Voltage detector, and battery control unit

Abstract

To provide a voltage detector powered by a battery pack capable of reducing measurement error of cell voltage value due to current consumption of the voltage detector without using any operational amplifier.SOLUTION: The voltage detector includes: a circuit for estimating route resistance 4 that is connected to a measurement line connected to the positive electrode of a highest potential battery cell and a measurement line connected to the negative electrode of a lowest potential battery cell, which is capable of switching between a state that current flows through the circuit for estimating route resistance 4 and a state that no current flows through the circuit for estimating route resistance 4; and a correction unit that corrects at least one of the cell voltage value of the highest potential battery cell and the lowest potential battery cell based on the current value flowing through the circuit for estimating route resistance 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a voltage detection device and a battery control device. [Background technology]

[0002] For example, Patent Document 1 discloses a voltage measuring device that measures the terminal voltage of each battery cell of a battery module. The voltage measuring device disclosed in Patent Document 1 includes a monitoring unit that measures the terminal voltage of the battery cell, a measurement line that inputs the voltage across both ends of the battery cell to the monitoring unit, and a microcomputer. Furthermore, the voltage measuring device disclosed in Patent Document 1 includes an operational amplifier that measures the voltage drop value of the low-potential measurement line, and the microcomputer corrects the terminal voltage using the voltage drop value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-71101 A Summary of the Invention [Problem to be solved by the invention]

[0004] A voltage detection device having a detection unit for acquiring a cell voltage value of a battery cell, such as the voltage measurement device disclosed in Patent Document 1, is supplied with power from an assembled battery such as the battery module of Patent Document 1. That is, the voltage detection device consumes power stored in the assembled battery. Supplying power to the voltage detection device from some of the battery cells among a plurality of battery cells causes the cell balance to be lost. For this reason, the voltage detection device is generally connected to the positive electrode of the battery cell with the highest potential and the negative electrode of the battery cell with the lowest potential, and acquires power from the total voltage of the assembled battery. However, if the resistance value of the path through which the current supplied to the voltage detection device flows is large, the voltage drop in the measurement line due to the current consumed by the voltage detection device flows becomes large. As a result, the measurement error of the cell voltage value becomes large. Particularly in recent years, the number of battery cells has increased, and the wiring distance of the harness has become longer and the harness wire has become thinner, which increases the resistance value of the path and increases the measurement error of the cell voltage value. For example, Patent Document 1 measures the voltage drop value of the low-potential measurement line using an operational amplifier as described above. However, in Patent Document 1, a separate path is required to constantly supply power from the battery pack to the operational amplifier. In addition, since high accuracy is required, an expensive operational amplifier is needed, and the voltage dependency and temperature dependency of the operational amplifier must also be taken into consideration.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to reduce measurement errors in cell voltage values ​​caused by the current consumption of a voltage detection device that is powered by a battery pack, without using an operational amplifier. [Means for solving the problem]

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

[0007] A first aspect of the present invention is a voltage detection device comprising: a detection unit connected via a measurement line to a battery pack in which a plurality of battery cells are connected in series, and detecting the voltage of each of the battery cells to obtain a cell voltage value of each of the battery cells; a path resistance estimation circuit unit connected to the measurement line connected to the positive electrode of a highest potential battery cell that is the battery cell with the highest potential among the plurality of battery cells and the measurement line connected to the negative electrode of a lowest potential battery cell that is the battery cell with the lowest potential among the plurality of battery cells, and capable of switching between a state in which current flows through the path resistance estimation circuit unit and a state in which current does not flow through the path resistance estimation circuit unit; and a correction unit that corrects at least one of the cell voltage value of the highest potential battery cell and the cell voltage value of the lowest potential battery cell based on the value of the current flowing in the path resistance estimation circuit unit.

[0008] A second aspect of the present invention is a battery control device comprising the voltage detection device of the first aspect and a control unit that controls the battery pack based on the cell voltage value acquired by the voltage detection device. Effect of the Invention

[0009] The present invention can correct the cell voltage value by passing a current from the battery pack to the path resistance estimation circuit unit. Furthermore, for example, the path resistance estimation circuit unit only needs to pass a current through a measurement line when calculating a correction value, and there is no need to provide a path for supplying power from the battery pack to the path resistance estimation circuit unit in addition to the measurement line. In this way, the present invention can correct the cell voltage value without using an operational amplifier, and can reduce measurement errors in the cell voltage value caused by power supply to the voltage detection device. Therefore, the present invention can reduce measurement errors in the cell voltage value caused by the current consumption of the voltage detection device in a voltage detection device that receives power from the battery pack, without using an operational amplifier. [Brief description of the drawings]

[0010] [Figure 1] 1 is a circuit diagram showing a schematic configuration of a voltage detection device according to a first embodiment of the present invention. [Diagram 2] 1 is a block diagram showing a functional configuration of a battery monitoring integrated circuit included in a voltage detection device according to a first embodiment of the present invention. [Diagram 3] 4 is a timing chart illustrating the operation of the voltage detection device in the first embodiment of the present invention. [Figure 4] FIG. 6 is a schematic configuration diagram of a battery control device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a voltage detection device and a battery control device according to the present invention will be described with reference to the drawings.

[0012] (First embodiment) FIG. 1 is a circuit diagram showing a schematic configuration of a voltage detection device 1 of this embodiment. The voltage detection device 1 of this embodiment is mounted on an electric vehicle such as an electric car or a hybrid car. The voltage detection device 1 of this embodiment detects the voltage of a battery module M (battery pack) mounted on the electric vehicle. A plurality of battery modules M are mounted on the electric vehicle. Each battery module M is connected in series. The voltage detection device 1 of this embodiment is provided for each battery module M. In other words, a plurality of voltage detection devices 1 of this embodiment are provided for the vehicle, just like the battery modules M.

[0013] The battery module M includes a plurality of battery cells c connected in series. The battery module M is a secondary battery that supplies DC power to an external load, the output voltage (battery voltage) being the sum of the electromotive voltages of the plurality of battery cells c. Such a battery module M is, for example, a lithium ion battery.

