Downhole high-temperature lithium battery capacity monitoring circuit and method

Abstract

The invention discloses an underground high-temperature lithium battery capacity monitoring circuit and method, and belongs to the technical field of petroleum and natural gas exploration and development, and the underground high-temperature lithium battery capacity monitoring circuit comprises an MCU chip, an EEPROM memory, an NANDFLASH chip, a CAN driving chip, an ADC module, an onboard temperature chip and a power supply module. According to the invention, temperature protection and current protection functions are added, battery explosion caused by over-current and over-temperature of the battery can be effectively prevented, underground instruments are protected, and battery accidents are reduced. According to the invention, capacity monitoring and automatic current and temperature protection during drilling-tool-passing, direct-push-type and while-drilling instrument cable-free logging are realized, and battery explosion accidents are reduced; use records are provided for battery use, battery use big data are gradually established, data support is provided for battery use, battery waste is reduced, and the battery use efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, and in particular to an underground high-temperature lithium battery capacity monitoring circuit and method. Background Art

[0002] There are many types of logging instruments on the market, with outer diameters ranging from 20mm to 172mm, temperature series from 155℃ to 230℃, and pressure indicators from 100MPa to 180MPa. Different series of instruments are divided into cable logging and cableless logging. The former uses ground power supply, and supplies power to downhole instruments in the form of AC or DC through cables of 5000m to 7000m, or even more than 10,000m; the latter uses downhole batteries and downhole mud generators to power downhole instruments.

[0003] The temperature of downhole instruments rises by more than 30°C for every 1,000-meter increase in ambient temperature. The deeper the well goes, the higher the temperature will be. The entire industry at home and abroad currently uses lithium batteries or lithium polymer batteries with good temperature performance, large capacity and stable voltage output. Currently, logging while drilling, through-hole logging and direct-push logging all use this type of battery to power downhole instruments. As the logging depth increases, the temperature limit of the battery is difficult to meet the temperature at the depth of the well, and lithium batteries will experience over-temperature and over-current explosion accidents. In order to better solve the problem of excessive temperature use, a thermos bottle + battery is generally used to ensure that the battery temperature does not exceed the battery limit temperature within the rated working time.

[0004] From the perspective of battery use, after battery logging is completed, there is currently no equipment or means that can directly and accurately detect the battery capacity, and the user cannot be informed of the remaining battery capacity and usage records. As a result, the user dare not easily use the battery for re-logging to avoid the situation where insufficient power is required during the re-use process and the logging is delayed. This way of using batteries has great uncertainty and waste, and a means and method for battery capacity detection is urgently needed.

[0005] Due to the voltage output characteristics of lithium batteries, it is impossible to detect the remaining capacity from the output voltage of lithium batteries alone, because there is no linear relationship between battery capacity and output voltage and current, and it is impossible to accurately calibrate, so the battery capacity can only be indirectly detected by battery monitoring methods. Before leaving the factory, battery manufacturers will perform temperature tests and discharge tests on batteries to detect and calculate the factory capacity of this model of battery; if the battery's operating temperature, voltage, and current can be recorded in real time during the use of the battery underground, the battery's usage capacity can be calculated in real time. After the well logging is completed, the value is read, and then based on the battery's factory capacity, a more accurate remaining capacity can be easily obtained. The on-site operation engineer can determine whether the battery can meet the next well logging requirements based on the remaining capacity, the operation time of the next well, and the operating power.

[0006] In summary, in the prior art, logging instruments cannot record parameters such as the output voltage, current, and temperature of the battery in real time, store the parameters in real time, and cannot determine whether the battery temperature may cause a battery explosion accident and damage downhole instruments. Summary of the Invention

[0007] To solve the problems existing in the prior art, the present invention provides a downhole high-temperature lithium battery capacity monitoring circuit and method to solve the problems in the background technology. The present invention realizes capacity monitoring, automatic current and temperature protection during non-cabled logging of through-drill string, direct-push type, and logging-while-drilling instruments, reducing the occurrence of battery explosion accidents; it also provides usage records for battery use, gradually establishing big data on battery use, providing data support for battery use, reducing battery waste, and improving battery use efficiency.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A downhole high-temperature lithium battery capacity monitoring circuit includes an MCU chip, an EEPROM memory, a NAND Flash chip, a CAN driver chip, an ADC module, an on-board temperature chip, and a power supply module;

