阅读说明：本技术 一种对锂电池的电压电阻的测试方法 (Method for testing voltage resistance of lithium battery ) 是由 李金勇 于 2021-08-02 设计创作，主要内容包括：本发明涉及锂电池电压测试的技术领域,且公开了一种对锂电池的电压电阻的测试方法,借由于电池通道选择开关,差分放大及绝对值电路,检测电压时,首先通过模拟开关选择相应的电池,经过差分放大器,消除共模电压,再经绝对值处理及滤波,通过AD采样,即可得到单体电池的电压值,使用CAN通信,可以实现电压检测系统的系统级联,通过对电池组电压电阻进行检测,利用MSP43F149单片机进行实际采样,同时借由MAX14752高压模拟开关实现多串锂电池组单体电池电压检测系统的生成,因此本方法的模拟前端只需要两个模块开关,一个差分放大器,一个四通道的精密放大器及少量电阻电容,以此达到可以做到很小的体积,同时成本也很低,并且检测后拥有极高的精准度。(The invention relates to the technical field of lithium battery voltage test, and discloses a method for testing the voltage resistance of a lithium battery, which comprises the steps of selecting a corresponding battery through a battery channel selection switch and a differential amplification and absolute value circuit when detecting the voltage, eliminating common-mode voltage through a differential amplifier, processing and filtering absolute values, obtaining the voltage value of a single battery through AD sampling, using CAN communication to realize the system cascade of a voltage detection system, detecting the voltage resistance of a battery pack, using an MSP43F149 single chip microcomputer to carry out actual sampling, and realizing the generation of a multi-string lithium battery pack single battery voltage detection system through an MAX14752 high-voltage analog switch, therefore, the analog front end of the method only needs two module switches, one differential amplifier, a four-channel precision amplifier and a small amount of resistance capacitors, therefore, the volume can be very small, the cost is very low, and the detection has extremely high precision.)

1. A method for testing voltage resistance of a lithium battery comprises the following steps:

(a) firstly, a flying capacitor method is used, the flying capacitor method is composed of a switch array, a flying capacitor and a voltage follower circuit, when in detection, the capacitor is connected with a battery through the switch array to charge the capacitor, then the switch is disconnected, the capacitor is connected with the voltage follower circuit, and the voltage output by the voltage follower circuit is sampled, so that the primary battery voltage can be obtained;

(b) the resistance voltage division method is characterized in that a precise resistance network is used for dividing the voltage of the positive electrode of each battery, the results are subtracted one by one after AD sampling, and then the voltage of each battery is obtained;

(c) the voltage constructed by the discrete device is utilized to carry out a current conversion circuit, and meanwhile, the voltage conversion circuit is matched with a chip for detecting the voltage of the battery pack to carry out voltage detection, so that the detection voltage is obtained;

(d) comparing the values obtained by voltage testing of the lithium battery by three different methods, and thus obtaining the most accurate voltage testing result;

(e) then, by means of the battery channel selection switch and the differential amplification and absolute value circuit, when detecting the voltage, the corresponding battery is selected through the analog switch, the common mode voltage is eliminated through the differential amplifier, then the voltage value of the single battery can be obtained through absolute value processing and filtering and AD sampling.

2. The method for testing the voltage resistance of a lithium battery as claimed in claim 1, wherein: the adoption flies the electric capacity method and influences the battery less, and the precision is also higher, and when the battery quantity is less, can adopt ordinary analog switch, when the battery quantity is more, has surpassed analog switch's output range, can adopt the relay as the switch, but receives the switching speed and the life-span influence of relay, causes detection speed slow, and the time of following the voltage action has the noise moreover, also can adopt the photoelectricity MOS relay this moment, carries out different devices according to the battery of different quantity and tests like this, improves the precision to battery voltage resistance detection.

3. The method for testing the voltage resistance of a lithium battery as claimed in claim 1, wherein: the method is influenced by resistance precision, the precision of detection by a resistance voltage division method is low, accumulated errors are easy to generate, the resolution ratio of AD sampling is reduced due to resistance voltage division, in addition, because the static current of each battery in the series battery pack is different due to a resistance network, the influence on the consistency of the battery pack is large for a long time, but the effect of low cost and quick detection can be achieved by adopting the resistance voltage division method for detection.

4. The method for testing the voltage resistance of a lithium battery as claimed in claim 3, wherein: when the number of the batteries is small, a differential mode voltage method can be adopted, and the operational amplifier is generally adopted to eliminate the common mode voltage at two ends of the batteries, so that the method for rapidly detecting the voltage and the resistance of the batteries can be achieved.