[0014] In the following description, the battery cell c with the lowest potential among the multiple battery cells c constituting one battery module M will be referred to as the lowest potential battery cell c1. Also, the battery cell c with the highest potential among the multiple battery cells c constituting one battery module M will be referred to as the highest potential battery cell cn. For example, if the n battery cells c constituting one battery module M are arranged in order of potential as a first battery cell, a second battery cell, a third battery cell, etc., in this embodiment, the first battery cell will be the lowest potential battery cell c1 and the nth battery cell will be the highest potential battery cell cn.

[0015] The voltage detection device 1 of this embodiment detects the voltage (cell voltage) of each battery cell c. The voltage detection device 1 of this embodiment may also detect the battery voltage of a battery module M. As shown in Fig. 1, the voltage detection device 1 of this embodiment includes a plurality of connection paths 2, a battery monitoring integrated circuit 3, and a path resistance estimation circuit unit 4. All or some of the plurality of connection paths 2, the battery monitoring integrated circuit 3, and the path resistance estimation circuit unit 4 are provided on, for example, a printed wiring board (not shown).

[0016] Each connection path 2 connects the battery module M and the battery monitoring integrated circuit 3. One end of the connection path 2 is connected to each electrode of the battery cell c, as shown in FIG. 1. A common connection path 2 is provided between the mutually connected positive and negative electrodes of adjacent battery cells c. In addition, a connection path 2 is provided between the negative electrode of the lowest potential battery cell c1 and the positive electrode of the highest potential battery cell cn. Such connection paths 2 are provided in a number (n+1) that is one more than the number of battery cells c.

[0017] Each connection path 2 has a measurement line 2a (e.g., a harness) located between the electrode of the battery cell c and the input terminal of the battery monitoring integrated circuit 3. The electrode voltage of the battery cell c is input to the battery monitoring integrated circuit 3 via these measurement lines 2a. Note that a fuse, a filter circuit, etc. may be provided at an intermediate location of each connection path 2. Such a connection path 2 has a path resistance resulting from the resistance of the measurement lines 2a, etc.

[0018] The battery monitoring integrated circuit 3 is an integrated circuit (semiconductor chip) connected to the battery module M via each of the connection paths 2. The battery monitoring integrated circuit 3 is driven by power supplied from the battery module M. The battery monitoring integrated circuit 3 is connected via a power supply line to each of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1 and the connection path 2 connected to the positive electrode of the highest potential battery cell cn, and is supplied with power from the total voltage of the battery module M. In other words, the battery monitoring integrated circuit 3 drives while consuming the power stored in all the battery cells c that constitute the battery module M. The battery monitoring integrated circuit 3 is connected to the measurement line 2a of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1, and the supply voltage of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1 is used as the ground voltage (reference voltage).

[0019] Such a battery monitoring integrated circuit 3 detects the voltage of each battery cell c based on the voltage input via each connection path 2, and obtains the detected value as the cell voltage value Vc. For example, when detecting the total voltage of the battery module M, the battery monitoring integrated circuit 3 obtains the difference between the input voltage (i.e., ground voltage) of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1 and the input voltage of the connection path 2 connected to the positive electrode of the highest potential battery cell cn as the total voltage value of the battery module M.

[0020] Furthermore, in the voltage detection device 1 of this embodiment, the battery monitoring integrated circuit 3 corrects the cell voltage value Vc of the lowest potential battery cell c1, which has the lowest potential, and the cell voltage value Vc of the highest potential battery cell cn, which has the highest potential, based on the value of the current (estimated circuit current value) flowing through the path resistance estimation circuit unit 4. This battery monitoring integrated circuit 3 will be described in more detail later.

[0021] 1, the path resistance estimation circuit unit 4 is connected to the power supply line of the battery monitoring integrated circuit 3. In other words, the path resistance estimation circuit unit 4 is connected via the power supply line to a measurement line 2a connected to the negative electrode of the lowest potential battery cell c1 and a measurement line 2a connected to the positive electrode of the highest potential battery cell cn.

[0022] In this embodiment, as described later, the battery monitoring integrated circuit 3 calculates a correction value for correcting the cell voltage value Vc of the lowest potential battery cell c1 based on the path resistance estimate value of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1. In addition, in this embodiment, as described later, the battery monitoring integrated circuit 3 calculates a correction value for correcting the cell voltage value Vc of the highest potential battery cell cn based on the path resistance estimate value of the connection path 2 connected to the positive electrode of the highest potential battery cell cn. The path resistance estimation circuit unit 4 is a circuit through which a current flows to calculate the path resistance estimate value of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1 and the path resistance estimate value of the connection path 2 connected to the positive electrode of the highest potential battery cell cn. As shown in FIG. 1, such a path resistance estimation circuit unit 4 includes a switching element 4a (switch) and a resistive element 4b (a first resistive element 4b1 and a second resistive element 4b2).

[0023] The switching element 4a is a semiconductor element for switching between a state in which a current flows through the path resistance estimation circuit unit 4 and a state in which a current does not flow through the path resistance estimation circuit unit 4. The switching element 4a is a transistor whose conductive state can be switched by the battery monitoring integrated circuit 3, and goes into a state in which a current flows when a drive voltage is applied from the battery monitoring integrated circuit 3. Furthermore, the switching element 4a goes into a state in which a current does not flow when a drive voltage is not applied from the battery monitoring integrated circuit 3. Note that a mechanical switch or the like can be provided instead of the switching element 4a.

[0024] The resistance element 4b is a resistor connected in series to the switching element 4a. In this embodiment, the resistance element 4b includes a first resistance element 4b1 and a second resistance element 4b2. That is, in this embodiment, the path resistance estimation circuit unit 4 includes two resistance elements 4b.

[0025] 1, one end of the first resistor element 4b1 is connected to the negative electrode of the lowest potential battery cell c1. The other end of the switching element 4a is connected to the first resistor element 4b1. One end of the second resistor element 4b2 is connected to the switching element 4a and the other end is connected to the positive electrode of the highest potential battery cell cn.

[0026] One end of the first resistor element 4b1 is connected to the negative electrode of the lowest potential battery cell c1 via a connection path 2 connected to the negative electrode of the lowest potential battery cell c1 and a power supply line. One end of the first resistor element 4b1 is connected to a connection path 2 (connection path 2 connected to the negative electrode of the lowest potential battery cell c1) that supplies a ground voltage to the battery monitoring integrated circuit 3. In other words, one end of the first resistor element 4b1 is connected to the ground. The other end of the second resistor element 4b2 is connected to the positive electrode of the highest potential battery cell cn via a connection path 2 connected to the negative electrode of the highest potential battery cell cn and a power supply line.

