On-vehicle battery condition inspection device

Abstract

To prevent a shunt resistor 11 connected between positive and negative terminals of an on-vehicle battery 1 for inspecting the condition of the battery during vehicle operation stoppage or stoppage from being burned out due to frequent application of voltages higher than the internal voltage of the battery.SOLUTION: In an on-vehicle battery condition inspection device 10, conduction of a shunt resistor connected between the positive and negative terminals of the battery so as to selectively conduct is executed after elapse of a predetermined standby time Ts from receipt of information indicating switching of a vehicle operation switch from ON to OFF. If the operation switch returns to ON during the standby, conduction of the shunt resistor is canceled before it happens. When a voltage VB between the positive and negative terminals of the battery exceeds a predetermined voltage value VBo after receipt of information indicating switching of the operation switch from ON to OFF, the predetermined standby time is extended.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a device for inspecting the condition of a battery mounted on a vehicle such as an automobile, and more particularly to a device configured to connect a shunt resistor between the positive and negative terminals of the battery and measure the current flowing through the shunt resistor in order to inspect the condition of the battery while the vehicle is not in operation. [Background technology]

[0002] To measure the current and voltage of a battery installed in a vehicle such as an automobile, a shunt resistor is connected to the battery and the current and voltage flowing through the shunt resistor are measured. For example, Patent Document 1 discloses a configuration in which, in order to measure the current of a vehicle's drive battery, a shunt resistor is inserted between multiple series-connected batteries and the voltage across the shunt resistor is measured to measure the current flowing through the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2012-217276 Summary of the Invention [Problem to be solved by the invention]

[0004] To inspect the condition of an on-board battery, a known configuration is to connect a shunt resistor between the positive and negative terminals of the battery when the vehicle is stopped or while it is stopped, for example, when the operation switch (ignition switch IGSW) is switched from ON to OFF or while the operation switch is in the OFF state, measure the current therethrough, and use this to estimate the internal resistance of the battery, and evaluate the condition of the battery based on the level of this internal resistance.

[0005] 1 , in an on-board battery 1, a current sensor 2 for measuring the current while the vehicle is operating is connected in series to the negative terminal of the battery 1, and a shunt resistor 11 for estimating the internal resistance of the battery 1 when the vehicle is stopped or while it is stopped is connected between the positive and negative terminals of the battery 1 via a relay 12 that is selectively open and closed. When the vehicle is operating, i.e., while the operation switch is ON, the relay 12 is in an open state and cuts off the conduction of the shunt resistor 11. When the vehicle is stopped, i.e., when the operation switch is turned OFF, a relay driver 15 responds by transitioning the relay 12 to a closed state and connecting the positive and negative terminals of the battery 1 via the shunt resistor 11. As a result, the internal resistance of the battery is calculated from the current measured by the shunt resistor 11 and the voltage between the positive and negative terminals of the battery.

[0006] In the configuration shown in Figure 1, the voltage between the positive and negative terminals of the battery is the voltage output from within the battery when the vehicle is stopped, but when the vehicle is operating, devices that output a higher voltage than the battery's output voltage (internal voltage), such as an alternator that charges the battery, are operating, and the output voltage of these devices is applied across the positive and negative terminals of the battery, so the voltage between the positive and negative terminals of the battery when the vehicle is operating is higher than when the vehicle is stopped.On the other hand, the shunt resistor connected across the positive and negative terminals to inspect the battery's condition when the vehicle is stopped or while it is stopped is intended to be selectively connected when the vehicle is stopped, so there is a risk of it burning out if a high voltage is frequently applied across the positive and negative terminals of the battery while the vehicle is operating. Furthermore, when the vehicle state is switched from an operating state to a stopped state, it takes a certain period of time (for example, about 10 minutes) for the voltage between the battery terminals to stabilize to the voltage when the vehicle is stopped. Therefore, in order to prevent the shunt resistor 11 from being burned by accidentally applying a voltage higher than the internal voltage of the battery, the transition of the relay 12 to the closed state, i.e., the conduction of the shunt resistor 11, is performed after the period from the switching of the vehicle state from an operating state to a stopped state until the battery state stabilizes has elapsed.

