Internal resistance detection device and power conversion device

Abstract

To provide an internal resistance detection device and a power conversion device capable of generating a more stable voltage equal to or greater than output voltage of a secondary battery when measuring internal resistance values by an AC impedance method.SOLUTION: An internal resistance detection device for detecting an internal resistance value of a secondary battery includes: an acquisition part for acquiring current and voltage values of the secondary battery; a charge pump circuit for boosting output voltage of the secondary battery; an AC wave generating part for generating an AC wave; and an internal resistance calculation part for calculating the internal resistance value based on the current value, the voltage value and the frequency of the AC wave when the AC wave is superimposed on the boost voltage, which is boosted by the charge pump circuit, and the AC voltage is applied to the secondary battery.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an internal resistance detection device and a power conversion device. [Background technology]

[0002] When measuring the internal resistance value of a secondary battery mounted on a vehicle such as a hybrid vehicle or an electric vehicle, an AC impedance method is sometimes used (for example, Patent Document 1). When measuring the internal resistance value of a secondary battery using the AC impedance method, it is necessary to apply an AC wave to the secondary battery at a voltage equal to or higher than the output voltage of the secondary battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-175556 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, a regenerative voltage from a motor can be used as a voltage source for applying a voltage equal to or higher than the output voltage of a secondary battery. However, since the regenerative voltage is generated depending on the actions of the user on the vehicle (hereinafter referred to as "user-dependent actions"), such as the foot brake operation by the driver driving the vehicle or the operation of releasing the accelerator pedal while driving, it may not be a stable voltage source.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide an internal resistance detection device and a power conversion device that are capable of generating a more stable voltage equal to or greater than the output voltage of a secondary battery when measuring internal resistance value using the AC impedance method. [Means for solving the problem]

[0006] (1) One aspect of the present invention is an internal resistance detection device that detects an internal resistance value of a secondary battery, the internal resistance detection device including: an acquisition unit that acquires a current value and a voltage value of the secondary battery; a charge pump circuit that boosts an output voltage of the secondary battery; an AC wave generation unit that generates an AC wave; and an internal resistance calculation unit that calculates the internal resistance value based on the current value, the voltage value, and the frequency of the AC wave when an AC voltage in which the AC wave is superimposed on a boosted voltage, which is a voltage boosted by the charge pump circuit, is applied to the secondary battery.

[0007] (2) One aspect of the present invention is the internal resistance detection device described above in (1), wherein the secondary battery is configured by connecting a plurality of battery cells in series, and the internal resistance calculation unit may calculate the internal resistance value for each battery cell.

[0008] (3) One aspect of the present invention is the internal resistance detection device according to (1) or (2) above, in which the calculation of the internal resistance value may be performed when an ignition switch is in an off state.

[0009] (4) One aspect of the present invention is the internal resistance detection device of any of (1) to (3) above, wherein the charge pump circuit includes a first diode having an anode connected to a positive terminal of the secondary battery, a first capacitor having one end connected to a cathode of the first diode, a first switch connected between the other end of the first capacitor and the negative terminal of the secondary battery, a second diode having an anode connected to one end of the first capacitor, a second capacitor having one end connected to the cathode of the second diode and the other end connected to the negative terminal, and a second switch connected between the other end of the first capacitor and the positive terminal of the secondary battery, and the AC wave generating unit may generate the AC voltage by superimposing the AC wave on the boosted voltage input from one end of the second capacitor, and apply the AC voltage to the positive terminal.