[0010] The MCU chip is respectively connected for data interaction with the EEPROM memory, the on-board temperature chip, the NAND Flash chip, and the CAN driver chip; the EEPROM memory is used to store the usage environment and initialization information of this capacity monitoring circuit; the on-board temperature chip is used to measure the temperature of the circuit board in real time; the NAND Flash chip is used to realize the real-time storage of measurement data and capacity calculation data for battery capacity monitoring; the CAN driver chip is used to receive and send commands and data; the CAN driver chip is connected to the instrument bus;

[0011] The MCU chip is connected to a battery current switch switching module; the battery current switch switching module is used for current threshold, voltage threshold, and temperature threshold protection;

[0012] The MCU chip performs data interaction with an analog signal conditioning circuit through the ADC module; the analog signal conditioning circuit includes a battery temperature conditioning circuit, a battery voltage conditioning circuit, and a battery current conditioning circuit; the battery temperature conditioning circuit is used to condition the output signal of the battery temperature sensor into a signal suitable for acquisition by the ADC module; the battery voltage conditioning circuit is used to condition the battery output voltage signal into a signal suitable for acquisition by the ADC module; the battery current conditioning circuit is used to condition the battery output current signal into a signal suitable for acquisition by the ADC module;

[0013] The power supply module is used for power supply.

[0014] Preferably, the battery temperature signal conditioning includes a three-wire thermocouple battery temperature sensor, the three-wire thermocouple battery temperature sensor is connected to a bridge circuit, the bridge circuit is connected to an instrument amplifier circuit, the instrument amplifier circuit is connected to a low-pass filter circuit; the low-pass filter circuit is connected to a corresponding channel of the ADC module;

[0015] The temperature data collected by the three-wire thermocouple battery temperature sensor is converted into a pressure difference signal through a bridge circuit, sent to the instrument amplifier circuit, and then sent to the corresponding channel of the ADC module after low-pass filtering.

[0016] Preferably, the battery output voltage conditioning circuit connects a voltage-dividing resistor network in parallel to the battery output terminal, draws out a voltage signal, and then passes it through an instrument amplifier and a low-pass filter before sending it to a corresponding channel of the ADC module.

[0017] Preferably, the battery output current conditioning circuit connects a current sampling resistor in series with the negative terminal of the battery output, draws a voltage sampling signal from both ends of the sampling resistor, and then passes through an instrument amplifier and a low-pass filter and is sent to a corresponding channel of the ADC module.

[0018] Preferably, the voltage conditioning circuit of the power module draws out a power supply voltage monitoring signal by connecting a voltage-dividing resistor in parallel to the output end of the power module, and sends the signal to the corresponding channel of the ADC module after passing through an instrument amplifier and low-pass filtering.

[0019] Preferably, the MCU chip controls the JFET tube through the isolation driver chip, and the JFET tube is in a normally open state, and is used for switching the battery output during current protection, voltage protection, and temperature protection of the battery.

[0020] A method for monitoring the capacity of a high-temperature lithium battery underground includes the following steps:

[0021] After the circuit is powered on, it performs command detection to determine whether there is a command. If there is no command, it starts to read the last storage state in the FLash, and then the timer starts ADC sampling. After sampling, it performs threshold judgment. When the voltage threshold, current threshold, and battery temperature threshold exceed the threshold, the battery output is turned off; under normal circumstances, the battery capacity continues to be calculated, and the data is packaged and written into the FLash;

[0022] When the circuit is powered on and there is a timing command, the circuit is timed by GPS and the latest time information is written into the timing chip. The timing chip uses this time as the starting point and is used as the start time of the underground circuit operation.

[0023] When the circuit is powered on, if there is a read / erase FLASH command, the read / erase storage data operation is performed, which is used to read the storage capacity data of the battery capacity and the battery process monitoring data after the logging instrument completes the logging.

[0024] Preferably, when the timing chip is timed according to the timing command and the time counting starts, the MCU timer method is used to store the time information in a double backup.

[0025] Preferably, the set thresholds of the battery output voltage, battery output current, and battery temperature are judged in real time. When any one of the thresholds is exceeded, the MCU chip turns off the JFET to disconnect the battery output current.

