CN203117397U - Battery leakage detection circuit - Google Patents

Abstract

The utility model discloses a battery leakage detection circuit. The circuit comprises an optical MOSFET switch circuit and a divider resistance network. The optical MOSFET switch circuit comprises an optical MOSFET pipe Q1, an optical MOSFET pipe Q2, an optical MOSFET pipe Q3 and an optical MOSFET pipe Q4. The divider resistance network comprises a precision resistor R1, a precision resistor R2, a precision resistor R3, a precision resistor R4, a precision resistor R5, a precision resistor R6 and a precision resistor R7. By using the circuit of the utility model, real-time monitoring can be performed on a battery pack. The design is simple and reasonable and cost is low.

Description

The battery drain testing circuit

Technical field

The utility model relates to earth detector, particularly relates to a kind of battery drain testing circuit.

Background technology

Lithium-ion-power cell in order to reach the certain power requirement, needs the multiple batteries series connection to use as the power source in the pure electric automobile.The voltage of the straight-flow system that lithium ion battery is now formed is up to last hectovolt, and the voltage of pure electronic motor bus electric battery is especially up to 500V.For driver and conductor's personal safety and the safety case of car load, need monitor in real time the electric leakage situation of the high direct voltage system of electric automobile.

At present electric automobile leakage current detect circuit generally adopts the measuring method that outer meeting resistance switches, but has several shortcomings, at first has been connected resistance between electric battery positive and negative busbar and the car body, has reduced insulating property; Secondly when positive and negative busbar equated the insulation resistance of car body, insulation resistance can't calculate; When assembled battery total voltage is crossed low or opened a way, also can't calculate at last.

This shows that above-mentioned existing outer meeting resistance changing method obviously still has inconvenience and defective, and demands urgently further being improved in structure and use.In order to solve the problem of its existence, relevant manufacturer there's no one who doesn't or isn't seeks solution painstakingly, but do not see always that for a long time suitable design finished by development, and common product does not have appropriate structure to address the above problem, this obviously is the problem that the anxious desire of relevant dealer solves.

Summary of the invention

The purpose of this utility model is that a kind of battery drain testing circuit is being provided, have simplicity of design rationally, low cost and other advantages.

The purpose of this utility model and to solve its technical matters be to adopt following technical scheme to realize.A kind of battery drain testing circuit of the utility model, it comprises light switch mosfet circuit, Q forms by light MOSFET pipe; And resistor voltage divider network, R forms by precision resistance, is connected with light switch mosfet circuit.

The purpose of this utility model and solve its technical matters and can also be further achieved by the following technical measures.

Preferable, aforesaid battery drain testing circuit, wherein this light switch mosfet circuit comprises light MOSFET pipe Q1, light MOSFET pipe Q2, light MOSFET pipe Q3 and light MOSFET pipe Q4, and this resistor voltage divider network comprises precision resistance R1, precision resistance R2, precision resistance R3, precision resistance R4, precision resistance R5, precision resistance R6 and precision resistance R7; Wherein, this light MOSFET pipe Q1 connects precision resistance R1 and precision resistance R2, the other end of precision resistance R2 is connecting precision resistance R3, the other end of precision resistance R3 connects precision resistance R4 and light MOSFET pipe Q4 simultaneously, the other end of light MOSFET pipe Q4 connects the car body earth polar, the other end of precision resistance R4 connects precision resistance R5, the other end of precision resistance R5 connects light MOSFET pipe Q2, the other end of light MOSFET pipe Q2 connects precision resistance R6 and light MOSFET pipe Q3 simultaneously, and the other end of precision resistance R6 and light MOSFET pipe Q3 is connected precision resistance R7 simultaneously.

By technique scheme, the utility model battery drain testing circuit has following advantage and beneficial effect at least: a kind of battery drain observation circuit of the utility model, by whether externally total positive pole of measuring electric battery is judged electric battery electric leakage to car body earth polar, total negative pole to the total voltage of car body earth polar and electric battery, realized the real-time monitoring to electric battery; And improve in this measuring method, just resistor network is directed in the battery system when needing to measure insulation resistance, has improved its insulating property, by switching different resistor networks, when positive and negative busbar equates the insulation resistance of car body, can go out insulation resistance by correct measurement.

