Battery diagnosis device and battery diagnosis method

Abstract

The present invention provides a battery diagnostic device and a battery diagnostic method. Provided are a battery diagnostic device and a battery diagnostic method that can accurately determine the deterioration state of a battery and use the battery until it is about to reach the end of its life or close to its life. The device comprises: a power supply monitoring unit (5) that detects that the power supply voltage changes from less than a given voltage to a given voltage or above; and a control unit (4) that measures the battery voltage during a given period after detecting that the power supply voltage changes to a given voltage or above, calculates the power related to the residual capacity of the battery (1) based on the battery voltage, and determines the deterioration of the battery (1) based on the power related to the residual capacity of the battery (1).

Description

Technical Field

[0001] The present disclosure relates to a battery diagnosis device and a battery diagnosis method. Background Art

[0002] In a device equipped with a battery, in order to determine the state in which the residual capacity of the battery is lower than a given value (hereinafter referred to as a degraded state), the following two methods are mainly used. One is a method of accumulating the amount of consumed charge based on the firmware of the device. This is a method of determining the degraded state of the battery by accumulating the amount of charge consumed by the device by setting the capacity of the battery in a full state (nominal capacity) and the amount of charge used in each action to fixed values. The other is a method of periodically diagnosing the internal resistance (for example, Patent Document 1). The method of periodically diagnosing the internal resistance is a method of periodically measuring the internal resistance of the battery and comparing it with a pre-set threshold value to determine the degraded state of the battery.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: JP Patent Publication No. 2009-63460 Summary of the invention

[0006] In the charge accumulation method, the full capacity of the battery and the amount of charge used in each operation need to be set as fixed values ​​to calculate the consumed charge. However, the amount of charge used in each operation varies depending on the type of battery, storage environment, usage environment, etc., making it difficult to accurately determine the deterioration state of the battery.

[0007] In addition, in the periodic diagnosis of internal resistance method, a threshold value is set taking into account the irregularities of components, so that depending on the components used in the device, there may be a large deviation from the ideal degradation detection timing. In addition, in order to accurately calculate the internal resistance of the battery, it is necessary to measure the ambient temperature and current load with high precision, which leads to an increase in circuit scale and cost.

[0008] Therefore, an object of the present disclosure is to provide a battery diagnosis device and a battery diagnosis method that can accurately determine the deterioration state of a battery and use the battery until just before or near the end of its life.

[0009] A battery diagnostic device according to some embodiments includes:

[0010] a power supply monitoring unit that detects that the power supply voltage changes from less than a given voltage to more than the given voltage; and

[0011] The control unit measures the battery voltage within a given period after detecting that the power supply voltage becomes equal to or higher than the given voltage, calculates the power related to the remaining capacity of the battery based on the battery voltage, and determines the deterioration of the battery based on the power related to the remaining capacity of the battery.

[0012] In this way, the battery diagnostic device involved in several embodiments measures the battery voltage after the CPU is reset, and determines the battery degradation based on the supplyable power calculated from the battery voltage. Therefore, the battery degradation state can be determined with good accuracy, and the battery can be used until it is about to reach the end of its life or is close to its life.

[0013] In one embodiment, the control unit determines that the battery is in a degraded state when power related to the remaining capacity of the battery is less than a threshold value, and the battery diagnosis device may further include: an output unit that outputs an alarm when the battery is determined to be in a degraded state.

[0014] In this way, the control unit compares the power that the battery can supply with the threshold, and when the power related to the remaining capacity of the battery is less than the threshold, it determines that the battery is in a degraded state. Thus, the degradation state of the battery can be determined with good accuracy, and the battery can be used until it is about to reach the end of its life or is close to its life.

[0015] In one embodiment, the control unit may determine that the battery is in a degraded state when a situation in which the power related to the remaining capacity of the battery is less than a threshold value occurs consecutively a given number of times.

[0016] In this way, the control unit compares the power that the battery can supply with a threshold value, and when the power related to the remaining capacity of the battery is less than the threshold value for a given number of consecutive times, it is determined that the battery is in a degraded state. Thus, the degradation state of the battery can be determined with high accuracy, and the battery can be used until it is about to reach the end of its life or is close to its life.

[0017] In one embodiment, the battery is a lithium thionyl chloride primary battery,

[0018] The control unit may further perform the degradation determination based on power calculated again at the battery voltage measured after the refresh current flows when the power related to the remaining capacity of the battery is less than the threshold value or when this occurs a predetermined number of times continuously.

[0019] Thus, when the battery is a lithium thionyl chloride primary battery, degradation determination is performed after a refresh current is passed to attempt battery recovery, thereby making it possible to determine the battery degradation state with greater accuracy and use the battery until just before or near the end of its life.

[0020] In one embodiment, the control unit may further shift an operation mode of the device to a power saving mode when determining that the battery is in a degraded state.

