Battery electric quantity detection circuit, device and system

Abstract

The utility model belongs to the technical field of battery detection, and particularly relates to a battery electric quantity detection circuit, device and system. The battery electric quantity detection circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, an operational amplifier, an MCU module and a power module, the positive phase input end of the operational amplifier is connected with one end of a first resistor R1 and one end of a second resistor R2, and the negative phase input end of the operational amplifier is connected with one end of a third resistor R3 and one end of a fourth resistor R4. And the output end is connected with the ADC input end of the MCU module. The device comprises a shell and a remote communication module, a battery electric quantity detection circuit is fixed in the shell, and the remote communication module is connected with an MCU module. The system comprises a plurality of battery electric quantity detection devices, a communication module and a monitoring display screen. According to the battery electric quantity detection circuit provided by the utility model, the differential amplification circuit is formed by using the operational amplifiers, and the voltage signal of the detected battery is amplified to the available measuring range of the ADC input end of the whole MCU module, so that the measurement precision is greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to battery detection technical field, especially relate to a battery electric quantity detection circuit, device and system. BACKGROUND

[0002] The equipment such as electric vehicle master control, intelligent hardware, internet of things device and so on needing built-in battery power supply usually needs to measure battery voltage to master battery state in real time and prevent battery power from being too low to cause equipment operation anomaly.Usually, special electric quantity meter chip or resistance composition voltage division circuit is used to measure battery power.Special electric quantity meter chip can accurately measure battery voltage but cost is higher, and resistance voltage division circuit cannot accurately measure voltage value, for example, the resistance voltage division circuit described in the published Chinese invention application electronic product micro-power consumption battery voltage measurement circuit and method (CN117665612A), the general circuit diagram is as shown in Figure 1 . Figure 1 Among them, VBAT is battery voltage, RU is pull-up resistance, RD is pull-down resistance, C is filter capacitor, and the voltage signal after voltage division is connected to the ADC pin of MCU for sampling. From the parallel circuit voltage calculation formula: U=VBATxRD / (RD+RU).

[0003] The commercial built-in battery suitable for the above-mentioned scene generally adopts lithium ion battery, and the full charge voltage of the battery is 4.2V. Figure 2 is the discharge curve diagram of certain lithium battery, and from Figure 2 , it can be known that the stable discharge voltage is generally 3-3.5V according to different battery models, and the battery voltage will quickly drop with discharge below this voltage, so the stable work of the power consumption end cannot be guaranteed.

[0004] As stated above, the effective battery voltage detection range is generally 3-4.2V, about 1V or so, multiplied by the voltage division coefficient RD / (RD+RU), and finally the measured signal range of the ADC of MCU is only a few hundred mV, as an example:

[0005] When VBAT=4.2V, U=RD / (RD+RU)xVBAT=1 / 2VBAT=2.1V, and when VBAT=3.3V, U=RD / (RD+RU)xVBAT=1 / 2VBAT=1.65V, 2.1V-1.65V=0.45V, the ADC measurement range of the general MCU is related to the supply voltage, and is mostly 3.3V or 1.8V, so that most of the available range is wasted. Furthermore, the normal noise of the general hardware circuit is also several tens of mV, and if the noise is 30mV, the measurement error caused by the noise is 30mV / 450mV≈6.7%. Therefore, the measurement method has the problems of wasted ADC measurement range of the MCU and large measurement error. Content of the utility model

[0006] The utility model discloses a battery power detection circuit, device and system, and the specific technical scheme is as follows:

[0007] A battery power detection circuit, comprising a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier, an MCU module and a power module.

[0008] The noninverting input end of the operational amplifier is connected with one end of the first resistor R1 and one end of the second resistor R2 respectively, and the other end of the first resistor R1 is connected with the output end of the battery to be measured.

[0009] The inverting input end of the operational amplifier is connected with one end of the third resistor R3 and one end of the fourth resistor R4 respectively, the other end of the third resistor R3 is connected with the output end of the power module, and the other end of the fourth resistor R4 is connected with the ADC input end of the MCU module.

[0010] The output end of the operational amplifier is connected with the ADC input end of the MCU module.

[0011] Preferably, the resistance value of the first resistor R1 is equal to the resistance value of the third resistor R3.

[0012] Preferably, the resistance value of the second resistor R2 is equal to the resistance value of the fourth resistor R4.

[0013] Preferably, the resistance value of the first resistor R1 and the resistance value of the second resistor R2 satisfy the following relationship:

[0014]

[0015] Wherein, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, U maxThe maximum voltage value of the measurement range is measured for the ADC input end of the MCU module; VBAT max The voltage value output by the output end of the battery to be measured; V o The voltage value output by the output end of the power module.

[0016] Preferably, the power positive connection end of the operational amplifier is connected with the output end of the power module, and the power negative connection end of the operational amplifier is grounded.