[0026] Preferably, the battery capacity calculation formula is:

[0027] Battery capacity 1: mAh i = [I i × (t i - t i-1 ) / 60] + mAh i-1 ;

[0028] Battery capacity 2: mWh i = [U i × I i × (t i - t i-1 ) / 60] + mWh i-1 ;

[0029] In the formula: mAh i is the battery consumption capacity in the current cycle, unit mAh;

[0030] I i is the measured value of the battery output current in the current cycle, unit A;

[0031] t i is the current cycle time, unit min;

[0032] t i-1 is the time of the previous cycle of the current time, unit min;

[0033] mAh i-1 is the battery output consumption capacity of the previous cycle time of the current time, unit mAh;

[0034] mWh i is another expression of the battery consumption capacity in the current cycle, unit mWh;

[0035] U i is the measured value of the battery output voltage in the current cycle, unit V;

[0036] mWh i-1 is another expression of the battery consumption capacity of the previous cycle time of the current time, unit mWh.

[0037] Compared with the prior art, the present invention has the following beneficial technical effects:

[0038] The present invention provides a downhole high-temperature lithium battery capacity monitoring circuit, which can record the output voltage, current, and temperature during the operation of the high-temperature downhole battery in real time, realizes real-time monitoring and storage of the battery capacity, provides a usage record for the battery, gradually establishes big data on battery usage, provides data support for battery usage, reduces battery waste, and improves battery usage efficiency; after adding the present invention to the cableless logging tool, it can realize the functions of real-time recording and storage of the battery output voltage, current, and temperature parameters; after adding the present invention to the cableless logging tool, it can realize real-time calculation and storage of the battery capacity; after adding the present invention to the cableless logging tool, it can realize battery current protection and temperature protection to ensure logging safety; the present invention adds temperature protection and current protection functions, which can effectively prevent battery explosion caused by overcurrent and overheating of the battery, protect downhole instruments, and reduce the occurrence of battery accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a hardware block diagram of the battery capacity monitoring circuit.

[0040] Figure 2 It is a hardware block diagram of the analog signal conditioning circuit.

[0041] Figure 3 It is a hardware block diagram of the battery current switch switching module.

[0042] Figure 4 It is a schematic diagram of the installation of the battery case temperature probe.

[0043] Figure 5 It is a schematic diagram of the stored data format.

[0044] Figure 6 It is a flowchart of the battery capacity monitoring method. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The following further elaborates on the present invention in detail with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0046] The present invention proposes a downhole high-temperature lithium battery capacity monitoring circuit that can be realized, including hardware such as an MCU chip, EEPROM, NAND FLASH chip, CAN driver chip, ADC, on-board temperature chip, battery temperature conditioning circuit, voltage conditioning circuit, current conditioning circuit, power supply module, and power supply monitoring circuit, as well as a supporting software development module.

[0047] The MCU chip is respectively connected for data interaction with the EEPROM memory, the on-board temperature chip, the NAND Flash chip, and the CAN driver chip; the EEPROM memory is used to store the usage environment and initialization information of this capacity monitoring circuit; the on-board temperature chip is used to measure the temperature of the circuit board in real time; the NAND Flash chip is used to realize the real-time storage of the measurement data and capacity calculation data for battery capacity monitoring; the CAN driver chip is used to receive and send commands and data; the CAN driver chip is connected to the instrument bus;

[0048] The MCU chip is connected to the battery current switch and switching module; the battery current switch and switching module is used for current threshold, voltage threshold, and temperature threshold protection;

[0049] The MCU chip conducts data interaction with the analog signal conditioning circuit through the ADC module; the analog signal conditioning circuit includes a battery temperature conditioning circuit, a battery voltage conditioning circuit, and a battery current conditioning circuit; the battery temperature conditioning circuit is used to condition the output signal of the battery temperature sensor into a signal suitable for acquisition by the ADC module; the battery voltage conditioning circuit is used to condition the output voltage signal of the battery into a signal suitable for acquisition by the ADC module; the battery current conditioning circuit is used to condition the output current signal of the battery into a signal suitable for acquisition by the ADC module; the power supply module is used for power supply.

