control unit 2 obtains the temperature of battery pack B (battery pack temperature t3) again from the temperature sensor T (step S3j). Subsequently, the control unit 2 determines whether the difference between the temperature of battery pack B at the time of the previous wiring resistance value R correction (battery pack temperature t2) and the current temperature of battery pack B (battery pack temperature t3) exceeds a predetermined threshold (re-correction threshold ta) (step S3k). The re-correction threshold ta can be set arbitrarily, but for example, it can be set to 5°C.

[0099] If the difference between the battery pack temperature t2 and the battery pack temperature t3 exceeds the recorrection threshold ta, the control unit 2 corrects the wiring resistance value R again (step S3l). Here, similar to step S3g, the control unit 2 corrects the wiring resistance value R based on the difference between the battery pack temperature t1 and the battery pack temperature t3. For example, the control unit 2 calculates the above difference, determines the correction value from a calculation formula showing the relationship between the difference and the correction value, and corrects the wiring resistance value R based on the correction value. The control unit 2 corrects the 0th wiring resistance value R0, the 1st wiring resistance value R1, the 2nd wiring resistance value R2, and the 3rd wiring resistance value R3, respectively.

[0100] After step S3l is completed, or if the difference between the battery pack temperature t2 and the battery pack temperature t3 in step S3k does not exceed the recorrection threshold ta, the control unit 2 returns to step S3h and obtains the actual cell voltage value Vr based on the corrected wiring resistance value R.

[0101] The voltage detection device D of this embodiment, as described above, comprises a discharge circuit M, a voltage detection circuit A, and a control unit 2. The discharge circuit M is connected in parallel to the battery cell c. The discharge circuit M also has a discharge resistor Z and an electronic switch G. The voltage detection circuit A detects the voltage of the battery cell c. The control unit 2 controls the electronic switch G. The control unit 2 is also capable of performing a wiring resistance value acquisition process to obtain the wiring resistance value R between the voltage detection circuit A and the battery cell c.

[0102] Furthermore, in the wiring resistance value acquisition process, the control unit 2 sets the electronic switch G to the ON state and, after the voltage stabilization period has elapsed, acquires the ON voltage value Va based on the detected value obtained from the voltage detection circuit A. Also in the wiring resistance value acquisition process, the control unit 2 sets the electronic switch G to the OFF state and acquires the OFF voltage value Vb based on the detected value obtained from the voltage detection circuit A. Furthermore, in the wiring resistance value acquisition process, the control unit 2 acquires the wiring resistance value R based on the ON voltage value Va and the OFF voltage value Vb.

[0103] According to the voltage detection device D of this embodiment, the on-voltage value Va is acquired after the voltage stabilization period has elapsed since the electronic switch G of the discharge circuit M was set to the ON state. Therefore, the on-voltage value Va can be acquired while avoiding the period when the output voltage of the battery cell c is unstable immediately after the electronic switch G changes from the OFF state to the ON state. Consequently, the voltage detection device D of this embodiment makes it possible to calculate the wiring resistance value R with high accuracy.

[0104] Furthermore, in the voltage detection device D of this embodiment, the control unit 2 is off Voltage value V b When obtaining the detected value, the sampling period is greater than the sampling period of the detected value. on Voltage value V a When acquiring the data, shorten the sampling period of the detected values ​​and calculate the average of multiple detected values. on Voltage value V a Let's assume that.

[0105] According to the voltage detection device D of this embodiment, the off-voltage value Vb is the average of multiple detected values. Therefore, even if each detected value contains errors, it becomes possible to obtain a more accurate off-voltage value Vb, and to calculate the wiring resistance value R with greater precision.

[0106] Furthermore, the voltage detection device D of this embodiment is installed in a vehicle equipped with an ignition switch S. The control unit 2 also performs wiring resistance value acquisition processing during the period when the ignition switch S is in the OFF state.

[0107] With the voltage detection device D of this embodiment, the wiring resistance value acquisition process is executed when the driver is not operating the vehicle. Therefore, it is possible to prevent the driver from having to wait for the wiring resistance value acquisition process to occur.