[0017] A battery power detection device comprises the battery power detection circuit, and further comprises a shell and a remote communication module, the battery power detection circuit is fixed in the shell, and the remote communication module is connected with the MCU module; a connection end is arranged on the shell, and the connection end is used for being connected with the output end of the battery to be measured.

[0018] A battery power detection system comprises a plurality of battery power detection devices, and further comprises a communication module and a monitoring display screen; the communication module is connected with the monitoring display screen and the plurality of battery power detection devices.

[0019] Compared with the prior art, the battery power detection circuit has the following beneficial effects:

[0020] The battery power detection circuit of the utility model discloses a differential amplifier circuit by using the operational amplifier, and the battery voltage signal to be measured is amplified to the available range of the ADC input end of the whole MCU module, so that the measurement precision is greatly improved, and the circuit design is simple and low in cost.

[0021] The battery power detection device of the utility model discloses that the detection result of the battery power can be remotely transmitted through the remote communication module, and the detection result of the battery power is conveniently collected.

[0022] The battery power detection system of the utility model comprises a communication module and a monitoring display screen, the detection results of a plurality of battery power detection devices are collected through the communication module, and the detection results are displayed through the monitoring display screen, so that the battery power can be centrally monitored and managed. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, each element or part is not necessarily drawn according to the actual proportion.

[0024] Figure 1 It is a battery voltage measurement principle diagram in the prior art.

[0025] Figure 2 It is a discharge curve diagram of a certain lithium battery.

[0026] Figure 3 is the principle diagram of the battery power detection circuit of the utility model.

[0027] Figure 4 is the principle diagram of the battery power detection system of the utility model. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the utility model.

[0029] In the description of the utility model, it needs to be explained that the orientation or position relationship indicated by the terms "center", "vertical", "horizontal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side" and the like is the orientation or position relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model.

[0030] In the description of the utility model, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, more than and the like are not included in the number, above, below, within and the like are included in the number. If the terms "first", "second", "third" are described, they are only for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0031] In the description of the utility model, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "setting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific situation. The embodiments of the utility model will be described below according to the overall structure of the utility model.

[0032] Embodiment 1:

[0033] As Figure 3 shown, the embodiment provides a battery power detection circuit, which comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier, an MCU module, a power module; the positive input end of the operational amplifier is connected with one end of the first resistor R1 and one end of the second resistor R2 respectively, and the other end of the first resistor R1 is connected with the output end of the battery to be measured; the other end of the second resistor R2 is grounded.

[0034] The negative input end of the operational amplifier is connected with one end of the third resistor R3 and one end of the fourth resistor R4 respectively; the other end of the third resistor R3 is connected with the output end of the power module; the other end of the fourth resistor R4 is connected with the ADC input end of the MCU module; the output end of the operational amplifier is connected with the ADC input end of the MCU module. The power positive connection end of the operational amplifier is connected with the output end of the power module, and the power negative connection end of the operational amplifier is grounded.

[0035] Among them, the resistance value of the first resistor R1 is equal to the resistance value of the third resistor R3, and the resistance value of the second resistor R2 is equal to the resistance value of the fourth resistor R4. That is, R1=R3, R2=R4. The resistance value of the first resistor R1 and the resistance value of the second resistor R2 satisfy the following relationship:

[0036]

[0037] Among them, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, U max is the maximum voltage value of the ADC input end of the MCU module; VBAT max is the voltage value output by the output end of the battery to be measured; V o is the voltage value output by the output end of the power module.

[0038] The specific working principle of the utility model is:

[0039] The first resistor R1 collects the voltage VBAT output by the output end of the battery to be measured, and obtains the voltage UP after voltage division through the first resistor R1 and the second resistor R2, and inputs the positive input end of the operational amplifier; the third resistor R3 collects the voltage value V o output by the output end of the power module, and obtains the voltage UN after voltage division through the third resistor R3 and the fourth resistor R4, and inputs the negative input end of the operational amplifier; the operational amplifier inputs the voltage UP and the voltage UN after differential amplification to the ADC input end of the MCU module for measurement to obtain the voltage VBAT output by the output end of the battery to be measured.

[0040] In Figure 3In the circuit, OP is a general operational amplifier, R1-R4 are resistors, UP and UN are the voltages of the positive input terminal and the negative input terminal of the operational amplifier OP respectively, the whole circuit is powered by 3.3V, i.e. the voltage output by the output terminal of the power module o is 3.3V, and the ADC measurement range is 0V-3.3V, i.e. U is 3.3V.

