Abnormality determination device and abnormality determination method

Abstract

To accurately determine whether an abnormality has occurred in a battery using an inexpensive semiconductor sensor without the need for frequent sensitivity calibration of the semiconductor sensor.SOLUTION: An abnormality detection device 1 comprises: a semiconductor sensor 3 which outputs a sensor output corresponding to the concentration of gas generated from a battery 12 housed in a battery housing unit 11; a calculation unit 73 which calculates a first ratio between the sensor output at a first time point and the sensor output at a second time point later than the first time point; and a determination unit 74 which determines that an abnormality has occurred in the battery 12 if the first ratio calculated by the calculation unit 73 is greater than or equal to a predetermined threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an abnormality determination device and an abnormality determination method. [Background technology]

[0002] Patent Document 1 discloses a system including a gas sensor that detects gas in a battery module. The system disclosed in Patent Document 1 includes a battery management circuit that determines whether a sensor signal transmitted from the gas sensor indicates the presence of gas in the battery module by determining whether the gas concentration is greater than a threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-508034 Summary of the Invention [Problem to be solved by the invention]

[0004] Consider a case where an inexpensive gas sensor is used in the system disclosed in Patent Document 1 to reduce costs. In this case, the system cannot accurately determine whether the sensor signal indicates that the gas concentration is greater than a threshold, and therefore cannot accurately determine whether an abnormality has occurred in the battery. One aspect of the present invention aims to accurately determine whether an abnormality has occurred in the battery using an inexpensive semiconductor sensor without frequent sensitivity calibration of the semiconductor sensor. [Means for solving the problem]

[0005] In order to solve the above problem, an abnormality determination device according to one embodiment of the present invention includes a semiconductor sensor that outputs a sensor output corresponding to the concentration of gas generated from a battery contained in a battery storage section, a calculation unit that calculates a first ratio relating to the sensor output of the semiconductor sensor at a second point in time after the first point in time to the sensor output of the semiconductor sensor at the first point in time, and a determination unit that determines that an abnormality has occurred in the battery if the first ratio calculated by the calculation unit is equal to or greater than a predetermined threshold value.

[0006] Furthermore, an abnormality determination method according to one aspect of the present invention includes an output step of outputting a sensor output from a semiconductor sensor corresponding to the concentration of gas generated from a battery contained in a battery accommodating section, a calculation step of calculating a ratio of the sensor output of the semiconductor sensor at a second point in time after the first point in time to the sensor output of the semiconductor sensor at the first point in time, and a determination step of determining that an abnormality has occurred in the battery if the ratio calculated by the calculation step is equal to or greater than a predetermined threshold value. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to accurately determine whether an abnormality has occurred in a battery using an inexpensive semiconductor sensor without frequent sensitivity calibration of the semiconductor sensor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of the configuration of an abnormality determination device according to an embodiment of the present invention; [Figure 2] 2 is a circuit diagram showing an example of a circuit including a semiconductor sensor, with respect to a circuit provided in the abnormality determination device shown in FIG. 1. FIG. [Figure 3] 2 is a flowchart showing an example of a process for determining whether or not a battery has an abnormality, which is performed by a control unit included in the abnormality determination device shown in FIG. [Figure 4] 4 is a graph showing gas sensor outputs of semiconductor sensors according to Examples 1 and 2 of the present invention. [Figure 5]10 is a graph showing a gas sensor output of a semiconductor sensor according to Example 3 of the present invention. [Figure 6] 10 is a graph showing the ratio of the maximum value of the gas sensor output to the moving average value of the gas sensor output one hour before the present time, regarding the gas sensor output of the semiconductor sensor according to Example 4 of the present invention. [Figure 7] 10 is a graph showing test results regarding the gas sensor output of the semiconductor sensor according to Example 5 of the present invention. [Figure 8] FIG. 10 is a diagram showing the results of measuring and plotting the rate of increase in gas sensor output versus P / V in Example 6 of the present invention. [Figure 9] 10 is a graph showing a third ratio of the gas sensor output of the semiconductor sensor according to Example 7 of the present invention in Modification 6. [Figure 10] 13 is a graph showing a moving average value of the gas sensor output of the semiconductor sensor according to Example 8 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Configuration of abnormality determination device 1> FIG. 1 is a block diagram showing an example of the configuration of an abnormality determination device 1 according to an embodiment of the present invention. The abnormality determination device 1 is an abnormality determination device that determines whether an abnormality has occurred in a battery 12 housed in a battery housing unit 11. The battery housing unit 11 is, for example, a container that houses a battery module in which multiple batteries 12 are connected in series or parallel, and is provided in a stationary storage battery facility installed outdoors. The battery 12 is, for example, a secondary battery such as a lithium-ion battery.

[0010] As shown in FIG. 1, the abnormality determination device 1 includes a temperature sensor 2, a semiconductor sensor 3, a voltage measurement unit 4, a notification unit 5, a memory unit 6, and a control unit 7. All or part of the abnormality determination device 1 may be installed inside the battery housing unit 11. The temperature sensor 2 and the semiconductor sensor 3 are provided inside the battery housing unit 11. The temperature sensor 2 detects the temperature inside the battery housing unit 11 and outputs the detected temperature inside the battery housing unit 11 to the control unit 7 as a temperature sensor output. More specifically, the temperature sensor 2 detects the temperature inside the battery housing unit 11 and in the vicinity of the semiconductor sensor 3.

[0011] <Configuration of semiconductor sensor 3> 2 is a circuit diagram showing an example of a circuit provided in the abnormality determination device 1 shown in FIG. 1, the circuit including the semiconductor sensor 3. The semiconductor sensor 3 is a gas sensor that outputs a gas sensor output corresponding to the concentration of the gas GS generated from the battery 12. In other words, the semiconductor sensor 3 is a gas sensor that outputs a gas sensor output corresponding to the concentration of the gas GS inside the battery housing portion 11.

[0012] Typical gases that are generated from a lithium ion battery when the lithium ion battery is abnormal include hydrogen, hydrocarbons, carbon monoxide, etc. Therefore, it is preferable that the semiconductor sensor 3 be capable of detecting the outgassing gas GS, such as hydrogen, hydrocarbons, or carbon monoxide.

[0013] It is preferable that the semiconductor sensor 3 is a sensor that responds to a wide range of typical gases rather than a sensor that responds to a specific gas. The reason for this is that the component ratio of the gas GS varies depending on the type of lithium-ion battery and the circumstances under which an abnormality occurs. In addition, the gas GS is an outgas that is released from the inside of the battery 12 to the outside when a pressure valve provided in the battery 12 opens when the battery 12 is in an overheated state or when the internal pressure of the battery 12 increases.

