CN109407013B - A backup battery power state monitoring circuit and method - Google Patents

Abstract

A backup battery state of charge monitoring circuit and method, wherein the circuit comprises: a backup battery temperature detection unit, a backup battery voltage and current detection unit, a controller and a memory; wherein the backup battery temperature detection unit detects a working temperature parameter of the backup battery; the backup battery The voltage and current detection unit detects the discharge parameters of the backup battery; the memory is used to store the performance parameters and initial monitoring parameters of the backup battery; the controller is connected with the backup battery temperature detection unit, the backup battery voltage and current detection unit and the memory, and is selectively based on the The detected operating temperature parameters of the backup battery, the detected discharge parameters of the backup battery, and the stored performance parameters and initial monitoring parameters, monitor the state of charge of the backup battery, and update the initial monitoring parameters or update the initial monitoring parameters and performance parameters . The technical solutions provided by the embodiments of the present invention are simple to implement, and can flexibly configure curves such as discharge parameters of various types of batteries, thereby reducing costs.

Description

A backup battery power state monitoring circuit and method

technical field

Embodiments of the present invention belong to the technical field of battery power management, and in particular relate to a circuit and method for monitoring the power state of a backup battery.

Background technique

Since October 1, 2016, my country has enforced the specification of "GB/T 32960.2-2016 Technical Specification for Electric Vehicle Remote Service and Management System Part 2: On-board Terminal" (hereinafter referred to as the "Specification"), in Section 4.2.7 of the "Specifications" stipulates "independent operation": "After the external power supply is abnormally disconnected, the vehicle terminal can still operate independently, and at least 10 minutes before the external power supply is disconnected. The data is uploaded to the enterprise platform." The "data" refers to the relevant data specified in GB/T 32960.3-2016.

In order to meet the above-mentioned product design requirements of "independent operation" in the "Specification", each vehicle-mounted data acquisition manufacturer adds built-in backup batteries to their vehicle-mounted data acquisition products to meet the requirements of "The vehicle-mounted terminal is abnormally disconnected from the external power supply" in the "Specification". It can still run independently, and at least 10 minutes before the external power supply is disconnected is guaranteed to be uploaded to the enterprise platform” product requirements. In order to ensure that the added built-in backup battery can meet the above-mentioned product requirements, it is necessary to manage the discharge of the built-in backup battery. Most of the existing vehicle terminal manufacturers realize the charge and discharge management of the built-in backup battery by adding a battery power management chip. This scheme of realizing backup battery charge and discharge management by adding a battery power management chip has the following disadvantages:

1. The system implementation is complex: a dedicated battery management chip is required, and a large number of peripheral separations and the cooperation of digital devices and dedicated battery management chips are required to achieve built-in backup battery power management;

2. Poor flexibility in system implementation: It is necessary to select the corresponding dedicated battery management chip according to the number of built-in backup batteries, and different dedicated battery management chips need to be selected for matching design for different numbers of built-in backup batteries, resulting in inflexible design scheme and parameter selection;

3. High cost of system implementation: Due to the influence of the battery management chip's need for power supply and its own peripheral circuit design, the circuit cost is higher than the implementation of the analog-to-digital converter ADC combined with the software algorithm.

SUMMARY OF THE INVENTION

In order to solve the technical problems of complicated system implementation, poor flexibility, and high cost in the above-mentioned built-in backup battery charge-discharge management method, embodiments of the present invention provide a backup battery power state monitoring circuit and method.

A backup battery power state monitoring circuit, comprising: a backup battery temperature detection unit, a backup battery voltage and current detection unit, a controller and a memory;

Wherein, the backup battery temperature detection unit detects the working temperature parameter of the backup battery;

The backup battery voltage and current detection unit detects the discharge parameter of the backup battery;

The memory is used to store the performance parameters and initial monitoring parameters of the backup battery;

The controller is connected with the backup battery temperature detection unit, the backup battery voltage and current detection unit and the memory, and the controller is selectively based on the detected operating temperature parameter of the backup battery, the detected discharge parameter of the backup battery, and the stored Performance parameters and initial monitoring parameters, monitor the state of charge of the backup battery, and update the initial monitoring parameters or update the initial monitoring parameters and performance parameters.

Further, the performance parameters include discharge voltages at different temperatures and corresponding calibrated battery capacities, and the state of charge of the backup battery includes the use time of the backup battery;

The controller determines the current operating temperature of the backup battery based on the detected operating temperature parameter of the backup battery; determines the current discharge voltage and current discharge current of the backup battery based on the detected discharge parameter of the backup battery; based on the determined The current operating temperature of the backup battery and the determined current discharge voltage of the backup battery, and the corresponding calibrated battery capacity is obtained from the performance parameters stored in the memory; based on the obtained calibrated battery capacity and the determined current discharge current of the backup battery, Determine how long the backup battery will last.

Further, the performance parameters further include self-discharge parameters of the backup battery at different temperatures, and the controller additionally determines the usage time of the backup battery based on the self-discharge parameters of the backup battery;

and / or,

The performance parameters further include use attenuation parameters of the backup battery at different temperatures, and the controller additionally determines the use duration of the backup battery comprehensively based on the use attenuation parameters of the backup battery.

Further, the backup battery temperature detection unit includes a thermistor and a thermistor terminal voltage detection unit, the thermistor is placed close to the backup battery or installed inside the backup battery, and the thermistor terminal voltage detection unit detects the terminal voltage across the thermistor. , connected with the first analog-to-digital conversion interface of the controller, the thermistor terminal voltage detection unit provides the detected terminal voltage at both ends of the thermistor to the controller through the first analog-to-digital conversion interface. The terminal voltage and the thermal characteristics of the thermistor are used as the working temperature parameters of the backup battery; the controller determines the current working temperature of the backup battery based on the obtained terminal voltage across the thermistor and the thermal characteristics of the thermistor.

Further, the thermistor is a positive temperature coefficient thermistor or a negative temperature coefficient thermistor.

Further, the backup battery voltage and current detection unit includes a series resistance, a series resistance terminal voltage collector and a backup battery terminal voltage collector; the discharge parameters include the load value of the load connected in series with the series resistance, the series resistance terminal voltage collector and the backup battery. The voltage values collected by the battery terminal voltage collector respectively;

The series resistance is connected in series with the backup battery;

The series resistor terminal voltage collector collects the terminal voltage across the series resistor, and provides the collected terminal voltage across the series resistor to the controller, and the controller determines the backup battery based on the acquired terminal voltage across the series resistor and the resistance value of the series resistor current discharge current;

The backup battery terminal voltage collector collects the terminal voltages at both ends of the backup battery, and provides the collected terminal voltages at both ends of the backup battery to the second analog-to-digital conversion interface of the controller; the controller is based on the collected terminal voltages at both ends of the backup battery. The voltage determines the current discharge voltage of the backup battery.

Further, when the number of backup batteries connected in series is increased, the voltage of the second analog-to-digital conversion interface of the controller is adjusted to realize the adaptation of the series circuits of multiple backup batteries;

When the number of parallel backup batteries is increased, the resistance value of the series resistor is adjusted to realize the adaptation of the parallel circuit of multiple backup batteries.

Further, the memory is a built-in memory provided in the controller, or the memory includes an external memory and a built-in memory provided in the controller.