[0010] (5) One aspect of the present invention includes an internal resistance detection device as described above in (4), an inverter that drives a motor used to run a vehicle, and a DC-DC converter having a plurality of switching elements and performing power conversion between the inverter and the secondary battery by switching the plurality of switching elements, wherein the plurality of switching elements may serve as both the first switch and the second switch. Effect of the Invention

[0011] As described above, according to the present invention, it is possible to provide an internal resistance detection device and a power conversion device capable of generating a more stable voltage when measuring an internal resistance value by an AC impedance method. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a vehicle 100 including a power conversion device 130 according to the present embodiment. [Diagram 2] 1 is a diagram illustrating an example of a schematic configuration of a power converter 200 according to the present embodiment. [Diagram 3] 1 is a diagram showing an example of a schematic configuration of an internal resistance detection device 300 according to an embodiment of the present invention. [Figure 4] 11 is a diagram illustrating a flow of an internal resistance calculation operation according to the embodiment. FIG. [Diagram 5] FIG. 4 is a diagram illustrating a first operation according to the present embodiment. [Figure 6] FIG. 11 is a diagram illustrating a second operation according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In the drawings, the same or similar parts may be given the same reference numerals, and duplicated explanations may be omitted. In addition, the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

[0014] 1 is a diagram showing an example of a schematic configuration of a vehicle 100 including a power conversion device 130 according to this embodiment. The vehicle 100 is, for example, a hybrid vehicle, an electric vehicle, or the like.

[0015] As shown in FIG. 1, a vehicle 100 includes a secondary battery 110, a motor 120, and a power conversion device .

[0016] The secondary battery 110 is mounted on the vehicle 100 and is a nickel-metal hydride battery, a lithium-ion battery, or the like. For example, the secondary battery 110 is used as a battery inside the vehicle 100. For example, the power of the secondary battery 110 is used as driving power for the motor 120 or operating power for devices mounted on the vehicle 100.

[0017] The secondary battery 110 is a group of multiple battery cells G (G 1 ~G n ), where n is an integer of 2 or more. 1 ~G n A plurality of battery cells C are connected in series to each battery cell group G 1 . . Gn (hereinafter also referred to as the “number of battery cells”) depends on the vehicle size of the vehicle 100 in which the secondary battery 110 is mounted, and so the number of battery cells may differ depending on the vehicle 100.

[0018] Each battery cell group G 1 ~G nIn the battery cell group G, the positive terminal of the battery cell (top cell) C located at the top is the positive terminal P1 of the secondary battery 110, and the negative terminal of the battery cell (bottom cell) C located at the bottom is the negative terminal P2 of the secondary battery 110. The positive terminal P1 and the negative terminal P2 of each battery cell C are connected to the power conversion device 130. 1 ~G n When there is no need to distinguish between the above groups, they will simply be referred to as "battery cell group G."

[0019] The motor 120 is an electric motor driven by power from the power conversion device 130. For example, the motor 120 is a motor for driving a vehicle. For example, the motor 120 is a three-phase (U, V, W) brushless motor. The motor 120 may be a motor generator. That is, the motor 120 may be used as a generator driven by the engine of the vehicle 100, and may also be used as an electric motor for starting the engine. The motor 120 of this embodiment mainly operates as an electric motor to drive the wheels of the vehicle 100.

[0020] The power conversion device 130 manages the secondary battery 110 and controls the driving of the motor 120. The power conversion device 130 includes a power converter 200 and an internal resistance detection device 300.

[0021] 2 is a diagram showing an example of a schematic configuration of a power converter 200 of the present embodiment. As shown in FIG. 2, the power converter 200 includes a capacitor 210, a boost converter 220, a capacitor 230, an inverter 240, and a control device 250.

[0022] The capacitor 210 is a smoothing capacitor provided on the primary side (secondary battery 110 side) of the boost converter 220. For example, one end of the capacitor 210 is connected to the positive electrode terminal P1 of the secondary battery 110, and the other end is connected to the negative electrode terminal P2 of the secondary battery 110. The negative electrode terminal P2 of the secondary battery 110 is grounded.

[0023] The boost converter 220 boosts the output voltage VBAT output from the secondary battery 110 at a predetermined boost ratio. The voltage boosted by the boost converter 220 is input to the inverter 240. The boost converter 220 generates a predetermined voltage Vs by boosting the output voltage VBAT output from the secondary battery 110 at a predetermined boost ratio, and outputs the voltage Vs to the inverter 240. The boost converter 220 may further include a function of stepping down the regenerative voltage input from the inverter 240 at a predetermined step-down ratio and outputting the voltage to the secondary battery 110. The boost converter 220 is an example of the "DCDC converter" of the present invention. The boost converter 220 may be a single-phase converter or a multi-phase converter. An example of a schematic configuration of the boost converter 220 will be described below.

