CN101359035A - Method and device for measuring battery internal resistance - Google Patents

Abstract

The invention provides a method and a device for measuring the battery internal resistance; the method and the device detect a discharge current or charge current I, as well as a discharge or charge voltage U1 of the battery under detection, and then detect a voltage U2 after discharge or charge of the battery under detection so as to calculate an internal resistance r of the battery under detection; and the internal resistance r is equal to (U2-U1)/I. The method and the device are easy to implement and are low in cost, which can be widely used in battery chargers, back-up power supplies and other mobile power supplies.

Description

Translated fromChinese

一种测量电池内阻的方法及装置Method and device for measuring battery internal resistance

技术领域technical field

本发明涉及一种测量电池内阻的方法及装置。The invention relates to a method and device for measuring battery internal resistance.

背景技术Background technique

测量电池内阻对于评价二次充电电池的寿命尤其重要。目前现有的电池内阻测量方法及装置主要有两种：一为交流测试法，如CN1818684A中公开的技术方案，其分别在对比电阻和待测电池两端施加峰值相同的周期性交流电流，然后测量该电流在对比电阻和待测电池两端引起的电压响应，由于电流相同则可通过比例运算以及对比电阻的阻值确定待测电池的内阻，这种方法及装置由于采用交流电所以需要各种信号处理电路、滤波电路等等，所以结构较为复杂、实施成本高、稳定性较差；二为直流脉冲测试法，这种方案通常使待测电池经由可变负载开始以大电流放电2分钟以上，这个大电流一般为5×(C/1小时)以上，其中C为电池额定容量，单位为毫安时(mAH)，然后以小电流放电，然后用计算机计算出两个电流所引起的电压差而计算出待测电池内阻，但是这种方案需要大电流放电，所以必然影响待测电池的寿命和容量，并且对方电电流要求比较高，电路比较复杂，成本高，且由于需要计算机所以适用范围受到很大限制。Measuring battery internal resistance is especially important for evaluating the life of secondary rechargeable batteries. At present, there are mainly two kinds of methods and devices for measuring the internal resistance of batteries: one is the AC test method, such as the technical solution disclosed in CN1818684A, which applies a periodic AC current with the same peak value at the two ends of the comparison resistance and the battery to be tested respectively, Then measure the voltage response caused by the current at both ends of the comparison resistor and the battery to be tested. Since the current is the same, the internal resistance of the battery to be tested can be determined through proportional calculations and the resistance value of the comparison resistor. This method and device require alternating current. Various signal processing circuits, filter circuits, etc., so the structure is relatively complex, the implementation cost is high, and the stability is poor; the second is the DC pulse test method, which usually makes the battery under test start to discharge with a large current through a variable load 2 Minutes or more, this large current is generally more than 5×(C/1 hour), where C is the rated capacity of the battery, and the unit is mAH, and then discharge with a small current, and then use a computer to calculate the current caused by the two currents. The internal resistance of the battery to be tested is calculated based on the voltage difference, but this solution requires large current discharge, so it will inevitably affect the life and capacity of the battery to be tested, and the current requirement of the other side is relatively high, the circuit is more complicated, the cost is high, and due to the need Therefore, the scope of application of computers is greatly limited.

综上所述，现有的测量电池内阻的方法及装置具有电路复杂、实施成本高、甚至影响电池寿命和容量的缺陷。To sum up, the existing methods and devices for measuring battery internal resistance have the disadvantages of complicated circuits, high implementation costs, and even affecting battery life and capacity.

发明内容Contents of the invention

本发明针对上述的现有的测量电池内阻的方法及装置具有电路复杂、实施成本高、甚至影响电池寿命和容量的缺陷，提供一种在不影响电池寿命和容量的前提下简单易行、成本低廉的测量电池内阻的方法及装置。The present invention aims at the above-mentioned existing methods and devices for measuring battery internal resistance, which have the defects of complex circuits, high implementation costs, and even affecting battery life and capacity, and provides a simple and easy-to-use method without affecting battery life and capacity. Method and device for measuring battery internal resistance with low cost.