[0014] 2, the semiconductor sensor 3 has a heater 31 that heats the sensitive part 32, and the sensitive part 32 is made of a semiconductor material and its resistance value changes when it comes into contact with the gas GS inside the battery holder 11. The heater 31 is electrically connected to a DC power supply at terminal T2. The DC power supply may be one that is provided in the abnormality determination device 1. The side of the heater 31 opposite to terminal T2 is connected to ground GD. The heater 31 is connected in parallel with the resistor 13 and the sensitive part 32. The semiconductor sensor 3 is used in a state in which the sensitive part 32 is heated to several hundred degrees Celsius by the heater 31.

[0015] The sensitive part 32 is electrically connected to a DC power supply at terminal T1. This DC power supply may be a DC power supply connected to the heater 31 at terminal T2. This DC power supply applies a constant DC voltage to the sensitive part 32 and resistor 13. The side of the sensitive part 32 opposite to terminal T1 is electrically connected in series with the resistor 13. The side of the resistor 13 opposite to the sensitive part 32 is connected to ground GD. A wire branching from the wire between the sensitive part 32 and resistor 13 is electrically connected to the voltage measurement part 4 at terminal T3.

[0016] <Configuration of voltage measurement unit 4 and notification unit 5> The voltage measuring unit 4 is a voltmeter that measures the voltage across the resistor 13 from the terminal T3, and outputs the measured voltage across the resistor 13 as a gas sensor output to the control unit 7. When the concentration of the gas GS inside the battery housing unit 11 increases, the resistance value of the sensitive unit 32 decreases, and the voltage across the sensitive unit 32 drops. At this time, a constant DC voltage is applied to the sensitive unit 32 and the resistor 13, so the voltage across the resistor 13 rises.

[0017] On the other hand, when the concentration of the gas GS inside the battery housing portion 11 decreases, the resistance value of the sensitive portion 32 increases, and the voltage of the sensitive portion 32 rises. At this time, a constant DC voltage is applied to the sensitive portion 32 and the resistor 13, so the voltage of the resistor 13 drops. In this way, the semiconductor sensor 3 outputs the voltage of the resistor 13 to the voltage measuring portion 4 as a gas sensor output corresponding to the concentration of the gas GS.

[0018] The notification unit 5 notifies that an abnormality has occurred in the battery 12. The notification unit 5 may be, for example, a display unit that displays information indicating that an abnormality has occurred in the battery 12, or an audio output unit such as a speaker that outputs audio information indicating that an abnormality has occurred in the battery 12. An abnormality in the battery 12 occurs when the battery 12 is in an overheated state or when the internal pressure of the battery 12 increases, causing a pressure valve provided in the battery 12 to open and outgas to be emitted from the inside of the battery 12 to the outside.

[0019] <Configuration of Storage Unit 6 and Control Unit 7> The storage unit 6 is, for example, a memory that stores the processing contents of the control unit 7. The control unit 7 has an acquisition unit 71, a correction unit 72, a calculation unit 73, a determination unit 74, and a notification control unit 75. The processing contents of each unit of the control unit 7 will be described later.

[0020] <Processing of the control unit 7> Fig. 3 is a flowchart showing an example of the process of determining an abnormality in the battery 12 by the control unit 7 included in the abnormality determination device 1 shown in Fig. 1. The control unit 7 repeatedly executes the flow shown in Fig. 3 at regular intervals to determine whether an abnormality has occurred in the battery 12. The regular interval is, for example, from 1 second to 10 seconds. Hereinafter, the flow shown in Fig. 3 will be simply referred to as the flow.

[0021] 3, the acquisition unit 71 of the control unit 7 acquires the temperature sensor output from the temperature sensor 2 and acquires the gas sensor output from the voltage measurement unit 4 (S1). In step S1, the acquisition unit 71 performs AD (Analog-Digital) conversion on the acquired temperature sensor output and gas sensor output, and provides the AD-converted temperature sensor output and gas sensor output to the correction unit 72.

[0022] The correction unit 72 corrects the gas sensor output provided by the acquisition unit 71 based on the temperature sensor output provided by the acquisition unit 71 and the temperature characteristics of the semiconductor sensor 3 (S2). In other words, the correction unit 72 corrects the gas sensor output output from the semiconductor sensor 3 based on the temperature detected by the temperature sensor 2 and the temperature characteristics of the semiconductor sensor 3. The correction unit 72 stores the corrected gas sensor output in the memory unit 6.

[0023] The temperature characteristic of the semiconductor sensor 3 is the temperature characteristic of the sensitivity of the semiconductor sensor 3, and is, for example, the black dot or straight line indicated by reference numeral 401 in Fig. 4 in Example 1 described later. The correction of the gas sensor output by the correction unit 72 will be described in detail in Example 1.

[0024] The calculation unit 73 calculates a moving average value of the gas sensor output corrected by the correction unit 72 (S3). Specifically, the calculation unit 73 refers to the gas sensor output corrected by the correction unit 72 for a period including a predetermined time point from the storage unit 6. The calculation unit 73 calculates a moving average value of the gas sensor output corrected by the correction unit 72 for a period including the predetermined time point.

[0025] The predetermined time point is, for example, the time point when the semiconductor sensor 3 outputs the gas sensor output, that is, the time point when the acquisition unit 71 acquires the gas sensor output in step S1. The period including the predetermined time point is, for example, one hour, and is the period between the time point one hour before the predetermined time point and the predetermined time point. The period including the predetermined time point may also be, for example, 10 minutes or more and 120 minutes or less. The calculation unit 73 stores the calculated moving average value in the memory unit 6.

[0026] Next, the calculation unit 73 calculates a first ratio of the gas sensor output of the semiconductor sensor 3 at a second time point after the first time point to the gas sensor output of the semiconductor sensor 3 at the first time point. Specifically, the calculation unit 73 references the moving average value for the period including the first time point and the gas sensor output at the second time point from the storage unit 6. The calculation unit 73 calculates a first ratio of the gas sensor output at the second time point to the moving average value for the period including the first time point (S4).

[0027] The first point in time is a predetermined time before the second point in time, for example, one hour before the second point in time. The predetermined time is preferably 5 minutes or more and 120 minutes or less, and more preferably 5 minutes or more and 90 minutes or less. The second point in time is, for example, the present time. Specifically, the second point in time is, for example, the time when the acquisition unit 71 acquires the gas sensor output in step S1 of the flow including the calculation of the first ratio by the calculation unit 73, that is, the time when the semiconductor sensor 3 outputs the gas sensor output.

[0028] The moving average value for the period including the first point in time is, for example, a moving average value between a point in time one hour before the second point in time and a point in time two hours before the second point in time, and is a value calculated from the gas sensor output corrected by the correction unit 72. The gas sensor output at the second point in time is the gas sensor output corrected by the correction unit 72.