[0024] The boost converter 220 includes a reactor 221 and an upper switching element Q1 and a lower switching element Q2 connected in series to each other.

[0025] The reactor 221 has one end connected to one end of the capacitor 210, and the other end connected to the connection point between the upper switching element Q1 and the lower switching element Q2.

[0026] Although the upper switching element Q1 and the lower switching element Q2 will be described as being IGBTs (Insulated Gate Bipolar Transistors), the present invention is not limited thereto and may be, for example, FETs (Field Effective Transistors) or the like.

[0027] A collector terminal of the upper switching element Q1 is connected to one terminal of the capacitor 230. An emitter terminal of the upper switching element Q1 is connected to the other end of the reactor 221. A base terminal of the upper switching element Q1 is connected to the control device 250.

[0028] The collector terminal of the low-side switching element Q2 is connected to the other end of the reactor 221. The emitter terminal of the low-side switching element Q2 is connected to the negative terminal P2 of the secondary battery 110. The base terminal of the low-side switching element Q2 is connected to the control device 250. The boost converter 220 includes diodes connected in parallel in the reverse direction to each of the high-side switching element Q1 and the low-side switching element Q2.

[0029] The capacitor 230 is connected to the secondary side (the inverter 240 side) of the boost converter 220. The capacitor 230 is a smoothing capacitor having one end connected to the collector terminal of the upper switching element Q1 and the other end connected to the negative terminal P2 of the secondary battery 110.

[0030] The inverter 240 converts a predetermined voltage Vs into AC power and supplies it to the motor 120. For example, the inverter 240 is supplied with a predetermined voltage Vs from the boost converter 220. The inverter 240 converts the power from the boost converter 220 into AC power and supplies it to the motor 120. For example, the inverter 240 is a three-phase inverter and includes three switching legs corresponding to the respective phases.

[0031] The control device 250 performs inverter control to control the inverter 240 based on a command value such as a torque command value. This inverter control can be performed using known techniques. The control device 250 performs converter control to control each of the upper switching element Q1 and the lower switching element Q2 to an ON state or an OFF state. The control device 250 may include a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) and a non-volatile or volatile semiconductor memory (e.g., a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory)). For example, the control device 250 may have a microcontroller such as an MCU. The control device 250 may also have driver circuits for the boost converter 220 and the inverter 240.

[0032] 3 is a diagram showing an example of a schematic configuration of an internal resistance detecting device 300 according to this embodiment. As shown in FIG. 3, the internal resistance detecting device 300 includes a charge pump circuit 310, an AC wave generating unit 320, a plurality of battery monitoring ICs 330 (330-1 to 330-n), and a processor 340.

[0033] The charge pump circuit 310 is connected to the secondary battery 110 and boosts the output voltage VBAT of the secondary battery 110. The voltage boosted by the charge pump circuit 310 (hereinafter referred to as the "boosted voltage") Vcc becomes twice the voltage of the output voltage VBAT. For example, the charge pump circuit 310 includes a first diode 400, a first capacitor 410, a first switch 420, a second diode 430, a second capacitor 440, and a second switch 450.

[0034] The first diode 400 has an anode connected to the positive electrode terminal P 1 of the secondary battery 110 , and a cathode connected to the first capacitor 410 .

[0035] A first capacitor 410 has one end connected to the cathode of the first diode 400 and the other end connected to a first switch 420 and a second switch 450 .

[0036] The first switch 420 is connected in series to the second switch 450. The first switch 420 is connected between the other end of the first capacitor 410 and the negative terminal P2. When the first switch 420 is in an on state, it electrically connects the negative terminal P2 and the other end of the first capacitor 410, and when the first switch 420 is in an off state, it cuts off the electrical connection between the negative terminal P2 and the other end of the first capacitor 410. As an example, the first switch 420 shown in FIG. 3 is an Nch MOSFET. In this case, the drain of the first switch 420 is connected to the other end of the first capacitor 410, the source is connected to the negative terminal P2, and the gate is connected to the processor 340. The first switch 420 is not limited to an electrical switch such as an IGBT or a MOSFET, and may be, for example, a mechanical switch.