本发明提供的测量电池内阻的方法包括以下步骤：使待测电池开始放电，或开始对待测电池充电；检测待测电池的放电电流或充电电流I，同时检测待测电池放电或充电时的电压U₁；使待测电池停止放电，或停止对待测电池充电；检测待测电池放电或充电后的电压U₂；计算待测电池的内阻r，该待测电池的内阻r＝(U₂-U₁)/I。The method for measuring the internal resistance of a battery provided by the present invention includes the following steps: starting to discharge the battery to be tested, or starting to charge the battery to be tested; detecting the discharge current or charging current I of the battery to be tested, and simultaneously detecting the battery to be tested. voltage U₁ ; stop the battery to be tested from discharging, or stop charging the battery to be tested; detect the voltage U₂ of the battery to be tested after discharging or charging; calculate the internal resistance r of the battery to be tested, and the internal resistance r of the battery to be tested = ( U₂ -U₁ )/I.

本发明提供的测量电池内阻的装置包括电流检测装置、电压检测装置和内阻计算器，所述电流检测装置用于检测待测电池放电或充电时的放电电流或充电电流I，所述电压检测装置用于分别检测待测电池放电或充电时的电压U₁以及待测电池放电或充电后的电压U₂，所述内阻计算器用于计算待测电池的内阻r，该待测电池的内阻r＝(U₂-U₁)/I。The device for measuring the internal resistance of the battery provided by the present invention includes a current detection device, a voltage detection device and an internal resistance calculator, the current detection device is used to detect the discharge current or the charging current I when the battery to be tested is discharged or charged, the voltage The detection device is used to respectively detect the voltage_U1 when the battery to be tested is discharged or charged and the voltage_U2 after the battery to be tested is discharged or charged. The internal resistance calculator is used to calculate the internal resistance r of the battery to be tested. The battery to be tested The internal resistance r=(U₂ −U₁ )/I.

通过使用本发明所提供的测量电池内阻的方法和装置可以通过控制待测电池放电或充电，然后停止放电或充电以此形成一个脉冲，通过检测到的放电或充电电流I以及放电或充电时的电压U₁、放电或充电后的电压U₂，根据欧姆定律计算电池内阻。从上面所描述的技术方案来看，本发明所提供的测量电池内阻的方法和装置电路简单、实施成本低廉、简单易行，并且这种方式提供的放电电流是小电流，不会影响电池的寿命和容量。本发明所提供的方法可以广泛应用于二次充电电池，特别适用于NI-MH、NI-Cd、锂离子电池，由于其简便易行，所以可以广泛适用于充电器和后备电源等可移动电源上。By using the method and device for measuring battery internal resistance provided by the present invention, it is possible to control the discharge or charge of the battery to be tested, and then stop the discharge or charge to form a pulse, through the detected discharge or charge current I and the time of discharge or charge The voltage U₁ of the battery, the voltage U₂ after discharge or charge, and the internal resistance of the battery are calculated according to Ohm's law. Judging from the technical solutions described above, the method and device for measuring battery internal resistance provided by the present invention have simple circuits, low implementation costs, and are simple and easy to implement, and the discharge current provided in this way is a small current, which will not affect the battery. life and capacity. The method provided by the present invention can be widely used in secondary rechargeable batteries, especially for NI-MH, NI-Cd, and lithium ion batteries. Because it is simple and easy to implement, it can be widely used in portable power sources such as chargers and backup power supplies superior.

附图说明Description of drawings

图1为根据本发明提供的测量电池内阻的装置的电路示意图；Fig. 1 is a schematic circuit diagram of a device for measuring battery internal resistance provided according to the present invention;

图2为根据本发明提供的测量电池内阻的装置的优选实施方式的电路示意图；2 is a schematic circuit diagram of a preferred embodiment of a device for measuring battery internal resistance provided by the present invention;

图3为根据本发明提供的测量电池内阻的装置的另一优选实施方式的电路示意图。Fig. 3 is a schematic circuit diagram of another preferred embodiment of the device for measuring battery internal resistance provided by the present invention.