[0050] In the above solution, the MCU chip, as the main control chip, completes all control functions for battery capacity monitoring, mainly including: 1) Communication, mainly including receiving CAN commands, decoding the commands, and being responsible for receiving and sending commands and data; 2) Acquisition, mainly including controlling the ADC to acquire voltage, current, board temperature, battery temperature, and voltage monitoring data; 3) Storage and reading, mainly including storing the acquired data according to the protocol and reading the stored data according to requirements; 4) Calculation, calculating the battery capacity in real time based on the acquired data to realize battery capacity monitoring; 5) Shutting down the battery output according to the voltage, current, and temperature monitoring data to protect the battery; 6) Timing the timing chip according to the timing command and starting timekeeping; for time safety, the MCU timer method is used to perform double backup of the time.

[0051] In the above solution, the high-temperature EEPROM chip is used to store the usage environment and initialization information of this capacity monitoring circuit, mainly including parameters such as the set operating voltage value of this instrument, the battery current protection threshold, the battery temperature protection threshold, factory parameters, and FLASH storage status, etc.;

[0052] In the above solution, the high-temperature NAND Flash chip is used to achieve real-time storage of the measurement data and capacity calculation data for battery capacity monitoring. It is readable and writable, and has power-off data protection, capable of saving the last state of battery use; it is used to achieve 1) querying the storage status of the NAND Flash, whether there are bad blocks, the block addresses, page addresses, and byte addresses occupied by data; 2) writing the collected data and the real-time capacity value calculated and packed according to the protocol into the storage space after the specified starting address of the NAND Flash;

[0053] 3) sequentially reading the data in the specified starting address and ending address of the NAND Flash according to the read protocol; 4) performing an erase operation on the data in the NAND Flash in units of blocks;

[0054] In the above solution, the high-temperature CAN driver chip and the software development module are used to achieve receiving and sending commands and data, and to realize communication and level isolation conversion with the instrument bus;

[0055] In the above solution, the high-temperature ADC chip and the software development module are used to collect data such as battery output voltage, current, board temperature, battery temperature, and voltage monitoring;

[0056] In the above solution, the board temperature chip and the software development module are used to measure the temperature of the circuit board in real time;

[0057] In the above solution, the battery temperature conditioning circuit is used to condition the output signal of the battery temperature sensor into a signal suitable for ADC acquisition;

[0058] In the above solution, the voltage conditioning circuit is used to condition the battery output voltage signal into a signal suitable for ADC acquisition;

[0059] In the above solution, the current conditioning circuit is used to condition the battery output current signal into a signal suitable for ADC acquisition;

[0060] In the above solution, the power supply module and the power supply monitoring circuit are used to provide all the power requirements of the circuit of the present invention, supply power to the MCU, ADC, and conditioning circuit, and take the power supply voltage as a monitoring parameter for ADC acquisition.

[0061] The battery status data acquisition hardware and the supporting software can monitor and collect status information such as battery output voltage, output current, battery temperature, board temperature, and power supply output voltage in real time, and some of the data can be used for battery capacity calculation.

[0062] The present invention can record the output voltage, current, and temperature during the operation of a high-temperature downhole battery in real time, realizes real-time monitoring and storage of the battery capacity, provides usage records for battery use, gradually establishes big data on battery use, provides data support for battery use, reduces battery waste, and improves battery use efficiency.

[0063] The present invention adds temperature protection and current protection functions, can effectively prevent battery explosion caused by overcurrent and over-temperature of the battery, protects downhole instruments, and reduces the occurrence of battery accidents. After adding the present invention to a wireline logging tool, it can realize the functions of real-time parameter recording and storage of the battery output voltage, current, and temperature; after adding the present invention to a wireline logging tool, it can realize real-time battery capacity calculation and storage; after adding the present invention to a wireline logging tool, it can realize battery current protection and temperature protection to ensure logging safety.

[0064] The present invention truly realizes capacity monitoring, automatic current and temperature protection during wireline logging with through-drill-string, direct-push, and logging-while-drilling tools, reduces the occurrence of battery explosion accidents; also provides usage records for battery use, gradually establishes big data on battery use, provides data support for battery use, reduces battery waste, and improves battery use efficiency.