Further, the negative electrode of the backup battery is grounded,

The backup battery temperature detection unit includes a negative temperature coefficient thermistor and a thermistor terminal voltage detection unit;

The negative temperature coefficient thermistor is placed close to the backup battery, and one end of the negative temperature coefficient thermistor is grounded;

The thermistor terminal voltage detection unit includes a thermistor voltage collector, one end of the thermistor voltage collector is connected to the other end of the negative temperature coefficient thermistor, and the other end of the thermistor voltage collector is connected to the controller. a first analog-to-digital conversion interface connection;

The backup battery voltage and current detection unit includes a series resistor, a series resistor terminal voltage collector and a backup battery terminal voltage collector;

One end of the series resistance is connected to the positive pole of the backup battery, the other end of the series resistance is connected to one end of the load, and the other end of the load is grounded;

The backup battery terminal voltage collector includes a backup battery voltage collector, one end of the backup battery voltage collector is connected to the positive pole of the backup battery, and the other end is connected to the second analog-to-digital conversion interface of the controller;

The series resistor terminal voltage collector includes a series resistor voltage collector, one end of the series resistor terminal voltage collector is connected to the other end of the series resistor, and the other end of the series resistor terminal voltage collector is connected to the third analog-to-digital conversion interface of the controller connect;

The controller is connected to the working power supply through the power interface, and is grounded through the ground interface;

The memory includes a built-in memory and an external memory, one end of the external memory is connected to a power supply, and the external memory is grounded.

Further, the backup battery temperature detection unit further includes a voltage dividing resistor, one end of the voltage dividing resistor is connected to the other end of the negative temperature coefficient thermistor, and the other end of the voltage dividing resistor is connected to the working power supply.

A method for monitoring the state of charge of a backup battery, comprising:

Obtain the performance parameters of the monitored backup battery;

Obtain the initial monitoring parameters of the monitored backup battery;

Detecting the operating parameters of the monitored backup battery, selectively monitoring the state of charge of the monitored backup battery based on the acquired performance parameters, the initial monitoring parameters and the detected operating parameters, and updating the initial monitoring parameters, the updated initial monitoring parameters As the obtained initial monitoring parameter, or, updating the initial monitoring parameter and the performance parameter, the updated initial monitoring parameter is used as the obtained initial monitoring parameter, and the updated performance parameter is used as the obtained performance parameter.

Further, the performance parameters include discharge voltages and corresponding calibrated battery capacities at different temperatures, the operating parameters include the monitored operating temperature parameters and discharge parameters of the backup battery, and the state of charge of the backup battery includes the backup battery. duration of use;

Monitoring the usage time of the monitored backup battery includes:

Detecting the monitored operating temperature parameter of the backup battery, and determining the current operating temperature of the backup battery based on the detected operating temperature parameter of the backup battery;

Detecting the discharge parameter of the monitored backup battery, and determining the current discharge voltage and current discharge current of the monitored backup battery based on the monitored discharge parameter of the backup battery;

Based on the determined current operating temperature and current discharge voltage of the monitored backup battery, the corresponding calibrated battery capacity is obtained from the performance parameters, based on the obtained calibrated battery capacity and the determined current discharge current of the monitored backup battery, Determine how long the battery backup is being monitored.

Further, the performance parameters also include: the calibration current and the corresponding calibration voltage under a specific load, the corresponding relationship between the capacity retention rate and the placement time at different temperatures, and the capacity ratio and cycle times at different temperatures. Correspondence;

The performance parameters are stored in the memory in the form of a table, the table storing the performance parameters is called a first table, and the updating the performance parameters includes updating the performance parameters stored in the first table;

Wherein, the first table is divided into a first sub-table corresponding to the initial cycle usage times of the monitored backup battery is less than the set threshold value and corresponding to the initial cycle usage times of the monitored backup battery is greater than or equal to the set threshold value according to the set threshold value The second subtable of .

Further, the initial monitoring parameters include: initial discharge current, initial discharge voltage, initial calibrated battery capacity, initial capacity retention rate and initial placement time, as well as initial capacity ratio and initial cycle times;

The initial monitoring parameters are stored in the memory in the form of a table, and the table storing the initial monitoring parameters is called a second table;

The updating of the initial monitoring parameters includes updating the initial monitoring parameters stored in the second table.

Further, the monitoring of the state of charge of the monitored backup battery, updating the initial monitoring parameters or updating the initial monitoring parameters and performance parameters, includes:

Detecting the operating temperature parameter of the monitored backup battery, and determining the current operating temperature of the monitored backup battery based on the monitored operating temperature parameter of the backup battery;

Determine whether the current operating temperature of the monitored backup battery is within the normal operating temperature range of the monitored backup battery;

If it is not within the normal working temperature range, an alarm message of abnormal temperature is issued, and the operation is stopped;

If it is within the normal operating temperature range, determine whether the initial cycle times of the monitored backup battery is less than the set threshold; if the initial cycle times of the monitored backup battery are less than the set threshold, read the first sub- The corresponding performance parameters in the table and the initial monitoring parameters in the second table, as well as the current operating temperature, current discharge voltage and current discharge current determined by the controller, monitor the state of the monitored backup battery power, and update the second table The initial monitoring parameters in the The current operating temperature, the current discharge voltage and the current discharge current are monitored, and the state of charge of the monitored backup battery is monitored, the initial monitoring parameters in the second table are updated, and the parameters in the second table and the second sub-table are matched to determine the Whether the monitored backup battery is in normal working state, and judge whether the monitored backup battery needs an alarm;

Then, check the service life of the monitored backup battery, and judge whether the monitored backup battery is fully charged and discharged;

If the monitored backup battery is not fully charged and discharged, indicating that the initial cycle usage times do not need to be updated, return to the operation described above if the initial cycle usage times of the monitored backup battery is less than the set threshold; if the monitored backup battery After complete charging and discharging, the update operation of the first table is performed.

Further, the update operation of the first table includes:

Add 1 to the initial number of cycles, and use the number of cycles after adding 1 as the new initial cycle, and then judge whether the new initial cycle is less than the set threshold. If the new initial cycle is less than the set value threshold, then perform the operation of whether the parameters of the first table are updated; if the new initial cycle times are greater than or equal to the set threshold, first update the first sub-table to the second sub-table, and compare the second table and the second sub-table to determine whether the monitored backup battery is in a normal working state, and to determine whether the monitored backup battery needs an alarm, and then perform the operation of whether to update the parameters of the first table.

Further, the operation of whether the parameters of the first table are updated includes: based on the current operating temperature, the current discharge voltage and the current discharge current determined by the controller, judging whether the calibration voltage and calibration current in the performance parameters stored in the first table are required. Update, if no update is required, execute the operation of whether to update the number of cycles in the performance parameters stored in the first table; if it needs to be updated, use the parameters of the second sub-table to update the calibration voltage in the performance parameters stored in the first table and calibration current, and then perform the operation of whether to update the cycle times in the performance parameters stored in the first table;

The operation of whether to update the cycle times in the performance parameters stored in the first table includes: based on whether the monitored backup battery is fully charged and discharged, judging whether the cycle times in the performance parameters stored in the first table needs to be updated, if not. If updating is required, the updating operation of the first table ends; if updating is required, the updating operation of the first table ends after updating the number of cycles of use in the performance parameters stored in the first table.

Further, the method is implemented by using the backup battery power state monitoring circuit as described in any one of the preceding items.

Beneficial effects of the embodiments of the present invention:

1. The backup battery power state monitoring circuit and method proposed in the embodiment of the present invention has a simple implementation method, and can flexibly configure discharge parameter curves of various types of batteries to monitor the battery charging and discharging process. In some embodiments, the detection of the battery working environment temperature and the charging and discharging parameters can be realized by using only two circuits and the cooperation of the negative temperature coefficient thermistor.

2. The circuit and method for monitoring the power state of the backup battery proposed by the embodiments of the present invention avoid using a complex and high-cost dedicated battery management chip to monitor the power state of the battery, and the implementation cost is low.

3. The backup battery power state monitoring circuit and method proposed in the embodiment of the present invention have a more flexible implementation method, and only need to adjust the voltage of the analog-to-digital conversion interface to realize multi-cell battery series circuit adaptation. In addition, the adaptation can be realized by adjusting the resistance value of the series resistance for the parallel battery pack.

4. The backup battery power state monitoring circuit and method proposed in the embodiment of the present invention achieves low error, only ±2% voltage/current error accuracy compared with the dedicated battery management chip, and the estimated battery service life error is ±2%.