具体实施方式Detailed ways

首先说明本发明提供的方法。First, the method provided by the present invention will be described.

本发明提供的测量电池内阻的方法包括以下步骤：使待测电池10开始放电，或开始对待测电池10充电；检测待测电池10的放电电流或充电电流I，同时检测待测电池放电或充电时的电压U₁；使待测电池10停止放电，或停止对待测电池10充电；检测待测电池放电或充电后的电压U₂；计算待测电池10的内阻r，该待测电池10的内阻r＝(U₂-U₁)/I。The method for measuring the internal resistance of the battery provided by the present invention includes the following steps: making the battery undertest 10 start to discharge, or start charging thebattery 10 under test; detecting the discharge current or charging current I of the battery undertest 10, and detecting the discharge or charging current I of the battery under test at the same time Voltage U₁ during charging; stop discharging thebattery 10 to be tested, or stop charging thebattery 10 to be tested; detect the voltage U₂ of the battery to be tested after discharging or charging; calculate the internal resistance r of the battery to be tested 10, the battery to be tested The internal resistance of 10 r=(U₂ −U₁ )/I.

其中通过将待测电池10与电阻26串联可以使得待测电池10对外放电，通过将待测电池10与电源串联可以对待测电池10充电。The battery undertest 10 can be discharged externally by connecting the battery undertest 10 in series with theresistor 26 , and the battery undertest 10 can be charged by connecting the battery undertest 10 in series with a power supply.

待测电池10刚开始放电或充电时放电或充电电流I并不稳定，所以优选是，当待测电池10开始放电或充电一段时间后，才检测待测电池10的放电电流或充电电流I、以及待测电池放电或充电时电压U₁。所经过的时间大于100毫秒，优选范围为100-1000毫秒。When the battery undertest 10 just begins to discharge or charge, the discharge or charging current I is not stable, so preferably, when the battery undertest 10 starts to discharge or charge after a period of time, the discharge current or the charging current I of the battery undertest 10 is detected. And the voltage U₁ of the battery under test when it is discharging or charging. The elapsed time is greater than 100 milliseconds, with a preferred range of 100-1000 milliseconds.

检测待测电池10的放电电流或充电电流I可以采用本领域人员公知的各种检测电流的方法，例如使用电流计、万用表、电流传感器等，也可以通过检测串联电阻26的电压并结合已知阻值获得。检测待测电池的电压U₁或U₂可以使用本领域人员公知的各种检测电压的方法，例如使用电压计等，可以通过检测待测电池10的对地电平而得到。Detecting the discharge current or charging current I of thebattery 10 to be tested can adopt various methods of detecting current known to those skilled in the art, such as using an ammeter, a multimeter, a current sensor, etc., or by detecting the voltage of theseries resistor 26 and combining known The resistance value is obtained. The voltage_U1 or_U2 of the battery under test can be detected by various voltage detection methods known to those skilled in the art, such as using a voltmeter, which can be obtained by detecting the ground level of the battery undertest 10 .

所述放电电流或充电电流I大于0.5×(C/1小时)，C为电池额定容量，例如1000mAH，这样I就大于500mA。这样的电流是小电流，不会影响电池寿命和容量。所述放电电流或充电电流I的优选范围为0.5×(C/1小时)-2×(C/1小时)。The discharge current or charge current I is greater than 0.5×(C/1 hour), C is the rated capacity of the battery, for example 1000mAH, so I is greater than 500mA. Such a current is a small current and will not affect battery life and capacity. The preferred range of the discharge current or charge current I is 0.5×(C/1 hour)-2×(C/1 hour).