[0021] Thus, when it is determined that the battery is in a degraded state, the control unit shifts the operation mode of the device to the power saving mode to suppress power consumption, thereby making it possible to effectively utilize the remaining capacity of the battery even in a degraded state.

[0022] In one embodiment, the control unit may further compare the power related to the remaining capacity of the battery with a plurality of threshold levels, classify the degree of degradation of the battery into levels, and change the operation mode of the device according to the degree of degradation.

[0023] In this way, the control unit switches the operation mode of the device according to the degree of battery degradation and suppresses power consumption, thereby making it possible to effectively use the remaining capacity of the battery according to the degree of degradation.

[0024] In one embodiment, the control unit may further perform the degradation determination based on an open circuit voltage of the battery.

[0025] In this way, by also using the open circuit voltage of the battery to perform the battery degradation determination, the battery degradation state can be determined with further accuracy, and the battery can be used until just before or near the end of its life.

[0026] In one embodiment, the control unit may determine whether to perform the degradation determination based on a change in electric power related to a residual capacity of the battery measured periodically.

[0027] In this way, by using the trend of the electric power related to the remaining capacity of the battery to determine whether to perform the battery degradation determination, it is possible to prevent insufficient consideration of the temporal change of the battery.

[0028] In one embodiment, the control unit may determine whether to perform the degradation determination further based on the ambient temperature of the battery.

[0029] In this way, by using the ambient temperature of the battery to determine whether to perform battery degradation determination, it is possible to prevent insufficient consideration of temperature changes.

[0030] Several embodiments of the present invention provide a battery diagnosis method including:

[0031] The step of detecting that the power supply voltage changes from less than a given voltage to more than the given voltage;

[0032] The step of measuring the battery voltage and calculating the power related to the remaining capacity of the battery within a given period after detecting that the power supply voltage has become equal to or higher than the given voltage; and

[0033] A step of performing a deterioration determination of the battery based on electric power related to a residual capacity of the battery.

[0034] In this way, the battery voltage is measured after the CPU is reset, and the battery degradation is determined based on the available power calculated from the battery voltage. Therefore, the battery degradation state can be determined with further accuracy, and the battery can be used until just before or near the end of its battery life compared to the past.

[0035] According to the present disclosure, it is possible to provide a battery diagnosis device and a battery diagnosis method that can determine the degradation state of a battery with higher accuracy and use the battery until just before or near the end of its life. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a functional block diagram of a battery diagnostic device according to one embodiment of the present disclosure.

[0037] Figure 2 1 is a flowchart showing a battery diagnosis method according to an embodiment of the present disclosure.

[0038] Figure 3 This is a flowchart showing an example of degradation determination processing.

[0039] Figure 4 This is a flowchart showing the degradation determination process according to the first modification.

[0040] Figure 5 This is a flowchart showing the degradation determination process according to the second modification.

[0041] Description of symbols

[0042] 1 Lithium thionyl chloride primary cell (battery)

[0043] 2 Constant voltage circuit

[0044] 3 Load current circuit

[0045] 4 Control Unit

[0046] 5 Power supply monitoring unit

[0047] 6 Constant voltage circuit primary side voltage holding unit

[0048] 7 Output section

[0049] 8 Storage

[0050] 10 Battery diagnostic device

[0051] 31 Discharge resistor

[0052] 32 Discharge switch

[0053] 61 diode

[0054] 62 Capacitor

[0055] 111 AD conversion unit

[0056] 112 Counting unit

[0057] 113 Discharge current control unit

[0058] 114 Reset Management Department

[0059] 115 Temperature measurement unit

[0060] 116 Battery Diagnostic Unit. DETAILED DESCRIPTION

[0061] Hereinafter, a battery diagnosis device 10 according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Figure 1 , the structure of the battery diagnosis device 10 involved in this embodiment is described.

[0062] The battery diagnosis device 10 according to the present embodiment includes a battery 1 , a constant voltage circuit unit 2 , a load current circuit 3 , a control unit 4 , a power supply monitoring unit 5 , a constant voltage circuit primary side voltage holding unit 6 , an output unit 7 , and a storage unit 8 .

[0063] The battery 1 is, for example, a lithium thionyl chloride primary battery. In the following embodiment, the battery 1 may also be referred to as a lithium thionyl chloride primary battery 1, but the type of battery is not limited thereto. In other words, with respect to the battery diagnostic device 10 involved in the present embodiment, diagnosis of any type of primary battery and secondary battery is possible. The lithium thionyl chloride primary battery 1 is connected to the input of the constant voltage circuit unit 2 via the primary side voltage holding unit 6 of the constant voltage circuit. The lithium thionyl chloride primary battery 1 has a high output voltage and low self-discharge, and has the characteristics of being able to be used for a long period of time, and is suitable as a power source for wireless devices used in factories and workshops that require stable operation for a long period of time. Since the lithium thionyl chloride primary battery 1 mainly has the following three characteristics, it is generally difficult to grasp the deterioration state of the battery.