[0029] Therefore, the calculation unit 73 calculates the first ratio using the gas sensor output at the first time point corrected by the correction unit 72 and the gas sensor output at the second time point corrected by the correction unit 72. Here, the gas sensor output at the first time point includes the meaning of a moving average value for a period including the first time point.

[0030] The determination unit 74 determines whether the first ratio calculated by the calculation unit 73 in step S4 is equal to or greater than a first predetermined threshold (S5). The first predetermined threshold is an example of a predetermined threshold that serves as a criterion for determining the first ratio, and is preferably, for example, equal to or greater than 2 and equal to or less than 20, and more preferably equal to or greater than 3 and equal to or less than 20. If the determination unit 74 determines that the first ratio is less than the first predetermined threshold (NO in S5), the calculation unit 73 assigns 0 to the variable i (S7), and the processing of the control unit 7 proceeds to step S10.

[0031] If the determination unit 74 determines that the first ratio is equal to or greater than the first predetermined threshold (YES in S5), the calculation unit 73 increments the variable i by 1 (S6). After the calculation unit 73 increments the variable i by 1, the determination unit 74 determines whether the variable i is equal to or greater than a first predetermined value (S8). The first predetermined value is a value such that the time it takes for the value of the variable i to increase from 0 to the first predetermined value is between 20 and 100 seconds. If the determination unit 74 determines that the variable i is less than the first predetermined value (NO in S8), the processing of the control unit 7 proceeds to step S10.

[0032] If the determination unit 74 determines that the variable i is equal to or greater than the first predetermined value (YES in S8), it determines that an abnormality has occurred in the battery 12. Here, in step S2, the correction unit 72 corrects the gas sensor output based on the temperature detected by the temperature sensor 2 and the temperature characteristics of the semiconductor sensor 3. Therefore, in steps S5, S6, and S8, the determination unit 74 can more accurately determine whether an abnormality has occurred in the battery 12 based on the first ratio of the gas sensor output that reflects the effect of the temperature inside the battery housing section 11 on the semiconductor sensor 3.

[0033] Furthermore, in step S3, the calculation unit 73 calculates a moving average value of the gas sensor output of the semiconductor sensor 3 during a period including the first time point, and calculates the first ratio using the moving average value as the gas sensor output at the first time point. The gas sensor output output from the semiconductor sensor 3 fluctuates significantly. For this reason, it is preferable that the gas sensor output at the first time point used when calculating the first ratio is the moving average value. The determination unit 74 can accurately determine whether an abnormality has occurred in the battery 12 based on the first ratio calculated from the moving average value during the period including the first time point.

[0034] Furthermore, in steps S6 to S8, the determination unit 74 determines that an abnormality has occurred in the battery 12 if the state in which the first ratio calculated by the calculation unit 73 is equal to or greater than the first predetermined threshold continues for a certain period of time.

[0035] As described above, the gas sensor output output from the semiconductor sensor 3 fluctuates greatly. For this reason, when determining whether an abnormality has occurred in the battery 12, it is preferable to check whether a state in which the first ratio of the gas sensor output is equal to or greater than the first predetermined threshold has continued for a certain period of time. Therefore, if a state in which the first ratio of the gas sensor output is equal to or greater than the first predetermined threshold has continued for a certain period of time, the determination unit 74 determines that an abnormality has occurred in the battery 12, thereby making it possible to accurately determine whether an abnormality has occurred in the battery 12.

[0036] When the determination unit 74 determines that an abnormality has occurred in the battery 12, the notification control unit 75 causes the notification unit 5 to notify first abnormality information indicating that an abnormality has occurred in the battery 12 (S9). In steps S5, S6, and S8, the determination unit 74 determines that an abnormality has occurred in the battery 12 when the first ratio calculated by the calculation unit 73 is equal to or greater than the first predetermined threshold.

[0037] After the notification control unit 75 causes the notification unit 5 to notify the first abnormality information, the determination unit 74 determines whether the first ratio calculated by the calculation unit 73 in step S4 is equal to or greater than a second predetermined threshold (S10). The second predetermined threshold is an example of a predetermined threshold, and is a value greater than the first predetermined threshold that serves as the basis for the determination in step S5, and is, for example, between 2 and 20, and more preferably between 3 and 20. If the determination unit 74 determines that the first ratio is less than the second predetermined threshold (NO in S10), it assigns 0 to the variable j (S12), and the control unit 7 ends the process.

[0038] When the determination unit 74 determines that the first ratio is equal to or greater than the second predetermined threshold (YES in S10), the calculation unit 73 increments the variable j by 1 (S11). After the calculation unit 73 increments the variable j by 1, the determination unit 74 determines whether the variable j is equal to or greater than the second predetermined value (S13).

[0039] The second predetermined value is a value that makes the time it takes for the value of variable j to increase from 0 to the second predetermined value between 5 and 20 seconds. The time it takes for the value of variable j to increase from 0 to the second predetermined value is shorter than the time it takes for the value of variable i to increase from 0 to the first predetermined value. If the determination unit 74 determines that the variable j is less than the second predetermined value (NO in S13), the control unit 7 ends the processing.

[0040] If the judgment unit 74 determines that the variable j is equal to or greater than the second predetermined value (YES in S13), the notification control unit 75 causes the notification unit 5 to notify second abnormality information indicating that an abnormality has occurred in the battery 12 (S14).

[0041] The second abnormality information indicates content that emphasizes the abnormality of the battery 12 more than the first abnormality information of step S9, and indicates content that is more important than the first abnormality information. For example, the first abnormality information indicates content that calls attention to an abnormality in the battery 12, and the second abnormality information indicates information that issues an alarm about an abnormality in the battery 12. After the notification control unit 75 causes the notification unit 5 to notify the second abnormality information, the control unit 7 ends the processing.

[0042] The gas sensor output from the semiconductor sensor 3 is an output corresponding to the concentration of the gas GS, i.e., an output relative to the concentration of the gas GS rather than a direct output of the concentration of the gas GS. Therefore, the determination unit 74 determines whether an abnormality has occurred in the battery 12 from a first ratio of the gas sensor output at the second time point to the gas sensor output at the first time point.

[0043] The first ratio is the ratio of the gas sensor output at the second time point to the gas sensor output at the first time point, and is therefore a value that is not related to the absolute value of the gas sensor output corresponding to the concentration of the gas GS measured by the semiconductor sensor 3. Therefore, the abnormality determination device 1 can accurately determine whether an abnormality has occurred in the battery 12 by using an inexpensive, long-life semiconductor sensor 3 that outputs a gas sensor output relative to the concentration of the gas GS, without having to frequently calibrate the sensitivity of the semiconductor sensor 3.