下面结合图1-3说明本发明提供的测量电池内阻的装置20，如图1所示，其中，该装置20包括电流检测装置21、电压检测装置22和内阻计算器23，所述电流检测装置21用于检测待测电池10放电或充电时的放电电流或充电电流I，所述电压检测装置22用于分别检测待测电池放电或充电时的电压U₁以及待测电池放电或充电后的电压U₂，所述内阻计算器23用于计算待测电池10的内阻r，该待测电池10的内阻r＝(U₂-U₁)/I。Thedevice 20 for measuring battery internal resistance provided by the present invention is described below in conjunction with FIGS. 1-3, as shown in FIG. Thedetection device 21 is used to detect the discharge current or the charging current I when the battery undertest 10 is discharged or charged, and thevoltage detection device 22 is used to detect respectively the voltage_U1 and the discharge or charge voltage of the battery under test when the battery under test is discharged or charged. After the voltage U₂ , theinternal resistance calculator 23 is used to calculate the internal resistance r of the battery to be tested 10, and the internal resistance of the battery to be tested 10 r=(U₂ −U₁ )/I.

优选情况下，如图2所示，当放电或充电电流稳定时才开始检测放电或充电电流，因此该装置20还包括计时器24，当待测电池10开始放电或充电时计时器24开始计时，并且当计时器24计时到达预定时间时，该计时器24通知电流检测装置21检测此时的放电电流或充电电流I，并通知电压检测装置22检测此时的待测电池放电或充电时的电压U₁。其中所述预定时间大于100毫秒，优选范围为100-1000毫秒。并且，当所述计时器24计时到达预定时间时，计时器24清零。Preferably, as shown in Figure 2, the discharge or charge current is detected when the discharge or charge current is stable, so thedevice 20 also includes atimer 24, and thetimer 24 starts counting when thebattery 10 under test starts to discharge or charge , and when thetimer 24 reaches the predetermined time, thetimer 24 notifies thecurrent detection device 21 to detect the discharge current or the charging current I at this time, and notifies thevoltage detection device 22 to detect the discharge current or the charging current I of the battery under test at this time. Voltage U₁ . Wherein the predetermined time is greater than 100 milliseconds, preferably in the range of 100-1000 milliseconds. And, when thetimer 24 reaches the predetermined time, thetimer 24 is cleared.

优选情况下，如图2所示，本发明提供的测量电池内阻的装置20还包括开关25，串联在待测电池10的放电电路或充电电路中，用于控制待测电池10的放电或充电状态。其中所述开关25可以为各种具有控制端的可控开关，例如继电器、三极管或场效应管。上述的计时器24与继电器还可以构成时间继电器。Preferably, as shown in FIG. 2, thedevice 20 for measuring the internal resistance of the battery provided by the present invention further includes aswitch 25, which is connected in series in the discharge circuit or charging circuit of the battery undertest 10, and is used to control the discharge or charge of the battery undertest 10. charging. Theswitch 25 can be various controllable switches with control terminals, such as relays, triodes or field effect transistors. Above-mentionedtimer 24 and relay can also constitute time relay.

这种情况下，该装置20还包括开关控制器(未图示)，用于控制开关25的断开和闭合，例如通过控制三极管或场效应管的控制端(基极或门极)电压从而控制三极管或场效应管的导通或截止。In this case, thedevice 20 also includes a switch controller (not shown), which is used to control the opening and closing of theswitch 25, for example, by controlling the voltage of the control terminal (base or gate) of the triode or field effect transistor so that Control the conduction or cut-off of the triode or field effect tube.