[0065] Embodiment

[0066] For wireline logging tools, high-temperature batteries are essential and consumable. The annual output value of the domestic high-temperature downhole lithium battery industry alone is in the hundreds of millions. So far, the capacity monitoring and detection of downhole high-temperature lithium batteries have not been applied and promoted. The on-site construction and the handling of high-temperature batteries still rely on experience to decide whether to continue using or scrap the battery or for the manufacturer to recycle, lacking effective battery capacity detection and monitoring means.

[0067] The basic requirements for downhole high-temperature battery capacity monitoring include the acquisition and calculation of output voltage, current, and battery temperature. After expanding the functions, overcurrent and over-temperature protection functions of the battery can be realized.

[0068] As Figure 1 shown is the hardware block diagram of the battery capacity monitoring circuit. The part in the left dashed box is the digital signal control circuit, and the part in the right dashed box is the analog signal conditioning circuit.

[0069] The EEPROM is used to store the usage environment and initialization information of this capacity monitoring circuit, mainly including parameter information such as the set operating voltage value of the instrument, the battery current protection threshold, the battery temperature protection threshold, the factory parameters, and the FLASH storage status, etc.; the on-board temperature chip is used for the digital thermometer to measure the real-time temperature of the circuit board; the CAN driver and software development module are used to receive and send commands and data, and realize communication and level isolation conversion with the instrument bus; the NAND FLASH storage is used to realize the real-time storage of the measurement data and capacity calculation data for battery capacity monitoring, which is readable and writable. Reading the stored data of the previous state is for calculating the battery capacity of this cycle; the timing chip is used to read and write the time information of the current state; the battery current switch switching module is used for battery temperature and current protection, and can realize current threshold, voltage threshold, and temperature threshold protection. Among them, voltage protection means that during the battery discharge process, the capacity becomes lower and lower, which will cause the battery output voltage value to become lower and lower. The voltage threshold will cause the power supply module to work abnormally. It is necessary to ensure that the output voltage can meet the working conditions of the power supply module, otherwise the entire circuit board will work abnormally and data will be lost; the ADC module is used to collect power supply voltage monitoring, battery output voltage, battery output current, and battery temperature signals; the power supply module is powered from the battery output and is converted into the power supply voltage required by this invention's circuit board.

[0070] As Figure 2 Shown is the hardware block diagram of the analog signal conditioning circuit, which mainly includes four parts of conditioning circuits. The battery temperature signal conditioning includes a three-wire thermocouple battery temperature sensor, which is converted into a differential pressure signal through a bridge circuit, sent to an instrumentation op-amp, and then sent to the corresponding ADC channel after low-pass filtering; the battery output voltage conditioning circuit includes a parallel voltage-dividing resistor network at the battery output terminal. After leading out the voltage signal, it is sent to the corresponding ADC channel after passing through an instrumentation op-amp and low-pass filtering; the battery output current conditioning circuit uses a series form to connect a current sampling resistor in series at the negative terminal of the battery output. The voltage sampling signal is led out from both ends of the sampling resistor and sent to the corresponding ADC acquisition channel after passing through an instrumentation op-amp and low-pass filtering; the power supply module voltage conditioning circuit is used to connect a parallel voltage-dividing resistor at the output terminal of the power supply module, lead out the power supply voltage monitoring signal, and send it to the corresponding ADC acquisition channel after passing through an instrumentation op-amp and low-pass filtering.

[0071] As Figure 3 Shown is the hardware block diagram of the battery current switch switching module, where the MCU is the main control MCU chip of this invention. It controls the JFET transistor through an isolation driver chip, and the JFET transistor is in a normally open state. This circuit is mainly used for switching the battery output during battery current protection, voltage protection, and temperature protection.

[0072] It should be noted that the downhole battery actually refers to a battery pack, which is composed of high-temperature lithium batteries connected in series one by one to form a downhole high-temperature battery. In this invention, the word "battery" specifically refers to the battery pack in this figure.

[0073] As shown Figure 4 in the schematic diagram of the installation of the temperature probe on the battery case, where Battery 1, Battery 2, Battery n-1, and Battery n refer to the battery pack composed of n single batteries connected in series for the downhole high-temperature battery; the PT100 thermocouple is the thermocouple attached to the battery case, and the three-wire thermocouple lead is used as the battery temperature probe.