[0044] Furthermore, the gas GS emitted from the battery 12 is flammable, and if the gas GS fills the inside of the battery housing section 11, the gas GS may burn. Therefore, it is preferable that the notification unit 5 notify the first abnormality information in step S9, or that the notification unit 5 notify the second abnormality information in step S14. This allows the user to recognize that an abnormality has occurred in the battery 12, and allows the user to start taking measures to address the abnormality in the battery 12.

[0045] Furthermore, fluctuations in the gas sensor output due to resistance drift (changes over time) of the semiconductor sensor 3 are unlikely to affect the first ratio. Therefore, by having the determination unit 74 make a determination based on the first ratio, it is possible to reduce the effect of deterioration of the semiconductor sensor 3 on the abnormality determination of the battery 12. Regardless of deterioration of the semiconductor sensor 3, it is possible to improve the accuracy of the abnormality determination of the battery 12.

[0046] <Variation 1> 3, the acquisition of the temperature sensor output in step S1 and the processes in steps S2 and S3 may be omitted. In this case, in step S4, the calculation unit 73 calculates a first ratio relating to the gas sensor output output from the semiconductor sensor 3 at the second time point to the gas sensor output output from the semiconductor sensor 3 at the first time point.

[0047] The gas sensor output output from the semiconductor sensor 3 at the first time point is the gas sensor output that has been AD converted by the acquisition unit 71 at the first time point. The gas sensor output output from the semiconductor sensor 3 at the second time point is the gas sensor output that has been AD converted by the acquisition unit 71 at the second time point. In the first modification, the abnormality determination device 1 does not need to include the temperature sensor 2.

[0048] <Variation 2> 3, the process of step S3 may be omitted. In this case, in step S4, the calculation unit 73 calculates a first ratio of the gas sensor output corrected by the correction unit 72 at a second time point to the gas sensor output corrected by the correction unit 72 at a first time point.

[0049] <Variation 3> 3, the acquisition of the temperature sensor output in step S1 and the processing in step S2 may be omitted. In this case, in step S3, the calculation unit 73 calculates a moving average value of the gas sensor output that has been AD converted by the acquisition unit 71. In addition, in step S4, the calculation unit 73 calculates a first ratio of the gas sensor output output from the semiconductor sensor 3 at a second time point to the moving average value for a period including the first time point.

[0050] The gas sensor output output from the semiconductor sensor 3 at the second time point is the gas sensor output that has been AD converted by the acquisition unit 71 at the second time point. In the third modification, the abnormality determination device 1 does not need to include the temperature sensor 2.

[0051] <Variation 4> In the flow shown in Fig. 3, the processes of steps S5 to S9 may be omitted. Also, in the flow shown in Fig. 3, the processes of steps S6 to S8 or steps S11 to S13 may be omitted.

[0052] Furthermore, instead of steps S6 to S8, the determination unit 74 may determine whether the time elapsed since the first ratio became equal to or greater than a first predetermined threshold is equal to or greater than a first time. Instead of steps S11 to S13, the determination unit 74 may determine whether the time elapsed since the first ratio became equal to or greater than a second predetermined threshold is equal to or greater than a second time. The second time is shorter than the first time. The first time is, for example, equal to or greater than 20 seconds and equal to or less than 100 seconds, and the second time is, for example, equal to or greater than 5 seconds and equal to or less than 20 seconds.

[0053] <Variation 5> The first predetermined threshold value that serves as the criterion for the determination in step S5 is the volume [m 3 It is preferable that the value is based on a second ratio relating to the capacity [Ahr] of the battery 12 to the volume of the battery accommodating section 11. The second ratio may be a ratio relating to the capacity of the battery 12 alone to the volume of the battery accommodating section 11.

[0054] When the capacity of the battery 12 housed in the battery housing portion 11 increases, the internal volume of the battery 12, which contains the electrolyte, increases by the amount of the increased capacity. As a result, when an abnormality occurs in the battery 12, the amount of gas GS generated from the battery 12 increases, and the increase in the gas sensor output of the semiconductor sensor 3 becomes significant.

[0055] On the other hand, when the volume of the battery housing section 11 increases, the gas GS generated from the battery 12 is more likely to be diluted by the increased volume, thereby suppressing an increase in the gas sensor output of the semiconductor sensor 3. In this way, the gas sensor output of the semiconductor sensor 3 depends on the capacity of the battery 12 and the volume of the battery housing section 11.

[0056] The second ratio is a ratio related to the capacity of the battery 12 relative to the volume of the battery accommodating section 11, and therefore is a value that reflects the capacity of the battery 12 and the volume of the battery accommodating section 11. Therefore, since the first predetermined threshold value is a value based on the second ratio, the abnormality determination device 1 can determine whether an abnormality has occurred in the battery 12, regardless of the capacity of the battery 12 and the volume of the battery accommodating section 11.

[0057] Furthermore, the abnormality determination device 1 can determine whether an abnormality has occurred in the battery 12 regardless of the capacity of the battery 12 and the volume of the battery housing portion 11, and can therefore determine whether an abnormality has occurred in the battery 12 for batteries 12 of various capacities and battery housing portions 11 of various volumes. The second predetermined threshold value may also be a value based on the second ratio.

[0058] How the first predetermined threshold is determined determines the accuracy of abnormality determination for the battery 12. If the first predetermined threshold is set low, the sensitivity for detecting abnormalities in the battery 12 increases, but there is a risk of false detection due to disturbance factors other than the abnormality in the battery 12. On the other hand, if the first predetermined threshold is set high, the possibility of false detection decreases, but there is a possibility that an abnormality in the battery 12 will not be detected.

[0059] Therefore, by setting the first predetermined threshold to a value based on the second ratio relating to the capacity of the battery 12 to the volume of the battery accommodating section 11, the accuracy of the first predetermined threshold is improved, and the accuracy of determining an abnormality in the battery 12 is improved. Also, an abnormality in the battery 12 can be reliably detected to ensure safety, while an increase in the gas sensor output due to causes other than outgassing can be ignored.

[0060] <Variation 6> A modified example of step S5 will be described below. Specifically, first, during a predetermined learning period, a third ratio, which is related to the maximum value of the gas sensor output of the semiconductor sensor 3 relative to the moving average value of the gas sensor output (hereinafter referred to as the gas sensor output), is recorded every hour. Then, the maximum value of the third ratio during the predetermined learning period is determined.

[0061] In Modification 6, the moving average value of the gas sensor output is the average value of the gas sensor output in the period between two hours before the time when the third ratio was recorded (hereinafter referred to as the recording time) and one hour before the recording time. The maximum value of the gas sensor output is the maximum value of the gas sensor output in the period between one hour before the recording time and the recording time. The predetermined learning period is, for example, one to three months. The period between one hour before the recording time and the recording time is an example of the predetermined period.

