CN214067341U - Battery internal resistance/voltage converter - Google Patents

Abstract

The utility model discloses a battery internal resistance/voltage converter in the technical field of battery measurement and test, which comprises an outer shell, wherein four-end test clamps and an output plug are respectively arranged outside the outer shell, a PCB (printed circuit board) is arranged inside the outer shell, and an intermittent constant current discharge circuit, a differential amplification circuit and a low-pass filter circuit are arranged on the PCB; intermittent type constant current discharge circuit includes constant current discharge circuit and square wave generator, and constant current discharge circuit presss from both sides with four end test respectively and square wave generator electricity is connected, and difference amplifier circuit is connected with four end test clamp's two-stage electricity, and difference amplifier circuit is connected with low pass filter circuit electricity, and low pass filter circuit is connected with the output plug electricity, the utility model discloses a battery undercurrent intermittent type discharges, to the harmless nondestructive test of battery, utilizes the battery power supply of being surveyed, need not other power, convenient to use, the utilization that improves the instrument space convert the battery internal resistance into voltage output, can conveniently cooperate various instruments to use.

Description

Battery internal resistance/voltage converter

Technical Field

The utility model relates to a battery measurement test technical field specifically is a battery internal resistance/voltage converter.

Background

With the technical progress, the types, manufacturing techniques and applications of the storage batteries are rapidly developed. The application from common batteries to lithium ion batteries and from illumination to new energy automobiles can be called as five-flower eight-door. However, the instrument for measuring the service life and the electrical parameters of the battery has complex circuit, high specialization and high price. And the measurement and judgment are mainly based on the test and analysis of the internal resistance parameters of the battery.

Based on this, the utility model designs a battery internal resistance/voltage converter to solve above-mentioned problem.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a battery internal resistance/voltage converter to solve above-mentioned technical problem.

In order to realize the purpose, the utility model provides the following technical scheme: a battery internal resistance/voltage converter comprises an outer shell, wherein four-end test clamps and an output plug are respectively arranged outside the outer shell, a PCB is arranged inside the outer shell, and an intermittent constant current discharge circuit, a differential amplification circuit and a low-pass filter circuit are arranged on the PCB;

the intermittent constant-current discharge circuit comprises a constant-current discharge circuit and a square wave generator, the constant-current discharge circuit is electrically connected with the four-terminal test clamp and the square wave generator respectively, the differential amplification circuit is electrically connected with two stages of the four-terminal test clamp, the differential amplification circuit is electrically connected with the low-pass filter circuit, and the low-pass filter circuit is electrically connected with the output plug.

Preferably, the outer shell is composed of an upper plastic shell and a lower plastic shell, and the four-end test clamp and the output plug are respectively arranged at two ends of the outer shell.

Preferably, the four-terminal test clamp comprises a red-black battery positive terminal and a battery negative terminal, the battery positive terminal and the battery negative terminal are respectively connected with the positive electrode and the negative electrode of the battery to be tested, and the output plug is connected with an external multimeter or a voltage measuring instrument.

Preferably, the constant current discharge circuit includes a discharge resistor R and a constant current circuit I, and the loop of the constant current discharge circuit is: the testing device comprises a battery anode, a battery anode end of a four-end testing clamp, a discharging resistor R, a constant current circuit I, a battery cathode end of the four-end testing clamp and a battery cathode.

Compared with the prior art, utility model's beneficial effect does:

1. the utility model discloses a battery undercurrent intermittent type discharges, to the harmless nondestructive test of battery.

2. The utility model discloses utilize and be surveyed the battery power supply, need not other power, convenient to use, the utilization in improvement instrument space.

3. The utility model discloses output voltage can conveniently cooperate various instruments to use.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive work.

FIG. 1 is the external structure diagram of the present invention

FIG. 2 is a schematic view of the internal structure of the present invention;

FIG. 3 is a schematic diagram of the electrical connection of the present invention;

FIG. 4 is a schematic circuit block diagram of the present invention;

FIG. 5 is a waveform chart of Vi in the principle of intermittent discharge operation of the secondary battery in example b;

fig. 6 is a waveform diagram of V0 and Va outputs in the principle of differential amplifier and filtering operation in embodiment c.