[0027] Such a path resistance estimation circuit unit 4 is connected to a measurement line 2a connected to the positive electrode of a highest potential battery cell cn, which is the battery cell with the highest potential among the multiple battery cells c, and a measurement line 2a connected to the negative electrode of a lowest potential battery cell c1, which is the battery cell with the lowest potential among the multiple battery cells c. In addition, the path resistance estimation circuit unit 4 is capable of switching between a state in which a current flows through the path resistance estimation circuit unit 4 and a state in which a current does not flow through the path resistance estimation circuit unit 4.

[0028] In this embodiment, the path resistance estimation circuit unit 4 includes a switching element 4a. However, when a state in which a current flows through the path resistance estimation circuit unit 4 and a state in which a current does not flow through the path resistance estimation circuit unit 4 can be switched using a switch or the like provided outside the path resistance estimation circuit unit 4, the path resistance estimation circuit unit 4 does not need to include the switching element 4a. Also, in this embodiment, the path resistance estimation circuit unit 4 includes two resistance elements 4b. However, the path resistance estimation circuit unit 4 may be configured to include one resistance element or three or more resistance elements.

[0029] Furthermore, in this embodiment, the voltage detection device 1 includes a resistive element voltage detection line 5 that connects the other end of the first resistive element 4b1 to the battery monitoring integrated circuit 3. The battery monitoring integrated circuit 3 detects the voltage applied to the first resistive element 4b1 based on the voltage input from the resistive element voltage detection line 5, and acquires the resistance voltage value VR.

[0030] 2 is a block diagram showing the functional configuration of the battery monitoring integrated circuit 3. As shown in this figure, the battery monitoring integrated circuit 3 includes a detection unit 3a, a correction unit 3b, a switch drive unit 3c, and a communication unit 3d. The battery monitoring integrated circuit 3 also includes a storage unit (not shown) for storing data and programs as necessary. Such a battery monitoring integrated circuit 3 is a semiconductor chip that is connected to the battery module M and includes at least the detection unit 3a and the correction unit 3b. The battery monitoring integrated circuit 3 is supplied with power from the total voltage of the battery module M as described above, and operates while consuming the power stored in all the battery cells c that constitute the battery module M.

[0031] The battery monitoring integrated circuit 3 includes a discharge circuit for adjusting and equalizing the cell voltage of each battery cell c. A discharge circuit is provided for each battery cell c. The battery monitoring integrated circuit 3 equalizes the cell voltages of the battery cells c by discharging in the discharge circuit based on an external instruction.

[0032] The detection unit 3a is connected to the battery module M via each measurement line 2a. The detection unit 3a calculates (acquires) a cell voltage value Vc indicating the value of the voltage of each battery cell c from the voltage input via each measurement line 2a. The detection unit 3a determines the cell voltage value Vc of a certain battery cell c to be a value indicating the difference between the voltage input from the measurement line 2a connected to the negative electrode of the battery cell c and the voltage input from the measurement line 2a connected to the positive electrode of the battery cell c.

[0033] For example, the detection unit 3a determines the cell voltage value Vc of the lowest potential battery cell c1 as the value indicated by the difference between the voltage input from the measurement line 2a connected to the negative electrode of the lowest potential battery cell c1 and the voltage input from the measurement line 2a connected to the positive electrode of the lowest potential battery cell c1. The detection unit 3a also determines the cell voltage value Vc of the highest potential battery cell cn as the value indicated by the difference between the voltage input from the measurement line 2a connected to the negative electrode of the highest potential battery cell cn and the voltage input from the measurement line 2a connected to the positive electrode of the highest potential battery cell cn.

[0034] Furthermore, the detection unit 3a acquires a value indicated by a voltage input from the resistance element voltage detection line 5. The value indicated by the voltage input from the resistance element voltage detection line 5 indicates the voltage value of the other end of the first resistance element 4b1, and is referred to as the first resistance element high-voltage side voltage value Vr. In other words, the detection unit 3a acquires the first resistance element high-voltage side voltage value Vr.

[0035] The correction unit 3b corrects the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1 based on the value of the current (estimated circuit current value It) flowing through the path resistance estimation circuit unit 4. In this embodiment, the correction unit 3b corrects both the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1, but is not limited to this. In this embodiment, the correction unit 3b may correct either the cell voltage value Vc of the highest potential battery cell cn or the cell voltage value Vc of the lowest potential battery cell c1. As shown in FIG. 2, the correction unit 3b includes a resistive element voltage detection unit 3b1, a current value calculation unit 3b2, a path resistance estimation value calculation unit 3b3, a correction value calculation unit 3b4, and a correction calculation unit 3b5.

[0036] The resistive element voltage detection unit 3b1 calculates the value of the voltage applied to the first resistive element 4b1 (resistance voltage value VR) based on the first resistive element high-voltage side voltage value Vr input from the detection unit 3a. The resistive element voltage detection unit 3b1 sets the difference between the first resistive element high-voltage side voltage value Vr and the ground voltage value as the resistance voltage value VR. In this way, the resistive element voltage detection unit 3b1 obtains the resistance voltage value VR, which is the value of the voltage applied to the first resistive element 4b1. The detection unit 3a may detect and output the resistance voltage value VR. In this case, the resistive element voltage detection unit 3b1 obtains the resistance voltage value VR from the detection unit 3a.

[0037] The current value calculation unit 3b2 calculates the value of the current (estimated circuit current value It) flowing through the path resistance estimation circuit unit 4 based on the resistance voltage value VR input from the resistance element voltage detection unit 3b1. The current value calculation unit 3b2 calculates the estimated circuit current value It using Ohm's law based on the resistance value of the first resistance element 4b1 pre-stored in the storage unit and the resistance voltage value VR. In this way, the current value calculation unit 3b2 calculates the estimated circuit current value It, which is the value of the current flowing through the path resistance estimation circuit unit 4, based on the resistance value of the resistance element (the first resistance element 4b1 in this embodiment) from which the resistance voltage value VR has been acquired and the resistance voltage value VR.