[0062] Furthermore, the fourth predetermined value and the fifth predetermined value are compared, and the higher of the fourth predetermined value and the fifth predetermined value is determined as the sixth predetermined value. The fourth predetermined value is a value obtained by adding a constant L to the maximum value of the third ratio. If the capacity of the battery 12 is P and the volume of the battery accommodating section 11 is V, the fifth predetermined value is 3 + ((P / V) - 0.2) × 8.75. In this way, the fourth predetermined value is a value based on the third ratio, and the fifth predetermined value is a value based on the second ratio (P / V).

[0063] Furthermore, if the sixth predetermined value is TH, instead of step S5, the determination unit 74 may determine whether at least one of the following conditions (A) and (B) is satisfied for TH.

[0064] Condition (A): The first ratio calculated by the calculation unit 73 in step S4 is equal to or greater than TH, and the first ratio is equal to or greater than (TH-1)×M1.

[0065] Condition (B): The first ratio calculated by the calculation unit 73 in step S4 is equal to or greater than (TH-1)×M2.

[0066] However, M2 is a value larger than M1. M1 is a constant when it is assumed that the gas sensor output is a relatively low value, and M2 is a constant when it is assumed that the gas sensor output is a relatively high value. "TH", "(TH-1)×M1", and "(TH-1)×M2" are examples of predetermined thresholds, and are values ​​obtained in advance by calculating the third ratio and by using TH.

[0067] If the determination unit 74 determines that at least one of the conditions (A) and (B) is satisfied, the determination unit 74 determines that an abnormality has occurred in the battery 12, and the processing of the control unit 7 proceeds to step S9. If the determination unit 74 determines that neither the condition (A) nor the condition (B) is satisfied, the processing of the control unit 7 proceeds to step S10.

[0068] If the determination unit 74 determines that at least one of the conditions (A) and (B) is satisfied, the process of the control unit 7 may proceed to step S6. On the other hand, if the determination unit 74 determines that neither the conditions (A) nor (B) is satisfied, the process of the control unit 7 may proceed to step S7.

[0069] According to the above configuration, the fifth predetermined value is a value based on the second ratio relating to the capacity of the battery 12 relative to the volume of the battery housing portion 11, and the sixth predetermined value used in conditions (A) and (B) is determined to be the higher of the fourth predetermined value and the fifth predetermined value. Therefore, the third predetermined threshold, the fourth predetermined threshold, and the fifth predetermined threshold are determined taking into account fluctuations in the first ratio due to disturbance factors specific to the monitoring location where the battery 12 is monitored. This improves the accuracy of determining whether an abnormality has occurred in the battery 12. The monitoring location is, for example, the battery housing portion 11.

[0070] Consider a case where the resistance value of the sensitive part 32 of the semiconductor sensor 3 is relatively high and the gas sensor output is relatively low when the battery 12 is normal. In this case, the determination part 74 determines whether at least one of the conditions (A) and (B) is satisfied, thereby reducing the likelihood of determining that an abnormality has occurred in the battery 12 due to a slight decrease in the resistance value of the sensitive part 32.

[0071] On the other hand, when the battery 12 is normal, if the resistance value of the sensitive part 32 of the semiconductor sensor 3 is relatively low and the gas sensor output is relatively high, the change in the first ratio may be small. Therefore, by having the determination unit 74 determine whether at least one of the conditions (A) and (B) is satisfied, it is possible to accurately determine whether an abnormality has occurred in the battery 12 even when the change in the first ratio is small.

[0072] Therefore, the influence of the gas sensor output becoming low or high due to resistance value drift of the semiconductor sensor 3 can be reduced, and the accuracy of determining whether an abnormality has occurred in the battery 12 can be improved.

[0073] Example 1 FIG. 4 is a graph showing the gas sensor output of the semiconductor sensor 3 according to Examples 1 and 2 of the present invention. Reference numeral 401 in FIG. 4 indicates the temperature characteristics of the semiconductor sensor 3 according to Example 1 of the present invention. In reference numeral 401 in FIG. 4, the horizontal axis indicates the temperature [°C] inside the battery accommodating section 11, and the vertical axis indicates the gas sensor output after AD conversion by the acquiring section 71. The black dots indicate the gas sensor output AD converted by the acquiring section 71 when the temperature inside the battery accommodating section 11 is changed while the concentration of the gas GS inside the battery accommodating section 11 is kept constant. The straight line indicates an approximation line obtained by linearly approximating the gas sensor output indicated by the black dots.

[0074] When the temperature inside the battery accommodating section 11 was changed while the concentration of the gas GS inside the battery accommodating section 11 was kept constant, the gas sensor output had a temperature characteristic, as shown by the black dots indicated by reference numeral 401 in Fig. 4. Furthermore, when the gas sensor output that had been AD converted by the acquiring section 71 was linearly approximated with a boundary of 20°C, the result was as shown by the straight line indicated by reference numeral 401 in Fig. 4.

[0075] Here, the gas sensor output converted by the acquisition unit 71 is denoted as S, and the corrected gas sensor output is denoted as ST. Based on the line denoted by reference numeral 401 in Fig. 4, the gas sensor output ST when the temperature is 20°C or higher is set as shown in the following formula (1).

[0076] ST=S×(1-(T-20)×0.018)···(1) Further, based on the line 401 in FIG. 4, the gas sensor output ST when the temperature is less than 20° C. is set as shown in the following equation (2).

[0077] ST=S×(1-(T-20)×0.033)···(2) By setting the gas sensor output ST according to the above formulas (1) and (2), the gas sensor output S can be accurately corrected within the temperature range of -10°C to 60°C, which is the temperature condition under which the semiconductor sensor 3 is used.

[0078] 3, it is preferable that the correction unit 72 corrects the gas sensor output provided by the acquisition unit 71 based on the temperature sensor output provided by the acquisition unit 71 and the temperature characteristics of the semiconductor sensor 3. In this case, the temperature sensor output provided by the acquisition unit 71 is defined as T, the gas sensor output provided by the acquisition unit 71 is defined as S, and the correction unit 72 outputs the corrected gas sensor output ST.

[0079] <Example 2> 4, reference numerals 402 and 403 indicate the gas sensor output of the semiconductor sensor 3 according to Example 2 of the present invention. In the reference numerals 402 and 403 in Fig. 4, the horizontal axis indicates time [hh:mm], and the vertical axis indicates the gas sensor output that has been AD converted by the acquisition unit 71 and corrected by the correction unit 72.

[0080] In Example 2, semiconductor sensors 3 were installed at the four corners inside the battery housing section 11 in which the battery 12 was housed. In addition, a test was conducted to determine whether the semiconductor sensors 3 could detect outgassing when outgassing was generated from a lithium ion battery inside the battery housing section 11.