[0108] Furthermore, in the voltage detection device D of this embodiment, the control unit 2 acquires the actual cell voltage value Vr based on the wiring resistance value R, excluding the voltage drop caused by the wiring resistance value R. With this voltage detection device D of this embodiment, it is possible to acquire the actual cell voltage value Vr more accurately.

[0109] Furthermore, in the voltage detection device D of this embodiment, the control unit 2 corrects the wiring resistance value R based on the difference between the temperature of the battery pack during the wiring resistance value acquisition process and the temperature of the battery pack when acquiring the actual cell voltage value Vr. The control unit 2 then acquires the actual cell voltage value Vr based on the corrected wiring resistance value R.

[0110] According to the voltage detection device D of this embodiment, the wiring resistance value R is corrected according to the temperature of the battery pack. Therefore, even if the temperature of the battery pack changes from the time the wiring resistance value R was acquired, it becomes possible to obtain a more accurate actual cell voltage value Vr.

[0111] Furthermore, in the voltage detection device D of this embodiment, the control unit 2 corrects the wiring resistance value R again if the difference between the temperature of the battery pack at the time of the previous correction of the wiring resistance value R and the current temperature of the battery pack exceeds a predetermined recorrection threshold ta.

[0112] According to the voltage detection device D of this embodiment, it is possible to obtain a more accurate actual cell voltage value Vr even when the temperature of the battery pack changes while the vehicle is in motion.

[0113] (Second Embodiment) Figure 8 is a schematic diagram showing the general configuration of the battery management device 10 of this embodiment. In this embodiment, the explanation of parts that are the same as those of the first embodiment described above will be omitted or simplified.

[0114] As shown in Figure 8, the battery management device 10 of this embodiment comprises the voltage detection device D of the first embodiment and a management device K. The management device K is connected to the voltage detection device D. The management device K is connected to the voltage detection IC1 of the voltage detection device D and inputs a voltage transmission command to the voltage detection IC1. The management device K also receives the actual cell voltage value Vr output from the voltage detection IC1 as input.

[0115] The management device K determines the amount of charge and charging timing for the battery pack B based on, for example, the actual cell voltage value Vr, and manages the battery pack B based on the determination result. According to this embodiment of the battery management device 10, a voltage detection device D is included. Therefore, the battery pack B can be managed based on the highly accurate actual cell voltage value Vr.

[0116] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to the above embodiments. The shapes and combinations of the constituent members shown in the above embodiments are examples, and can be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention.

[0117] For example, in the above embodiment, a configuration in which the battery of the present invention is a battery cell c was described. However, the present invention is not limited thereto. For example, it is also possible for a battery pack B to be the battery of the present invention.

[0118] Furthermore, the above embodiments can also be described, for example, as shown in the following appendix.

[0119] (Note 1) A voltage detection device comprising a discharge circuit connected in parallel to a battery and having a discharge resistor and an electronic switch, a voltage detection circuit for detecting the voltage of the battery, and a control unit for controlling the electronic switch, The control unit is capable of performing a wiring resistance value acquisition process to acquire the wiring resistance value between the voltage detection circuit and the battery. In the wiring resistance value acquisition process, the control unit performs the following: After setting the electronic switch to the ON state and after the voltage stabilization period has elapsed, a first detection voltage value for calculating wiring resistance is obtained based on the detection value obtained from the voltage detection circuit. The electronic switch is set to the OFF state, and a second detection voltage value for calculating wiring resistance is obtained based on the detection value obtained from the voltage detection circuit. The wiring resistance value is obtained based on the first detection voltage value for calculating the wiring resistance and the second detection voltage value for calculating the wiring resistance. A voltage detection device characterized by the following features.

[0120] (Note 2) The control unit, The above wiring resistance calculation method 2 When acquiring the detected voltage value, the sampling period of the detected value is greater than the sampling period of the wiring resistance calculation. 1 When acquiring the detected voltage value, the sampling period of the detected value is shortened, and the average value of multiple detected values ​​is used for calculating the wiring resistance. 1 This will be used as the detected voltage value. The voltage detection device according to Appendix 1, characterized by the features described herein.

