A gas meter and a method for evaluating the selection of supercapacitors

Abstract

The present invention discloses a method for evaluating the selection of supercapacitors. The supercapacitors are adopted and loaded in the circuit of an electronic device. The method for evaluating the selection of supercapacitors is used to determine whether the supercapacitors that may be selected by the electronic device meet the reliability requirements of the electronic device. The evaluation method includes the following steps: obtaining the proportion of different operating voltages in the total operating time when the electronic device is working; obtaining the proportion of different ambient temperatures in the total operating time when the electronic device is working; obtaining the expected life time of the supercapacitors at different temperatures; and calculating and evaluating whether the supercapacitors meet the design life requirements of the electronic device according to the obtained data.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic equipment development, and in particular relates to a gas meter and a method for selecting a supercapacitor based on its expected life span. Background Art

[0002] Gas meters have been widely used. As the core component of gas meters, the controller in gas meters is stable and reliable, which is the premise for ensuring the product life cycle. Among them, the supercapacitor on the controller is an energy storage element. On the one hand, it ensures the large current supply reported by the meter on a daily basis. On the other hand, it can ensure that the meter closes the valve and reports when an abnormality occurs in the meter, notify the gas company of relevant alarm information, and remind repairs and maintenance. It plays an immeasurable role in the entire working cycle of the controller. Therefore, since the supercapacitor participates in the power supply process of the entire working process of the gas meter controller, its own quality stability, reliability and expected life assessment are particularly important for the stability of the gas meter.

[0003] At present, domestic gas manufacturers choose supercapacitors mainly from the two aspects of brand and withstand voltage. The main brands are Panasonic, Black King Kong, and Sapphire. The withstand voltage of the capacitor is mainly rated voltage 2.7V single, 3.0V single, 5.0V dual, 5.5V dual, etc. Many gas meter manufacturers only know the withstand voltage of the capacitor when choosing supercapacitors, and do not consider the power supply characteristics of the gas meter at all when designing. The quality and life are guaranteed by the brand. There is no reliable basis for whether the design is reasonable and whether the design is redundant. Often, the circuit is damaged due to unreasonable supercapacitor circuit design, which leads to accidents of batch recall of gas meters. Of course, it may also be because the supercapacitor circuit design is too redundant, which may cause the supercapacitor to work unsaturated and fail to achieve the expected function on the one hand, and on the other hand, it will cause a lot of design waste, affecting the profit of the product. Summary of the invention

[0004] One embodiment of the present invention provides a method for evaluating the expected life of a supercapacitor in a gas meter, wherein the supercapacitor is used and loaded on a circuit of the gas meter. The evaluation method comprises the following steps:

[0005] Obtaining the proportion of different working voltages in the total working time of the gas meter when it is working;

[0006] Obtaining the proportion of different ambient temperatures in the total working time of the gas meter when it is working;

[0007] Obtaining the expected life span of the supercapacitor at different temperatures;

[0008] The obtained data is used to calculate and evaluate whether the supercapacitor meets the design life requirements of the gas meter.

[0009] One of the beneficial effects of the embodiment of the present invention is that, starting from the power supply characteristics of the gas meter, the temperature factor and the voltage factor are discussed respectively, and a method for evaluating the expected life of the supercapacitor in the gas meter is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, in which:

[0011] Figure 1 Current consumption and discharge pulse curve of a gas meter according to one embodiment of the present invention.

[0012] Figure 2 A circuit diagram of a gas meter operating current power consumption simulation test according to one embodiment of the present invention. DETAILED DESCRIPTION

[0013] According to one or more embodiments, the expected life of existing supercapacitors has the following characteristics:

[0014] 1) Life expectancy is inversely proportional to temperature factor and voltage factor;

[0015] 2) Life expectancy doubles for every 10 degrees drop in temperature;

[0016] 3) For every 0.2V drop in operating voltage, the expected life span doubles.

[0017] A process for evaluating the expected life of a supercapacitor on a gas meter. Based on the characteristics of the expected life of the supercapacitor and the problem that the initial withstand voltage of the supercapacitor is relatively high, the following evaluation is carried out:

[0018] S101, if it is assumed that the gas meter uses 4 dry batteries, the actual voltage range used by the gas meter is 6.5-4.8V, and the usage ratio of the gas meter under different voltages is obtained; the gas meter is powered by 4 1.5V dry batteries connected in series, and the voltage of a single dry battery is generally around 1.62-1.63V when it is fully charged, and 4 batteries are 6.5V. After using for a period of time, the voltage of the dry battery will drop. When it drops to a total voltage of 4 batteries in series below 4.8V, the gas meter cannot guarantee the normal operation of all functions, so the working voltage range of the gas meter is set to 6.5-4.8V.

[0019] S102, obtaining the actual temperature environment and weight of the gas meter (the design temperature range of the gas meter is: -25 to 55°C);

[0020] S103, obtaining life expectancy data of supercapacitors of different models used in the gas meter at different voltages and temperatures;

[0021] S104, evaluating whether the original design of the supercapacitor working environment meets the expected life span based on the acquired data and the actual working conditions of the table.