[0007] However, since the switching of the vehicle's operating state is achieved by switching the operating switch ON / OFF as described above, the state of the operating switch is usually transmitted to each part of the vehicle via an in-vehicle network such as LIN communication, and the transmission of the switch switching information may be delayed depending on the part. Therefore, in the configuration for inspecting the battery state described above, the arrival of information that the operating switch has changed from OFF to ON to the relay driving unit 15 may be delayed compared to the return of the vehicle from a stopped state to an operating state due to the switching of the operating switch to ON. In such a case, for example, if the driver of the vehicle switches the activation switch from ON to OFF and then switches it from OFF to ON again shortly after the battery state has stabilized, the timing at which shunt resistor 11 becomes conductive may coincide with the time at which the vehicle is returning from a stopped state to an active state, even though the information that the activation switch has been turned ON has not yet reached relay drive unit 15. If this situation is repeated, a voltage higher than the internal voltage of the battery may be repeatedly applied to shunt resistor 11, potentially causing burnout of shunt resistor 11. In this regard, while most drivers relatively rarely switch the activation switch ON immediately after switching it from ON to OFF, drivers who switch the activation switch from OFF to ON relatively soon after switching it from ON to OFF tend to perform such an operation frequently. Therefore, in the case of a driver who tends to repeatedly switch the operation switch ON / OFF, the waiting period until the shunt resistor 11 is turned on, which is executed after the battery state has stabilized after the operation of the vehicle has been stopped by switching the operation switch from ON to OFF, is set longer than usual, so that when the operation of turning the operation switch OFF and then ON immediately is performed, information that the operation switch has been returned to ON reaches the relay drive unit 15 during the waiting period until the shunt resistor 11 is turned on, and when the vehicle is returning from a stopped state to an operating state, the conduction of the shunt resistor 11 can be stopped in advance (when information that the operation switch has been turned ON reaches the relay drive unit 15, the shunt resistor is not turned on).), it is preferable that frequent application of a voltage higher than the internal voltage of the battery to the shunt resistor 11 can be prevented.

[0008] Thus, the main object of the present invention is to prevent a shunt resistor connected between the positive and negative terminals of a battery when the vehicle is stopped or is stopped in order to check the condition of the on-board battery from being burned out due to frequent application of a voltage higher than the internal voltage of the battery. [Means for solving the problem]

[0009] According to the present invention, the above problem is solved by an on-board battery state inspection device, a shunt resistor connected to selectively conduct between the positive and negative terminals of the battery; a current detection means for detecting a current flowing through the shunt resistor; a voltage detection means for detecting a voltage between the positive and negative terminals of the battery; a shunt resistor conduction switching means for transitioning the shunt resistor from a cut-off state to a conduction state after a predetermined waiting time has elapsed since the arrival of information indicating that an operation switch of a vehicle has been switched from ON to OFF, and for transitioning the shunt resistor from a conduction state to a cut-off state after the current detection means detects the current flowing through the shunt resistor; and a battery status evaluation device that evaluates the state of the battery based on the current detected by the current detection means and the voltage between the positive and negative terminals of the battery detected by the voltage detection means, This is achieved by a device configured such that, after the predetermined waiting time has elapsed since the arrival of information that the vehicle's operating switch has been switched from ON to OFF, if the voltage between the positive and negative terminals of the battery detected by the voltage detection means exceeds a predetermined voltage value, the shunt resistor conduction switching means extends the predetermined waiting time.

[0010] In the above configuration, the "battery" may be any battery installed in a vehicle, such as an auxiliary lead battery or a lithium battery. The "shunt resistor" may be a resistive element commonly used in this field or a component having an appropriate resistance. The "current detection means" and "voltage detection means" may be current detection means or voltage detection means commonly used in this field. The "shunt resistor conduction switching means" may be a relay element or switching element connected in series with the shunt resistor between the positive and negative terminals of the battery to selectively open and close the shunt resistor, and a means for controlling the state of the element. The "information regarding the switching of the vehicle's activation switch from ON to OFF" is information indicating the operating state of the activation switch transmitted from an in-vehicle network system such as LIN communication or CAN communication. The "predetermined waiting time" may basically be set to the period until the voltage between the positive and negative terminals of the battery settles to the voltage output by the battery itself and the dark current stabilizes when the activation switch is switched from ON to OFF and the vehicle state changes from an operating state to a stopped state, or may be determined experimentally. The "predetermined voltage value" for the voltage between the positive and negative terminals of the battery is a voltage higher than the voltage output by the battery itself, and may typically be a voltage equivalent to the output voltage of a device such as an alternator that operates while the vehicle is in operation, and may be determined experimentally through adaptation. The extension time width when extending the "predetermined standby time" may be set appropriately through adaptation.