Description of drawings

1 is a schematic structural diagram of a backup battery power state monitoring circuit proposed in an embodiment of the present invention;

2 is a flowchart of a method for monitoring the state of charge of a backup battery proposed by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a preferred embodiment of a backup battery power state monitoring circuit provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. However, those skilled in the art know that the present invention is not limited to the accompanying drawings and the following embodiments. The words "first" and "second" used in the text are only for the purpose of distinguishing the technical features, and do not constitute a limitation on the technical solution. As used herein, the term "including" and its various variants can be understood as open-ended terms meaning "including but not limited to". The term "based on" or based on may be understood as "based at least in part on" or "based at least in part on". The term "one embodiment" may be understood to mean "at least one embodiment." The term "another embodiment" may be understood to mean "at least one other embodiment."

In the embodiment of the present invention, by using the volt-ampere curves of different batteries under different working temperature conditions (volt-ampere curves: commonly used the ordinate represents the current I, the abscissa represents the voltage U, and the I-U image drawn by this is called the volt-ampere characteristic curve of the conductor. Figure), the relationship between voltage and battery capacity, etc. as a reference, through the combination with the multi-channel analog-to-digital conversion circuit of the controller, the backup battery system inside the CDU (Conversion&Distribution Unit) can be discharged under different operating temperature conditions. Calculation, charge and discharge statistics, battery life warning and other power status monitoring, to avoid the problem that the product function does not meet the relevant specifications due to the use of the backup battery system temperature, excessive charge and discharge and other reasons during the use process.

CDU refers to a high-voltage "electronic control" system integration method that integrates functions such as DC/DC converters, on-board chargers, and high-voltage junction boxes. CDU system integration is divided into "two-in-one" (including DC/DC converter and on-board charger in one, DC/DC converter and high-voltage junction box in one, or on-board charger and high-voltage junction box in one), "three-in-one" One” (ie DC/DC converter, on-board charger and high-voltage junction box in one) assembly, CDU system integration is selected by more and more domestic and foreign OEMs, and is becoming one of the mainstream technologies in the world.

An embodiment of the present invention provides a backup battery power state monitoring circuit, as shown in FIG. 1 , including: a backup battery temperature detection unit, a backup battery voltage and current detection unit, a controller, and a memory.

The backup battery can be a rechargeable battery such as a nickel-metal hydride battery, a lithium battery, or a lead-acid battery.

Wherein, the backup battery temperature detection unit detects the working temperature parameter of the backup battery.

The backup battery voltage and current detection unit detects the discharge parameters of the backup battery.

The memory is used to store the performance parameters and initial monitoring parameters of the backup battery.

The controller is connected with the backup battery temperature detection unit, the backup battery voltage and current detection unit and the memory, and the controller is selectively based on the detected operating temperature parameter of the backup battery, the detected discharge parameter of the backup battery, and the stored Performance parameters and initial monitoring parameters, monitor the state of charge of the backup battery, and update the initial monitoring parameters or update the initial monitoring parameters and performance parameters.

The performance parameters include discharge voltages at different temperatures and corresponding calibrated battery capacities, and the state of charge of the backup battery includes the usage time of the backup battery. The controller determines the current operating temperature of the backup battery based on the detected operating temperature parameter of the backup battery; determines the current discharge voltage and current discharge current of the backup battery based on the detected discharge parameter of the backup battery; based on the determined The current operating temperature of the backup battery and the determined current discharge voltage of the backup battery, and the corresponding calibrated battery capacity is obtained from the performance parameters stored in the memory; based on the obtained calibrated battery capacity and the determined current discharge current of the backup battery, Determine how long the backup battery will last.

The operating temperature parameters may include operating temperature parameters obtained based on the thermistor.

The discharge parameters may include discharge current parameters or discharge voltage parameters.

The controller may also store the current discharge voltage and current discharge current of the backup battery acquired in real time in the memory based on the discharge parameters of the backup battery detected by the backup battery voltage and current detection unit.

The state of charge of the backup battery includes the current battery capacity and usage time of the backup battery, and may also include the number of cycles (cycle) of the backup battery. In the embodiment of the present invention, the use time is used to represent the time length that the current battery capacity of the backup battery can maintain the system communication function. In the embodiment of the present invention, the number of cycles used to represent the number of charge-discharge cycles of the backup battery can be used to determine the service life of the backup battery; The lithium battery is fully charged and then discharged to less than 10%. It is considered that the lithium battery has undergone a process of full discharge (or complete charge and discharge), which is counted as 1 charge and discharge cycle; it can also be further considered that the lithium battery has not In the case of full discharge, the number of times of charge and discharge is appropriately calculated, for example, it is appropriately recorded as 0.5 charge and discharge cycles according to the situation.

In addition, the controller can also judge whether the monitored backup battery is completely charged and discharged based on the calibrated battery capacity obtained during the discharge process, and in a charge-discharge cycle, based on the calibrated battery capacity obtained during charging Whether the monitored backup battery is fully charged, judge whether the monitored backup battery is fully discharged based on the calibrated battery capacity obtained during the discharge process, and if it is fully charged and discharged, the cycle times of the backup battery are updated by adding 1 . In the embodiment of the present invention, the cycle times (cycle) and the corresponding capacity ratio (capacity ratio) of the backup battery are used as usage decay parameters to characterize the battery capacity decay condition of the backup battery. Parameters such as the cycle times of the backup battery and the corresponding capacity ratio can also be stored in the memory in real time.

Furthermore, the controller may further update the storage time of the backup battery based on the monitored actual usage time of the backup battery. In the embodiment of the present invention, the storage period and the corresponding capacity retention of the backup battery are used as self-discharge parameters to characterize the self-discharge condition of the backup battery. Parameters such as the storage time of the backup battery and the corresponding capacity retention rate can also be stored in the memory in real time.

In one embodiment, the controller further comprehensively determines the state of charge of the backup battery (for example, the duration of use) based on the self-discharge parameters of the backup battery at different temperatures and/or the use decay parameters of the backup battery at different temperatures. , thereby increasing the monitoring dimension of the state of charge of the backup battery and improving the monitoring accuracy.

The power state monitoring circuit of the backup battery monitors the power state of the backup battery, which may occur during the charging process of the backup battery or during the discharging process of the backup battery.

The power state monitoring circuit of the backup battery may monitor the power state of the backup battery at predetermined time intervals, for example, every 1 hour, or every 12 hours. Alternatively, the time interval for the next monitoring can be determined based on the current parameters of the backup battery. For example, when the current remaining battery capacity of the backup battery is much larger than the battery capacity of the backup battery to maintain the 10-minute communication function of the system, the time interval for the next monitoring can be determined as With a slightly longer time interval, when the current remaining battery capacity of the backup battery is close to the battery capacity of the backup battery to maintain the 10-minute communication function of the system, the time interval for the next monitoring can be determined to be a slightly shorter time interval. Of course, the backup battery can also be considered comprehensively. Parameters such as battery operating temperature parameters and cycle times.

The backup battery state of charge monitoring circuit may further determine whether the backup battery needs to be charged or whether it needs to be replaced based on the obtained state of charge of the backup battery.

In one embodiment, a volt-ampere characteristic curve composed of the rated voltage and rated current of the backup battery under a specific load is also added, so as to obtain the corresponding rated voltage according to the initial current when the system is initialized. During the use process of the specific load, based on the determined current discharge voltage of the backup battery, the corresponding calibration current is found in the volt-ampere characteristic curve by taking the determined current discharge voltage as the calibration voltage, and based on the found The calibration current and the determined current discharge current of the backup battery are used to determine the working error of the backup battery, and the state of charge of the backup battery is corrected based on the working error.