[0064] (1) The nominal capacity (e.g., capacity at full capacity) varies greatly depending on the ambient temperature of the battery. For example, if the battery is stored in a high-temperature environment, the nominal capacity decreases to less than half.

[0065] (2) If used in a high temperature environment, a chloride film is generated inside the battery, causing the internal resistance to increase, and the voltage to drop when used at a high current. If the device suddenly switches to high-load operation in this state, it may not be able to maintain the desired voltage, and it may become impossible to maintain stable operation. In this case, even if there is sufficient capacity left in the battery, the battery cannot be used.

[0066] (3) Since the open circuit voltage is maintained at a substantially constant level until just before or when the battery capacity is close to being lost, it is difficult to grasp the degradation state by measuring the battery voltage.

[0067] Thus, in the case of a lithium thionyl chloride primary battery 1, the nominal capacity varies greatly depending on the ambient temperature and load conditions, and therefore, in an environment where the temperature changes drastically, it is impossible to accurately determine the degradation state of the lithium thionyl chloride primary battery 1. In addition, in the case where the internal resistance does not increase but the battery 1 deteriorates, the degradation state cannot be detected in the periodic diagnosis of the internal resistance method. In the case of a lithium thionyl chloride primary battery 1, there are: a mode in which the chloride film grows and the internal resistance increases, and a mode in which the open circuit voltage decreases under the influence of the ambient temperature or the life span in the battery degradation. In the periodic diagnosis of the internal resistance method, the latter degradation mode cannot be detected. In addition, with respect to the charge accumulation method, since the amount of charge used is continuously subtracted from the full state of the battery, it is also difficult to accurately determine the degradation state when a half-worn battery or a battery in poor storage condition is installed.

[0068] The constant voltage circuit unit 2 converts the output voltage of the lithium thionyl chloride primary battery 1 into a predetermined voltage (eg, 3.3 V), and outputs the voltage as a power source for the control unit 4 , the power source monitoring unit 5 , the output unit 7 , and the storage unit 8 .

[0069] The load current circuit 3 includes a discharge resistor 31 and a discharge switch 32. The discharge switch 32 is switched on / off based on the control of the discharge current control unit 113 described later. The discharge switch 32 is, for example, a FET (field effect transistor). By turning on the discharge switch 32, the battery voltage when there is a load (when a current flows through the discharge resistor 31) is measured.

[0070] The control unit 4 is a CPU (central processing unit) or a part of the CPU, and controls each unit of the battery diagnosis device 10 while executing processing related to the operation of the battery diagnosis device 10. The control unit 4 includes an AD conversion unit 111, a counting unit 112, a discharge current control unit 113, a reset management unit 114, a temperature measurement unit 115, and a battery diagnosis unit 116.

[0071] The AD converter 111 converts the analog data of the battery voltage into digital data and transmits the digital data to the counter 112. The counter 112 calculates the power related to the remaining capacity from the lithium thionyl chloride primary battery 1 based on the digital data transmitted from the AD converter 111. The power is calculated according to the following formula (1).

[0072] Pbat=Vb 2 / R··············(1)

[0073] Pbat is the power related to the residual capacity of the lithium thionyl chloride primary battery 1; Vb is the battery voltage when there is a load; and R is the resistance value of the discharge resistor 31 of the load current circuit 3. The counting unit 112 transmits the calculated power value (Pbat) to the battery diagnosis unit 116. In addition, Pbat is the power that can be supplied from the lithium thionyl chloride primary battery 1 to the inside of the battery diagnosis device 10.

[0074] The discharge current control unit 113 switches the on / off of the discharge switch 32 of the load current circuit 3. Through this control, the control unit 4 measures the battery voltage of the lithium thionyl chloride primary battery 1 when it is loaded. Specifically, the discharge current control unit 113 sets the discharge switch 32 to be turned on after the CPU reset is executed by the power supply voltage drop. Through this control, the control unit 4 measures the battery voltage during a given period after the CPU reset is executed by the power supply voltage drop. The given period is usually the period from the CPU reset to the start. Alternatively, the period can also be the period from the CPU reset until the refresh current flows. The refresh current is the current that flows in order to reduce the internal resistance of the lithium thionyl chloride primary battery 1. In addition, at the initial startup, the discharge current control unit 113 can be set to turn on the discharge switch 32 after the CPU reset is executed by the power supply voltage being a low voltage close to zero volts.

[0075] The reset management unit 114 performs a CPU reset (restarting the control unit 4) when the power supply voltage drops based on the monitoring result of the power supply monitoring unit 5. The power supply monitoring unit 5 periodically monitors the power supply voltage of the device. When the reset management unit 114 performs a CPU reset, it stores information related to the cause of the CPU reset in the storage unit 8. Specifically, for example, the reset management unit 114 stores bit information related to power supply abnormality in the storage unit 8. In addition, the reset management unit 114 can also perform the same operation at the time of initial startup.