[0011] In the above configuration, to briefly state it, in order to check the state of the on-board battery when the vehicle is stopped or while it is stopped, when a predetermined waiting time has elapsed since the arrival of information that the vehicle's operation switch has been switched from ON to OFF, the voltage between the positive and negative terminals of the battery is measured, and the shunt resistor connected thereto is made conductive, measuring the current flowing through the shunt resistor, and the state of the battery is evaluated from the voltage and current. In this case, if the voltage between the positive and negative terminals of the battery exceeds a predetermined voltage value even after the predetermined waiting time has elapsed since the arrival of information that the vehicle's operation switch has been switched from ON to OFF, it is considered that the information that the operation switch has been turned ON has not yet reached the shunt resistor conductivity switching means, but that the output voltage of equipment such as an alternator that operates while the vehicle is in operation is acting between the positive and negative terminals of the battery, i.e., it is presumed that the operation switch was once switched from ON to OFF and then returned to ON relatively soon after. In this case, it is estimated that the driver of the vehicle has a tendency to frequently switch the activation switch ON / OFF, and therefore, in order to prevent the shunt resistor from becoming conductive when the vehicle is in an operating state due to a delay in the information reaching the shunt resistor conductivity switching means when the activation switch is subsequently switched ON → OFF → ON again within a relatively short period of time, the shunt resistor conductivity switching means is configured to extend the predetermined waiting time for waiting for the shunt resistor to transition from a cut-off state to a conductive state after receiving information that the vehicle's activation switch has been switched from ON to OFF. With this configuration, if the operating switch is initially switched ON → OFF → ON in a short period of time, there is a possibility that the shunt resistor will transition from a cut-off state to a conductive state. However, after that, the waiting time from when the information that the vehicle's operating switch has been switched from ON to OFF arrives until the shunt resistor transitions from a cut-off state to a conductive state becomes longer. Therefore, it is expected that during this waiting time, information that the operating switch has been turned OFF once and then immediately turned ON will reach the shunt resistor conduction switching means. If this information arrives during the waiting time, it is possible to prevent the shunt resistor from becoming conductive when the vehicle is returned to an operating state, thereby preventing the high voltage from being frequently applied to the shunt resistor when the vehicle is in an operating state.

[0012] In the above configuration, the extension of the "predetermined standby time" may be repeatedly performed. That is, after the standby time has been extended once, if the voltage between the positive and negative terminals of the battery again exceeds the predetermined voltage value after the elapse of the predetermined standby time from the next arrival of information that the vehicle's activation switch has been switched from ON to OFF, the predetermined standby time may be further extended. This increases the likelihood that information that the activation switch has been turned OFF and then immediately turned ON during the standby time will reach the shunt resistor conduction switching means, thereby increasing the likelihood that conduction of the shunt resistor can be avoided when the vehicle is restored to an operational state. Note that, to prevent the extension of the predetermined standby time from being performed indefinitely, once the predetermined standby time has been extended an arbitrarily set number of times, the standby time may no longer be extended thereafter.

[0013] In the device of the present invention, if the battery condition is good when the shunt resistor is first turned on and the current and voltage measured after receiving information that the activation switch has been switched from ON to OFF is measured, then the battery condition may not be checked by turning the shunt resistor on until the next time information is received that the activation switch has been switched from ON to OFF. On the other hand, if the battery condition is not good when the shunt resistor is first turned on, the shunt resistor may be turned on and the battery condition may be checked at appropriately settable intervals until the next time the activation switch is switched on. If battery degradation is detected, an alarm to that effect may be issued in any manner. [Effects of the Invention]

[0014] Thus, in the configuration of the present invention, if the operating switch is switched ON → OFF → ON in a short period of time, but the shunt resistor is made conductive before the information that the operating switch has turned ON again reaches the shunt resistor conductivity switching means, the waiting time until the shunt resistor transitions from a cut-off state to a conductive state when the operating switch is subsequently turned from ON to OFF will be longer.Therefore, if the operating switch is switched ON → OFF → ON in a short period of time, it is expected that the information that the operating switch has turned ON again will reach the shunt resistor conductivity switching means during the above-mentioned waiting time, and the conductivity of the shunt resistor will be prevented from occurring.Thus, it is possible to prevent the shunt resistor from burning out due to the shunt resistor being repeatedly made conductive when the vehicle is in an operating state. In the present invention, the battery voltage is measured after a predetermined waiting time has elapsed since the information that the vehicle's operation switch has been switched from ON to OFF has arrived, and based on the results, the waiting time from the arrival of the information that the vehicle's operation switch has been switched from ON to OFF until the shunt resistor transitions from a cut-off state to a conductive state is extended, thereby protecting the shunt resistor.This is advantageous in that it can be achieved without adding any additional components to the on-board battery status inspection device, and does not complicate the configuration.