An embodiment of the present invention further provides a method for monitoring the power state of a backup battery, as shown in FIG. 2 , including:

Obtain the performance parameters of the monitored backup battery;

Obtain the initial monitoring parameters of the monitored backup battery;

Detecting the operating parameters of the monitored backup battery, selectively monitoring the state of charge of the monitored backup battery based on the acquired performance parameters, the initial monitoring parameters and the detected operating parameters, and updating the initial monitoring parameters, the updated initial monitoring parameters As the obtained initial monitoring parameter, or, updating the initial monitoring parameter and the performance parameter, the updated initial monitoring parameter is used as the obtained initial monitoring parameter, and the updated performance parameter is used as the obtained performance parameter.

Wherein, the performance parameter includes the discharge voltage at different temperatures and the corresponding calibrated battery capacity, and the state of charge of the backup battery includes the usage time of the backup battery;

Monitoring the usage time of the monitored backup battery includes:

Detecting the working temperature parameter of the backup battery, and determining the current working temperature of the backup battery based on the detected working temperature parameter of the backup battery;

Detecting the discharge parameter of the monitored backup battery, and determining the current discharge voltage and current discharge current of the monitored backup battery based on the monitored discharge parameter of the backup battery;

Based on the determined current operating temperature and current discharge voltage of the monitored backup battery, the corresponding calibrated battery capacity is obtained from the performance parameters, based on the obtained calibrated battery capacity and the determined current discharge current of the monitored backup battery, Determine how long the battery backup is being monitored. For example, duration of use=acquired nominal battery capacity÷determined current discharge current of the monitored backup battery.

The content of the method of the embodiment of the present invention is the same as that of the foregoing circuit, which is not repeated here.

The circuit and method for monitoring the state of charge of the backup battery proposed by the embodiments of the present invention refer to the strong correlation between the battery charge and discharge parameters and the ambient temperature, and the calibrated battery charge and discharge parameter curve parameters, based on the battery voltage and current during the battery charge and discharge process. , judging the power status of the battery, even the number of cycles and lifespan, etc., to realize the monitoring of the battery power status, the function is simple, and the charge and discharge parameter curves of various types of batteries can be flexibly configured, reducing the cost; strong compatibility, compatible with almost all vehicles Use batteries (such as lead-acid batteries, nickel-metal hydride batteries, lithium batteries, etc.).

The preferred embodiments of the circuit and method for monitoring the state of charge of a backup battery provided by the embodiments of the present invention will be exemplarily described below.

Example 1:

In this embodiment 1, a preferred embodiment of the backup battery temperature detection unit included in the backup battery state of charge monitoring circuit is exemplarily described.

Referring to Figure 3, the backup battery temperature detection unit includes a thermistor and a thermistor terminal voltage detection unit. The thermistor is placed near the backup battery or installed inside the backup battery, and the thermistor terminal voltage detection unit detects the thermistor. The terminal voltage at both ends is connected to the first analog-to-digital conversion interface (ADC interface) of the controller, and the thermistor terminal voltage detection unit provides the detected terminal voltage at both ends of the thermistor to the thermistor through the first analog-to-digital conversion interface. The controller, the detected terminal voltage at both ends of the thermistor is used as the operating temperature parameter of the backup battery; the controller calculates the backup battery Operating temperature.

The thermistor can be a positive temperature coefficient thermistor or a negative temperature coefficient thermistor.

Those skilled in the art understand that, in some embodiments, the thermistor may be integrated inside the controller, that is, the controller is a controller capable of providing internal temperature sampling.

Example 2:

In this embodiment 2, a preferred embodiment of the backup battery voltage and current detection unit included in the backup battery state of charge monitoring circuit is exemplarily described. In this embodiment, the discharge parameter includes a discharge voltage parameter, and the backup battery voltage and current detection unit detects the relevant voltage value of the backup battery. Of course, if conditions permit, the relevant current value of the backup battery can also be detected.

Referring to FIG. 3 , the backup battery voltage and current detection unit includes a series resistor, a terminal voltage collector of the series resistor, and a backup battery terminal voltage collector.

A series resistor is connected in series with the backup battery.

The series resistance terminal voltage collector collects the terminal voltage across the series resistor when the backup battery is charged and discharged, and provides the collected terminal voltage across the series resistor to the controller, and the obtained terminal voltage across the series resistor is used as the discharge parameter of the backup battery ; The controller calculates the current discharge current of the backup battery based on the obtained terminal voltage across the series resistance and the resistance value of the series resistance.

The backup battery terminal voltage collector collects the terminal voltage at both ends of the backup battery when the backup battery is charged and discharged, and provides the collected terminal voltage at both ends of the backup battery as the determined current discharge voltage of the backup battery to the second model of the controller. digital conversion interface.

When the number of backup batteries connected in series is increased, the terminal voltage at both ends of the entire backup battery will increase accordingly. At this time, the adaptation of the series circuit of multiple backup batteries can be realized by adjusting the voltage of the second analog-to-digital conversion interface of the controller. .

When the number of parallel backup batteries is increased, the terminal current of the entire backup battery will increase accordingly. At this time, the adaptation of the parallel circuit of multiple backup batteries can be realized by simply adjusting the resistance value of the series resistor.

Example 3:

This Embodiment 3 exemplifies a preferred embodiment of the memory included in the backup battery state of charge monitoring circuit.

The memory may be a built-in memory provided in the controller, or may include an external memory and a built-in memory provided in the controller (refer to FIG. 3 ). The external memory is connected to the external memory interface of the controller, and the controller can write data into the memory, and can also read data from the memory.

Whether the memory also includes external memory can be determined according to the storage space of the built-in memory and actual application requirements. If the storage space of the built-in memory can meet the actual application requirements, the external memory may not be provided.

Example 4:

The preferred embodiment of the backup battery power state monitoring circuit is exemplarily described in this Embodiment 4, and reference may be made to FIG. 3 .

In this embodiment, the discharge parameter includes a discharge voltage parameter, and the backup battery voltage and current detection unit detects the relevant voltage value of the backup battery.

In this embodiment, the negative electrode of the backup battery B1 is grounded.

The backup battery temperature detection unit includes a negative temperature coefficient thermistor RT1 and a thermistor terminal voltage detection unit.

The negative temperature coefficient thermistor RT1 is placed close to the backup battery B1, and one end of the negative temperature coefficient thermistor RT1 is grounded.

Since one end of the negative temperature coefficient thermistor RT1 is grounded, the thermistor terminal voltage detection unit may only include a thermistor voltage collector V3 for collecting the voltage at the other end of the negative temperature coefficient thermistor RT1 . One end of the thermistor voltage collector V3 is connected to the other end of the negative temperature coefficient thermistor RT1, and the other end of the thermistor voltage collector V3 is connected to the first analog-to-digital conversion interface of the controller U1.

In order to prevent the voltage applied to the negative temperature coefficient thermistor RT1 by the working power supply V0 from being too large, the backup battery temperature detection unit further includes a voltage dividing resistor R2, one end of the voltage dividing resistor R2 is connected to all the negative temperature coefficient thermistor RT1. The other end is connected to the above, and the other end of the voltage dividing resistor R2 is connected to the working power supply V0. In this embodiment, the thermistor RT1, the voltage dividing resistor R2 and the working power supply V0 form a temperature detection circuit, and the terminal voltage of the negative temperature coefficient thermistor RT1 when the backup battery B1 is charged and discharged is [V0/(RT1+R2)] *RT1. Of course, those skilled in the art understand that the thermistor RT1 can be integrated inside the controller U1, and the voltage dividing resistor R2 can be omitted in this case.

The backup battery voltage and current detection unit includes a series resistor R1, a series resistor terminal voltage collector and a backup battery terminal voltage collector.

One end of the series resistor R1 is connected to the positive electrode of the backup battery B1, the other end of the series resistor R1 is connected to one end of the load, and the other end of the load is grounded. In this embodiment, the backup battery B1, the series resistance R1 and the load form a backup battery discharge circuit.