[0038] The path resistance estimation value calculation unit 3b3 calculates, based on the estimated circuit current value It, a lowest path resistance estimation value Rk1, which is the path resistance estimation value of the connection path 2 connected to the negative electrode of the lowest potential battery cell c1, and a highest path resistance estimation value Rkn, which is the path resistance estimation value of the connection path 2 connected to the positive electrode of the highest potential battery cell cn.

[0039] The path resistance estimation value calculation unit 3b3 calculates the lowest path resistance estimation value Rk1 by subtracting the cell voltage value Vc of the lowest potential battery cell c1 in a state where a current flows through the path resistance estimation circuit unit 4 from the cell voltage value Vc of the lowest potential battery cell c1 in a state where a current does not flow through the path resistance estimation circuit unit 4, and dividing the value obtained by the subtraction by the estimated circuit current value It. In other words, the path resistance estimation value calculation unit 3b3 calculates the lowest path resistance estimation value Rk1 by dividing the difference between the cell voltage value Vc of the lowest potential battery cell c1 in a state where a current does not flow through the path resistance estimation circuit unit 4 and the cell voltage value Vc of the lowest potential battery cell c1 in a state where a current flows through the path resistance estimation circuit unit 4 by the estimated circuit current value It.

[0040] Furthermore, the path resistance estimation value calculation unit 3b3 calculates the highest path resistance estimation value Rkn by subtracting the cell voltage value Vc of the highest potential battery cell cn in a state where a current is flowing through the path resistance estimation circuit unit 4 from the cell voltage value Vc of the highest potential battery cell cn in a state where no current is flowing through the path resistance estimation circuit unit 4, and dividing the value obtained by the subtraction by the estimated circuit current value It. In other words, the path resistance estimation value calculation unit 3b3 calculates the highest path resistance estimation value Rkn by dividing the difference between the cell voltage value Vc of the highest potential battery cell cn in a state where no current is flowing through the path resistance estimation circuit unit 4 and the cell voltage value Vc of the highest potential battery cell cn in a state where a current is flowing through the path resistance estimation circuit unit 4 by the estimated circuit current value It.

[0041] In this way, the path resistance estimate calculation unit 3b3 can calculate the highest path resistance estimate Rkn, which is the path resistance estimate of the connection path 2 (highest path 2H) including the measurement line 2a connected to the positive electrode of the highest potential battery cell cn, based on the estimated circuit current value It. Also, the path resistance estimate calculation unit 3b3 can calculate the lowest path resistance estimate Rk1, which is the path resistance estimate of the connection path 2 (lowest path 2L) including the measurement line 2a connected to the negative electrode of the lowest potential battery cell c1, based on the estimated circuit current value It.

[0042] In this embodiment, as described above, both the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1 are corrected. Therefore, the path resistance estimate value calculation unit 3b3 calculates the highest path resistance estimate value Rkn and the lowest path resistance estimate value Rk1. However, when correcting either the cell voltage value Vc of the highest potential battery cell cn or the cell voltage value Vc of the lowest potential battery cell c1, it is sufficient to calculate the path resistance estimate value corresponding to the cell voltage value Vc to be corrected.

[0043] The correction value calculation unit 3b4 can calculate a correction value An for the cell voltage value Vc of the highest potential battery cell cn based on the highest path resistance estimate value Rkn, and can calculate a correction value A1 for the cell voltage value Vc of the lowest potential battery cell c1 based on the lowest path resistance estimate value Rk1.

[0044] The correction value calculation unit 3b4 calculates a correction value An by multiplying the current consumption of the battery monitoring integrated circuit 3 (i.e., the current consumption of the voltage detection device 1) by the highest path resistance estimated value Rkn. The correction value calculation unit 3b4 also calculates a correction value A1 by multiplying the current consumption of the battery monitoring integrated circuit 3 by the lowest path resistance estimated value Rk1. Here, the rated current consumption (design value) of the battery monitoring integrated circuit 3 can be used as the current consumption. However, the actual current consumption of the battery monitoring integrated circuit 3 can be measured and the measurement result can be used.

[0045] In this manner, in this embodiment, the current consumption of the battery monitoring integrated circuit 3 is multiplied by the path resistance estimate value to calculate the voltage drop component of the connection path 2 caused by the current consumption of the battery monitoring integrated circuit 3, and the correction value is set as the correction value. That is, the correction value calculation unit 3b4 multiplies the current consumption of the battery monitoring integrated circuit 3 by the highest path resistance estimate value Rkn to calculate the voltage drop component of the highest path 2H caused by the current consumption of the battery monitoring integrated circuit 3, and sets the correction value An. In addition, the correction value calculation unit 3b4 multiplies the current consumption of the battery monitoring integrated circuit 3 by the lowest path resistance estimate value Rk1 to calculate the voltage drop component of the lowest path 2L caused by the current consumption of the battery monitoring integrated circuit 3, and sets the correction value A1. The correction values ​​An and A1 are stored in, for example, a storage unit.

[0046] The correction calculation unit 3b5 corrects the cell voltage value Vc detected by the detection unit 3a by adding a correction value to the cell voltage value Vc. In this embodiment, the correction calculation unit 3b5 corrects the cell voltage value Vc of the highest potential battery cell cn by adding the correction value An to the cell voltage value Vc of the highest potential battery cell cn. The correction calculation unit 3b5 also corrects the cell voltage value Vc of the highest potential battery cell cn by adding the correction value A1 to the cell voltage value Vc of the lowest potential battery cell c1.

[0047] The switch driving unit 3c drives the switching element 4a of the path resistance estimation circuit unit 4. For example, the switch driving unit 3c drives the switching element 4a so that the switching element 4a passes a current based on a command signal input from the outside via the communication unit 3d. The communication unit 3d communicates with the outside. For example, the communication unit 3d outputs a signal indicating the cell voltage value Vc. The communication unit 3d also receives a command signal from the outside. This communication unit 3d is connected to the detection unit 3a, the correction unit 3b, and the switch driving unit 3c.

[0048] Next, the operation of the voltage detecting device 1 of this embodiment when the correction values ​​An and A1 are calculated will be described with reference to Fig. 3. Fig. 3 is a timing chart when the correction values ​​An and A1 are calculated.