[0022] In order to obtain the evaluation data, in S101, the current consumption and discharge pulse curve of the gas meter in actual operation are first obtained. The data is evaluated according to the following Table 1:

[0023] Table 1

[0024]

[0025] In the above table 1, pulse 1 means that the meter works for 1.5 seconds every hour, which is similar to a pulse signal. Similarly, pulse 2 means that the meter works for 60 seconds every 24 hours. The pulse is generated by the MCU in response to the events of the gas meter (for example, data storage is performed every hour and data reporting communication is performed every day). The period of pulse generation is determined by the period of events in the gas meter. Pulse 3 is a specific peak under the whole of pulse 2.

[0026] Secondly, according to the current consumption and discharge pulse curve of the gas meter, a single battery constant resistance discharge is used to approximate the working condition of the gas meter. The discharge current is controlled at about 30mA, and the simulated discharge interval is 4h / d to speed up the test time.

[0027] Take a single battery under 43Ω constant resistance discharge, discharge interval 4h / d, discharge current about 30mA, simulate the external power supply current of the gas meter, the following Table 2 is the original battery discharge table provided by a battery manufacturer.

[0028] Table 2

[0029]

[0030]

[0031] Here, the voltage of the supercapacitor = (battery voltage - diode voltage drop) / 2;

[0032] like Figure 2 In the simulation test circuit shown, the two diodes D1 and D2 are a group of reliability devices in the explosion-proof system. The voltage drop is calculated according to the tube voltage drop of a single diode, and the diode tube voltage drop is calculated as 0.6V; C1 and C2 are both supercapacitors connected in series in the circuit, and R1 is a power resistor that limits the charging current of the supercapacitor to ensure that the explosion-proof requirements of the meter are met.

[0033] The proportion of working voltage of supercapacitors in the whole life cycle of the corresponding gas meter is shown in Table 3:

[0034] Table 3

[0035] Actual approximate equivalent capacitive load voltage Weight 2.8V (actual 2.9~2.7V, take 2.8V) 3.858％ 2.6V (actual 2.7~2.5V, take 2.6V) 13.818％ 2.4V (actual 2.5~2.3V, take 2.4V) 35.927％ 2.2V (actual 2.3~2.1V, take 2.2V) 46.398％

[0036] The evaluation of the temperature ratio of the supercapacitor in the gas meter throughout its life cycle is carried out according to the following Table 4:

[0037] Table 4

[0038] Working temperature(℃) -25 -10 5 20 35 50 55 percentage(%) 2 10 15 50 15 5 3

[0039] When calculating the expected life, the expected life table provided by the supercapacitor manufacturer is used for evaluation. The evaluation temperature point is 55℃ (the highest operating temperature in Table 4), and the selected data for evaluation is as shown in the red box mark in the figure above. The 2.4V and 2.2V parts are calculated as 10.57 years (the actual value is greater than 10.57 years). The actual table is as follows in Table 5:

[0040] Table 5

[0041]

[0042] Finally, it can be obtained that the minimum expected life of the supercapacitor at 55°C is 10.37 years. According to the previous derivation and analysis, it can be known that the expected life of the supercapacitor at other temperatures (-25°C ≤ T < 55°C) will be higher than the value at 55°C, which meets the requirement that the full life cycle of the gas meter is not less than 10 years.

[0043] Therefore, the beneficial technical effects of the present invention include:

[0044] The expected life span of supercapacitors in gas meters has been evaluated;

[0045] Reduces the uncertainty of product design and avoids the batch recall of gas meters due to unreasonable design of supercapacitor life expectancy;

[0046] Avoid design waste in gas meter controllers due to conservative design, which will affect product competitiveness.

[0047] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for evaluating the expected life of a super capacitor in a gas meter, characterized in that, the method includes the steps: S101. The gas meter uses 4 dry batteries, and the voltage range used by the gas meter is 6.5 - 4.8V. Obtain the usage proportion of the gas meter at different voltages; S102. Obtain the actual temperature environment conditions and weights of the gas meter used. The designed temperature range of the gas meter is: -25 - 55°C; S103. Obtain the expected life data of the super capacitor used in the gas meter at different voltages and different temperatures; S104. Evaluate whether the working environment of the super capacitor meets the expected life. Among them, According to the current consumption and discharge pulse curve of the gas meter, use a single - cell battery constant - resistance discharge to simulate the working condition of the gas meter. The discharge current is controlled at 30mA. To accelerate the test time, the simulated discharge interval is 4h / d. Take the case of a single - cell battery discharging at a constant resistance of 43Ω, with a discharge interval of 4h / d and a discharge current of 30mA to simulate the external power supply current situation of the gas meter, obtain the proportion of the working voltage of the super capacitor in the gas meter during its entire life cycle, the proportion of the temperature of the super capacitor in the gas meter during its entire life cycle, Add up the expected life durations at different working voltages to obtain the minimum expected life of the super capacitor.

2. A gas meter, characterized in that, the super capacitor in the gas meter is selected by using the evaluation method described in claim 1.

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