In the drawings, the components represented by the respective reference numerals are listed below:

the test device comprises a shell 1, a test clamp 2, an output plug 3, a PCB 4, an intermittent constant current discharge circuit 5, a differential amplification circuit 6, a constant current discharge circuit 8, a square wave generator 9 and a low-pass filter circuit 10.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by a person skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention.

Referring to fig. 1-6, the utility model provides a technical solution:

a battery internal resistance/voltage converter comprises an outer shell 1, wherein the outer shell 1 is composed of an upper plastic shell and a lower plastic shell, and electronic components are mounted on a PCB; the four-end test clamp 2 is connected to an input bonding pad of the PCB 4, the four-end test clamp 2 is red and black, an output plug 3 is divided into positive and negative outputs and is connected to an output bonding pad of the PCB 4 through a lead;

the internal resistance of battery generally is milliohm level low resistance, and the line resistance of test wire also generally has milliohm level, consequently the utility model discloses a four-terminal measurement method avoids test wire line resistance to the influence of measuring.

The four-end test clip 2 is a pair of red and black clips, the upper part and the lower part of each clip are respectively provided with a sawtooth metal sheet, when the clips are opened, the two metal sheets are not contacted with each other and are respectively connected with a conducting wire, and the number of the conducting wires is 2; the four-terminal test clamp 2 forms two loops in the test circuit, one loop is a power supply for providing circuit work and a loop for discharging the battery by using a battery positive electrode line and a battery negative electrode line, and the other loop is a loop for detecting the voltage change of the battery by using a positive electrode detection line and a negative electrode detection line.

The current end passes through the battery positive pole, the battery negative pole wire of four ends test clamp 2, and the signal sampling end passes through the positive pole of four ends test clamp 2 and detects, negative pole detection wire, and the voltage drop that the electric current produced on the wire can not influence the sampled signal like this, reduces the error.

The electrical principle of the battery internal resistance/voltage converter consists of a battery to be tested, a four-terminal test clamp 2, an intermittent constant-current discharge circuit 5, a differential amplification circuit 6, a low-pass filter circuit 10 and an output plug 3; the four-terminal test clip 2 has two terminals, red connected to the positive electrode of the battery and black connected to the negative electrode of the battery.

The battery anode, the battery anode end of the four-end test clamp 2, the discharge resistor R1, the constant current circuit I0, the battery cathode end of the four-end test clamp 2 and the battery cathode form an intermittent constant current discharge loop.

The constant current circuit is controlled by the square wave output by the square wave generator 9, when the level is high, the constant current circuit works, the battery discharges, and when the level is low, the discharging current is cut off to form intermittent discharging on the battery.

The battery is influenced by intermittent discharge due to internal resistance, the output voltage of the battery also forms an intermittent reduction state, the signal is tested by four terminals, and the positive electrode detection end and the negative electrode detection end of the battery 2 are detected from the positive electrode and the negative electrode of the battery.

The differential amplifier 9 processes and amplifies the intermittent reduced voltage at the detection end of the four-end test clamp 2, and outputs a square wave voltage, the amplitude of which is the multiple of the voltage drop on the internal resistance when the battery discharges, so that the internal resistance is in direct proportion to the voltage amplitude, and an alternating voltage signal output is formed after the voltage amplitude is processed by the low-pass filter, so that the measured output voltage can be directly converted into the internal resistance value of the battery.

Working principle embodiment:

embodiment a. intermittent constant current working principle:

when the square wave generator outputs a voltage signal with amplitude a (high level), the base current of transistor Q1:

Ib＝(A-Vce)/R2；

where A, Vce, R2 are all fixed values, and hence Ib is a fixed value;

according to the characteristics of the triode: i0 ═ β Ib, β is the current amplification factor, so I0 is constant current;

when the output amplitude of the square wave generator is 0 (low level), the triode Q1 is cut off, and the battery stops discharging;

therefore, through square wave control, an intermittent discharge working current is formed.

Embodiment b. the intermittent discharge working principle of the storage battery:

the simple equivalent circuit of the storage battery can be simplified into an ideal battery and a resistance value which is the series connection of the internal resistances of the batteries.

The ideal battery has no internal resistance loss, and the voltage of the battery cannot be changed due to load change.