[0049] As shown in FIG. 3, the battery monitoring integrated circuit 3 first acquires the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn. As shown in FIG. 3, the battery monitoring integrated circuit 3 acquires the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn when the switching element 4a of the path resistance estimation circuit unit 4 is in the OFF state (i.e., a state in which no current flows through the path resistance estimation circuit unit 4). Here, the battery monitoring integrated circuit 3 acquires the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn using the detection unit 3a. Note that in this embodiment, the cell voltage value Vc of the lowest potential battery cell c1 is acquired first, and then the cell voltage value Vc of the highest potential battery cell cn is acquired. However, the cell voltage value Vc of the highest potential battery cell cn may be acquired first, and then the cell voltage value Vc of the lowest potential battery cell c1 may be acquired.

[0050] Next, the battery monitoring integrated circuit 3 switches the switching element 4a of the path resistance estimation circuit unit 4 to the ON state (i.e., a state in which current flows through the path resistance estimation circuit unit 4). Here, the battery monitoring integrated circuit 3 switches the switching element 4a from the OFF state to the ON state using the switch drive unit 3c. Note that, as shown in Fig. 3, the battery monitoring integrated circuit 3 switches the switching element 4a of the path resistance estimation circuit unit 4 to the ON state after completing acquisition of the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn.

[0051] Next, the battery monitoring integrated circuit 3 acquires the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn while keeping the switching element 4a of the path resistance estimation circuit unit 4 in the ON state (i.e., a state in which a current flows through the path resistance estimation circuit unit 4). Here, the battery monitoring integrated circuit 3 acquires the cell voltage value Vc of the lowest potential battery cell c1 and the cell voltage value Vc of the highest potential battery cell cn using the detection unit 3a. Note that in this embodiment, the cell voltage value Vc of the lowest potential battery cell c1 is acquired first, and then the cell voltage value Vc of the highest potential battery cell cn is acquired. However, it is also possible to acquire the cell voltage value Vc of the highest potential battery cell cn first, and then the cell voltage value Vc of the lowest potential battery cell c1.

[0052] Next, the battery monitoring integrated circuit 3 detects the voltage applied to the first resistor element 4b1 to obtain the resistance voltage value VR while keeping the switching element 4a of the path resistance estimation circuit unit 4 in the ON state (i.e., a state in which a current flows through the path resistance estimation circuit unit 4). Here, the battery monitoring integrated circuit 3 obtains the first resistor element high-voltage side voltage value Vr using the detection unit 3a, and calculates the resistance voltage value VR using the resistor element voltage detection unit 3b1.

[0053] Next, the battery monitoring integrated circuit 3 sets the switching element 4a of the path resistance estimation circuit unit 4 to the OFF state (i.e., a state in which no current flows through the path resistance estimation circuit unit 4). Here, the battery monitoring integrated circuit 3 switches the switching element 4a from the ON state to the OFF state using the switch drive unit 3c. Note that, as shown in FIG. 3, the battery monitoring integrated circuit 3 sets the switching element 4a of the path resistance estimation circuit unit 4 to the OFF state after acquiring the resistance voltage value VR.

[0054] Next, the battery monitoring integrated circuit 3 calculates the estimated circuit current value It. Here, the battery monitoring integrated circuit 3 causes the current value calculation unit 3b2 to calculate the estimated circuit current value It. The current value calculation unit 3b2 calculates the estimated circuit current value It using Ohm's law based on the resistance value of the first resistor element 4b1 and the resistance voltage value VR, which are stored in advance in the storage unit.

[0055] Next, the battery monitoring integrated circuit 3 calculates the lowest path resistance estimation value Rk1 and the highest path resistance estimation value Rkn. Here, the battery monitoring integrated circuit 3 causes the path resistance estimation value calculation unit 3b3 to calculate the lowest path resistance estimation value Rk1 and the highest path resistance estimation value Rkn. The path resistance estimation value calculation unit 3b3 calculates the lowest path resistance estimation value Rk1 by subtracting the cell voltage value Vc of the lowest potential battery cell c1 in a state where a current is flowing through the path resistance estimation circuit unit 4 from the cell voltage value Vc of the lowest potential battery cell c1 in a state where no current is flowing through the path resistance estimation circuit unit 4, and dividing the value obtained by the subtraction by the estimated circuit current value It. In addition, the path resistance estimation value calculation unit 3b3 subtracts the cell voltage value Vc of the highest potential battery cell cn when current is flowing through the path resistance estimation circuit unit 4 from the cell voltage value Vc of the highest potential battery cell cn when no current is flowing through the path resistance estimation circuit unit 4, and divides the value obtained by the subtraction by the estimated circuit current value It to calculate the highest path resistance estimation value Rkn.

[0056] Next, the battery monitoring integrated circuit 3 calculates the correction value A1 and the correction value An. Here, the battery monitoring integrated circuit 3 causes the correction value calculation unit 3b4 to calculate the correction value A1 and the correction value An. The correction value calculation unit 3b4 calculates the correction value An by multiplying the current consumption of the battery monitoring integrated circuit 3 by the highest path resistance estimated value Rkn. In addition, the correction value calculation unit 3b4 calculates the correction value A1 by multiplying the current consumption of the battery monitoring integrated circuit 3 by the lowest path resistance estimated value Rk1.

[0057] The correction value A1 and the correction value An calculated in this way are stored in, for example, a memory unit of the voltage detection device 1. When acquiring the cell voltage value Vc of the lowest potential battery cell c1, the voltage detection device 1 corrects the cell voltage value Vc of the lowest potential battery cell c1 using the correction value A1. When acquiring the cell voltage value Vc of the highest potential battery cell cn, the voltage detection device 1 corrects the cell voltage value Vc of the highest potential battery cell cn using the correction value An. The voltage detection device 1 outputs these corrected cell voltage values ​​Vc to the outside via the communication unit 3d. Furthermore, the voltage detection device 1 outputs the cell voltage values ​​Vc of the battery cells c other than the lowest potential battery cell c1 and the highest potential battery cell cn to the outside via the communication unit 3d without correction.