[0037] The second diode 430 has an anode connected to one end of the first capacitor 410 and the cathode of the first diode 400 , and a cathode connected to the second capacitor 440 and the AC wave generating unit 320 .

[0038] The second capacitor 440 has one end connected to the cathode of the second diode 430 and the other end connected to the negative terminal P2.

[0039] The second switch 450 is connected between the other end of the first capacitor 410 and the positive terminal P1. When the second switch 450 is in an on state, it electrically connects the positive terminal P1 and the other end of the first capacitor 410, and when the second switch 450 is in an off state, it cuts off the electrical connection between the positive terminal P1 and the other end of the first capacitor 410. As an example, the second switch 450 shown in FIG. 3 is an Nch MOSFET. In this case, the drain of the second switch 450 is connected to the positive terminal P1, the source is connected to the other end of the first capacitor 410, and the gate is connected to the processor 340. In addition, the source of the second switch 450 is connected to the drain of the first switch 420. The second switch 450 is not limited to an electrical switch such as a MOSFET, and may be, for example, a mechanical switch.

[0040] The AC wave generating unit 320 generates an AC wave. The AC wave generating unit 320 is connected to one end of the second capacitor 440, and generates an AC voltage Vr by superimposing an AC wave on the boosted voltage Vcc input from the one end. The AC wave generating unit 320 applies the AC voltage Vr to the positive electrode terminal P1. The frequency fx of the AC wave generated by the AC wave generating unit 320 can be changed by the processor 340. The timing of application of the AC voltage Vr to the positive electrode terminal P1 is controlled by the processor 340.

[0041] The battery monitoring ICs 330 (330-1 to 330-n) are ICs (integrated circuits) that are electrically connected to the battery cells C and monitor the state of each battery cell C. 1 ~G n The battery monitoring ICs 330-1 to 330-n each have the same configuration, and when there is no need to distinguish between the battery monitoring ICs 330-1 to 330-n, they are simply referred to as "battery monitoring ICs 330."

[0042] The battery monitoring IC 330 acquires a current value Ix and a voltage value Vx of the secondary battery 110. The battery monitoring IC 330 is an example of an "acquisition unit".

[0043] For example, the battery monitoring IC 330 is provided corresponding to the battery cell group G, and has a number of input terminals corresponding to the output terminals (positive or negative terminals of the battery cells C) of each battery cell C in the battery cell group G. The output terminals (positive or negative terminals) of each battery cell C and the multiple input terminals of the battery monitoring IC 330 are connected one-to-one by, for example, connection lines. This electrically connects both ends of each battery cell C to the battery monitoring IC 330. The battery monitoring IC 330 monitors the state of each battery cell C by detecting a potential difference (hereinafter referred to as a "cell voltage value") Vcell between both ends of each battery cell C. The cell voltage value Vcell is an example of a voltage value Vx of the secondary battery 110.

[0044] The battery monitoring IC 330 detects the current value Ix flowing through the secondary battery 110. In the example shown in FIG. 3, the battery monitoring IC 330 detects the current value Ix flowing through the secondary battery 110 using a shunt resistor R. This shunt resistor R is connected in series to the battery cell C. The battery monitoring IC 330 detects the current value Ix flowing through the secondary battery 110 by detecting the potential difference between both ends of the shunt resistor R. The current value Ix flowing through each of the multiple battery cells C connected in series is the same. Therefore, it is sufficient that one battery monitoring IC 330 among the multiple battery monitoring ICs 330-1 to 330-n detects the current value Ix flowing through the secondary battery 110.

[0045] Each battery monitoring IC 330 transmits the detected cell voltage values, i.e., the voltage value Vx of the secondary battery 110, to the processor 340. At least one of the battery monitoring ICs 330-1 to 330-n transmits the detected current value Ix to the processor 340.