5. The method for testing the voltage resistance of a lithium battery as claimed in claim 1, wherein: because the output of the differential amplifier has negative voltage, a high-precision absolute value processing circuit is added at the rear end of the differential amplifier, and the absolute value circuits all adopt resistors with the precision of 0.1%, so that the voltage resistor detection result can be obtained with the maximum precision.

6. The method for testing the voltage resistance of a lithium battery as claimed in claim 1, wherein: the battery pack voltage resistance is detected, the MSP43F149 single chip microcomputer is used for actual sampling, and meanwhile, the generation of a multi-string lithium battery pack single cell voltage detection system is realized by virtue of the MAX14752 high-voltage analog switch, so that the analog front end of the method only needs two module switches, a differential amplifier, a four-channel precision amplifier and a small amount of resistance capacitors, thereby achieving the purposes of small volume, low cost and extremely high precision after detection.

7. The method for testing the voltage resistance of a lithium battery as claimed in claim 1, wherein: when the battery pack is detected, the system cascade of the voltage detection system CAN be realized by using CAN communication, and the single voltage test is provided for a plurality of series lithium battery packs.

Technical Field

The invention relates to the technical field of lithium battery voltage testing, in particular to a method for testing voltage resistance of a lithium battery.

Background

With the development of lithium ion battery technology, lithium ion batteries are increasingly used in many new energy fields such as power and energy storage. In the applications, dozens of or even hundreds of single batteries need to be connected in series to achieve the required voltage, in order to ensure the normal operation of the battery pack, the safety management of the lithium ion battery is needed, the real-time monitoring of the voltage, the temperature and the total current of the single batteries in the lithium battery pack is an important basis of the safety management, the detection of the temperature and the total current of the battery is relatively simple, the temperature detection can be detected by adopting a thermistor or a digital temperature sensor, the total current detection can be detected by adopting a hall current sensor or a shunt resistor, and the detection of the voltage of the single batteries of the battery pack cannot directly sample the voltage of the battery due to the existence of common-mode voltage at two ends of the battery, and other measures are needed to detect the voltage of the single batteries of the battery pack.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a method for testing the voltage resistance of a lithium battery.

(II) technical scheme

In order to achieve the purposes of low cost and extremely high precision after detection, the invention provides the following technical scheme: a method for testing voltage resistance of a lithium battery comprises the following steps:

(a) firstly, a flying capacitor method is used, the flying capacitor method is composed of a switch array, a flying capacitor and a voltage follower circuit, when in detection, the capacitor is connected with a battery through the switch array to charge the capacitor, then the switch is disconnected, the capacitor is connected with the voltage follower circuit, and the voltage output by the voltage follower circuit is sampled, so that the primary battery voltage can be obtained;

(b) the resistance voltage division method is characterized in that a precise resistance network is used for dividing the voltage of the positive electrode of each battery, the results are subtracted one by one after AD sampling, and then the voltage of each battery is obtained;

(c) the voltage constructed by the discrete device is utilized to carry out a current conversion circuit, and meanwhile, the voltage conversion circuit is matched with a chip for detecting the voltage of the battery pack to carry out voltage detection, so that the detection voltage is obtained;

(d) comparing the values obtained by voltage testing of the lithium battery by three different methods, and thus obtaining the most accurate voltage testing result;

(e) then, by means of the battery channel selection switch and the differential amplification and absolute value circuit, when detecting the voltage, the corresponding battery is selected through the analog switch, the common mode voltage is eliminated through the differential amplifier, then the voltage value of the single battery can be obtained through absolute value processing and filtering and AD sampling.

Preferably, the flying capacitor method is adopted to have small influence on the batteries, the precision is high, when the number of the batteries is small, a common analog switch can be adopted, when the number of the batteries is large, the output range of the analog switch is exceeded, a relay can be adopted as the switch, the detection speed is low due to the influence of the switching speed and the service life of the relay, noise exists when voltage acts, the photoelectric MOS relay can be adopted, different devices can be tested according to the number of the batteries, and the accuracy of detecting the voltage resistance of the batteries is improved.

Preferably, the accuracy of detection by the resistance voltage division method is relatively low and is easy to generate accumulated errors due to the influence of resistance accuracy, the resolution of AD sampling is reduced due to resistance voltage division, and in addition, static currents of each battery in the series battery pack are different due to a resistance network, so that the consistency of the battery pack is relatively large in long-term influence, but the effect of low cost and rapid detection can be achieved by adopting the resistance voltage division method for detection.

Preferably, when the number of the batteries is small, a differential mode voltage method can be adopted, and an operational amplifier is generally adopted to eliminate the common mode voltage at two ends of the batteries, so that a method for rapidly detecting the voltage and the resistance of the batteries can be achieved.