Since the negative electrode of the backup battery B1 is grounded, the backup battery terminal voltage collector may only include a backup battery voltage collector V2. One end of the backup battery voltage collector V2 is connected to the positive electrode of the backup battery B1, and the other end is connected to the second mode of the controller. digital conversion interface. In this embodiment, the voltage collected by the backup battery voltage collector V2 when the backup battery B1 is charged and discharged is the current discharge voltage of the backup battery B1.

Since the voltage of the one end of the series resistor R1 is equal to the voltage collected by the backup battery voltage collector V2, the series resistor terminal voltage collector can obtain the voltage between the one end of the series resistor R1 and the backup battery with the help of the backup battery voltage collector V2. The voltage at the positive connection of B1, the series resistance terminal voltage collector also needs a series resistance voltage collector V1 to obtain the voltage at the other end of the series resistance R1. One end of the series resistance terminal voltage collector V1 is connected to the other end of the series resistance R1, and the other end of the series resistance terminal voltage collector V1 is connected to the third analog-to-digital conversion interface of the controller U1. In this embodiment, when the backup battery B1 is discharged, the discharge current of the backup battery flows from one end of the series resistor R1 to the other end, and the current discharge current of the backup battery is (V2-V1)/R1; the backup battery B1 is charged When , the charging current of the backup battery flows from the other end of the series resistor R1 to the one end, and the current charging current of the backup battery is (V1-V2)/R1.

Among them, the internal resistance of the series resistance voltage collector V1, the backup battery voltage collector V2 and the thermistor voltage collector V3 is very large, so the current in the backup battery discharge circuit and the temperature detection circuit hardly flows into the controller U1.

The controller is connected to the working power supply V0 through the power interface VCC, and is grounded through the ground interface GND.

In this embodiment, the memory includes a built-in memory and an external memory, one end of the external memory is connected to the power supply V0, and the external memory is grounded. The external memory communicates with the controller U1 through the external memory interface of the controller U1.

Example 5:

This embodiment exemplarily describes the parameters used to monitor the state of charge of the backup battery in the circuit and method for monitoring the state of charge of the backup battery provided by the embodiments of the present invention.

Since battery products are chemicals, their electrochemical properties are strongly related to temperature. Therefore, according to the actual working temperature of the battery, such as the working range of -20°C to +85°C, the battery discharge parameters are calibrated (for example, the nickel-metal hydride battery is at +20°C). condition its battery capacity is 100%).

For different heat dissipation conditions, you only need to set different parameters according to the battery operating temperature requirements. The calibrated parameters can be stored in a fixed storage space in the built-in memory.

During calibration, the charge-discharge parameter characteristic curve composed of the charge-discharge voltage and battery capacity of the backup battery at different temperatures is measured, and the charge-discharge voltage corresponding to some nodes on the charge-discharge parameter characteristic curve at each temperature and the calibration battery are obtained. capacity. The corresponding relationship between temperature, charge-discharge voltage and calibrated battery capacity can be recorded in the form of a table. Table 1 shows the corresponding calibrated battery capacity values when the backup battery is at -20°C, -10°C, 0°C, 20°C and 85°C, and the charge and discharge voltages are 1400mV, 1300mV, 1250mV, 1200mV, 1100mV and 1000mV, respectively. (The nominal battery capacity is in mAh).

Table 1 Relationship between temperature, charge-discharge voltage and battery capacity (example)

According to Table 1, at 85°C, when the voltage of the backup battery is discharged from 1200mV to 1000mV, no current can be released, indicating that the backup battery has been completely discharged at this time.

When monitoring the state of charge of the backup battery, the corresponding calibrated battery capacity can be found according to the determined current operating temperature and current discharge voltage of the backup battery. You can get the operating time of the backup battery. For example, it is determined that the current operating temperature of the backup battery is -20°C, the current discharge voltage of the backup battery is determined to be 1100mV, and the current discharge current is 20mA, then according to the temperature of -20°C and the voltage of 1100mV, the corresponding calibration battery can be found. The capacity is 180mAh, which gives a backup battery life of 9 hours.

In addition to monitoring the state of charge of the backup battery from the aforementioned temperature, voltage and battery capacity, the dimension of battery self-discharge parameters can also be added to comprehensively monitor the state of charge of the backup battery, and monitor the remaining capacity of the backup battery according to the self-discharge curve. , to improve the accuracy of monitoring.

The self-discharge curve composed of capacity retention and storage period of the backup battery was measured at different temperatures, and the capacity retention rate and storage period corresponding to some nodes on the self-discharge curve at each temperature were obtained. The relationship between temperature, capacity retention and standing time is recorded in a tabular form. Table 2 shows the capacity retention rates of the backup batteries at -20°C, 45°C, and 60°C, which are 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, respectively. The length of time (in months) to hold in %.

Table 2 Relationship between temperature, capacity retention rate and storage time (example)

When monitoring the power status of the backup battery, the corresponding battery capacity can be found according to the determined current operating temperature and charge-discharge voltage of the backup battery. The capacity retention rate is adjusted, and the adjusted use time of the backup battery can be obtained from the adjusted battery capacity and the determined current discharge current of the backup battery. In this way, the accuracy of monitoring the state of charge of the backup battery can be effectively improved. Also taking the temperature of -20 degrees Celsius, the discharge voltage of 1100mV, and the discharge current of 20mA as an example, if the backup battery has been placed for 0.3 months, it can be seen from Table 2 that the capacity retention rate at this time is 90%, then the adjusted backup battery The usage time is 8.1 hours.

In addition, since the battery is a chemical, during the charging and discharging process, with the change of the density, temperature and active material of the electrolyte, the stability of the link structure between the corresponding current collector and the active material of the positive and negative electrodes will decrease, so A loose structure appears. This will cause the internal resistance of the battery to become larger, and the larger internal resistance of the battery will directly affect the working voltage, working current, output energy and power of the battery. Therefore, in this embodiment, the number of cycles of battery use (cycle) may also be used as an indicator to measure the remaining battery power, so as to further increase the monitoring dimension of the power state of the backup battery.

The capacity ratio and cycle times of the backup battery at different temperatures are measured as the use attenuation curve composed of the use attenuation parameters, and the relationship between temperature, capacity ratio, and cycle times is recorded in the form of a table . Table 3 shows the cycle times corresponding to the capacity ratios of 100%, 90%, 80%, 70%, and 60% of the backup battery at 20°C.

Table 3 Relationship between temperature, capacity ratio and number of cycles (example)

When monitoring the state of charge of the backup battery, the corresponding battery capacity can be found according to the determined current operating temperature of the backup battery and the measured discharge voltage. The relationship between medium temperature, capacity ratio and cycle times, the battery capacity is adjusted twice according to the capacity retention rate and capacity ratio, and the battery capacity after the two adjustments and the determined current discharge current of the backup battery can be Get twice the adjusted battery life of the backup. In this way, the accuracy of monitoring the state of charge of the backup battery can be more effectively improved. Also taking the temperature of -20 degrees Celsius, the charge-discharge voltage of 1100mV, and the discharge current of 20mA as an example, if the backup battery has been placed for 0.3 months, it can be seen from Table 2 that the capacity retention rate at this time is 90%; After 900 cycles of use, it can be found from Table 3 (not shown). The capacity ratio at this time is assumed to be 70%, so the use time of the backup battery after the two adjustments is 5.67 hours.

Therefore, in this embodiment of the present invention, the current operating temperature, voltage, current, and self-discharge parameters and/or cycle times of the backup battery can be integrated to determine the state of charge of the backup battery. Through multi-dimensional comprehensive consideration, the monitoring accuracy of backup battery power status is improved.

In some embodiments, for the convenience of query, Table 1, Table 2 and Table 3 can be organized into one table, and the table can be stored in the built-in memory or the external memory.