[0015] Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram showing the configuration of an on-board battery state inspection device to which this embodiment is applied. [Figure 2] FIG. 2 is a flowchart illustrating the operation of the vehicle-mounted battery state inspection device according to this embodiment. [Explanation of symbols]

[0017] 1...In-vehicle battery, 2...Current sensor (for use while vehicle is in operation), 10...Battery state inspection device, 11...Shunt resistor, 12...Relay, 13...Operation switch state receiving unit, 14...Voltage detection unit, 15...Relay driving unit, 16...Current detection unit, 20...In-vehicle network system, 30...Battery state evaluation unit BEST MODE FOR CARRYING OUT THE INVENTION

[0018] The present invention will now be described in detail with reference to some preferred embodiments thereof with reference to the accompanying drawings, in which like reference numerals indicate like parts.

[0019] Battery condition inspection device configuration Referring to FIG. 1, in the vehicle battery state inspection device 10 to which this embodiment is applied, as already mentioned in the "Summary of the Invention" section, a current sensor 2 is connected in series between the negative terminal of the vehicle battery 1 and ground GND, and a shunt resistor 11 that is selectively made conductive by a relay 12 is connected in parallel between the positive terminal of the vehicle battery 1 and ground GND. When the vehicle operation switch IGSW is turned from ON to OFF to stop the operation of the vehicle, the shunt resistor 11 becomes conductive, the voltage and current at the shunt resistor are measured, and the internal resistance of the battery is estimated from the measured voltage and current values, and the state of the battery is evaluated.

[0020] More specifically, when the activation switch IGSW is ON and the vehicle is in operation, a relatively large current flows through the battery 1, and the current value is monitored by the current sensor 2. Furthermore, while the vehicle is in operation, a device that outputs a voltage higher than the internal voltage of the battery 1, such as an alternator (not shown), is connected to the positive terminal of the battery 1, so that the voltage between the positive and negative terminals of the battery 1 is higher than the internal voltage of the battery 1. When the activation switch IGSW is switched OFF while the vehicle is in operation and an instruction is given to stop the vehicle operation, the state of the activation switch IGSW is detected by the in-vehicle network system 20, and information that the activation switch IGSW has been turned OFF is transmitted to various parts of the vehicle and also to the activation switch state receiving unit 13 in the battery state inspection device 10. When the operation switch status receiving unit 13 receives this information, it waits for a sufficient time for the dark current of the battery 1 measured by the current sensor 2 to settle and for the voltage between the positive and negative terminals of the battery 1 to stabilize, after which the voltage detecting unit 14 detects the voltage V between the positive and negative terminals of the battery 1, the relay driving unit 15 drives the relay 12 to the closed state, conducting the shunt resistor 11 between the positive and negative terminals of the battery 1, and the current detecting unit 16 detects the current I flowing through the shunt resistor 11. Thus, when the voltage between the positive and negative terminals of the battery 1 and the current through the shunt resistor 11 are detected, the battery status evaluating unit 30 estimates the internal resistance ri of the battery as described above using the resistance value Rs of the shunt resistor and the resistance value rm of the current sensor 2 as follows: ri=V / I-Rs-rm In assessing the state of the battery 1, generally speaking, it may be determined that the larger the internal resistance ri, the more deteriorated the battery 1 is.

[0021] Shunt Resistor Protection In the above-described configuration of the device 10 for inspecting the state of an on-board battery 1, the shunt resistor 11 is basically assumed to be conductive when the vehicle is in a stopped state and the voltage between the positive and negative terminals of the battery 1 is the voltage output from the battery 1 (internal voltage). If the shunt resistor 11 is frequently applied with a voltage (e.g., approximately 16 V) from an alternator or other device that is significantly higher than the internal voltage (e.g., approximately 12 V) of the battery 1, the shunt resistor 11 may be burned. To avoid this situation, the shunt resistor 11 is turned on after a predetermined waiting time has elapsed since the information about the switching of the operating switch IGSW from ON to OFF reaches the operating switch status receiving unit 13, allowing the dark current of the battery 1 to settle and the voltage between the positive and negative terminals of the battery 1 to stabilize. If the operating switch is turned ON and the vehicle is switched to an operating state during this predetermined waiting time, the shunt resistor 11 is preferably not turned on because the alternator or other device would be operating.