[0058] The voltage detection device 1 of the present embodiment as described above includes a detection unit 3a, a path resistance estimation circuit unit 4, and a correction unit 3b. The detection unit 3a is connected to a battery module M in which a plurality of battery cells c are connected in series via a measurement line 2a. The detection unit 3a detects the voltage of each battery cell c to obtain a cell voltage value Vc of each battery cell c. The path resistance estimation circuit unit 4 is connected to a measurement line 2a connected to a positive electrode of a highest potential battery cell cn, which is a battery cell c with the highest potential among the plurality of battery cells c, and a measurement line 2a connected to a negative electrode of a lowest potential battery cell c1, which is a battery cell c with the lowest potential among the plurality of battery cells c. The path resistance estimation circuit unit 4 is capable of switching between a state in which a current flows through the path resistance estimation circuit unit 4 and a state in which a current does not flow through the path resistance estimation circuit unit 4. The correction unit 3b calculates correction values ​​(correction value An and correction value A1) for correcting the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1 based on the value of the current flowing through the path resistance estimation circuit unit 4.

[0059] The voltage detection device 1 of this embodiment can correct the cell voltage value Vc by passing a current from the battery module M to the path resistance estimation circuit unit 4. In addition, for example, the path resistance estimation circuit unit 4 only needs to pass a current through the measurement line 2a when calculating a correction value, and there is no need to provide a path for supplying power from the battery module M to the path resistance estimation circuit unit 4 in addition to the measurement line 2a. In this way, the voltage detection device 1 of this embodiment can correct the cell voltage value Vc without using an operational amplifier, and can reduce measurement errors of the cell voltage value Vc caused by power supply to the voltage detection device 1. Therefore, the voltage detection device 1 of this embodiment can reduce measurement errors of the cell voltage value Vc caused by the current consumption of the voltage detection device 1 in a voltage detection device that receives power from the battery module M without using an operational amplifier.

[0060] In the voltage detection device 1 of this embodiment, the path resistance estimation circuit unit 4 includes a switching element 4a and resistance elements (a first resistance element 4b1 and a second resistance element 4b2). The switching element 4a is capable of switching between a state in which a current flows through the path resistance estimation circuit unit 4 and a state in which a current does not flow through the path resistance estimation circuit unit 4. The resistance elements are connected in series to the switching element 4a.

[0061] In the voltage detection device 1 of the present embodiment, by turning on the switching element 4a, a current can flow through the path resistance estimation circuit unit 4. Therefore, it is possible to change the conduction state of the path resistance estimation circuit unit 4 with a simple structure.

[0062] Furthermore, in the voltage detection device 1 of this embodiment, the path resistance estimation circuit unit 4 includes a first resistor element 4b1, a switching element 4a, and a second resistor element 4b2. The first resistor element 4b1 is a resistor element having one end connected to the negative electrode of the lowest potential battery cell c1. The switching element 4a is connected to the other end of the first resistor element 4b1. The second resistor element 4b2 is a resistor element having one end connected to the switching element 4a and the other end connected to the positive electrode of the highest potential battery cell cn.

[0063] In the voltage detection device 1 of this embodiment, the switching element 4a is located between the first resistor element 4b1 and the second resistor element 4b2. Therefore, the voltage applied to the switching element 4a can be adjusted by voltage division by the first resistor element 4b1 and the second resistor element 4b2. Therefore, it is possible to use, for example, any field effect transistor as the switching element 4a. Therefore, the switching element 4a may be an n-channel junction type field effect transistor. Also, the switching element 4a may be a p-channel junction type field effect transistor.

[0064] In the voltage detecting device 1 of the present embodiment, one end of the first resistive element 4b1 is connected to the ground. The voltage detecting device 1 of the present embodiment can easily calculate the voltage applied to the first resistive element 4b1 from the difference between the voltage at the other end of the first resistive element 4b1 and the ground voltage.

[0065] In the voltage detection device 1 of this embodiment, the correction unit 3b includes a resistance element voltage detection unit 3b1, a current value calculation unit 3b2, a path resistance estimation value calculation unit 3b3, and a correction value calculation unit 3b4. The resistance element voltage detection unit 3b1 acquires a resistance voltage value VR, which is the value of the voltage applied to the first resistance element 4b1. The current value calculation unit 3b2 calculates an estimated circuit current value It, which is the value of a current flowing through the path resistance estimation circuit unit 4, based on the resistance voltage value VR. The correction value calculation unit 3b4 can calculate a top-level path resistance estimation value Rkn, which is the estimated resistance value of the top-level path 2H including the measurement line 2a connected to the positive electrode of the highest potential battery cell cn, based on the estimated circuit current value It. The correction value calculation unit 3b4 can also calculate a bottom-level path resistance estimation value Rk1, which is the estimated resistance value of the bottom-level path 2L including the measurement line 2a connected to the negative electrode of the lowest potential battery cell c1. The correction value calculation unit 3b4 can calculate a correction value An for the cell voltage value Vc of the highest potential battery cell cn based on the highest path resistance estimate value Rkn, and can calculate a correction value A1 for the cell voltage value Vc of the lowest potential battery cell c1 based on the lowest path resistance estimate value Rk1.

[0066] The voltage detection device 1 of this embodiment calculates a correction value An for the cell voltage value Vc of the highest potential battery cell cn and a correction value A1 for the cell voltage value Vc of the lowest potential battery cell c1 based on the estimated resistance value of the top path 2H and the estimated resistance value of the bottom path 2L. Therefore, the voltage detection device 1 of this embodiment can correct the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1 by taking into account the estimated resistance value of the top path 2H and the estimated resistance value of the bottom path 2L. Therefore, the voltage detection device 1 of this embodiment can more accurately obtain the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1.

[0067] In the voltage detection device 1 of this embodiment, the path resistance estimation value calculation unit 3b3 calculates the highest path resistance estimation value Rkn by dividing the difference between the cell voltage value Vc of the highest potential battery cell cn when no current flows through the path resistance estimation circuit unit 4 and the cell voltage value Vc of the highest potential battery cell cn when current flows through the path resistance estimation circuit unit 4 by the estimated circuit current value It. In addition, the path resistance estimation value calculation unit 3b3 calculates the lowest path resistance estimation value Rk1 by dividing the difference between the cell voltage value Vc of the lowest potential battery cell c1 when no current flows through the path resistance estimation circuit unit 4 and the cell voltage value Vc of the lowest potential battery cell c1 when current flows through the path resistance estimation circuit unit 4 by the estimated circuit current value It.