Above-mentioned explanation only is the general introduction of technical solutions of the utility model, for can clearer understanding technological means of the present utility model, and can be implemented according to the content of instructions, and for above-mentioned and other purposes, feature and advantage of the present utility model can be become apparent, below especially exemplified by preferred embodiment, and conjunction with figs., be described in detail as follows.

Description of drawings

Fig. 1: the principle of work synoptic diagram of the utility model battery drain testing circuit.

Fig. 2: the system chart of battery drain monitoring.

Embodiment

Be to reach technological means and the effect that predetermined goal of the invention is taked for further setting forth the utility model, below in conjunction with accompanying drawing and preferred embodiment, to according to a kind of its embodiment of battery drain testing circuit, structure, feature and the effect thereof that the utility model proposes, describe in detail as after.

Consulting shown in Figure 1ly, is the principle of work synoptic diagram of the utility model battery drain testing circuit, and this battery drain testing circuit comprises light switch mosfet circuit and resistor voltage divider network; Wherein, this light switch mosfet circuit mainly is made up of light MOSFET pipe Q, and this resistor voltage divider network mainly is made up of precision resistance R; In course of normal operation, this light switch mosfet circuit can be adjusted the potential-divider network of precision resistance R, obtains different measuring voltage values, measures for the AD Acquisition Circuit.

In the present embodiment, this light switch mosfet circuit comprises light MOSFET pipe Q1, Q2, Q3 and Q4, and this resistor voltage divider network comprises precision resistance R1, R2, R3, R4, R5, R6 and R7; Wherein, this light MOSFET pipe Q1 connects precision resistance R1 and precision resistance R2, the other end of precision resistance R2 is connecting precision resistance R3, the other end of precision resistance R3 connects precision resistance R4 and light MOSFET pipe Q4 simultaneously, the other end of light MOSFET pipe Q4 connects the car body earth polar, the other end of precision resistance R4 connects precision resistance R5, the other end of precision resistance R5 connects light MOSFET pipe Q2, the other end of light MOSFET pipe Q2 connects precision resistance R6 and light MOSFET pipe Q3 simultaneously, and the other end of precision resistance R6 and light MOSFET pipe Q3 is connected precision resistance R7 simultaneously; Consult shown in Figure 1ly, represent the car body electrical model in the frame of broken lines among the figure, wherein Vb represents lithium-ion-power cell group total voltage, and ground is electric automobile chassis, and Rp and Rn represent positive and negative busbar insulation resistance over the ground, and frame of broken lines is outward the battery drain observation circuit of structure; Wherein, the other end of the precision resistance R1 of this battery drain observation circuit connects insulation resistance Rp and battery anode, the other end of this precision resistance R7 connects insulation resistance Rn and electric battery negative pole simultaneously, and the other end of this insulation resistance Rn and insulation resistance Rp is connected the car body earth polar.

When detecting, the AD Acquisition Circuit can be measured voltage V1 and the V2 at precision resistance R2 and precision resistance R5 two ends respectively, and wherein, over against car body ground pole tension, V2 is that the car body earth polar is to total negative voltage to V1 for always.

At first closed light MOSFET pipe Q1, Q2, disconnect light MOSFET pipe Q3, Q4, form resistor voltage divider network by precision resistance R1, R2, R3, R4, R5, R6, R7, measure the magnitude of voltage V1 of precision resistance R2 with the AD Acquisition Circuit, according to the electric resistance partial pressure principle, calculate battery total voltage Vb by formula 1:

$\mathrm{Vb}=\frac{V1}{R2}(R1+R2+R3+R4+R5+R6+R7)---\left(1\right)$

Secondly closed light MOSFET pipe Q1, Q2, Q4, disconnect light MOSFET pipe Q3, form resistor voltage divider network by precision resistance R1, R2, R3, R4, R5, R6, R7 and insulation resistance Rp, Pn, measure one group of V1 and V2 magnitude of voltage with the AD Acquisition Circuit, insulation resistance Rp and one group of relation of Rn of being calculated by formula 2:

$\frac{V1{(R1+\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA00002485578700011.png"\; state="\{\{state\}\}">R</figure-callout>}2+R3)}^2\mathrm{Rp}}{R2(R1+R2+R3+\mathrm{Rp})}=\frac{V2{(R4+R5+R6+R7)}^2\mathrm{Rn}}{R5(R4+R5+R6+R7+\mathrm{Rn})}---\left(2\right)$

