CN2692690Y

CN2692690Y - Detecting device for internal resistance of battery

Info

Publication number: CN2692690Y
Application number: CN 200320121520
Authority: CN
Inventors: 吴中明
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-12-29
Filing date: 2003-12-29
Publication date: 2005-04-13
Anticipated expiration: 2013-12-29

Abstract

The utility model relates to a detecting device for internal resistance of battery, adding a controlled current source circuit to measure in short time and to control and adjust measuring current. The detecting device for internal resistance of battery may obtain greater current magnitude and more stable closed current by using the controlled current source, thus more ideal measuring numeric area is obtained.

Description

A kind of accumulator internal resistance pick-up unit

Technical field

The utility model relates to a kind of accumulator internal resistance pick-up unit, uses controllable current source specifically and realizes the structural design of detection automatically.

Background technology

Along with Chinese national economy maintains sustained and rapid growth, all kinds of accumulators that are applied in office space and the daily life have also obtained being extensive use of, and the growth of particularly present various automobile sales volumes has driven the development and the renewal of battery technology more.Existing accumulator itself is a comparatively complicated electrochemical appliance, no matter is to use or stand-by state, and its internal soundness and electric property are all constantly changing.Do not use if place a period of time, because himself voltage reduces and can cause losing efficacy.Thereby, before using accumulator, all need it is detected or safeguards, otherwise can not guarantee the stable of voltage applying circuit.

Have at the measuring battery method multiple, existing comparatively common and adopted be the performance state of testing accumulator by the detection accumulator internal resistance.At present, the internal resistance measurement method is divided into modes such as DC-method and AC method again.AC measurment method adaptive surface is wider, but the result who measures and the wave mode of used signal, and with frequency and be that strength of current is relevant, the measuring instrument of different model differs greatly for the measurement result of same accumulator.DC-method is that accumulator is inserted dead load and carries out the discharge of big electric current, to measure the voltage drop before and after cutting off the power supply and to calculate the internal resistance of cell.

In a word, existing internal resistance measurement method all needs the long energising test duration, and the mode of this repeated measurement can cause progressive damage for the low capacity accumulator; And the range of current of existing internal resistance measurement method is comparatively limited, generally is to pacify between 70 peaces, so for large-capacity battery, its measuring accuracy is lower 30; Sometimes also can produce electric spark, thereby cause security threat surrounding environment.

Summary of the invention

Accumulator internal resistance pick-up unit described in the utility model is intended to address the above problem with deficiency and designs the novel detection device that the increase controllable current source is arranged, with the purpose that realizes that short time measurement and measurement electric current can be controlled and regulate.

Accumulator internal resistance pick-up unit described in the utility model mainly includes measurement data memory module, single-chip microcomputer, current probe, voltage probe, A/D converter, controlled DC current source, current sensor, current channel analog to digital converter, voltage channel analog to digital converter and voltage conversion circuit.

Described controlled DC current source links to each other with 2 current probes, and it measures the control that electric current is subjected to D/A converter.

Described controllable current source after the internal battery and jumbo capacitor parallel connection by measurement mechanism, is connected with power V-MOS pipe and is constituted.Capacitor can adopt electrochemical capacitor or ultracapacitor etc., and its effect is to play accumulation of energy discharge, the terminal voltage of protection internal battery and steady voltage source.

Power V-MOS pipe can adopt multitube parallel with the extend current scope as the current regulator of current source.

The drain electrode of the V-MOS pipe of described controlled DC current source connects the positive pole of tested accumulator.When controlled DC current source is controlled and when being in low-voltage, described V-MOS pipe is cut off.

When controlled DC current source is controlled and when reaching the cut-in voltage of V-MOS pipe, the V-MOS pipe is switched on, the source electrode and the voltage drop between the grid of V-MOS pipe are very little, thereby improve the electric current of tested accumulator higher value.

Comprise the voltage at the controllable current source two ends of V-MOS pipe by adjusting, reaching under the V-MOS pipe cut-in voltage situation that V-MOS pipe two ends are switched on and tested accumulator big electric current of moment is provided.

By using above-mentioned controllable current source structure, can reach tested range of current and improve bigger.

As the existing measuring battery current maxima that does not adopt above-mentioned controllable current source structure be:

I _Max=(E-η)/(R+R _X), wherein

RX is an outside batteries resistance, such as probe wire resistance and probe contact resistance;

R is the internal resistance of cell; E is a cell emf; Polarizing voltage when η is battery discharge.

After adopting controllable current source described in the utility model, the maximal value that can measure electric current is:

I _MAX=[(E-η)+E ₀]/(R+R _X), wherein

E ₀Being the equivalent voltage source of current source inside, is to be made of accumulator and its internal capacitance parallel connection.

The ratio of the maximum current flow that above-mentioned dual mode is measured is:

I _MAX/I _max＝(E-η)+E ₀/(E-η)＝1+E ₀/(E-η)

As tested cell emf value 12V, when imitating voltage source 12V, then maximum measurement electric current can increase more than 1 times.