[0068] The voltage detection device 1 of this embodiment is capable of calculating the highest path resistance estimated value Rkn and the lowest path resistance estimated value Rk1 through simple calculations, and therefore can correct the cell voltage value Vc of the highest potential battery cell cn and the cell voltage value Vc of the lowest potential battery cell c1 through simple calculations.

[0069] In the voltage detection device 1 of this embodiment, the correction value calculation unit 3b4 calculates a correction value An for the cell voltage value Vc of the highest potential battery cell cn by multiplying the current consumption of a semiconductor chip (battery monitoring integrated circuit 3) that is connected to the battery module M and includes at least the detection unit 3a and the correction unit 3b by the highest path resistance estimate value Rkn. In addition, the correction value calculation unit 3b4 calculates a correction value A1 for the cell voltage value Vc of the lowest potential battery cell c1 by multiplying the current consumption by the lowest path resistance estimate value Rk1.

[0070] The voltage detection device 1 of this embodiment can calculate the correction value An and the correction value A1 by using the current consumption of the battery monitoring integrated circuit 3. For example, the current consumption of the battery monitoring integrated circuit 3 may be a rated current consumption. Therefore, the voltage detection device 1 of this embodiment can calculate the correction value An and the correction value A1 without recalculating the current consumption of the battery monitoring integrated circuit 3.

[0071] The actual current consumption of the battery monitoring integrated circuit 3 varies by about 30% from the rated current consumption, which is the design value, due to individual differences, voltage dependency, and temperature dependency. Therefore, in order to suppress the influence of the difference between the actual current consumption and the rated current consumption on the correction value, it is preferable to make the amount of current flowing through the path resistance estimation circuit 4 larger relative to the current consumption.

[0072] Second embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 4. Note that in this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0073] 4 is a schematic diagram showing a schematic configuration of a battery control device 10 of this embodiment. The battery control device 10 of this embodiment controls multiple battery modules M connected in series. As shown in FIG. 4, the battery control device 10 of this embodiment includes multiple voltage detection devices 1 and a single control unit 11.

[0074] A voltage detection device 1 is provided for each battery module M. That is, in this embodiment, the same number of voltage detection devices 1 are provided as the number of battery modules M. Each voltage detection device 1 outputs a cell voltage value Vc of each of the multiple battery cells c that constitute the battery module M.

[0075] The control unit 11 is a so-called battery management unit, and controls the battery module M based on the cell voltage values ​​Vc acquired by each voltage detection device 1. For example, the control unit 11 causes the battery module M to execute an equalization process for equalizing the cell voltages. For example, the control unit 11 determines the battery cells c that need to be discharged and calculates the amount of discharge based on the cell voltage values ​​Vc input from each voltage detection device 1.

[0076] The battery control device 10 of this embodiment includes the voltage detection device 1 of the first embodiment. Therefore, it is possible to accurately obtain the cell voltage value Vc in each battery module M. Therefore, the battery control device 10 of this embodiment can more accurately control the battery module M.

[0077] Although the preferred embodiment of the present invention has been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to the above embodiment. The shapes and combinations of the components shown in the above embodiment are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0078] For example, in the above embodiment, the estimated circuit current value It is calculated based on the voltage (resistance voltage value VR) applied to the first resistor element 4b1 out of the first resistor element 4b1 and the second resistor element 4b2. However, the present invention is not limited to this. For example, the estimated circuit current value It may be calculated based on the voltage applied to the second resistor element 4b2.

[0079] In the above embodiment, the path resistance estimation circuit unit 4 is connected only to the measurement line 2a of the top path 2H and the measurement line 2a of the bottom path 2L. However, the present invention is not limited to this. The path resistance estimation circuit unit 4 may be connected to other measurement lines 2a. In such a case, it is possible to correct the cell voltage value Vc of a battery cell c that is different from the lowest potential battery cell c1 and the highest potential battery cell cn, for example.

[0080] The above embodiment can also be described as, for example, the following supplementary notes.

[0081] (Appendix 1) a detection unit that is connected via a measurement line to an assembled battery in which a plurality of battery cells are connected in series, and detects the voltage of each of the battery cells to obtain a cell voltage value of each of the battery cells; a path resistance estimation circuit section connected to the measurement line connected to a positive electrode of a highest potential battery cell that is the battery cell having the highest potential among the plurality of battery cells and to the measurement line connected to a negative electrode of a lowest potential battery cell that is the battery cell having the lowest potential among the plurality of battery cells, and capable of switching between a state in which a current flows in the path resistance estimation circuit section and a state in which a current does not flow in the path resistance estimation circuit section; a correction unit that corrects at least one of the cell voltage value of the highest potential battery cell and the cell voltage value of the lowest potential battery cell based on a value of a current flowing in the path resistance estimation circuit unit; A voltage detection device comprising:

[0082] (Appendix 2) The path resistance estimation circuit unit includes: a switch capable of switching between a state in which a current flows through the path resistance estimation circuit unit and a state in which a current does not flow through the path resistance estimation circuit unit; A resistive element connected in series with the switch; 2. A voltage detection device according to claim 1, comprising:

[0083] (Appendix 3) The path resistance estimation circuit unit includes: a first resistor element, one end of which is connected to the negative electrode of the lowest potential battery cell; the switch connected to the other end of the first resistor; a second resistor element, one end of which is connected to the switch and the other end of which is connected to the positive electrode of the highest potential battery cell; 3. A voltage detection device according to claim 2, comprising:

[0084] (Appendix 4) 4. The voltage detection device according to claim 3, wherein one end of the first resistive element is connected to ground.