In addition, the volt-ampere characteristic curve composed of the rated voltage and rated current of the backup battery under a specific load can also be added. According to the volt-ampere characteristic curve, not only the working parameters are initialized, but also the performance parameters of the backup battery can be known. Changes, and adaptively Correct the monitoring result of the state of charge of the backup battery, for example, take the determined current discharge voltage of the backup battery as the calibration voltage, obtain the corresponding calibration current from the volt-ampere characteristic curve, and compare the obtained calibration current with the determined calibration current. By comparing the current discharge current of the backup battery, it can be known whether the volt-ampere characteristic curve of the backup battery has changed. In order to facilitate the query, the relationship between Table 1, Table 2, Table 3 and the volt-ampere characteristic curve can be organized into a table, and the table can be stored in the built-in memory or external memory.

Example 6:

The process of the method for monitoring the state of charge of a backup battery provided by the embodiment of the present invention is exemplarily described below.

The performance parameters include the rated current and rated voltage of the monitored backup battery under a specific load, the charge and discharge voltage at different temperatures and the corresponding rated battery capacity, the corresponding relationship between the capacity retention rate and the storage time, and the capacity ratio and The corresponding relationship of the number of cycles;

First, obtain the performance parameters of the monitored backup battery, including:

Based on the model or type of the monitored backup battery, obtain the calibrated current and corresponding calibrated voltage of the monitored backup battery under a specific load, the charge and discharge voltage at different temperatures and the corresponding calibrated battery capacity;

Obtain the corresponding relationship between the capacity retention rate of the monitored backup battery and the storage time; and the corresponding relationship between the capacity ratio and the number of cycles;

The performance parameter may be stored in the memory in the form of a table, the table storing the performance parameter is called a first table, and the updating the performance parameter includes updating the performance parameter stored in the first table. In one embodiment, the first table is divided into first sub-tables corresponding to the initial cycle times of the monitored backup battery less than the set threshold according to the set threshold and first sub-tables corresponding to the initial cycle times of the monitored backup batteries greater than Equal to the second sub-table of the set threshold; the parameters stored in the first sub-table and the parameters stored in the second sub-table may be the same or different.

Second, obtain the initial monitoring parameters of the monitored backup battery, including:

Based on the type or type of the monitored backup battery, estimate the initial discharge current of the monitored backup battery; take the initial discharge current as the calibration current, and obtain the calibration voltage corresponding to the calibration current as the initial discharge voltage; based on the initial discharge voltage, to obtain the initial calibrated battery capacity corresponding to the initial discharge voltage;

Obtain the initial capacity retention rate and initial storage time of the monitored backup battery, as well as the initial capacity ratio and initial cycle times;

The initial monitoring parameters may also be stored in the memory in the form of a table, and the table storing the initial monitoring parameters is called a second table, and the updating of the initial monitoring parameters includes updating the initial monitoring parameters stored in the second table.

Then, the monitoring of the state of charge of the monitored backup battery, updating the initial monitoring parameters or updating the initial monitoring parameters and performance parameters, includes:

Detecting the operating temperature parameter of the monitored backup battery, and determining the current operating temperature of the monitored backup battery based on the monitored operating temperature parameter of the backup battery;

Determine whether the current operating temperature of the monitored backup battery is within the normal operating temperature range of the monitored backup battery, for example, whether it is within a temperature range of 20°C to 65°C;

If it is not within the normal working temperature range, an alarm message of abnormal temperature is issued, and the operation is stopped.

If it is within the normal operating temperature range, it is determined whether the initial cycle times of the monitored backup battery is less than the set threshold, for example, the set threshold is 900 times; if the initial cycle times of the monitored backup battery is less than the set threshold threshold value, then read the corresponding performance parameters in the first sub-table and the initial monitoring parameters in the second table, and according to the current operating temperature, current discharge voltage and current discharge current determined by the controller, the state of charge of the monitored backup battery Perform monitoring, and update the initial monitoring parameters in the second table; if the initial cycle times of the monitored backup battery is greater than or equal to the set threshold, read the corresponding performance parameters in the second sub-table and the initial monitoring in the second table parameters, and according to the current operating temperature, current discharge voltage and current discharge current determined by the controller, monitor the state of the monitored backup battery power, and update the initial monitoring parameters in the second table, and then match the second table and the second table. The parameters in the sub-table determine whether the monitored backup battery is in a normal working state, and whether the monitored backup battery needs an alarm (such as a service life alarm);

Then, check the service life of the monitored backup battery, and judge whether the monitored backup battery is fully charged and discharged;

If the monitored backup battery is not fully charged and discharged, indicating that the initial cycle usage times do not need to be updated, return to the operation if the initial cycle usage counts of the monitored backup battery are less than the set threshold and continue to execute;

If it is fully charged and discharged, indicating that the initial cycle times need to be updated, the update operation of the first table is performed.

The update operation of the first table includes: adding 1 to the initial cycle usage number, adding the 1 cycle usage number as the new initial cycle usage number, and then judging whether the new initial cycle usage number is less than the set threshold value, If the new initial cycle usage times is less than the set threshold, perform the operation of whether to update the parameters of the first table; if the new initial cycle usage times are greater than or equal to the set threshold value, first update the first sub-table to the second sub-table , compare the parameters in the second table and the second sub-table, determine whether the monitored backup battery is in a normal working state, and determine whether the monitored backup battery needs an alarm (such as a service life alarm), and then execute the described Whether the parameters of the first table are updated.

The operation of whether the parameters of the first table are updated includes: based on the current operating temperature, current discharge voltage and current discharge current determined by the controller, judging whether the calibration voltage and calibration current in the performance parameters stored in the first table need to be updated, if If no update is required, perform the operation of whether to update the number of cycles in the performance parameters stored in the first table; if it needs to be updated, use the parameters of the second sub-table to update the calibration voltage and calibration current in the performance parameters stored in the first table , and then perform the operation of whether to update the number of cycles of use in the performance parameters stored in the first table.

The operation of whether to update the cycle times in the performance parameters stored in the first table includes: based on whether the monitored backup battery is fully charged and discharged, judging whether the cycle times in the performance parameters stored in the first table needs to be updated, if not. If updating is required, the updating operation of the first table ends; if updating is required, the updating operation of the first table ends after updating the number of cycles of use in the performance parameters stored in the first table.

Wherein, the monitoring of the usage duration of the monitored backup battery includes:

Detecting the working temperature parameter of the backup battery, and determining the current working temperature of the backup battery based on the detected working temperature parameter of the backup battery;

Detecting the discharge parameter of the monitored backup battery, and determining the current discharge voltage and current discharge current of the monitored backup battery based on the monitored discharge parameter of the backup battery;

Based on the determined current operating temperature and current discharge voltage of the monitored backup battery, the corresponding calibrated battery capacity is obtained from the first table through a table look-up method, and the obtained calibrated battery capacity and the initial capacity obtained from the second table are maintained. rate and initial capacity ratio and the determined current discharge current of the monitored backup battery, and determine the usage time of the monitored backup battery, for example, usage duration=acquired nominal battery capacity*acquired initial capacity retention rate*initial capacity ratio ÷ Determined current discharge current of the monitored backup battery.