When the battery is discharged by taking the load current as I0, the voltage drop on the internal resistance of the battery is I0Ri, and the ideal battery voltage is V1;

therefore, at discharge, the battery output voltage: V2-V1-V Ri-V1-I0 Ri;

so Ri ═ (V1-V2)/I0;

thus, under square wave control, the waveform of Vi is as shown in fig. 5.

Embodiment c. differential amplifier and filter operation principle

Vi is isolated from direct current through C3 and C4, and R4 and R5 are connected with a reference end of analog ground, and Vi variation signals relative to the analog ground are obtained at R4 and R5, namely V Ri;

v Ri accurately extracts voltage changes at two ends of the battery through a differential circuit composed of A1, R6, R7, R8 and R9, and then forms a square wave Va with amplitude in direct proportion to V Ri after the voltage changes are amplified through an amplifier composed of A2, VR1, R10 and R11;

va generates a fundamental wave sine wave voltage signal V0 after higher harmonics are filtered by a low-pass filter consisting of R12 and C3, V0 is in direct proportion to Va, and the fundamental wave sine wave voltage signal is output through an output plug as shown in figure 6;

Va＝k1(V1-V2＝k1 V Ri；

Vo＝k2 Va＝k2 k1 V Ri＝k2 k1 V Ri＝k2 k1 I0Ri；

Ri＝Vo/k2 k1 I0；

let K2K 1I 0;

Ri＝Vo/k；

therefore, the Vo can be converted into a Ri value only by measuring the Vo, and the measurement of the internal resistance of the battery is realized;

for example, VR1 is adjusted so that k is 10mV/m Ω, if Vo is measured 100 mV;

Ri＝Vo/k＝100/10＝10(mΩ)；

the utility model discloses use as the universal meter is additional usually, and most digital universal meters alternating current frequency response on the existing market is 45Hz ~ 400Hz, therefore the square wave frequency setting is about 100Hz usually.

In the description of the present invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inner", "front", "center", "both ends", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

In the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," "fixed," "screwed" and the like are to be construed broadly, e.g., as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; the term "connected" may refer to a direct connection, an indirect connection through an intermediate, a connection between two elements or an interaction relationship between two elements, and unless otherwise specifically defined, the term should be understood as having a specific meaning in the present application by those skilled in the art.

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.

Claims (4)

1. A battery internal resistance/voltage converter comprising an outer casing (1), characterized in that: the testing device is characterized in that a four-end testing clamp (2) and an output plug (3) are respectively arranged outside the outer shell (1), a PCB (printed circuit board) is arranged inside the outer shell (1), and an intermittent constant current discharge circuit (5), a differential amplification circuit (6) and a low-pass filter circuit (10) are arranged on the PCB (4);

the intermittent constant-current discharge circuit (5) comprises a constant-current discharge circuit (8) and a square wave generator (9), the constant-current discharge circuit (8) is electrically connected with the four-terminal test clamp (2) and the square wave generator (9) respectively, the differential amplification circuit (6) is electrically connected with two stages of the four-terminal test clamp (2), the differential amplification circuit (6) is electrically connected with the low-pass filter circuit (10), and the low-pass filter circuit (10) is electrically connected with the output plug (3).

2. The battery internal resistance/voltage converter according to claim 1, characterized in that: the outer shell (1) is composed of an upper plastic shell and a lower plastic shell, and the four-end test clamp (2) and the output plug (3) are arranged at two ends of the outer shell (1) respectively.

3. The battery internal resistance/voltage converter according to claim 1, characterized in that: the four-end test clamp (2) comprises a red-black battery positive end and a battery negative end, the battery positive end and the battery negative end are respectively connected with the positive pole and the negative pole of the tested battery, and the output plug (3) is connected with an external universal meter or a voltage measuring instrument.

4. The battery internal resistance/voltage converter according to claim 1, characterized in that: the constant current discharge circuit (8) comprises a discharge resistor R1 and a constant current circuit I0, and the loop of the constant current discharge circuit (8) is as follows: the device comprises a battery anode, a battery anode end of a four-terminal test clamp (2), a discharge resistor R1, a constant current circuit I0, a battery cathode end of the four-terminal test clamp (2) and a battery cathode.

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