[0046] In one example of this embodiment, the battery monitoring ICs 330-1 to 330-n are daisy-chained and connected to one another by a communication line L. This communication line L1 is a communication line capable of bidirectional communication. That is, each battery monitoring IC 330 can communicate bidirectionally with the adjacent battery monitoring IC 330.

[0047] Further, among the plurality of battery monitoring ICs 330-1 to 330-n connected in a daisy chain, only the battery monitoring IC 330-n on the lowest potential side (one end side) is communicatively connected to the processor 340 via a communication line L2. The communication line L2 is a communication line capable of bidirectional communication and may be provided with an insulating section. As a result, the battery monitoring IC 330-n and the processor 340 can transmit and receive information by communicating in a state electrically insulated from each other. Therefore, the cell voltage Vcell detected by each of the plurality of battery monitoring ICs 330-1 to 330-n connected in a daisy chain and the current value Ix detected by at least one battery monitoring IC 330 are transmitted from the battery monitoring IC 330-n to the processor 340 via the communication line L2.

[0048] The insulating section insulates the electrical connection between the battery monitoring IC 330-4 and the processor 340, and is, for example, a photocoupler or a magnetic coupler.

[0049] The processor 340 is, for example, a microprocessor, a microcomputer, a central processing unit (CPU), or a digital signal processor (DSP). The processor 340 is operable to execute computer program instructions and to perform operations described by the computer program instructions. The processor 340 is an example of an "internal resistance calculation unit."

[0050] The processor 340 obtains the cell voltages Vcell detected by the battery monitoring ICs 330-1 to 330-n from the battery monitoring IC 330-4 to monitor the state of each battery cell C, and monitors the voltage VBAT of the secondary battery 110.

[0051] The processor 340 obtains the internal resistance value of the secondary battery 110 by the AC impedance method. Specifically, the processor 340 calculates the internal resistance value of the secondary battery 110 based on the current value Ix, voltage value Vx, and frequency fx of the AC wave of the secondary battery 110 when the AC voltage Vr, which is the boosted voltage Vcc that is the voltage boosted by the charge pump circuit 310 and the AC wave superimposed by the AC wave generating unit 320, is applied to the secondary battery 110. In one example of this embodiment, the processor 340 obtains the internal resistance value of the secondary battery 110 by calculating the internal resistance value of the battery cell C for each battery cell C based on the current value Ix of the secondary battery 110, each battery cell Vcell, and the frequency fx of the AC wave. For example, the processor 340 may obtain the internal resistance value by calculating a Cole-Cole plot. This internal resistance value is used to determine the presence or absence of an abnormality in the battery cell C or the secondary battery 110, or to calculate the SOC (State Of Charge).

[0052] An operation for calculating the internal resistance value of the secondary battery 110 by the AC impedance method according to this embodiment (hereinafter referred to as "internal resistance calculation operation") will be described below with reference to Fig. 4. This internal resistance calculation operation is performed when the ignition switch is in an OFF state, etc. For example, the internal resistance calculation operation may be executed when the ignition switch is turned OFF. However, this is not limited, and the internal resistance calculation operation may be executed when the ignition switch is in an ON state. For example, the internal resistance calculation operation may be executed when the ignition switch is turned ON. Fig. 4 is a diagram for explaining the flow of the internal resistance calculation operation according to this embodiment.

[0053] The internal resistance detection device 300 generates a boosted voltage Vcc by alternately performing a first operation and a second operation (step S101). First, the internal resistance detection device 300 performs a first operation. FIG. 5 is a diagram for explaining the first operation according to this embodiment. The first operation is an operation for charging the first capacitor 410 in order to generate the boosted voltage Vcc.

[0054] 5, as a first operation, the processor 340 turns the first switch 420 on and turns the second switch 450 off. This forms a charging path through which a current from the positive terminal P1 of the secondary battery 110 passes through the first diode 400, the first capacitor 410, and the first switch 420 and returns to the negative terminal P2 of the secondary battery 110. The first capacitor 410 is charged by the secondary battery 110 through this charging path. When the secondary battery 110 is charged, the potential difference across the first capacitor 410 becomes VBT. That is, the voltage at one end of the first capacitor 410 becomes VBT.