[0041] For the general operational amplifier OP, UP=UN, and since the input impedance is very large, the current flowing into the positive input terminal and the negative input terminal is approximately 0mA, so:

[0042]

[0043] i.e. Simplifying formula (2) can obtain:

[0044]

[0045] Since UP=UN, (1) is brought into (3) to obtain:

[0046]

[0047] Setting R1=R3 and R2=R4, (4) can be simplified as:

[0048] U=R2 / R1*(VBAT-3.3); (5)

[0049] Formula (5) shows that U is the difference between the battery voltage VBAT to be measured and the voltage V o of the power module, which is then amplified by R2 / R1, so:

[0050]

[0051] If the upper limit VBAT max of the battery voltage VBAT to be measured is 4.2V, the upper limit voltage U max of the ADC measurement range is 3.3V, then R2 / R1≈3.667. Using this circuit to measure the battery voltage, VBAT=U*R1 / R2+3.3, the influence of 30mV noise on the measurement accuracy is 30mV / 3300mV≈0.9%, so the measurement error is greatly reduced.

[0052] The values of R1 and R2 can be selected according to the above ratio. Since VBAT is always discharged through R1 and R2, and considering the low power consumption requirement, the values of R1 and R2 can be selected to be larger. As an example, R1=100K@1% precision, R2=365K@1% precision, and the power consumption is about 38uA.

[0053] Embodiment 2:

[0054] Based on the same inventive concept as embodiment 1, this embodiment provides a battery power detection device, which comprises the battery power detection circuit, and further comprises a shell and a remote communication module, the battery power detection circuit is fixed in the shell, and the remote communication module is connected with the MCU module; the shell is provided with a connecting end, and the connecting end is used for connecting with the output end of the battery to be detected.

[0055] The working principle of the device is as follows: the principle of the battery power detection circuit is described above, and will not be repeated here. After the voltage VBAT of the battery to be detected is measured by the battery power detection circuit, the remote communication module uploads the measurement result of the battery power detection circuit.

[0056] The device can interact with external equipment, and the measurement result of the battery power detection circuit can be conveniently managed.

[0057] Embodiment 3:

[0058] Based on the same inventive concept as embodiment 1, this embodiment provides a battery power detection system, which comprises a plurality of battery power detection devices, and further comprises a communication module and a monitoring display screen; the communication module is connected with the monitoring display screen and the plurality of battery power detection devices.

[0059] The working principle of the system is as follows: after the measurement results of the battery power detection circuits are uploaded by the remote communication module, the system receives the transmission result of the remote communication module through the communication module, and displays the transmission result on the monitoring display screen, so that the monitoring personnel can check.

[0060] The foregoing description of the specific exemplary embodiments of the present application is for the purpose of illustration and explanation, and is not intended to limit the present application to the precise forms disclosed, and as is apparent to those skilled in the art, many changes and modifications can be made to the embodiments described herein, in light of the above teachings. Although embodiments of the present application have been shown and described, it is to be understood that the present application is not limited to the specific embodiments described, and that many changes and modifications can be made by one skilled in the art without departing from the scope of the present application. The specific features, structures, materials or characteristics described are chosen for the purpose of explanation only, and are not intended to limit the present application. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the present application and its practical application, so that those skilled in the art can make modifications, replacements, variations and various different selections and changes to the embodiments without creative contribution after reading the specification, as long as they are within the scope of the claims of the present application.

Claims

1. A battery power detection circuit, characterized by, The battery capacity detection circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier, an MCU module and a power module. The noninverting input end of the operational amplifier is connected with one end of the first resistor R1 and one end of the second resistor R2, respectively, and the other end of the first resistor R1 is connected with the output end of the battery to be detected; and the other end of the second resistor R2 is grounded. The inverting input end of the operational amplifier is connected with one end of the third resistor R3 and one end of the fourth resistor R4, respectively; the other end of the third resistor R3 is connected with the output end of the power module; and the other end of the fourth resistor R4 is connected with the ADC input end of the MCU module. The output end of the operational amplifier is connected with the ADC input end of the MCU module.

2. The battery power detection circuit according to claim 1, wherein The resistance value of the first resistor R1 is equal to that of the third resistor R3.

3. The battery power detection circuit according to claim 1, wherein The resistance value of the second resistor R2 is equal to that of the fourth resistor R4.

4. The battery power detection circuit of claim 1, wherein, The resistance value of the first resistor R1 and that of the second resistor R2 satisfy the following relationship: Wherein, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, U max The maximum voltage value of the measurement range for the ADC input end of the MCU module; VBAT max The voltage value output by the output end of the battery to be measured; V o The voltage value output by the output end of the power module.

5. The battery power detection circuit according to claim 1, wherein The power positive connection end of the operational amplifier is connected with the output end of the power module, and the power negative connection end of the operational amplifier is grounded.

6. A battery charge level detection apparatus characterized by comprising: The battery capacity detection circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier, an MCU module and a power module.

7. A battery power detection system, characterized by, The battery capacity detection circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier, an MCU module and a power module.

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