[0076] The temperature measuring unit 115 measures the ambient temperature of the lithium thionyl chloride primary battery 1 and transmits the measured ambient temperature value to the battery diagnosis unit 116. The ambient temperature may be the surface temperature of the lithium thionyl chloride primary battery 1 or the temperature near the battery 1.

[0077] The battery diagnosis unit 116 makes a degradation judgment on the lithium thionyl chloride primary battery 1 based on Pbat transmitted from the counting unit 112 and, although arbitrarily, the ambient temperature value transmitted from the temperature measuring unit 115. Various methods can be used to judge the degradation. For example, a threshold value related to power can also be compared with Pbat, and when Pbat is less than the threshold value, it is judged that the lithium thionyl chloride primary battery 1 is in a degraded state. The threshold value is a value determined by the power of the action required in the device. For example, the threshold value can also be set to the power of the action that requires the most power in the device. In addition, the threshold value can also be set to the power of the action required for at least a part of the various parts of the device to perform the action. The threshold value can be a predetermined fixed value, or it can be determined by calculating based on the ambient temperature value transmitted from the temperature measuring unit 115.

[0078] The power supply monitoring unit 5 monitors the power supply voltage of the device (for example, the output voltage of the constant voltage circuit unit 2). When the power supply voltage is less than a given voltage, for example, when a drop in the power supply voltage is detected, and when the power supply voltage is detected to be greater than a given voltage, the power supply monitoring unit 5 transmits the detection result to the reset management unit 114. The reset management unit 114 performs a CPU reset based on the detection result. In addition, the power supply monitoring unit 5 can also perform the same operation at the initial startup. Here, for example, after the CPU is reset, it means that after the power supply monitoring unit 5 detects that the power supply voltage has changed from less than a given voltage to greater than a given voltage.

[0079] The constant voltage circuit primary side voltage holding unit 6 is a structure obtained by combining a diode 61 and a capacitor 62, and supplies a driving current to the control unit 4 when measuring the battery voltage. In addition, the current does not flow from the capacitor 62 to the load current circuit 3 through the diode 61. Therefore, when the discharge switch 32 of the load current circuit 3 is turned on, the current supplied from the lithium thionyl chloride primary battery 1 flows to the load current circuit 3. In the constant voltage circuit primary side voltage holding unit 6, the side connected to the battery 1 is the primary side, and the side connected to the constant voltage circuit unit 2 is the secondary side.

[0080] The output unit 7 outputs data obtained by the operation of the battery diagnostic device 10. Specifically, for example, when the lithium thionyl chloride primary battery 1 is determined to be in a degraded state by the control unit 4, the output unit 7 outputs an alarm for notifying the degraded state of the battery. The alarm can be in various forms. For example, the alarm can also indicate that the battery remaining is low. In addition, the alarm can also indicate that the battery remaining is, for example, 1%. The battery remaining may not be a calculated value. For example, the battery remaining may be a value low enough to urge the user to replace the battery.

[0081] The output unit 7 can also be a communication interface. The communication interface is, for example, a LAN interface, a WAN interface, an interface corresponding to a mobile communication standard such as LTE (Long Term Evolution), 4G (fourth generation) or 5G (fifth generation), or an interface corresponding to short-range wireless communication. The communication interface can generally communicate with the host system through a communication protocol used in industrial products (ISA100, LoRa communication, field bus / field bus (Fieldbus / Profibus), HART, Brain, etc.). The host system notifies the user of the alarm based on the alarm output from the output unit 7. For example, the host system can also display the situation that the output battery remaining is 1%.

[0082] In addition, the output unit 7 may also be a display, a speaker, etc. The display may be, for example, an LCD (liquid crystal display) or an organic EL (electro luminescence) display. In the case where the output unit 7 is a display, the output unit 7 may also display a mark indicating that the power of the battery is reduced, so that the on-site operator can easily identify the device in which the battery 1 should be replaced.

[0083] The storage unit 8 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a RAM (random access memory) or a ROM (read only memory). The RAM is, for example, an SRAM (static random access memory) or a DRAM (dynamic random access memory). The ROM is, for example, an EEPROM (electrically erasable programmable read only memory), a flash ROM, or a FRAM (Ferroelectric RAM). The storage unit 8 functions as, for example, a main storage device, an auxiliary storage device, or a cache memory. In the storage unit 8, data used in the operation of the battery diagnostic device 10 and data obtained by the operation of the battery diagnostic device 10 are stored.

[0084] Next, a battery diagnosis method executed by the battery diagnosis device 10 according to an embodiment of the present disclosure will be described. Figure 2 Detailed description of the invention A flowchart of a battery diagnosis method according to an embodiment of the present disclosure is shown in FIG.