For another example, based on the obtained calibrated battery capacity, initial capacity retention rate and initial capacity ratio of the monitored backup battery, and the determined current discharge current, determine the usage time of the monitored backup battery, and determine whether it is necessary to The monitored backup battery is charged to avoid over-discharge of the monitored backup battery. For another example, based on the obtained rated battery capacity of the monitored backup battery, it is determined whether the monitored backup battery is fully charged and discharged. , and update the initial cycle times stored in the memory, and update the initial capacity ratio accordingly. For another example, according to the actual usage time of the monitored backup battery, the initial storage time and the initial capacity ratio are updated. For another example, the service life of the monitored backup battery is determined according to the obtained cycle times of the monitored backup battery, so as to determine whether the monitored backup battery needs to be replaced, for example, the cycle times exceed the rated service life of the monitored backup battery. , it is judged that the monitored backup battery needs to be replaced. For another example, according to the obtained rated battery capacity of the monitored backup battery, it is determined whether it is necessary to stop the charging operation of the monitored backup battery to avoid overcharging of the monitored backup battery.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (15)

1. A backup battery state of charge monitoring circuit, comprising: a backup battery temperature detection unit, a backup battery voltage and current detection unit, a controller and a memory; Wherein, the backup battery temperature detection unit detects the working temperature parameter of the backup battery; The backup battery voltage and current detection unit detects the discharge parameter of the backup battery; The memory is used to store the performance parameters and initial monitoring parameters of the backup battery; The controller is connected with the backup battery temperature detection unit, the backup battery voltage and current detection unit and the memory, and the controller is selectively based on the detected operating temperature parameter of the backup battery, the detected discharge parameter of the backup battery, and the stored Performance parameters and initial monitoring parameters, monitor the power status of the backup battery, and update the initial monitoring parameters or update the initial monitoring parameters and performance parameters; Wherein, the performance parameter includes the discharge voltage at different temperatures and the corresponding calibrated battery capacity, and the state of charge of the backup battery includes the usage time of the backup battery; The length of time the controller monitors backup battery usage includes: Detecting the working temperature parameter of the backup battery, and determining the current working temperature of the backup battery based on the detected working temperature parameter of the backup battery; Detecting the discharge parameter of the backup battery, and determining the current discharge voltage and current discharge current of the backup battery based on the detected discharge parameter of the backup battery; Based on the determined current operating temperature and current discharge voltage of the backup battery, the corresponding calibrated battery capacity is obtained from the performance parameters, and based on the obtained calibrated battery capacity and the determined current discharge current of the backup battery, the use time of the backup battery is determined ; The performance parameters also include: the calibration current and the corresponding calibration voltage under a specific load, the corresponding relationship between the capacity retention rate and the storage time at different temperatures, and the corresponding relationship between the capacity ratio and the number of cycles at different temperatures; The performance parameters are stored in the memory in the form of a table, the table storing the performance parameters is called a first table, and the updating the performance parameters includes updating the performance parameters stored in the first table; Wherein, the first table is divided into a first sub-table corresponding to the initial cycle times of the backup battery less than the set threshold and a second sub-table corresponding to the initial cycle times of the backup battery greater than or equal to the set threshold according to the set threshold; The initial monitoring parameters include: initial discharge current, initial discharge voltage, initial calibrated battery capacity, initial capacity retention rate and initial storage time, as well as initial capacity ratio and initial cycle times; The initial monitoring parameters are stored in the memory in the form of a table, and the table storing the initial monitoring parameters is called a second table; The controller updating the initial monitoring parameters includes updating the initial monitoring parameters stored in the second table; The controller monitors the state of charge of the backup battery, updates the initial monitoring parameters or updates the initial monitoring parameters and performance parameters, including: Detecting the working temperature parameter of the backup battery, and determining the current working temperature of the backup battery based on the working temperature parameter of the backup battery; Determine whether the current operating temperature of the backup battery is within the normal operating temperature range of the backup battery; If it is not within the normal working temperature range, an alarm message of abnormal temperature is issued, and the operation is stopped; If it is within the normal operating temperature range, determine whether the initial cycle times of the backup battery is less than the set threshold; if the initial cycle times of the backup battery are less than the set threshold, read the corresponding performance parameters in the first sub-table and the initial monitoring parameters in the second table, and according to the current operating temperature, current discharge voltage and current discharge current determined by the controller, monitor the state of charge of the backup battery, and update the initial monitoring parameters in the second table; if the backup battery If the number of initial cycles is greater than or equal to the set threshold, read the corresponding performance parameters in the second sub-table and the initial monitoring parameters in the second table, as well as the current operating temperature, current discharge voltage and current discharge current determined by the controller , monitor the power state of the backup battery, update the initial monitoring parameters in the second table, and then match the parameters in the second table and the second sub-table to determine whether the backup battery is in a normal working state, and determine whether the backup battery needs the situation of the alarm; Then, check the service life of the backup battery, and judge whether the backup battery is fully charged and discharged; If the backup battery is not fully charged and discharged, it indicates that the initial cycle times do not need to be updated, return to the operation if the initial cycle times of the backup battery is less than the set threshold and continue to execute; if the backup battery is fully charged and discharged, execute the first table update operation. 2. The backup battery state of charge monitoring circuit according to claim 1, wherein the updating operation of the first table comprises: Add 1 to the initial number of cycles, and use the number of cycles after adding 1 as the new initial cycle, and then judge whether the new initial cycle is less than the set threshold. If the new initial cycle is less than the set value threshold, then perform the operation of whether the parameters of the first table are updated; if the new initial cycle times are greater than or equal to the set threshold, first update the first sub-table to the second sub-table, and compare the second table and the second sub-table The parameters in , determine whether the backup battery is in a normal working state, and determine whether the backup battery needs an alarm, and then perform the operation of whether the parameters of the first table are updated. 3. The backup battery state of charge monitoring circuit according to claim 1, wherein the performance parameters further include self-discharge parameters of the backup battery at different temperatures, and the controller is additionally based on the self-discharge of the backup battery parameters, comprehensively determine the use time of the backup battery; and / or, The performance parameters further include use attenuation parameters of the backup battery at different temperatures, and the controller additionally determines the use duration of the backup battery comprehensively based on the use attenuation parameters of the backup battery. 4. The backup battery state of charge monitoring circuit according to any one of claims 1 to 3, wherein the backup battery temperature detection unit comprises a thermistor and a thermistor terminal voltage detection unit, and the thermistor is close to the backup battery Placed or installed inside the backup battery, the thermistor terminal voltage detection unit detects the terminal voltage at both ends of the thermistor, and is connected to the first analog-to-digital conversion interface of the controller, and the thermistor terminal voltage detection unit passes the first analog-to-digital conversion interface. The conversion interface provides the detected terminal voltage at both ends of the thermistor to the controller, and the terminal voltage at both ends of the thermistor and the thermal characteristics of the thermistor are used as the operating temperature parameters of the backup battery; The terminal voltage of the terminal and the thermal characteristics of the thermistor determine the current operating temperature of the backup battery. 5. The backup battery state of charge monitoring circuit according to claim 4, wherein the thermistor is a positive temperature coefficient thermistor or a negative temperature coefficient thermistor. 6. The backup battery state of charge monitoring circuit according to any one of claims 1 to 3, wherein the backup battery voltage and current detection unit comprises a series resistor, a series resistor terminal voltage collector and a backup battery terminal voltage collector; The discharge parameter includes the load value of the load connected in series with the series resistance and the voltage values collected by the series resistance terminal voltage collector and the backup battery terminal voltage collector respectively; The series resistance is connected in series with the backup battery; The series resistor terminal voltage collector collects the terminal voltage across the series resistor, and provides the collected terminal voltage across the series resistor to the controller, and the controller determines the backup battery based on the acquired terminal voltage across the series resistor and the resistance value of the series resistor current discharge current; The backup battery terminal voltage collector collects the terminal voltages at both ends of the backup battery, and provides the collected terminal voltages at both ends of the backup battery to the second analog-to-digital conversion interface of the controller; the controller is based on the collected terminal voltages at both ends of the backup battery. The voltage determines the current discharge voltage of the backup battery. 7 . The backup battery state of charge monitoring circuit according to claim 6 , wherein when the number of backup batteries connected in series is increased, the voltage of the second analog-to-digital conversion interface of the controller is adjusted to realize a plurality of backup battery series circuits. 