[0055] The internal resistance detection device 300 performs a first operation and then a second operation. FIG. 6 is a diagram for explaining the second operation according to the present embodiment. As shown in FIG. 6, the processor 340 turns the first switch 420 to an off state and turns the second switch 450 to an on state as the second operation. As a result, the other end of the first capacitor 410 is electrically connected to the positive terminal P1 instead of the negative terminal P2, and the voltage of one end of the first capacitor 410 becomes VBT×2. Therefore, a boost voltage Vcc, which is a voltage of VBT×2, is generated at one end of the second capacitor 440 via the second diode 430. The first operation and the second operation are repeated, so that the boost voltage Vcc is maintained at one end of the second capacitor 440.

[0056] The processor 340 operates the AC wave generating unit 320. When the AC wave generating unit 320 starts operating, the AC wave generating unit 320 generates the AC voltage Vr by superimposing an AC wave of frequency f on the boosted voltage Vcc. Then, the processor 340 outputs a command signal to the AC wave generating unit 320 to apply the AC voltage Vr to the positive terminal P1 (step S102).

[0057] The processor 340 varies the frequency f while applying the AC voltage Vr to the secondary battery 110, and acquires the current value Ix and voltage value Vx of the secondary battery 110 from the battery monitoring IC 330 during the period in which the AC voltage Vr is being applied (step S103). Then, the processor 340 determines the internal resistance value of each battery cell C as the internal resistance value of the secondary battery 110 based on the current value Ix and voltage value Vx acquired from the battery monitoring IC 330 and the frequency fx of the AC wave (step S104).

[0058] As described above, the internal resistance detection device 300 according to this embodiment detects the internal resistance value of the secondary battery 110 by an AC impedance method. The internal resistance detection device 300 includes a charge pump circuit 310 that boosts the output voltage of the secondary battery 110, and an AC wave generation unit 320 that generates an AC wave. The internal resistance detection device 300 calculates the internal resistance value based on the current value Ix, the voltage value Vx, and the frequency f of the AC wave when an AC voltage Vr in which an AC wave is superimposed on a boosted voltage Vcc, which is a voltage boosted by the charge pump circuit 310, is applied to the secondary battery 110.

[0059] With this configuration, the internal resistance detection device 300 according to this embodiment can generate a voltage equal to or higher than the output voltage of the secondary battery 110 regardless of user-dependent operations. Therefore, the internal resistance detection device 300 can generate a more stable voltage equal to or higher than the output voltage of the secondary battery when measuring the internal resistance value by the AC impedance method.

[0060] A plurality of switching elements (upper side switching element Q1 and lower side switching element Q2) in the boost converter 220 may serve as both the first switch 420 and the second switch 450. For example, the upper side switching element Q1 serves as the second switch 450, and the lower side switching element Q2 serves as the first switch 420.

[0061] With this configuration, the boost voltage Vcc can be generated without using a switch for the charge pump circuit 310.

[0062] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included.

[0063] In this embodiment, the multiple battery monitoring ICs 330-1 to 330-n are daisy-chain connected, but the present invention is not limited to this.

[0064] In this embodiment, the cell voltage Vcell is detected as the voltage Vx of the secondary battery 110, but the present invention is not limited to this, and the voltage Vx of the secondary battery 110 may be the inter-terminal voltage between the positive terminal P1 and the negative terminal P2. In this case, the processor 340 may calculate the voltage Vx of the secondary battery 110 by summing up the cell voltages of the battery cells C connected in series, or may detect the voltage Vx by a voltage sensor.

[0065] In this embodiment, the battery monitoring IC 330 detects the current value Ix using a shunt resistor R, but is not limited to this and may use a current sensor, etc. Similarly, the battery monitoring IC 330 may detect the voltage value Vx using a voltage sensor, etc.