[0022] In general, in a vehicle, as described above, the switching state of the activation switch is detected and processed by the in-vehicle network system 20, such as via LIN communication, and then transmitted to each component of the vehicle. In particular, when the activation switch is switched from OFF to ON, the in-vehicle network system 20 is started from a stopped state. Therefore, it takes some time for the in-vehicle network system 20 to transmit information that the activation switch has been turned ON, i.e., information that the vehicle has been instructed to start operating, to each component of the vehicle. Depending on the component, the transmission of this information may be delayed. In such a configuration, even if the activation switch status receiving unit 13 in the state inspection device 10 for the in-vehicle battery 1 receives information that the activation switch has been switched OFF and then performs a shunt resistor conduction during the predetermined waiting time until the operation of the shunt resistor is performed, and even if devices such as an alternator start operating in response to the operation, the information that the activation switch has been switched ON again may not reach the activation switch status receiving unit 13 by the time the predetermined waiting time has elapsed. This may cause the shunt resistor to become conductive when a high voltage from an alternator or other device is applied between the positive and negative terminals of the battery 1. If this situation occurs frequently, there is a possibility that the shunt resistor may burn out as described above.

[0023] As mentioned in the "Summary of the Invention," drivers who switch the activation switch from ON to OFF to ON in a relatively short time tend to do so frequently. Therefore, in this embodiment, when it is estimated that the activation switch was switched from ON to OFF to ON in a relatively short time, it is determined that similar operations are likely to occur frequently, and a predetermined waiting time is extended from the time when information that the activation switch has been switched OFF is first received until the shunt resistor is turned ON. With this configuration, the longer waiting time increases the likelihood that information indicating that the activation switch has been turned ON relatively quickly after being turned OFF will reach the activation switch status receiving unit 13 before the waiting time has elapsed. If this occurs, the shunt resistor will not be turned ON in advance. This is expected to prevent, as much as possible, a situation in which the shunt resistor is turned ON even when the vehicle has returned to an operating state. Whether the vehicle has returned to an operating state is determined by observing the voltage between the positive and negative terminals of the battery 1 after a predetermined waiting time has elapsed since the information that the activation switch has been turned OFF was first received. If the vehicle has returned to an operating state, the voltage between the positive and negative terminals of the battery 1 will be significantly higher than the internal voltage of the battery 1.

[0024] Battery condition inspection device operation Thus, in the vehicle battery 1 status inspection device 10 according to this embodiment, if the voltage between the positive and negative terminals of the battery 1 is significantly high after a predetermined waiting time has elapsed between the time when the information that the activation switch has been switched OFF is first received and the time when the shunt resistor is turned on, it is assumed that the activation switch has been switched ON and the vehicle has returned to an operating state, and the predetermined waiting time for the next time the activation switch is switched from ON to OFF is extended. The length of the extension may be set appropriately depending on the application. If, even after the waiting time has been extended, the voltage between the positive and negative terminals of the battery 1 is still significantly high after the predetermined waiting time has elapsed between the time when the information that the activation switch has been switched OFF is first received and the time when the shunt resistor is turned on, the waiting time may be further extended.