[0085] (Appendix 5) The correction unit is a resistor voltage detection unit for acquiring a resistor voltage value, which is a value of a voltage applied to the resistor element; a current value calculation unit that calculates an estimated circuit current value, which is a value of a current flowing in the path resistance estimation circuit unit, based on the resistance value of the resistor element from which the resistance voltage value is acquired and the resistance voltage value; a path resistance estimate calculation unit capable of calculating, based on the estimated circuit current value, a top path resistance estimate that is an estimated resistance value of a top path that includes the measurement line connected to the positive electrode of the highest potential battery cell, and a bottom path resistance estimate that is an estimated resistance value of a bottom path that includes the measurement line connected to the negative electrode of the lowest potential battery cell; a correction value calculation unit capable of calculating a correction value for the cell voltage value of the highest potential battery cell based on the highest path resistance estimated value and calculating a correction value for the cell voltage value of the lowest potential battery cell based on the lowest path resistance estimated value; 5. The voltage detection device according to claim 2, further comprising:

[0086] (Appendix 6) The path resistance estimation value calculation unit calculating the highest path resistance estimation value by dividing a difference between the cell voltage value of the highest potential battery cell in a state where no current flows through the path resistance estimation circuit unit and the cell voltage value of the highest potential battery cell in a state where a current flows through the path resistance estimation circuit unit by the estimated circuit current value; The lowest path resistance estimation value is calculated by dividing a difference between the cell voltage value of the lowest potential battery cell in a state where no current flows through the path resistance estimation circuit unit and the cell voltage value of the lowest potential battery cell in a state where a current flows through the path resistance estimation circuit unit by the estimated circuit current value. 6. A voltage detection device according to claim 5.

[0087] (Appendix 7) The correction value calculation unit calculating the correction value for the cell voltage value of the highest potential battery cell by multiplying the highest path resistance estimated value by a current consumption of a semiconductor chip that is connected to the battery pack and that includes at least the detection unit and the correction unit; The correction value for the cell voltage value of the lowest potential battery cell is calculated by multiplying the current consumption by the lowest path resistance estimated value. 7. The voltage detection device according to claim 5 or 6.

[0088] (Appendix 8) A voltage detection device according to any one of appendixes 1 to 7; a control unit that controls the battery pack based on the cell voltage value acquired by the voltage detection device; A battery control device comprising: [Explanation of symbols]

[0089] 1 Voltage detection device 2. Connection Path 2a Measurement line 2H Top Route 2L Lowest Route 3 Battery monitoring integrated circuit 3a Detection section 3b Correction section 3b1 Resistor voltage detection section 3b2 Current value calculation section 3b3 Route resistance estimation calculation unit 3b4 Correction value calculation section 3b5 Correction calculation section 3c Switch drive unit 3d communication department 4. Circuit for estimating route resistance 4a Switching element 4b Resistance element 4b1 First resistor element 4b2 Second resistor element 5 Resistor voltage detection wire 10 Battery control device 11 Control section A1 correction value An correction value c Battery cell c1 Lowest potential battery cell cn Highest potential battery cell It Estimated circuit current value M Battery Module Rk1 Lowest route resistance estimate Rkn Top-level route resistance estimate Vc Cell voltage value Vr High voltage side voltage of the first resistor element VR Resistance Voltage Value

Claims

1. a detection unit that is connected via a measurement line to an assembled battery in which a plurality of battery cells are connected in series, and detects the voltage of each of the battery cells to obtain a cell voltage value of each of the battery cells; a path resistance estimation circuit section connected to the measurement line connected to a positive electrode of a highest potential battery cell that is the battery cell having the highest potential among the plurality of battery cells and to the measurement line connected to a negative electrode of a lowest potential battery cell that is the battery cell having the lowest potential among the plurality of battery cells, and capable of switching between a state in which a current flows in the path resistance estimation circuit section and a state in which a current does not flow in the path resistance estimation circuit section; a correction unit that corrects at least one of the cell voltage value of the highest potential battery cell and the cell voltage value of the lowest potential battery cell based on a value of a current flowing in the path resistance estimation circuit unit; A voltage detection device comprising:

2. The path resistance estimation circuit unit includes: a switch capable of switching between a state in which a current flows through the path resistance estimation circuit unit and a state in which a current does not flow through the path resistance estimation circuit unit; A resistive element connected in series with the switch; 2. The voltage detection device according to claim 1, further comprising:

3. The path resistance estimation circuit unit includes: a first resistor element, one end of which is connected to the negative electrode of the lowest potential battery cell; the switch connected to the other end of the first resistor; a second resistor element, one end of which is connected to the switch and the other end of which is connected to the positive electrode of the highest potential battery cell; 3. The voltage detection device according to claim 2, further comprising:

4. 4. The voltage detection device according to claim 3, wherein one end of the first resistor element is connected to ground.

5. The correction unit is a resistor voltage detection unit for acquiring a resistor voltage value, which is a value of a voltage applied to the resistor element; a current value calculation unit that calculates an estimated circuit current value, which is a value of a current flowing in the path resistance estimation circuit unit, based on the resistance value of the resistor element from which the resistance voltage value is acquired and the resistance voltage value; a path resistance estimate calculation unit capable of calculating, based on the estimated circuit current value, a top path resistance estimate that is an estimated resistance value of a top path that includes the measurement line connected to the positive electrode of the highest potential battery cell, and a bottom path resistance estimate that is an estimated resistance value of a bottom path that includes the measurement line connected to the negative electrode of the lowest potential battery cell; a correction value calculation unit capable of calculating a correction value for the cell voltage value of the highest potential battery cell based on the highest path resistance estimated value and calculating a correction value for the cell voltage value of the lowest potential battery cell based on the lowest path resistance estimated value; The voltage detection device according to any one of claims 2 to 4, further comprising:

6. The path resistance estimation value calculation unit calculating the highest path resistance estimation value by dividing a difference between the cell voltage value of the highest potential battery cell in a state where no current flows through the path resistance estimation circuit unit and the cell voltage value of the highest potential battery cell in a state where a current flows through the path resistance estimation circuit unit by the estimated circuit current value; The lowest path resistance estimation value is calculated by dividing a difference between the cell voltage value of the lowest potential battery cell in a state where no current flows through the path resistance estimation circuit unit and the cell voltage value of the lowest potential battery cell in a state where a current flows through the path resistance estimation circuit unit by the estimated circuit current value.

6. The voltage detection device according to claim 5.

7. The correction value calculation unit calculating the correction value for the cell voltage value of the highest potential battery cell by multiplying the highest path resistance estimated value by a current consumption of a semiconductor chip that is connected to the battery pack and that includes at least the detection unit and the correction unit; The correction value for the cell voltage value of the lowest potential battery cell is calculated by multiplying the current consumption by the lowest path resistance estimated value.

6. The voltage detection device according to claim 5.

8. A voltage detection device according to any one of claims 1 to 3, a control unit that controls the battery pack based on the cell voltage value acquired by the voltage detection device; A battery control device comprising:

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