所述电流检测装置21用于检测待测电池10的放电电流或充电电流I，如上所述，该放电电流或充电电流I大于0.5×(C/1小时)。所述放电电流或充电电流I的优选范围为0.5×(C/1小时)-2×(C/1小时)。所述电流检测装置21可以为本领域技术人员公知的各种用于检测电流的装置，优选为能将测得的电流输出到内阻计算器23的装置。优选情况下，如图2、3所示，本发明提供的测量电池内阻的装置还包括阻值为R的电阻26，该电阻26串联在待测电池10的放电电路或充电电路中，这时可以利用电压检测装置22通过检测该电阻26两端的电压U_R，从而获得所述放电电流或充电电流I，所述放电电流或充电电流I＝U_R/R，所以此时电压检测装置22与电流检测装置21实际上为同一电压检测装置。Thecurrent detection device 21 is used to detect the discharge current or charge current I of thebattery 10 to be tested. As mentioned above, the discharge current or charge current I is greater than 0.5×(C/1 hour). The preferred range of the discharge current or charge current I is 0.5×(C/1 hour)-2×(C/1 hour). Thecurrent detecting device 21 can be various devices for detecting current known to those skilled in the art, preferably a device capable of outputting the measured current to theinternal resistance calculator 23 . Preferably, as shown in Figures 2 and 3, the device for measuring the internal resistance of the battery provided by the present invention also includes aresistor 26 with a resistance value R, which is connected in series in the discharge circuit or charging circuit of thebattery 10 to be tested. At this time, thevoltage detecting device 22 can be used to detect the voltage_UR at both ends of theresistor 26, thereby obtaining the discharge current or charging current I, and the discharging current or charging current I=_UR /R, so thevoltage detecting device 22 It is substantially the same voltage detection device as thecurrent detection device 21 .

所述电压检测装置22可以选用本领域人员公知的各种用于检测电压的装置，如电压计等等，优选为能将测得的电压输出到内阻计算器23的装置。Thevoltage detecting device 22 can be selected from various devices for detecting voltage known to those skilled in the art, such as a voltmeter, etc., preferably a device capable of outputting the measured voltage to theinternal resistance calculator 23 .

所述内阻计算器23可以为具有普通计算功能的简单的计算机、单片机(MCU)等，如为单片机则上述的计时器24、开关控制器、电流检测装置21、电压检测装置22也可通过单片机实现，这种方式在图3中显示。图3中MCU可以通过检测待测电池10一端的对地电平获得待测电池10的电压U₁或U₂，而通过检测电阻26一端的对地电平获得电阻26的电压U_R。这样上述的电流检测装置21、电压检测装置22均可通过MCU实现，MCU也可以通过输出电平信号来控制开关25，此外MCU可以具备一般简单的计算功能，可以集成有内阻计算器23来计算内阻r。这样通过一个单片机就可以完成功能，更为简单易行。Describedinternal resistance calculator 23 can be simple computer, single-chip microcomputer (MCU) etc. that have common calculation function, as then above-mentionedtimer 24, switch controller,current detection device 21,voltage detection device 22 also can pass through as single-chip microcomputer SCM implementation, this way is shown in Figure 3. In FIG. 3 , the MCU can obtain the voltage U₁ or U₂ of the battery undertest 10 by detecting the ground level of one end of thebattery 10 to be tested, and obtain the voltage_UR of theresistor 26 by detecting the ground level of one end of theresistor 26 . In this way, the above-mentionedcurrent detection device 21 andvoltage detection device 22 can be realized by MCU, and the MCU can also control theswitch 25 by outputting a level signal. In addition, the MCU can have general and simple calculation functions, and can be integrated with aninternal resistance calculator 23 to Calculate the internal resistance r. In this way, the function can be completed by a single-chip microcomputer, which is simpler and easier to implement.

采用图2所提供的本发明的测量电池内阻的装置20的优选实施方式时，首先闭合开关25，待测电池10对外放电或充电，经过预定时间后检测电阻26两端的电压U_R，从而获得放电电流或充电电流I＝U_R/R，同时检测待测电池放电或充电时电压U₁。然后断开开关25，检测待测电池放电或充电后电压U₂。然后利用欧姆定律，由内阻计算器23计算待测电池10的内阻r＝(U₂-U₁)/I。本发明提供的方法和装置实施简单，成本低廉，可广泛使用于充电器和后备电源等可移动电源上。When using the preferred embodiment of thedevice 20 for measuring battery internal resistance provided in FIG. 2 , theswitch 25 is first closed, thebattery 10 to be tested is discharged or charged externally, and the voltage_UR at both ends of theresistor 26 is detected after a predetermined period of time, thereby Obtain the discharge current or charge current I=_UR /R, and detect the voltage U₁ of the battery under test at the time of discharge or charge. Then theswitch 25 is turned off to detect the voltage U₂ of the battery under test after discharge or charge. Then, the internal resistance r=(U₂ −U₁ )/I of thebattery 10 to be tested is calculated by theinternal resistance calculator 23 using Ohm's law. The method and device provided by the invention are simple to implement and low in cost, and can be widely used in mobile power sources such as chargers and backup power sources.