[0081] The lithium-ion battery abnormality test was performed by heating the lithium-ion battery with a heater installed near the battery to increase its temperature. The first predetermined threshold in step S5 was set to 2, and the second predetermined threshold in step S10 was set to 4. The first predetermined value was set to a value that would allow 30 seconds for the value of variable i to increase from 0 to the first predetermined value, and the second predetermined value was set to a value that would allow 10 seconds for the value of variable j to increase from 0 to the second predetermined value.

[0082] The change in gas sensor output in the first test is shown by reference numeral 402 in Figure 4. Under normal circumstances, there is no outgassing inside the battery housing section 11, so the gas sensor output remained constant at a value of about 12. As the temperature of the lithium-ion battery was increased, the semiconductor sensor 3 overheated, causing the internal pressure of the semiconductor sensor 3 to increase, and at around 11:30, the pressure valve installed in the lithium-ion battery opened, causing the outgassing to escape.

[0083] When the semiconductor sensor 3 detected the outgassing, the gas sensor output continued to rise, and the state in which the first ratio in step S4 was equal to or greater than the first predetermined threshold continued for 30 seconds, causing the alarm unit 5 to issue a first abnormality notification. While the first abnormality notification was being issued, the gas sensor output continued to rise, and four minutes after the outgassing was detected, the gas sensor output reached 50 or more, which is more than four times the normal gas sensor output.

[0084] Furthermore, since the state in which the first ratio was equal to or greater than the second predetermined threshold continued for 10 seconds, second abnormality information was issued by the notification unit 5. The outgas remained for several tens of minutes or more until ventilation was performed, during which time the second abnormality information was issued.

[0085] The change in gas sensor output during the second test is shown by reference number 403 in Figure 4. The second test was similar to the first test. As shown by reference number 403 in Figure 4, outgassing occurred at around 9:37, causing the gas sensor output to rise once, but then the gas sensor output rose again at around 9:47, indicating a change in the gas sensor output.

[0086] The determination unit 74 determines whether a first ratio of the gas sensor output at a second time point to a moving average value of the gas sensor output for a period including the first time point is equal to or greater than a first predetermined threshold value or a second predetermined threshold value. Therefore, as shown by reference numeral 403 in Fig. 4, even when the gas sensor output fluctuates significantly in two stages, the abnormality determination device 1 can respond without reducing sensitivity. The determination unit 74 determines whether there is an abnormality in the lithium-ion battery from the current gas sensor output, using the gas sensor output during normal times when no outgas is present as a reference.

[0087] The above tests have shown that by installing the semiconductor sensor 3 in the battery storage section 11, it is possible to quickly detect outgassing from the lithium ion battery and notify the outside of the outgassing, thereby ensuring safety.

[0088] Example 3 Fig. 5 is a graph showing the gas sensor output of the semiconductor sensor 3 according to Example 3 of the present invention. In the reference numerals 501 and 502 in Fig. 5, the horizontal axis indicates the measurement date and time, and the vertical axis indicates the gas sensor output that has been AD converted by the acquisition unit 71 and corrected by the correction unit 72. Reference numeral 501 in Fig. 5 indicates the maximum value of the gas sensor output per hour, and reference numeral 502 in Fig. 5 indicates the average value of the gas sensor output per hour.

[0089] In Example 3, the abnormality determination device 1 was installed for about one month in the battery housing section 11 housing a normal battery 12. As shown by reference numerals 501 and 502 in Figure 5, the gas sensor output changes over time, but the general shape of the graph relating to the maximum gas sensor output and the general shape of the graph relating to the average gas sensor output are similar. Therefore, it can be confirmed from Figure 5 that there is no peculiar gas sensor output that would be observed when the battery 12 is abnormal.

[0090] Example 4 6 is a graph showing the ratio of the maximum value of the gas sensor output to the average value of the gas sensor output one hour prior to the present time for the semiconductor sensor 3 according to Example 4 of the present invention. In FIG. 6, the horizontal axis indicates the measurement date and time, and the vertical axis indicates the ratio of the maximum value. In addition, the gas sensor output in FIG. 6 is the gas sensor output that has been AD converted by the acquisition unit 71 and corrected by the correction unit 72.

[0091] 6, the ratio of the maximum gas sensor output to the average gas sensor output one hour prior to the present time was at most about 1.5 times. Therefore, by setting the first predetermined threshold to 2 or more, more preferably 3 or more, it is possible to reduce the risk of erroneously determining an abnormality in the battery 12.

[0092] <Example 5> 7 is a graph showing test results for the gas sensor output of the semiconductor sensor 3 according to Example 5 of the present invention. In the graphs 701 and 702 in Fig. 7, the horizontal axis indicates time [hh:mm], and the vertical axis indicates the gas sensor output that has been AD converted by the acquisition unit 71 and corrected by the correction unit 72.

[0093] Reference numeral 701 in FIG. 7 indicates a battery 12 with a capacity P of 3.4 Ahr and a battery accommodating section 11 with a volume V of 92.4 m 3 The reference numeral 702 in FIG. 7 indicates a battery storage facility in which the capacity P of the battery 12 is 75 Ahr and the volume V of the battery housing section 11 is 108 m 3 The test results for a battery storage facility with a P / V of 0.069 are shown below.

[0094] In the test results indicated by reference numeral 701 in FIG. 7, the pressure vent on the lithium-ion battery opened at approximately 11:30, causing outgassing. The gas sensor output after the pressure vent opened was approximately 4.5 times the gas sensor output before the pressure vent opened. In the test results indicated by reference numeral 702 in FIG. 7, the pressure vent on the lithium-ion battery opened at approximately 11:05, causing outgassing. The gas sensor output after the pressure vent opened was approximately 16 times the gas sensor output before the pressure vent opened.

[0095] Therefore, as the capacity P of the battery 12 housed in the battery housing section 11 increases, the amount of outgassing from the battery 12 increases when an abnormality occurs in the battery 12, resulting in a significant increase in the gas sensor output of the semiconductor sensor 3. On the other hand, as the volume V of the battery housing section 11 increases, the increase in the gas sensor output of the semiconductor sensor 3 is suppressed. Therefore, it can be seen that the value of P / V is an index of the degree of increase in the gas sensor output for the conditions of the capacity P of the battery 12 and the volume V of the battery housing section 11.

[0096] Example 6 FIG. 8 is a diagram showing the results of measuring and plotting the rate of increase in gas sensor output versus P / V in Example 6 of the present invention. P is the capacity of the battery 12, and V is the volume of the battery housing section 11. The rate of increase in gas sensor output is the ratio of the gas sensor output after the pressure valve provided on the battery 12 is opened to the gas sensor output before the pressure valve is opened. The graph shown in FIG. 8 is a double logarithmic graph. In FIG. 8, the horizontal axis represents the P / V value, and the vertical axis represents the rate of increase in gas sensor output.