Thereby, by the I that measures _MaxValue, and tested accumulator both end voltage difference can calculate the numerical value of the internal resistance R of tested accumulator.

As mentioned above, using accumulator internal resistance pick-up unit described in the utility model has the following advantages:

1, utilizes described controllable current source can obtain big current value, also can obtain comparatively stable closed current simultaneously, thereby reach comparatively desirable measurement span;

2, the controllable current source that is adopted can reach required range of current in the ultrashort time, thereby very little for tested internal storage battery performance damaged condition.The characteristic that this up to standard and release time is short can guarantee not damage the accumulator of low capacity basically;

3, adopting single-chip microcomputer is main control mode, by D/A digital-to-analog conversion Control current source current value range, thereby can effectively improve detection speed and precision.

Description of drawings

Fig. 1 is the circuit and the structural representation of described accumulator internal resistance pick-up unit;

Fig. 2 is described controllable current source and tested accumulator connection diagram.

Embodiment

As Fig. 1-shown in Figure 2, accumulator internal resistance pick-up unit described in the utility model mainly includes communication module, LCD MODULE, measurement data memory module, temperature sensor, single-chip microcomputer, keyboard, current probe, voltage probe, A/D converter, controlled DC current source, current sensor, current channel analog to digital converter, voltage channel analog to digital converter and voltage conversion circuit.

Described controlled DC current source links to each other with 2 current probes, and it measures the control that electric current is subjected to D/A converter, as shown in Figure 2,

Behind the internal battery Eo and jumbo capacitor C parallel connection of controllable current source by measurement mechanism, connect with power V-MOS pipe again and constitute.

Capacitor adopts electrochemical capacitor.

The drain electrode of V-MOS pipe connects the positive pole of tested accumulator.When controlled DC current source is controlled and when being in low-voltage, described V-MOS pipe is cut off.

When controlled DC current source is controlled and when reaching the cut-in voltage of V-MOS pipe, the V-MOS pipe is switched on, the source electrode of V-MOS pipe and the voltage drop VG between the grid are very little, thereby the electric current of tested accumulator higher value is provided.

When actual measurement, under the effect of voltage source Eo, power V-MOS pipe works in the constant current source region, as shown in Figure 2, source electrode by control V-MOS pipe and the voltage VG between the grid can the control survey electric currents, make electric current the utmost point in the short time (time that actual measurement goes out is between the 20-30 μ s) reach stable.

Described communication module can adopt RS232, RS484 or CAN type interface module, and realizes that data communication connects PC, thereby data output is handled for further statistics and analysis.

Described LCD MODULE is connected with single-chip microcomputer, can provide test data to show.

Described measurement data memory module is connected with single-chip microcomputer, can be set to ROM (read-only memory).

Described temperature sensor and single-chip microcomputer provide test battery environment temperature.

Described single-chip microcomputer can select 51 family chips.

Described current probe connects tested accumulator and controllable current source.

Described voltage probe connects current probe and tested accumulator, in order to the test battery tension.

Described D/A converter connects single-chip microcomputer and controllable current source, realizes the control output to controllable current source.

Described current sensor is exported in order to tested current conversion is become voltage V, and is sent to current channel modulus converter A/D 1;

Described voltage conversion circuit connects voltage probe and tested accumulator.To realize that tested battery tension is converted to the receptible range of voltage channel analog to digital converter.

Described voltage channel modulus converter A/D 2 converts the magnitude of voltage of voltage conversion circuit output to digital signal and transfers in the single-chip microcomputer.

Accumulator internal resistance pick-up unit as depicted in figs. 1 and 2, its workflow is:

Single-chip microcomputer is by D/A control controllable current source output current, measures closed circuit terminal voltage V1 after reaching setting value;

Cut off current source, after the inverse voltage of inductance is avoided in time-delay, record open end voltage V2;

Above-mentioned load voltage can record within 0.2 millisecond.

When calculated difference V2-V1, significant figure more than this difference has the 2-3 position, test result is effective, stops to measure result of calculation;

Promptly use voltage difference V2-V1 divided by the measured current value, thereby can obtain internal resistance of cell R.

Otherwise, the electric current preset value of adjustment current source, behind the battery recovery, starting current carries out next round to be measured, till the result is effectively by the time.

Claims

1, a kind of accumulator internal resistance pick-up unit, its measurement data memory module is connected with single-chip microcomputer, current probe connects tested accumulator, voltage probe connects current probe and tested accumulator, D/A converter connects single-chip microcomputer, voltage conversion circuit connects voltage probe and tested accumulator, and it is characterized in that: the controlled DC current source of described accumulator internal resistance pick-up unit links to each other with 2 current probes respectively.

2, accumulator internal resistance pick-up unit according to claim 1 is characterized in that: described controlled DC current source links to each other with current probe, after the internal battery and large value capacitor parallel connection by pick-up unit, connects with power V-MOS pipe and constitutes.。

3, accumulator internal resistance pick-up unit according to claim 2 is characterized in that: the drain electrode of the V-MOS pipe of described controlled DC current source connects the positive pole of tested accumulator.