[0074] As shown Figure 5 in the stored data format, where the time is the year, month, day, hour, minute, and second after the time is set; the counting time refers to the timing generated by the MCU itself, which is used as a double backup of the time tag, mainly to prevent time errors caused by the time of the time-setting chip due to battery shutdown; the battery voltage is the battery output voltage value; the battery current is the battery output current value; Capacity 1 is a way of expressing the battery capacity, with the unit of mAh; Capacity 2 is another way of expressing the battery capacity, with the unit of mWh; the power supply monitoring is the voltage measurement value of the power supply module; the on-board temperature is the temperature measurement value of the circuit board; the battery temperature is the monitoring value of the lithium battery case.

[0075] As shown Figure 6 in the software flow chart of the battery capacity monitoring. After the circuit is powered on, command detection is performed to determine whether there is a start time-setting command or a read / erase FLASH command. The former is mainly used to perform GPS time setting on the circuit and write the latest time information into the time-setting chip. The time-setting chip uses this time as the starting time for timing, which is used as the starting timing time for the downhole circuit to work. The latter is mainly used to read the stored capacity data of the battery capacity and the battery process monitoring data after the logging instrument finishes logging; after normal operation, start to read the last storage state in the FLash, then start the ADC sampling by the timer, and after sampling, perform threshold judgment. When the voltage threshold, current threshold, and battery temperature threshold exceed the threshold, the battery output is turned off; under normal circumstances, continue to calculate the battery capacity and pack the data for writing into the FLash.

[0076] The calculation formula for the battery capacity is as follows:

[0077] Battery Capacity 1: mAh i =|I i ×(t i -t i-1 ) / 60]+mAh i-1

[0078] Battery Capacity 2: mWh 1 =[U i ×I i ×(t i -t i-1 ) / 60]+mWh i-1

[0079] mAh i Is the battery consumption capacity for the current cycle, unit mAh

[0080] I i Is the measured value of the battery output current for the current cycle, unit A

[0081] t i Is the time for the current cycle, unit min

[0082] t i-1 Is the time of the previous cycle of the current time, unit min

[0083] mAh i-1 Is the battery output consumption capacity of the previous cycle of the current time, unit mAh

[0084] mWh i Is another expression of the battery consumption capacity for the current cycle, unit mWh

[0085] U i Is the measured value of the battery output voltage for the current cycle, unit V

[0086] mWh i-1 Is another expression of the battery consumption capacity of the previous cycle of the current time, unit mWh

[0087] It should be noted that the MCU stores capacity data in units of min, and the ADC also outputs the sampling average value in units of min.

Claims

1. An underground high-temperature lithium battery capacity monitoring circuit, characterized in that, it includes an MCU chip, an EEPROM memory, a NAND FLASH chip, a CAN driver chip, an ADC module, an on-board temperature chip and a power supply module; the MCU chip is respectively connected for data interaction with the EEPROM memory, the on-board temperature chip, the NAND FLASH chip and the CAN driver chip; the EEPROM memory is used to store the usage environment and initialization information of this capacity monitoring circuit; the on-board temperature chip is used to measure the temperature of the circuit board in real time; the NAND FLASH chip is used to realize the real-time storage of the measurement data and capacity calculation data for battery capacity monitoring; the CAN driver chip is used to receive and send commands and data; the CAN driver chip is connected to the instrument bus; the MCU chip is connected to the battery current switch switching module; the battery current switch switching module is used for current threshold, voltage threshold and temperature threshold protection; the MCU chip conducts data interaction with the analog signal conditioning circuit through the ADC module; the analog signal conditioning circuit includes a battery temperature conditioning circuit, a battery voltage conditioning circuit and a battery current conditioning circuit; the battery temperature conditioning circuit is used to condition the output signal of the battery temperature sensor into a signal suitable for acquisition by the ADC module; the battery voltage conditioning circuit is used to condition the battery output voltage signal into a signal suitable for acquisition by the ADC module; the battery current conditioning circuit is used to condition the battery output current signal into a signal suitable for acquisition by the ADC module; the power supply module is used for power supply.