Preferably, since the output of the differential amplifier has a negative voltage, a high-precision absolute value processing circuit is added at the rear end of the differential amplifier, and the absolute value processing circuit adopts resistors with 0.1% precision, so that a voltage resistor detection result can be obtained with maximum precision.

Preferably, the battery pack voltage resistance is detected, the MSP43F149 single chip microcomputer is used for actual sampling, and the generation of the multi-string lithium battery pack single cell voltage detection system is realized by virtue of the MAX14752 high-voltage analog switch, so that the analog front end of the method only needs two module switches, a differential amplifier, a four-channel precision amplifier and a small amount of resistance capacitors, thereby achieving the purposes of small volume, low cost and extremely high precision after detection.

Preferably, when the battery pack is detected, the system cascade of the voltage detection system CAN be realized by using CAN communication, and the single voltage test is provided for a plurality of series lithium battery packs.

(III) advantageous effects

Compared with the prior art, the invention provides a method for testing the voltage resistance of a lithium battery, which has the following beneficial effects:

1. according to the method for testing the voltage resistance of the lithium battery, the voltage resistance of the battery pack is detected, the MSP43F149 single chip microcomputer is used for actually sampling, and meanwhile, the MAX14752 high-voltage analog switch is used for generating a multi-string lithium battery pack single battery voltage detection system, so that the analog front end of the method only needs two module switches, a differential amplifier, a four-channel precision amplifier and a small amount of resistance capacitors, and therefore the method can achieve the purposes of achieving a very small size, is very low in cost and has extremely high precision after detection.

2. This test method to voltage resistance of lithium cell, it is less to adopt the flying capacitor method to influence the battery, the precision is also higher, when the battery quantity is less, can adopt ordinary analog switch, however when the battery quantity is more, surpass analog switch's output range, can adopt the relay as the switch, but receive the switching speed and the life-span influence of relay, cause detection speed slow, and noise when relaying voltage action, also can adopt photoelectricity MOS relay this moment, carry out different devices according to the battery of different quantity and test like this, improve the precision to battery voltage resistance detection.

3. According to the method for testing the voltage resistance of the lithium battery, due to the influence of resistance precision, the detection precision of a resistance voltage division method is low, accumulated errors are easy to generate, the resolution ratio of AD sampling is reduced due to resistance voltage division, in addition, due to the fact that static currents of all batteries in a series battery pack are different due to a resistance network, the influence on the consistency of the battery pack is large for a long time, but the effect of low cost and rapid detection can be achieved by adopting the resistance voltage division method for detection.

4. According to the method for testing the voltage resistance of the lithium battery, a differential mode voltage method can be adopted when the number of batteries is small, and the common mode voltage at two ends of the batteries is generally eliminated by adopting an operational amplifier, so that the method for rapidly detecting the voltage and the resistance of the batteries can be achieved.

5. According to the method for testing the voltage resistance of the lithium battery, the negative voltage is generated due to the output of the differential amplifier, so that a high-precision absolute value processing circuit is added at the rear end of the differential amplifier, and the absolute value processing circuit adopts the resistors with the precision of 0.1%, so that the voltage resistance detection result can be obtained with the maximum precision.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

A method for testing voltage resistance of a lithium battery comprises the following steps:

(a) firstly, a flying capacitor method is used, which comprises a switch array, a flying capacitor and a voltage follower circuit, when in detection, the capacitor is connected with a battery through the switch array to charge the capacitor, then the switch is disconnected, the capacitor is connected with the voltage follower circuit, and the voltage output by the voltage follower circuit is sampled, so that the preliminary battery voltage can be obtained, the flying capacitor method has small influence on the battery and higher precision, when the number of the battery is less, a common analog switch can be adopted, however, when the number of the battery is more, the output range of the analog switch is exceeded, a relay can be adopted as the switch, but the detection speed is slow due to the influence of the switching speed and the service life of the relay, and noise exists when the voltage acts, a photoelectric MOS relay can also be adopted, so that different devices can be tested according to different numbers of the battery, the accuracy of detecting the voltage resistance of the battery is improved;

(b) the resistance voltage division method is characterized in that a precise resistance network is used for dividing the voltage of the positive electrode of each battery, the results are subtracted one by one after AD sampling, the voltage of each battery is obtained and is influenced by resistance precision, the detection precision of the resistance voltage division method is low, accumulated errors are easy to generate, the resolution of AD sampling is reduced due to resistance voltage division, in addition, because the static current of each battery in a series battery pack is different due to the resistance network, the influence on the consistency of the battery pack is large for a long time, but the detection of the resistance voltage division method can achieve the effects of low cost and rapid detection;