[0025] 2, in the operation of the state inspection device 10 for the vehicle-mounted battery 1, when information that the activation switch (IGSW) has changed from ON to OFF reaches the activation switch status receiving unit 13 (step 1), the current sensor 2 detects the dark current Id flowing through the battery 1 at appropriate intervals (e.g., 30 seconds) until the elapsed time T from that point reaches a predetermined waiting time Ts (e.g., about 10 minutes) (step 2). If information that the activation switch has returned to ON reaches the activation switch status receiving unit 13 during this time (step 2a), the process ends and the device enters a waiting state until the next information that the activation switch has changed from ON to OFF arrives (return). On the other hand, when the elapsed time T exceeds the waiting time Ts and the dark current Id falls below a predetermined value Id (set to a value at which it can be determined that the dark current has settled), the voltage detection unit 14 measures the voltage VB between the positive and negative terminals of the battery 1 (step 3). If VB is below a predetermined value VBo corresponding to the internal voltage of the battery 1 (step 4), the relay driving unit 15 closes (ON) the relay 12 to conduct the shunt resistor 11 (step 5), the current detection unit 16 measures the current Is flowing through the shunt resistor 11 (step 6), and then the relay driving unit 15 opens (OFF) the relay 12 to cut off the shunt resistor 11 (step 7).The voltage detection unit 14 again measures the voltage VB between the positive and negative terminals of the battery 1 (step 8), and if VB is below the predetermined value VBo (step 9), the battery may be evaluated as described above using the measured voltage VB and current Is (step 9a—the evaluation result may be notified by an appropriate method). If the battery condition is evaluated as good (internal resistance is sufficiently low, etc.) (step 10), the condition inspection process is completed, and the system enters a standby state until the next information arrives that the activation switch has been turned from ON to OFF (return). On the other hand, if the battery condition cannot be determined to be good, steps 4 to 10 may be repeated after an appropriately set standby time Tw has elapsed (step 11), unless information arrives that the activation switch (IGSW) has been turned ON (step 12).If information is received here that the operation switch (IGSW) has been turned ON, the status inspection process is completed and the system enters a standby state (return) until information is received that the operation switch has been turned from ON to OFF.

[0026] In the above processing cycle, if VB exceeds a predetermined value VBo corresponding to the internal voltage of battery 1 in steps 4 and 9, the information that the operating switch (IGSW) has turned ON has not reached the operating switch state receiving unit 13, but it can be assumed that the vehicle has returned to an operating state and that devices such as the alternator are operating, so the inspection processing is interrupted. Then, a predetermined waiting time Ts from the time when the information that the operating switch (IGSW) has turned OFF from ON reaches the operating switch state receiving unit 13 is extended by a time width ΔT (for example, about 2 minutes) that may be set appropriately (step 13). As a result, as already mentioned, when information arrives that the operating switch has next been turned from ON to OFF, the waiting time Ts until the shunt resistor 11 is made conductive is extended. Therefore, if the operating switch is turned OFF once and then turned ON again in a short period of time, the information will arrive before the extended waiting time Ts has elapsed, increasing the likelihood that the conduction of the shunt resistor 11 can be prevented beforehand, and that the shunt resistor 11 can be prevented from being made conductive when the vehicle is returned to its operating state.

[0027] The extension of the waiting time Ts (step 13) may be repeated in steps 4 and 9 each time VB exceeds the predetermined value VBo. This further increases the likelihood that, if the activation switch is turned OFF and then ON again in a short period of time, the information will arrive before the extended waiting time Ts has elapsed. To prevent the waiting time Ts from being extended indefinitely, the number of extensions n may be counted when the waiting time Ts is extended (step 13). When the number of extensions n reaches a predetermined number no, which may be set as appropriate (step 14), the extension time width ΔT may be set to 0 (step 15), and the waiting time Ts may no longer be extended.

[0028] Thus, the configuration of this embodiment is expected to prevent the shunt resistor connected between the positive and negative terminals of the battery when the vehicle is stopped or while it is stopped from burning out due to frequent application of a voltage higher than the internal voltage of the battery to the shunt resistor when the vehicle is stopped or while it is stopped in order to check the condition of the on-board battery.

[0029] Although the above description has been made in relation to the embodiments of the present invention, it will be apparent that many modifications and changes can be easily made by those skilled in the art, and the present invention is not limited to the above-described exemplary embodiments, but can be applied to various devices without departing from the concept of the present invention.

Claims

[Claim 1] An on-board battery condition inspection device, a shunt resistor connected to selectively conduct between the positive and negative terminals of the battery; a current detection means for detecting a current flowing through the shunt resistor; a voltage detection means for detecting a voltage between the positive and negative terminals of the battery; a shunt resistor conduction switching means for transitioning the shunt resistor from a cut-off state to a conduction state after a predetermined waiting time has elapsed since the arrival of information indicating that an operation switch of a vehicle has been switched from ON to OFF, and for transitioning the shunt resistor from a conduction state to a cut-off state after the current detection means detects the current flowing through the shunt resistor; and a battery status evaluation device that evaluates the state of the battery based on the current detected by the current detection means and the voltage between the positive and negative terminals of the battery detected by the voltage detection means, The device is configured such that, after the predetermined waiting time has elapsed since the arrival of information that the vehicle's operating switch has been switched from ON to OFF, if the voltage between the positive and negative terminals of the battery detected by the voltage detection means exceeds a predetermined voltage value, the shunt resistor conduction switching means extends the predetermined waiting time.

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