[0097] As shown in Fig. 8, it was confirmed that the accuracy of detecting an abnormality in the battery 12 can be improved by setting the first predetermined threshold to 3 as shown by the thick line when P / V<0.2, and by setting the first predetermined threshold to 3+((P / V)-0.2)×8.75 as shown by the thick line when P / V≧0.2. Furthermore, when P / V≧0.2, the first predetermined threshold is a value proportional to P / V on a double logarithmic graph.

[0098] Therefore, it is preferable to determine the first predetermined threshold value by comparing the following two methods. The first method is to measure and record the gas sensor output of the semiconductor sensor 3 for a certain period of time to take into account variations in the gas sensor output under normal conditions (the state before the pressure valve opens), and to determine the first predetermined threshold value from the measurement results. The second method is to determine an optimal first predetermined threshold value based on P / V. The first and second methods are compared, and the first predetermined threshold value is determined so that the threshold value of the second method is higher than the threshold value of the first method.

[0099] Therefore, in Modification 5, as shown in Fig. 8, the first predetermined threshold is preferably a constant value within a range R1 of the second ratio where the second ratio (P / V) is less than a third predetermined value GV. Furthermore, the first predetermined threshold is preferably a value that is positively correlated with the second ratio within a range R2 of the second ratio where the second ratio is equal to or greater than the third predetermined value GV. The third predetermined value GV is, for example, 0.2.

[0100] In the range R1 of the second ratio where the second ratio is less than the third predetermined value GV, the sensor output of the semiconductor sensor 3 tends to be constant. In the range R2 of the second ratio where the second ratio is equal to or greater than the third predetermined value GV, there is a positive correlation between the sensor output of the semiconductor sensor 3 and the second ratio. Therefore, it is preferable that the predetermined threshold be a constant value in the range R1 of the second ratio where the second ratio is less than the third predetermined value GV, and a value that is positively correlated with the second ratio in the range R2 of the second ratio where the second ratio is equal to or greater than the third predetermined value GV. This improves the accuracy of the determination by the abnormality determination device 1, which reflects the capacity P of the battery 12 and the volume V of the battery housing portion 11.

[0101] The second predetermined threshold is also preferably a constant value within a range R1 of the second ratio where the second ratio is less than the third predetermined value GV, and is preferably a value that is positively correlated with the second ratio within a range R2 of the second ratio where the second ratio is equal to or greater than the third predetermined value GV.

[0102] Example 7 9 is a graph showing the third ratio of the gas sensor output of the semiconductor sensor 3 according to Example 7 of the present invention in Modification 6. In Fig. 9, the horizontal axis indicates the measurement date when the third ratio was measured, and the vertical axis indicates the third ratio of Modification 6.

[0103] As shown in Figure 9, the third ratio generally fluctuates between 1 and 1.2, but can temporarily increase due to disturbances such as work being performed around the battery equipment. The maximum value of the third ratio during the period in which the third ratio was measured was 1.67. Table 1 below lists the maximum values ​​of the third ratio obtained from the trend data of the third ratio for each facility. Column 1 of Table 1 shows each facility, column 2 of Table 1 shows the monitoring period for each facility (the period in which the maximum value of the third ratio was measured), and column 3 of Table 1 shows the maximum value of the third ratio. [Table 1]

[0104] Facility A shown in Table 1 is the facility where the measurement of the third ratio shown in Figure 9 was performed. As shown in Table 1, the maximum value of the third ratio is in the range of 1.25 to 1.67. A certain period of time after the start of measurement of the third ratio is used as a learning period, and the maximum value of the third ratio is found. By adding the constant L to the maximum value of the third ratio, it is possible to set an appropriate fourth predetermined value.

[0105] The learning period is, for example, about 1 to 5 months, and preferably about 2 to 4 months. The constant L is, for example, 1 to 8, and preferably 1.5 to 5. The sixth predetermined value used to determine whether an abnormality has occurred in the battery 12 may be the higher of the fifth predetermined value "3 + ((P / V) - 0.2) × 8.75", which also takes into account the capacity P of the battery 12 relative to the volume V of the battery accommodating section 11, and the fourth predetermined value.

[0106] Example 8 10 is a graph showing the moving average value of the gas sensor output for the semiconductor sensor 3 according to Example 8 of the present invention. Here, the moving average value of the gas sensor output is the average value of the gas sensor output for the period between two hours before the time the moving average value was measured and one hour before the time the moving average value was measured. In FIG. 10, the horizontal axis indicates the measurement date when the moving average value was measured, and the vertical axis indicates the moving average value of the gas sensor output.

[0107] As shown in Figure 10, the moving average value of the gas sensor output fluctuates between approximately 10 and 50. When the moving average value of the gas sensor output is relatively low, even a small fluctuation in the gas sensor output can cause the first ratio to reach the first predetermined threshold for abnormality detection, which can result in abnormality detection being more sensitive than necessary. On the other hand, when the moving average value of the gas sensor output is relatively high, even if the gas sensor output fluctuates significantly, the first ratio will not reach the first predetermined threshold, which can result in abnormality detection being less sensitive.

[0108] In order to reduce the possibility of a decrease in the accuracy of anomaly detection, the determination unit 74 determines whether at least one of the above-mentioned conditions (A) and (B) is satisfied. In the eighth embodiment, as shown by the dotted line in Fig. 10, M1 is set to 15 and M2 is set to 40. The numerical values ​​of M1 and M2 may be determined based on the characteristics of the semiconductor sensor 3. Alternatively, the numerical values ​​of M1 and M2 may be determined based on the fluctuation range of the gas sensor output under normal conditions obtained from a certain learning period.

[0109] [Software implementation example] The functions of the abnormality determination device 1 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly each part included in the control unit 7).

[0110] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program to realize the functions described in the above embodiment. The storage device may be a storage unit 6.

[0111] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0112] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0113] 〔summary〕 The abnormality determination device according to aspect 1 of the present invention comprises a semiconductor sensor that outputs a sensor output corresponding to the concentration of gas generated from a battery contained in a battery accommodating section, a calculation unit that calculates a first ratio relating the sensor output of the semiconductor sensor at a second point in time after the first point in time to the sensor output of the semiconductor sensor at the first point in time, and a determination unit that determines that an abnormality has occurred in the battery if the first ratio calculated by the calculation unit is equal to or greater than a predetermined threshold value.

[0114] The abnormality determination device according to a second aspect of the present invention may be configured in the above-mentioned first aspect such that the predetermined threshold value is a value based on a second ratio relating to a capacity of the battery relative to a volume of the battery housing portion.