[0085] First, the reset management unit 114 of the control unit 4 performs a CPU reset (step S100) when a drop in the power supply voltage of the device is detected based on the monitoring result of the power supply monitoring unit 5, or when the power supply voltage is detected to be above a given voltage. When performing a CPU reset, the reset management unit 114 stores information related to the cause of the CPU reset in the storage unit 8. Specifically, for example, the reset management unit 114 stores bit information related to power supply abnormality in the storage unit 8.

[0086] Next, the control unit 4 determines whether the cause of the CPU reset is due to a drop in the power supply voltage (step S200). Specifically, the control unit 4 refers to the bit information related to the power supply abnormality stored in the storage unit 8 to determine the cause of the CPU reset. If it is determined that the cause of the CPU reset is a drop in the power supply voltage, the process proceeds to step S300. If it is determined that the cause of the CPU reset is not a drop in the power supply voltage, the process proceeds to step S600.

[0087] When it is determined that the reason for the CPU reset is a drop in the power supply voltage, the control unit 4 measures the battery voltage and calculates the power that can be supplied (step S300). Specifically, the discharge current control unit 113 switches the discharge switch 32 of the load current circuit 3 to on after the CPU is reset. Through this control, the control unit 4 measures the battery voltage of the lithium thionyl chloride primary battery 1 under load during a given period after the CPU is reset. The AD conversion unit 111 converts the analog data of the battery voltage into digital data and transmits the digital data to the counting unit 112. The counting unit 112 calculates the power related to the residual capacity of the lithium thionyl chloride primary battery 1 based on the digital data transmitted from the AD conversion unit 111. The calculation of the power is performed by the above-mentioned formula (1).

[0088] The battery diagnosis unit 116 performs a deterioration determination process of the lithium thionyl chloride primary battery 1 based on the Pbat transmitted from the counting unit 112 and, optionally, the ambient temperature value transmitted from the temperature measurement unit 115 (step S400 ). Figure 3 An example of degradation determination processing is shown in . In step S401, the battery diagnosis unit 116 compares the power (Pbat) related to the residual capacity calculated from the battery voltage with the threshold value involved in the power, and determines the degradation state by whether Pbat is less than the threshold value. When Pbat is less than the threshold value, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is in a degraded state (step S402), and the degradation determination processing ends. On the other hand, in step S401, when Pbat is not less than the threshold value, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is not in a degraded state (step S403), and the degradation determination processing ends.

[0089] Refer again Figure 2, the output unit 7 outputs an alarm according to the result of the degradation determination process (step S500). Specifically, when the lithium thionyl chloride primary battery 1 is determined to be in a degraded state by the control unit 4, the output unit 7 outputs an alarm for notifying the degradation state of the battery. On the other hand, when the lithium thionyl chloride primary battery 1 is determined to be not in a degraded state by the control unit 4, the output unit 7 does not output the alarm. The alarm can take various forms. For example, the alarm can also indicate that the battery remaining is low. In addition, the alarm can also indicate that the battery remaining is, for example, 1%. The battery remaining may not be a calculated value. For example, the battery remaining is a value that is low enough to urge the user to replace the battery. Then, the control unit 4 starts the device normally (step S600), and the process ends. In addition, for example, after normal startup, the battery diagnostic device 10 can also send data based on sensor data obtained from a built-in or external sensor (not shown) to a host system via the output unit 7. Furthermore, after normal activation, the battery diagnostic device 10 may receive various setting data from a host system or the like via the output unit 7 and store the data in the storage unit 8 .

[0090] Thus, according to the present embodiment, the battery voltage is measured after the CPU is reset, and the control unit 4 determines the degradation of the battery 1 based on the available power calculated from the battery voltage, so that the degradation state of the battery 1 can be determined with good accuracy. In addition, the control unit 4 compares the available power of the battery with the threshold value, and outputs an alarm through the output unit 7 when the power related to the residual capacity of the battery 1 is less than the threshold value, so that compared with the past, it is possible to quickly remind the user before the battery life is about to end or when the battery life is close, and it is possible to replace the battery 1 before the battery life is about to end or when the battery life is close. In other words, according to the present embodiment, compared with the past, the battery can be used until the battery life is about to end or when the battery life is close.

[0091] The present disclosure is described based on the drawings and embodiments. However, it is noted that it is easy for a person skilled in the art to make various modifications and variations based on the present disclosure. Therefore, it is noted that these modifications and variations are included in the scope of the present disclosure. For example, the functions included in each structure or each step can be reconfigured in a logically non-contradictory manner, and multiple structures or steps can be combined into one or divided.

[0092] For example, as a first modification, in the degradation determination process, the control unit 4 may determine that the lithium thionyl chloride primary battery 1 is in a degraded state when the power related to the remaining capacity of the battery 1 is less than a threshold value for a predetermined number of consecutive times. Figure 4 This is a flowchart showing the degradation determination process according to the first modification.