2. The underground high-temperature lithium battery capacity monitoring circuit according to claim 1, characterized in that, the battery temperature signal conditioning includes a three-wire thermocouple battery temperature sensor, the three-wire thermocouple battery temperature sensor is connected to a bridge circuit, the bridge circuit is connected to an instrumentation amplifier circuit, and the instrumentation amplifier circuit is connected to a low-pass filter circuit; the low-pass filter circuit is connected to the corresponding channel of the ADC module; the temperature data collected by the three-wire thermocouple battery temperature sensor is converted into a differential pressure signal through the bridge circuit, sent to the instrumentation amplifier circuit, and then sent to the corresponding channel of the ADC module after low-pass filtering.

3. The underground high-temperature lithium battery capacity monitoring circuit according to claim 1, characterized in that, the battery output voltage conditioning circuit leads out a voltage signal through a parallel voltage dividing resistor network from the battery output terminal, and after passing through an instrumentation amplifier and a low-pass filter, it is sent to the corresponding channel of the ADC module.

4. The underground high-temperature lithium battery capacity monitoring circuit according to claim 1, characterized in that, the battery output current conditioning circuit adopts a series form to serially connect a current sampling resistor from the negative terminal of the battery output, and leads out a voltage sampling signal from both ends of the sampling resistor, and after passing through an instrumentation amplifier and a low-pass filter, it is sent to the corresponding channel of the ADC module.

5. The underground high-temperature lithium battery capacity monitoring circuit according to claim 1, characterized in that, The voltage conditioning circuit of the power supply module extracts the power supply voltage monitoring signal by paralleling a voltage-dividing resistor at the output end of the power supply module, and after passing through an instrumentation operational amplifier and a low-pass filter, it is sent to the corresponding channel of the ADC module.

6. A downhole high-temperature lithium battery capacity monitoring circuit according to claim 1, wherein, the MCU chip controls the JFET transistor through an isolation drive chip, and the JFET transistor is in a normally open state, which is used to switch the battery output during the current protection, voltage protection, and temperature protection of the battery.

7. A downhole high-temperature lithium battery capacity monitoring method, wherein, it includes the following processes, After the circuit is powered on, command detection is performed to determine whether there is a command. When there is no command, the last storage state in the FLash is read, and then the timer starts ADC sampling. After sampling, threshold judgment is performed. When the voltage threshold, current threshold, and battery temperature threshold exceed the thresholds, the battery output is turned off; under normal circumstances, the battery capacity is continuously calculated, and the data is packed and written into the FLash. When the circuit is powered on and there is a timing command, GPS timing is performed on the circuit, and the latest time information is written into the timing chip. The timing chip uses this time as the starting time for timing the operation of the downhole circuit. When the circuit is powered on and there is a read / erase FLASH command, read / erase storage data operations are performed, which are used to read the storage capacity data of the battery capacity and the battery process monitoring data after the logging tool has completed logging.

8. A downhole high-temperature lithium battery capacity monitoring method according to claim 7, wherein, When timing the timing chip according to the timing command and starting timekeeping, the MCU timer method is used to perform double backup of the stored time information.

9. A downhole high-temperature lithium battery capacity monitoring method according to claim 7, wherein, The set thresholds of the battery output voltage, battery output current, and battery temperature are judged in real time. When any one of the thresholds is exceeded, the MCU chip turns off the JFET to disconnect the battery output current.

10. A downhole high-temperature lithium battery capacity monitoring method according to claim 7, wherein, The battery capacity calculation formula is: Battery capacity 1: mAh i = [I i × (t i - t i-1 ) / 60] + mAh i-1 ; Battery capacity 2: mWh i = [U i × I i × (t i - t i-1 ) / 60] + mWh i-1 ; Where: mAh i is the battery consumption capacity in the current cycle, with the unit of mAh; I i Measured value of the battery output current for the current cycle, unit: A; t i is the current cycle time, unit min; t i-1 is the time of the previous cycle of the current time, in minutes; mAh i-1 The battery output consumption capacity for the previous cycle time of the current time, unit mAh; mWh i Another expression for the battery consumption capacity in the current cycle, with the unit of mWh; U i Measured value of the battery output voltage for the current cycle, unit: V; mWh i-1 Another expression for the battery consumption capacity in the previous cycle of the current time, with the unit of mWh.

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