Claims (11)

1. method of measuring the internal resistance of cell, wherein, this method may further comprise the steps:

Make mesuring battary (10) begin discharge, or begin mesuring battary (10) is charged;

Detect discharge current or the charging current I of mesuring battary (10), the voltage U when detecting simultaneously mesuring battary discharge or charging₁

Make mesuring battary (10) stop discharge, or stop mesuring battary (10) is charged;

Voltage U after the discharge of detection mesuring battary or the charging₂

Calculate the internal resistance r of mesuring battary (10), the internal resistance r=(U of this mesuring battary (10)₂-U₁)/I.

2. method according to claim 1 wherein, after mesuring battary (10) begins at least 100 milliseconds of discharge or chargings, just detects discharge current or charging current I and the mesuring battary discharge of mesuring battary (10) or the voltage U when charging₁

3. method according to claim 2, wherein, when mesuring battary (10) begins discharge or charging 100-1000 millisecond, the voltage U when detecting the discharge current of mesuring battary (10) or charging current I and mesuring battary discharge or charging₁

4. method according to claim 1 and 2, wherein, discharge current or charging current I greater than 0.5 * (battery rated capacity/1 hour), less than 2 * (battery rated capacity/1 hour).

5. device of measuring the internal resistance of cell, wherein, this device (20) comprises current sensing means (21), voltage check device (22) and internal resistance counter (23); Voltage U when discharge current or charging current I when described current sensing means (21) is used to detect mesuring battary (10) discharge or charging, described voltage check device (22) are used for detecting mesuring battary discharge or charging respectively₁And the voltage U after mesuring battary discharge or the charging₂, described internal resistance counter (23) is used to calculate the internal resistance r of mesuring battary (10), the internal resistance r=(U of this mesuring battary (10)₂-U₁)/I.

6. device according to claim 5, wherein, this device (20) also comprises timer (24), timer (24) picks up counting when mesuring battary (10) begins discharge or charging, and when timer (24) timing arrives greater than scheduled time of 100 milliseconds, this timer (24) notice current sensing means (21) detects discharge current or the charging current I of this moment, and the voltage U of notice voltage check device (22) when detecting the mesuring battary discharge of this moment or charging₁

7. device according to claim 6, wherein, this device (20) also comprises timer (24), timer (24) picks up counting when mesuring battary (10) begins discharge or charging, and when timer (24) timing arrival span is the scheduled time of 100-1000 millisecond, this timer (24) notice current sensing means (21) detects discharge current or the charging current I of this moment, and the voltage U of notice voltage check device (22) when detecting the mesuring battary discharge of this moment or charging₁

8. according to the described device of arbitrary claim among the claim 5-7, wherein, this device (20) comprises that also resistance is the resistance (26) of R, is connected in the discharge circuit or charging circuit of mesuring battary (10) voltage U of described voltage check device (22) when detecting mesuring battary discharge or charging₁The time also detect the voltage U at this resistance (26) two ends simultaneously_RThereby, obtain described discharge current or charging current I, described discharge current or charging current I=U_R/ R.

9. according to the described device of arbitrary claim among the claim 5-7, wherein, discharge current or charging current I greater than 0.5 * (battery rated capacity/1 hour), less than 2 * (battery rated capacity/1 hour).

10. according to the described device of arbitrary claim among the claim 5-7, wherein, this device also comprises switch (25), is connected in the discharge circuit or charging circuit of mesuring battary (10), is used to control the discharge or the charged state of mesuring battary (10).

11. device according to claim 10, wherein, described switch (25) is relay, triode or field effect transistor, and this device also comprises on-off controller, is used for the closed and disconnected of gauge tap (25).

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