[0093] First, the battery diagnosis unit 116 determines whether the power (Pbat) related to the remaining capacity of the battery 1 calculated from the battery voltage is less than a threshold value (step S411). When Pbat is less than the threshold value, the battery diagnosis unit 116 adds 1 to the value of the counter (step S412). The value of the counter indicates the number of times it is detected that the power related to the remaining capacity of the battery 1 is continuously less than the threshold value. For example, the value of the counter indicates the number of times the process of step S412 is continuously performed through the determination in step S411. The counter is stored in the storage unit 8.

[0094] After step S412, the battery diagnosis unit 116 determines whether the counter value is greater than a given number of times (step S414). If the counter value is greater than a given number of times, the process proceeds to step S415. In this case, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is in a degraded state (step S415), and the degradation determination process ends.

[0095] If the counter value is not equal to or greater than the predetermined number in step S414 , the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is not in a degraded state (step S416 ), and the degradation determination process ends.

[0096] If Pbat is smaller than the threshold value in step S411, the battery diagnosis unit 116 resets the counter value (step S413). Then, the battery diagnosis unit 116 determines that the battery 1 is not in a degraded state (step S416), and the degradation determination process ends.

[0097] In this way, the control unit 4 compares the power that can be supplied by the battery with the threshold value, and when the power related to the remaining capacity of the battery 1 is less than the threshold value for a given number of consecutive times, the output unit 7 outputs an alarm. Therefore, the user can be quickly reminded before the battery life is about to end, and the lithium thionyl chloride primary battery 1 can be replaced before the battery life is about to end or when the battery life is close.

[0098] In addition, for example, as a second variation, in the degradation judgment process, the control unit 4 can also make a refresh current flow to try to recover when the power related to the residual capacity of the battery 1 is less than a threshold, and then judge the degradation state of the battery 1 again based on the calculated power. Generally, the battery 1 has an internal resistance, and the internal resistance increases with degradation. In a new battery, the internal resistance is also easy to increase due to environmental conditions (extremely high and low temperatures and rapid temperature changes) when it has not been used for a long time (a state where current does not flow). If the battery 1 has a sufficient amount of charge, it is known that the protective film accumulated inside the battery 1 and the internal resistance can be destroyed by forcibly flowing a current (refresh current) from the battery 1 to discharge. Therefore, after the battery 1 is once judged to be in a degraded state, it is possible to perform a forced discharge, perform a diagnosis again, and make a final degradation judgment. Figure 5 This is a flowchart showing the degradation determination process according to the second modification.

[0099] First, the battery diagnosis unit 116 determines whether the power (Pbat) related to the residual capacity of the battery 1 calculated from the battery voltage is less than a threshold value (step S421). If Pbat is less than the threshold value, the battery diagnosis unit 116 temporarily determines that the battery 1 is in a degraded state (step S422). On the other hand, if Pbat is not less than the threshold value, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is not in a degraded state (step S423), and the degradation determination process ends.

[0100] After step S422, the control unit 4 allows the refresh current to flow through the lithium thionyl chloride primary battery 1 (step S424). Next, after stopping the refresh current, the control unit 4 measures the battery voltage and calculates the power that can be supplied (step S425). Specifically, the discharge current control unit 113 uses, for example, a circuit (not shown) through which the refresh current flows to flow through the refresh current to flow through the refresh current, and after the refresh current flows through the refresh current, the discharge switch 32 of the load current circuit 3 is switched to be turned on. In addition, the circuit through which the refresh current flows can also use the load current circuit 3. Through this control, the control unit 4 measures the battery voltage of the lithium thionyl chloride primary battery 1 when there is a load after the refresh current flows through the refresh current. The AD conversion unit 111 converts the analog data of the battery voltage into digital data and transmits the digital data to the counting unit 112. The counting unit 112 calculates the power related to the residual capacity from the lithium thionyl chloride primary battery 1 based on the digital data transmitted from the AD conversion unit 111. The calculation of the power is performed by the above-mentioned formula (1).

[0101] Next, the battery diagnosis unit 116 determines whether the power (Pbat) related to the remaining capacity of the battery 1 calculated from the battery voltage is less than a threshold value (step S426). If Pbat is less than the threshold value, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is in a degraded state (step S427), and the degradation determination process ends. On the other hand, if Pbat is not less than the threshold value, the battery diagnosis unit 116 determines that the lithium thionyl chloride primary battery 1 is not in a degraded state (step S423), and the degradation determination process ends.

[0102] In this way, the control unit 4 calculates the power related to the residual capacity of the lithium thionyl chloride primary battery 1 from the battery voltage at the time point after the refresh current flows through the battery after the CPU is reset, and performs a degradation judgment after attempting to restore the lithium thionyl chloride primary battery 1. By setting it in this way, the degradation state of the lithium thionyl chloride primary battery 1 can be judged with further good accuracy. In addition, by passing the refresh current, removing the protective film accumulated inside the battery to reduce the internal resistance, and attempting to restore the battery 1, the life of the battery 1 can be extended.