(c) the voltage constructed by discrete devices is utilized to carry out a current conversion circuit, and meanwhile, the voltage detection is carried out by matching with a chip for detecting the voltage of the battery pack, so that the detection voltage is obtained, when the number of batteries is small, a differential mode voltage method can be adopted, and the operational amplifier is generally adopted to eliminate the common mode voltage at two ends of the batteries, so that the method for rapidly detecting the voltage and the resistance of the batteries can be achieved;

(d) comparing the values obtained by voltage testing of the lithium battery by three different methods, and obtaining the most accurate voltage testing result according to the values, wherein a high-precision absolute value processing circuit is added at the rear end of the differential amplifier due to the fact that negative voltage exists in the output of the differential amplifier, and the absolute value processing circuit adopts resistors with 0.1% precision, so that the voltage resistance testing result can be obtained with the maximum accuracy;

(e) then, with the aid of a battery channel selection switch and a differential amplification and absolute value circuit, when detecting voltage, a corresponding battery is selected through an analog switch, common-mode voltage is eliminated through a differential amplifier, then absolute value processing and filtering are carried out, voltage values of single batteries can be obtained through AD sampling, voltage resistance of the battery pack is detected, actual sampling is carried out through an MSP43F149 single chip microcomputer, and meanwhile generation of a multi-string lithium battery pack single battery voltage detection system is achieved through an MAX14752 high-voltage analog switch.

Example two

A method for testing voltage resistance of a lithium battery comprises the following steps:

(a) firstly, a flying capacitor method is used, which comprises a switch array, a flying capacitor and a voltage follower circuit, when in detection, the capacitor is connected with a battery through the switch array to charge the capacitor, then the switch is disconnected, the capacitor is connected with the voltage follower circuit, and the voltage output by the voltage follower circuit is sampled, so that the preliminary battery voltage can be obtained, the flying capacitor method has small influence on the battery and higher precision, when the number of the battery is less, a common analog switch can be adopted, however, when the number of the battery is more, the output range of the analog switch is exceeded, a relay can be adopted as the switch, but the detection speed is slow due to the influence of the switching speed and the service life of the relay, and noise exists when the voltage acts, a photoelectric MOS relay can also be adopted, so that different devices can be tested according to different numbers of the battery, the accuracy of detecting the voltage resistance of the battery is improved;

(b) the resistance voltage division method is characterized in that a precise resistance network is used for dividing the voltage of the positive electrode of each battery, the results are subtracted one by one after AD sampling, the voltage of each battery is obtained and is influenced by resistance precision, the detection precision of the resistance voltage division method is low, accumulated errors are easy to generate, the resolution of AD sampling is reduced due to resistance voltage division, in addition, because the static current of each battery in a series battery pack is different due to the resistance network, the influence on the consistency of the battery pack is large for a long time, but the detection of the resistance voltage division method can achieve the effects of low cost and rapid detection;

(c) the voltage constructed by discrete devices is utilized to carry out a current conversion circuit, and meanwhile, the voltage detection is carried out by matching with a chip for detecting the voltage of the battery pack, so that the detection voltage is obtained, when the number of batteries is small, a differential mode voltage method can be adopted, and the operational amplifier is generally adopted to eliminate the common mode voltage at two ends of the batteries, so that the method for rapidly detecting the voltage and the resistance of the batteries can be achieved;

(d) comparing the values obtained by voltage testing of the lithium battery by three different methods, and obtaining the most accurate voltage testing result according to the values, wherein a high-precision absolute value processing circuit is added at the rear end of the differential amplifier due to the fact that negative voltage exists in the output of the differential amplifier, and the absolute value processing circuit adopts resistors with 0.1% precision, so that the voltage resistance testing result can be obtained with the maximum accuracy;

(e) then, when detecting the voltage, the corresponding battery is selected by the analog switch, the common mode voltage is eliminated by the differential amplifier, the voltage value of the single battery CAN be obtained by absolute value processing and filtering and AD sampling, the voltage resistance of the battery pack is detected, the actual sampling is carried out by the MSP43F149 single chip microcomputer, and the generation of the voltage detection system of the single battery of the multi-string lithium battery pack is realized by the MAX14752 high-voltage analog switch, therefore, the analog front end of the method only needs two module switches, one differential amplifier, a four-channel precise amplifier and a small amount of resistance capacitance, thereby achieving the small volume, simultaneously having low cost and extremely high precision after detection, and when detecting the battery pack, the CAN communication is used, the system cascade of the voltage detection system can be realized, and the single voltage test is provided for a plurality of series lithium battery packs.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.