8 . adaptation; When the number of parallel backup batteries is increased, the resistance value of the series resistor is adjusted to realize the adaptation of the parallel circuit of multiple backup batteries. 8. The backup battery state of charge monitoring circuit according to any one of claims 1 to 3, wherein the memory is a built-in memory provided in the controller, or the memory comprises an external memory and a memory provided in the controller. Built-in memory in the controller. 9. The backup battery state of charge monitoring circuit according to any one of claims 1 to 3, wherein the negative electrode of the backup battery is grounded, The backup battery temperature detection unit includes a negative temperature coefficient thermistor and a thermistor terminal voltage detection unit; The negative temperature coefficient thermistor is placed close to the backup battery, and one end of the negative temperature coefficient thermistor is grounded; The thermistor terminal voltage detection unit includes a thermistor voltage collector, one end of the thermistor voltage collector is connected to the other end of the negative temperature coefficient thermistor, and the other end of the thermistor voltage collector is connected to the controller. a first analog-to-digital conversion interface connection; The backup battery voltage and current detection unit includes a series resistor, a series resistor terminal voltage collector and a backup battery terminal voltage collector; One end of the series resistance is connected to the positive pole of the backup battery, the other end of the series resistance is connected to one end of the load, and the other end of the load is grounded; The backup battery terminal voltage collector includes a backup battery voltage collector, one end of the backup battery voltage collector is connected to the positive pole of the backup battery, and the other end is connected to the second analog-to-digital conversion interface of the controller; The series resistor terminal voltage collector includes a series resistor voltage collector, one end of the series resistor terminal voltage collector is connected to the other end of the series resistor, and the other end of the series resistor terminal voltage collector is connected to the third analog-to-digital conversion interface of the controller connect; The controller is connected to the working power supply through the power interface, and is grounded through the ground interface; The memory includes a built-in memory and an external memory, one end of the external memory is connected to a power supply, and the external memory is grounded. 10 . The backup battery state of charge monitoring circuit according to claim 9 , wherein the backup battery temperature detection unit further comprises a voltage dividing resistor, one end of the voltage dividing resistor and the other end of the negative temperature coefficient thermistor. 11 . Connect, the other end of the voltage divider resistor is connected to the working power supply. 11. A method for monitoring the state of charge of a backup battery, comprising: Obtain the performance parameters of the monitored backup battery; Obtain the initial monitoring parameters of the monitored backup battery; Detecting the operating parameters of the monitored backup battery, selectively monitoring the state of charge of the monitored backup battery based on the acquired performance parameters, the initial monitoring parameters and the detected operating parameters, and updating the initial monitoring parameters, the updated initial monitoring parameters As the obtained initial monitoring parameter, or, updating the initial monitoring parameter and the performance parameter, the updated initial monitoring parameter is used as the obtained initial monitoring parameter, and the updated performance parameter is used as the obtained performance parameter; Wherein, the performance parameters include discharge voltages and corresponding calibrated battery capacities at different temperatures, the operating parameters include operating temperature parameters and discharge parameters of the monitored backup battery, and the monitored state of charge of the backup battery includes The duration of use of the monitored backup battery; Monitoring the usage time of the monitored backup battery includes: Detecting the operating temperature parameter of the monitored backup battery, and determining the current operating temperature of the monitored backup battery based on the monitored operating temperature parameter of the backup battery; Detecting the discharge parameter of the monitored backup battery, and determining the current discharge voltage and current discharge current of the monitored backup battery based on the monitored discharge parameter of the backup battery; Based on the determined current operating temperature and current discharge voltage of the monitored backup battery, the corresponding calibrated battery capacity is obtained from the performance parameters, based on the obtained calibrated battery capacity and the determined current discharge current of the monitored backup battery, Determining how long the backup battery is being monitored; The performance parameters also include: the calibration current and the corresponding calibration voltage under a specific load, the corresponding relationship between the capacity retention rate and the storage time at different temperatures, and the corresponding relationship between the capacity ratio and the number of cycles at different temperatures; The performance parameters are stored in the memory in the form of a table, the table storing the performance parameters is called a first table, and the updating the performance parameters includes updating the performance parameters stored in the first table; Wherein, the first table is divided into a first sub-table corresponding to the initial cycle usage times of the monitored backup battery is less than the set threshold value and corresponding to the initial cycle usage times of the monitored backup battery is greater than or equal to the set threshold value according to the set threshold value The second subtable of ; The initial monitoring parameters include: initial discharge current, initial discharge voltage, initial calibrated battery capacity, initial capacity retention rate and initial storage time, as well as initial capacity ratio and initial cycle times; The initial monitoring parameters are stored in the memory in the form of a table, and the table storing the initial monitoring parameters is called a second table; The updating of the initial monitoring parameters includes updating the initial monitoring parameters stored in the second table; The monitoring of the state of charge of the monitored backup battery, updating the initial monitoring parameters or updating the initial monitoring parameters and performance parameters, includes: Detecting the operating temperature parameter of the monitored backup battery, and determining the current operating temperature of the monitored backup battery based on the monitored operating temperature parameter of the backup battery; Determine whether the current operating temperature of the monitored backup battery is within the normal operating temperature range of the monitored backup battery; If it is not within the normal working temperature range, an alarm message of abnormal temperature is issued, and the operation is stopped; If it is within the normal operating temperature range, determine whether the initial cycle times of the monitored backup battery is less than the set threshold; if the initial cycle times of the monitored backup battery are less than the set threshold, read the first sub- The corresponding performance parameters in the table and the initial monitoring parameters in the second table, as well as the current operating temperature, current discharge voltage and current discharge current determined by the controller, monitor the state of the monitored backup battery power, and update the second table If the initial cycle times of the monitored backup battery is greater than or equal to the set threshold, read the corresponding performance parameters in the second sub-table and the initial monitoring parameters in the second table, and determine according to the controller current operating temperature, current discharge voltage and current discharge current, monitor the state of charge of the monitored backup battery, update the initial monitoring parameters in the second table, and then match the parameters in the second table and the second sub-table to determine Whether the monitored backup battery is in normal working state, and judge whether the monitored backup battery needs an alarm; Then, check the service life of the monitored backup battery, and judge whether the monitored backup battery is fully charged and discharged; If the monitored backup battery is not fully charged and discharged, indicating that the initial cycle usage times do not need to be updated, return to the operation described above if the initial cycle usage times of the monitored backup battery is less than the set threshold; if the monitored backup battery After complete charging and discharging, the update operation of the first table is performed. 12. The method of claim 11, wherein the performance parameters further comprise self-discharge parameters of the monitored backup battery at different temperatures, and wherein the controller is additionally based on the monitored self-discharge of the backup battery. Discharge parameters, comprehensively determine the usage time of the monitored backup battery; and / or, The performance parameter further includes a usage decay parameter of the monitored backup battery at different temperatures, and the controller additionally determines the usage time of the monitored backup battery comprehensively based on the monitored usage decay parameter of the backup battery. 13. The method according to claim 11, wherein the updating operation of the first table comprises: Add 1 to the initial number of cycles, and use the number of cycles after adding 1 as the new initial cycle, and then judge whether the new initial cycle is less than the set threshold. If the new initial cycle is less than the set value threshold, then perform the operation of whether the parameters of the first table are updated; if the new initial cycle times are greater than or equal to the set threshold, first update the first sub-table to the second sub-table, and compare the second table and the second sub-table to determine whether the monitored backup battery is in a normal working state, and to determine whether the monitored backup battery needs an alarm, and then perform the operation of whether to update the parameters of the first table. 14. The method according to claim 13, wherein the operation of whether the parameters of the first table are updated comprises: based on the current operating temperature, the current discharge voltage and the current discharge current determined by the controller, judging that the first table is stored Whether the calibration voltage and calibration current in the performance parameters of Update the calibration voltage and calibration current in the performance parameters stored in the first table, and then perform an operation of whether to update the cycle times in the performance parameters stored in the first table; The operation of whether to update the cycle times in the performance parameters stored in the first table includes: based on whether the monitored backup battery is fully charged and discharged, judging whether the cycle times in the performance parameters stored in the first table needs to be updated, if not. If updating is required, the updating operation of the first table ends; if updating is required, the updating operation of the first table ends after updating the number of cycles of use in the performance parameters stored in the first table. 15. The method according to any one of claims 11 to 14, characterized in that, the method is implemented by using the backup battery state of charge monitoring circuit according to any one of claims 1 to 10.

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