[0066] The control device 250 and the processor 340 may be integrated together.

[0067] The term "unit" in the specification means a unit that processes at least one function or operation, which may be embodied as hardware or software, or a combination of hardware and software. [Explanation of symbols]

[0068] 100...vehicle, 110...secondary battery, 120...motor, 130...power conversion device, 200...power converter, 220...boost converter (DCDC converter), 300...internal resistance detection device, 310...charge pump circuit, 320...AC wave generation unit, 330...battery monitoring IC (acquisition unit), 340...processor (internal resistance calculation unit)

Claims

1. An internal resistance detection device for detecting an internal resistance value of a secondary battery, an acquisition unit that acquires a current value and a voltage value of the secondary battery; a charge pump circuit for boosting an output voltage of the secondary battery; an AC wave generating unit that generates an AC wave; an internal resistance calculation unit that calculates the internal resistance value based on the current value, the voltage value, and the frequency of the AC wave when an AC voltage obtained by superimposing the AC wave on a boosted voltage that is a voltage boosted by the charge pump circuit is applied to the secondary battery; Equipped with The calculation of the internal resistance value is performed when an ignition switch is in an off state. Internal resistance detection device.

2. An internal resistance detection device for detecting an internal resistance value of a secondary battery, an acquisition unit that acquires a current value and a voltage value of the secondary battery; a charge pump circuit for boosting an output voltage of the secondary battery; an AC wave generating unit that generates an AC wave; an internal resistance calculation unit that calculates the internal resistance value based on the current value, the voltage value, and the frequency of the AC wave when an AC voltage obtained by superimposing the AC wave on a boosted voltage that is a voltage boosted by the charge pump circuit is applied to the secondary battery; Equipped with The charge pump circuit includes: A first diode having an anode connected to a positive terminal of the secondary battery; a first capacitor having one end connected to the cathode of the first diode; a first switch connected between the other end of the first capacitor and a negative terminal of the secondary battery; a second diode having an anode connected to one end of the first capacitor; a second capacitor having one end connected to the cathode of the second diode and the other end connected to the negative terminal; a second switch connected between the other end of the first capacitor and the positive terminal of the secondary battery; having The AC wave generating unit generates the AC voltage by superimposing the AC wave on the boosted voltage input from one end of the second capacitor, and applies the AC voltage to the positive terminal. Internal resistance detection device.

3. The secondary battery is configured by connecting a plurality of battery cells in series, The internal resistance calculation unit calculates the internal resistance value for each of the battery cells.

3. The internal resistance detection device according to claim 1 or 2.

4. An internal resistance detection device comprising: An internal resistance detection device for detecting an internal resistance value of a secondary battery, an acquisition unit that acquires a current value and a voltage value of the secondary battery; a charge pump circuit for boosting an output voltage of the secondary battery; an AC wave generating unit that generates an AC wave; an internal resistance calculation unit that calculates the internal resistance value based on the current value, the voltage value, and the frequency of the AC wave when an AC voltage obtained by superimposing the AC wave on a boosted voltage that is a voltage boosted by the charge pump circuit is applied to the secondary battery; Equipped with The charge pump circuit comprises: A first diode having an anode connected to a positive terminal of the secondary battery; a first capacitor having one end connected to the cathode of the first diode; a first switch connected between the other end of the first capacitor and a negative terminal of the secondary battery; a second diode having an anode connected to one end of the first capacitor; a second capacitor having one end connected to the cathode of the second diode and the other end connected to the negative terminal; a second switch connected between the other end of the first capacitor and the positive terminal of the secondary battery; having The AC wave generating unit generates the AC voltage by superimposing the AC wave on the boosted voltage input from one end of the second capacitor, and applies the AC voltage to the positive electrode terminal; The internal resistance detection device; an inverter that drives a motor used for driving a vehicle; a DC-DC converter having a plurality of switching elements and performing power conversion between the inverter and the secondary battery by switching the plurality of switching elements; having The plurality of switching elements serve as both the first switch and the second switch. Power conversion equipment.

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