[0103] In addition, a limit may be set for the number of times the refresh current flows and the diagnosis process is performed again. Specifically, the control unit 4 counts the number of times the refresh current flows, and when the number of times the refresh current flows reaches a certain number, the control unit 4 may determine that the lithium thionyl chloride primary battery 1 is in a degraded state without attempting to recover after temporarily determining that it is in a degraded state.

[0104] In addition, as a third modification, in Figures 1 to 4In the embodiment, for example, the control unit 4 can also transfer the operation mode of the device from the normal operation mode to the power saving mode when it is determined that the battery 1 is in a degraded state. For example, the so-called normal operation mode refers to an operation mode in which all functions of the device are operated; the so-called power saving mode refers to an operation mode in which only a part of the functions of the device are operated and other functions are stopped. The replacement of the battery 1 in a degraded state may not be implemented immediately. Therefore, when the battery 1 becomes degraded, the control to transfer to the power saving mode can be performed, which can extend the life of the battery until replacement. The function that is stopped in the power saving mode can also be a wireless communication function. For example, after the output unit 7 outputs an alarm through wireless communication, the control unit 4 stops the normal communication (for example, the transmission of the output value of the sensor, etc.). In this way, the power consumption of the device can be suppressed. In addition, the function that is stopped in the power saving mode can also be a measurement function. For example, the control unit 4 can also change the temperature measurement cycle of the temperature measurement unit 115. When the measurement unit performs normal operation in a 10-minute cycle, for example, the control unit 4 can also change the cycle to a 24-hour cycle. In this way, the control unit 4 can suppress power by changing the operation cycle of the measurement unit. Furthermore, the functions that are restricted in the power saving mode are not limited to the communication function and the measurement function, and any other functions that the device has may be restricted.

[0105] In addition, as a fourth modification, in Figures 1 to 4 For example, the threshold level of power used in the degradation judgment of the battery 1 may be set to multiple levels. Specifically, the control unit 4 may set multiple thresholds as multiple threshold levels, compare the multiple thresholds with the power related to the residual capacity of the battery 1, and classify the degree of degradation of the battery 1. In addition, the control unit 4 may limit the functions that can be used according to the degree of degradation of the battery 1. In other words, the control unit 4 may classify the degree of degradation of the battery 1 by comparing the power related to the residual capacity of the battery 1 with multiple threshold levels, and change the operation mode of the device according to the degree of degradation. The power used by each part of the device is different. For example, it is assumed that the power consumed by the wireless communication unit, the measurement unit, and the storage unit is 50mW, 30mW, and 10mW respectively. In this case, by setting three levels of thresholds corresponding to these power consumptions, the control unit 4 classifies the degree of degradation of the battery 1 corresponding to each threshold in stages, and as a change in the operation mode, only the unusable functions are stopped according to each level, thereby enabling control to temporarily continue the operation of the device. Thus, the control unit 4 switches the operation mode of the device according to the degree of battery degradation and suppresses power consumption, thereby making effective use of the remaining capacity of the battery 1 according to the degree of degradation. For example, when the remaining capacity is less than 50mW, the function of the wireless communication unit is stopped.

[0106] In addition, as a fifth modification, in Figures 1 to 4 In the third to fourth modified examples, for example, the control unit 4 may also measure the voltage of the battery (hereinafter referred to as the open circuit voltage) while keeping the switch of the load current circuit 3 disconnected when judging the degradation of the battery 1, and make a degradation judgment based on the open circuit voltage. In other words, the control unit 4 may also make a degradation judgment of the battery 1 based on the power related to the residual capacity of the battery 1 and the open circuit voltage. For example, the open circuit voltage of the battery 1 is measured, and if the open circuit voltage is below the threshold level, the control unit 4 may also output an alarm through the output unit 7 to notify that the power related to the residual capacity of the battery 1 is above the threshold but is close to the life of the battery 1. In this way, by also using the open circuit voltage of the battery 1 to judge the degradation of the battery 1, the degradation state of the battery 1 can be judged with further good accuracy.

[0107] Furthermore, as a sixth modification, in Figures 1 to 4 In the third to fifth variants, for example, the control unit 4 may also predict the trend of power reduction by periodically measuring power, and use it as a criterion for determining the deterioration of the battery 1. Figure 2 Before the degradation determination process of step S400 shown, it is determined whether to perform degradation determination process based on the trend of power decrease. By setting it in this way, it is possible to perform diagnosis combined with changes over time. For example, it is known that the power measurement values ​​of new batteries and used batteries are different, and when the degradation continues to progress, they are close to the determination value. In the case where such changes are not observed, the influence caused by rapid environmental changes, user's operational errors, etc. is also considered. In this case, the control unit 4 can also skip the degradation determination of the battery 1 in order to prevent insufficient consideration of changes over time. In other words, the control unit 4 can also determine whether to perform degradation determination of the battery 1 based on the change of power related to the residual capacity of the battery 1 measured regularly. In this way, by using the trend of power related to the residual capacity of the battery 1 to determine whether to perform degradation determination of the battery 1, it is possible to prevent insufficient consideration of changes over time of the battery 1. In addition, the control unit 4 can also output an alarm based on the trend from the output unit 7 to urge battery replacement in advance. In addition, the control unit 4 can also save the changes over time estimated from the trend to the storage unit 8.