[0115] An abnormality determination device according to aspect 3 of the present invention may be configured in the above-mentioned aspect 2 such that the predetermined threshold value is a constant value in the range of the second ratio where the second ratio is less than a predetermined value, and is a value that is positively correlated with the second ratio in the range of the second ratio where the second ratio is equal to or greater than the predetermined value.

[0116] An abnormality determination device according to a fourth aspect of the present invention, in any one of the first to third aspects described above, may further include a temperature sensor that detects the temperature inside the battery accommodating section, and a correction unit that corrects the sensor output output from the semiconductor sensor based on the temperature detected by the temperature sensor and the temperature characteristics of the semiconductor sensor, and the calculation unit may be configured to calculate the first ratio using the sensor output at the first point in time corrected by the correction unit and the sensor output at the second point in time corrected by the correction unit.

[0117] An abnormality determination device according to aspect 5 of the present invention may be configured such that, in any of aspects 1 to 4 above, the calculation unit calculates a moving average value of the sensor output of the semiconductor sensor during a period including the first time point, and calculates the first ratio using the moving average value as the sensor output at the first time point.

[0118] An abnormality determination device according to aspect 6 of the present invention may be configured in any one of aspects 1 to 5 above, wherein the determination unit determines that an abnormality has occurred in the battery if the first ratio calculated by the calculation unit remains equal to or greater than the predetermined threshold for a certain period of time.

[0119] An abnormality determination device according to aspect 7 of the present invention may be configured in the above-mentioned aspect 1 such that the predetermined threshold value is a value obtained in advance by calculating a third ratio relating to the maximum value of the sensor output in a predetermined period relative to the moving average value of the sensor output.

[0120] An abnormality determination device according to aspect 8 of the present invention may be configured such that, in the above-mentioned aspect 7, the predetermined threshold value is a value obtained in advance by using the higher value of a value based on a second ratio relating to the capacity of the battery to the volume of the battery accommodating section, and a value based on the third ratio.

[0121] An abnormality determination device according to a ninth aspect of the present invention may be configured such that, in the above-mentioned eighth aspect, the higher of the value based on the second ratio and the value based on the third ratio is TH, a constant is M1, and a constant greater than M1 is M2, and the determination unit determines that an abnormality has occurred in the battery when at least one of the following conditions (A) and (B) is satisfied:

[0122] Condition (A): The first ratio calculated by the calculation unit is equal to or greater than TH as the predetermined threshold, and the first ratio is equal to or greater than (TH-1)×M1 as the predetermined threshold.

[0123] Condition (B): The first ratio calculated by the calculation unit is equal to or greater than the predetermined threshold value (TH-1)×M2.

[0124] The abnormality determination method according to aspect 10 of the present invention includes an output step of outputting from a semiconductor sensor a sensor output corresponding to the concentration of gas generated from a battery contained in a battery accommodating section, a calculation step of calculating a ratio of the sensor output of the semiconductor sensor at a second point in time after the first point in time to the sensor output of the semiconductor sensor at the first point in time, and a determination step of determining that an abnormality has occurred in the battery if the ratio calculated by the calculation step is equal to or greater than a predetermined threshold value.

[0125] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0126] 1 Abnormality determination device 2 Temperature Sensors 3 Semiconductor sensors 11 Battery compartment 12 batteries 71 Acquisition Department 72 Correction unit 73 Calculation Unit 74 Judgment section R1: The range of the second ratio in which the second ratio is less than a predetermined value R2: The range of the second ratio where the second ratio is equal to or greater than a specified value

Claims

1. a semiconductor sensor that outputs a sensor output corresponding to the concentration of gas generated from the battery housed in the battery housing portion; a calculation unit that calculates a first ratio of the sensor output of the semiconductor sensor at a first time point to the sensor output of the semiconductor sensor at a second time point that is later than the first time point; and a determination unit that determines that an abnormality has occurred in the battery when the first ratio calculated by the calculation unit is equal to or greater than a predetermined threshold.

2. 2. The abnormality determination device according to claim 1, wherein the predetermined threshold value is a value based on a second ratio relating to a capacity of the battery relative to a volume of the battery housing portion.

3. The predetermined threshold value is the second ratio is a constant value within a range of the second ratio that is less than a predetermined value, 3. The abnormality determination device according to claim 2, wherein the second ratio is a value that is positively correlated with the second ratio in a range of the second ratio that is equal to or greater than the predetermined value.

4. a temperature sensor for detecting the temperature inside the battery housing; a correction unit that corrects the sensor output output from the semiconductor sensor based on the temperature detected by the temperature sensor and the temperature characteristics of the semiconductor sensor, 4. The abnormality determination device according to claim 1, wherein the calculation unit calculates the first ratio using the sensor output at the first time point corrected by the correction unit and the sensor output at the second time point corrected by the correction unit.

5. The calculation unit calculating a moving average value of the sensor output of the semiconductor sensor during a period including the first time point; 4. The abnormality determination device according to claim 1, wherein the first ratio is calculated using the moving average value as the sensor output at the first time point.

6. The abnormality determination device according to any one of claims 1 to 3, characterized in that the determination unit determines that an abnormality has occurred in the battery if the first ratio calculated by the calculation unit remains equal to or greater than the predetermined threshold for a certain period of time.

7. 2. The abnormality determination device according to claim 1, wherein the predetermined threshold value is a value obtained in advance by calculating a third ratio of a maximum value of the sensor output in a predetermined period to a moving average value of the sensor output.

8. 8. The abnormality determination device according to claim 7, wherein the predetermined threshold value is a value obtained in advance by using a higher value of a value based on a second ratio relating to the capacity of the battery to the volume of the battery accommodating portion and a value based on the third ratio.

9. If the higher of the value based on the second ratio and the value based on the third ratio is TH, a constant is M1, and a constant greater than M1 is M2, then:

9. The abnormality determination device according to claim 8, wherein the determination unit determines that an abnormality has occurred in the battery when at least one of the following conditions (A) and (B) is satisfied: Condition (A): The first ratio calculated by the calculation unit is equal to or greater than TH as the predetermined threshold, and the first ratio is equal to or greater than (TH-1)×M1 as the predetermined threshold. Condition (B): The first ratio calculated by the calculation unit is equal to or greater than the predetermined threshold value (TH-1)×M2.

10. an output step of outputting a sensor output from the semiconductor sensor according to the concentration of gas generated from the battery housed in the battery housing portion; a calculation step of calculating a ratio of the sensor output of the semiconductor sensor at a second time point after the first time point to the sensor output of the semiconductor sensor at a first time point; and a determining step of determining that an abnormality has occurred in the battery if the ratio calculated in the calculating step is equal to or greater than a predetermined threshold value.

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