Closed light MOSFET manages Q1, Q2, Q3, Q4 then, form new resistor voltage divider network by precision resistance R1, R2, R3, R4, R5, R7 and insulation resistance Rp, Pn, measure new one group of V1 ' and V2 ' magnitude of voltage with the AD Acquisition Circuit, insulation resistance Rp and the new one group of relation of Rn calculated by formula 3:

$\frac{{V1}^{\&prime;}{(R1+R2+R3)}^2\mathrm{Rp}}{R2(R1+R2+R3+\mathrm{Rp})}=\frac{{V2}^{\&prime;}{(R4+R5+R7)}^2\mathrm{Rn}}{R5(R4+R5+R7+\mathrm{Rn})}---\left(3\right)$

Solve two unknown numbers by formula (2) and formula (3), namely insulation resistance Rp and Rn calculate the class of insulation according to the total voltage value that records again, judge whether electric leakage by the class of insulation.With reference to the national standard of relevant electric automobile, if people and other objects constitute the external circuit between high-tension circuit and the ground, the minimum level of the insulation resistance of regulation high-tension circuit is 100 ohm of every volts, if less than this value, the leakage current of generation will danger close.

Consult shown in Figure 2ly, be to be used for the system chart of battery drain monitoring the electric leakage situation of vehicle-mounted lithium-ion-power cell group is monitored.In the present embodiment, single-chip microcomputer is controlled light switch mosfet circuit by output pin, selects for use to have I ²C interface AD Acquisition Circuit, digital signal buffer circuit and single-chip microcomputer by special use communicate, and this interface circuit antijamming capability is strong and Electro Magnetic Compatibility good; Light switch mosfet circuit is used for adjusting the adaptation network of battery drain observation circuit; The AD Acquisition Circuit is used for gathering the magnitude of voltage of battery drain observation circuit measurement point.So, by light MOSFET pipe Q1, Q2 and Q3, precision resistance R1, R2, R3, R4, R5, R6 and R7 and AD Acquisition Circuit, finished the electric leakage situation of lithium-ion-power cell group has been monitored in real time, solve lithium-ion-power cell group safety problem in use, guaranteed driver and conductor's personal safety.

The above, it only is preferred embodiment of the present utility model, be not that the utility model is done any pro forma restriction, though the utility model discloses as above with preferred embodiment, yet be not in order to limit the utility model, any those skilled in the art, in not breaking away from the technical solutions of the utility model scope, when the technology contents that can utilize above-mentioned announcement is made a little change or is modified to the equivalent embodiment of equivalent variations, in every case be the content that does not break away from technical solutions of the utility model, any simple modification that foundation technical spirit of the present utility model is done above embodiment, equivalent variations and modification all still belong in the scope of technical solutions of the utility model.

Claims (2)

1. battery drain testing circuit is characterized in that it comprises:

Light switch mosfet circuit is made up of a plurality of smooth MOSFET pipes; And

Resistor voltage divider network is made up of a plurality of precision resistances, is connected with light switch mosfet circuit.

2. battery drain testing circuit according to claim 1, it is characterized in that, wherein this light switch mosfet circuit comprises light MOSFET pipe Q1, light MOSFET pipe Q2, light MOSFET pipe Q3 and light MOSFET pipe Q4, and this resistor voltage divider network comprises precision resistance R1, precision resistance R2, precision resistance R3, precision resistance R4, precision resistance R5, precision resistance R6 and precision resistance R7;

Wherein, this light MOSFET pipe Q1 connects precision resistance R1 and precision resistance R2, the other end of precision resistance R2 is connecting precision resistance R3, the other end of precision resistance R3 connects precision resistance R4 and light MOSFET pipe Q4 simultaneously, the other end of light MOSFET pipe Q4 connects the car body earth polar, the other end of precision resistance R4 connects precision resistance R5, the other end of precision resistance R5 connects light MOSFET pipe Q2, the other end of light MOSFET pipe Q2 connects precision resistance R6 and light MOSFET pipe Q3 simultaneously, and the other end of precision resistance R6 and light MOSFET pipe Q3 is connected precision resistance R7 simultaneously.

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