[0108] In addition, as a seventh modification, in Figures 1 to 4In the third to sixth variants, for example, when a sudden temperature change occurs, there is a possibility that the power of the battery 1 will temporarily decrease. Therefore, when a sudden temperature change is detected, the control unit 4 may not make a degradation determination and ignore it in order to prevent insufficient consideration of the temperature change. In other words, the control unit 4 may also decide whether to make a degradation determination based on the ambient temperature of the battery 1. Specifically, the control unit 4 may also Figure 2 Before the degradation determination process of step S400 shown, whether or not to perform degradation determination process is to be performed is determined based on the ambient temperature of battery 1. In this way, by using the ambient temperature of battery 1 to determine whether or not to perform degradation determination of battery 1, insufficient consideration of temperature changes can be prevented. In addition, for example, the control unit 4 may also pass without performing degradation determination when environmental conditions (such as temperature, vibration, etc.) that exceed the specification range of the product occur. In addition, when this state is detected, the control unit 4 may also output an alarm to the effect that the environmental conditions exceed the usage range through the output unit 7.

Claims

1. A battery diagnostic device, wherein: have: The constant voltage circuit part converts the battery voltage into a given voltage and uses it as the power supply voltage; Discharge resistor; a power supply monitoring unit for detecting a decrease in the power supply voltage and a state where the power supply voltage becomes higher than a given voltage; and The control unit performs a CPU reset when detecting a drop in the power supply voltage and when detecting that the power supply voltage becomes higher than a given voltage. When the CPU reset is caused by the drop in the power supply voltage, the control unit measures the battery voltage, calculates the power related to the remaining capacity of the battery based on the battery voltage and the resistance value of the discharge resistor, and determines that the battery is in a deteriorated state when the power related to the remaining capacity of the battery is less than a threshold value related to the given power. The battery voltage is measured during a predetermined period after the CPU is reset due to a drop in power supply voltage, the predetermined period being a period from the restart of the control unit to the normal startup of the device.

2. The battery diagnostic device according to claim 1, wherein: The battery diagnosis device includes an output unit that outputs an alarm when the battery is determined to be in a degraded state.

3. The battery diagnostic device according to claim 1, wherein: The control unit determines that the battery is in a deteriorated state when a situation in which the power related to the remaining capacity of the battery is less than a threshold value occurs continuously for a given number of times.

4. The battery diagnosis device according to any one of claims 1 to 3, wherein: The battery is a lithium thionyl chloride primary battery, When the power related to the remaining capacity of the battery is less than the threshold, or when the power related to the remaining capacity of the battery is less than the threshold for a given number of consecutive times, the control unit makes a degradation judgment based on the power recalculated at the battery voltage measured after the refresh current flows.

5. The battery diagnostic device according to any one of claims 1 to 3, wherein: The control unit shifts the operation mode of the device to a power saving mode when determining that the battery is in a degraded state.

6. The battery diagnostic device according to any one of claims 1 to 3, wherein: The control unit compares the power related to the remaining capacity of the battery with a plurality of threshold levels, classifies the degree of degradation of the battery into levels, and changes the operation mode of the device according to the degree of degradation.

7. The battery diagnostic device according to any one of claims 1 to 3, wherein: The control unit further performs the degradation determination based on an open circuit voltage of the battery.

8. The battery diagnostic device according to any one of claims 1 to 3, wherein: The control unit further determines whether to perform the degradation determination based on a change in electric power related to a residual capacity of the battery measured periodically.

9. The battery diagnostic device according to any one of claims 1 to 3, wherein: The control unit further determines whether to perform the degradation determination based on the ambient temperature of the battery.

10. A battery diagnosis method, in, include: Convert the battery voltage into a given voltage and use it as a step of the power supply voltage; A step of detecting a decrease in the power supply voltage and a state where the power supply voltage becomes higher than a given voltage; A step of resetting the CPU when a drop in the power supply voltage is detected and when the power supply voltage is detected to be above a given voltage, and when the CPU reset is caused by the drop in the power supply voltage, measuring the battery voltage and calculating the power related to the remaining capacity of the battery based on the battery voltage and the resistance value of the discharge resistor; and The step of determining that the battery is in a deteriorated state when the power related to the remaining capacity of the battery is less than a threshold value related to a predetermined power, The battery voltage is measured during a predetermined period after the CPU is reset due to a drop in power supply voltage, the predetermined period being a period from the restart of the control unit to the normal startup of the device.

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