[0121] (Note 3) It is installed in vehicles equipped with an ignition switch. The control unit executes the wiring resistance value acquisition process during the period when the ignition switch is in the OFF state. A voltage detection device as described in Appendix 1 or 2, characterized by the above.

[0122] (Note 4) The voltage detection device according to any one of the appendices 1 to 3, characterized in that the control unit acquires an actual battery voltage value based on the wiring resistance value, excluding the voltage drop caused by the wiring resistance value.

[0123] (Note 5) The control unit, Based on the difference between the battery temperature during the wiring resistance acquisition process and the battery temperature when acquiring the actual battery voltage, the wiring resistance value is corrected. The actual battery voltage value is obtained based on the corrected wiring resistance value. The voltage detection device described in Appendix 4, characterized by the features described herein.

[0124] (Note 6) The voltage detection device according to Appendix 5, characterized in that the control unit corrects the wiring resistance value again when the difference between the battery temperature at the time of the previous correction of the wiring resistance value and the current battery temperature exceeds a predetermined threshold.

[0125] (Note 7) A voltage detection device described in any one of the appendices 1 to 6, A management device that manages the battery based on the detection result of the voltage detection device. A battery management device characterized by being equipped with the following features. [Explanation of Symbols]

[0126] 1...Voltage detection IC, 2...Control unit, 10...Battery management device, A...Voltage detection circuit, B...Battery pack, c...Battery cell (battery), D...Voltage detection device, F...CR filter, G...Electronic switch, H...Connection wiring, K...Management device, M...Discharge circuit, S...Ignition switch, T...Temperature sensor, U...Power supply unit, Z...Discharge resistor

Claims

1. A voltage detection device comprising a discharge circuit connected in parallel to a battery and having a discharge resistor and an electronic switch, a voltage detection circuit for detecting the voltage of the battery, and a control unit for controlling the electronic switch, The control unit is capable of performing a wiring resistance value acquisition process to acquire the wiring resistance value between the voltage detection circuit and the battery. In the wiring resistance value acquisition process, the control unit performs the following: After setting the electronic switch to the ON state and after the voltage stabilization period has elapsed, a first detected voltage value for calculating wiring resistance is obtained based on the detected value obtained from the voltage detection circuit. Before the electronic switch is set to the ON state, in the OFF state, a second detection voltage value for calculating wiring resistance is obtained based on the detection value obtained from the voltage detection circuit. Based on the first detection voltage value for calculating the wiring resistance and the second detection voltage value for calculating the wiring resistance, the wiring resistance value is obtained. Based on the aforementioned wiring resistance value, the actual battery voltage value, with the voltage drop caused by the aforementioned wiring resistance value excluded, is obtained as the detection result. The control unit, When acquiring the second detection voltage value for calculating the wiring resistance, the sampling period of the detection value when acquiring the first detection voltage value for calculating the wiring resistance is made shorter than the sampling period of the detection value when acquiring the second detection voltage value for calculating the wiring resistance, and the average value of the multiple detection values ​​obtained to acquire the first detection voltage value for calculating the wiring resistance is set as the first detection voltage value for calculating the wiring resistance. A voltage detection device characterized by the following features.

2. It is installed in vehicles equipped with an ignition switch. The control unit executes the wiring resistance value acquisition process during the period when the ignition switch is in the OFF state. The voltage detection device according to claim 1, characterized in that it is as described above.

3. The control unit, Based on the difference between the battery temperature during the wiring resistance acquisition process and the battery temperature when acquiring the actual battery voltage, the wiring resistance value is corrected. The actual battery voltage value is obtained based on the corrected wiring resistance value. A voltage detection device according to claim 1 or 2, characterized in that it is a voltage detection device according to claim 1 or 2.

4. The voltage detection device according to claim 3, characterized in that the control unit corrects the wiring resistance value again when the difference between the battery temperature at the time of the previous correction of the wiring resistance value and the current battery temperature exceeds a predetermined threshold.

5. A voltage detection device according to claim 1 or 2, A management device that manages the battery based on the detection result of the voltage detection device. A battery management device characterized by being equipped with the following features.

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