CN201293825Y - Device for testing battery internal resistance - Google Patents

Abstract

The utility model relates to a battery internal resistance testing device, which comprises a battery unit, a sampling unit and a control unit, wherein the battery unit is composed of a controller, a switch circuit and a single battery or a battery pack, the switch circuit and the single battery or the battery pack form a return circuit, the controller is connected to a control end of the switch circuit, the sampling unit is used to collect voltage at two ends of the battery and current flowing through the return circuit of the battery, and the control unit calculates the internal resistance of the single battery or the battery pack according to current values and voltage values output by the sampling unit. In the battery internal resistance testing device, the controller and the switch circuit are arranged in the battery unit, the controller is utilized to control periodical on-and-off of the switch circuit to enable the battery pack to generate excitation source signals without externally adding an excitation source circuit, thereby reducing complexity of hardware, reducing cost, saving space, simultaneously reducing outside interference and effectively increasing measuring accuracy and reliability.

Description

A kind of internal resistance of cell proving installation

Technical field

The utility model relates to a kind of internal resistance of cell proving installation, particularly a kind of internal resistance of cell proving installation that is applied in electric motor car and PHEV.

Background technology

The application of accumulator aspect electric automobile, hybrid vehicle is more and more.What battery system generally adopted is the mode that is connected in series.The state deterioration of some cell batteries directly influences the capacity status of battery pack integral body in battery pack, and the whole volume state that also is battery pack is by a certain or several the accumulator capacity decisions that deterioration state is the most serious in the system.So the state of accurately measuring each cell is to preventing that the battery pack fault from being necessary.

The method of accumulator internal resistance test at present comprises direct-current discharge method and ac-current inject method etc.Direct-current discharge method concrete grammar is to produce a momentary load electric current by electric battery, measure the instantaneous variation of voltage on the battery electrode column then, according to calculating the internal resistance of cell, its defective is: need the frequent detection of carrying out residual capacity and demonstration, this just requires internally resistance to carry out frequent detection, can influence the residual capacity of the cruising and the minimizing battery of electric motor car, moreover number of batteries is a lot of in the electric motor car, will have caused huge battery capacity waste; Only be fit to measure high capacity cell or accumulator, small-capacity cells can't be at the big electric current of the short time in several seconds internal loading tens peaces; Big electric current has certain damage by battery to the electrode of inside battery, and influences measuring accuracy, and the direct-current discharge method can't be used on PHEV.

Its principle of ac-current inject method is: add a constant AC audio current source i at the accumulator two ends _s(t)=I _sCos (ω t+ α _i), detect battery both end voltage v then _o(t)=V _oCos (ω t+ α _o), and phase differential α between the two, according to Ohm law as can be known complex impedance be:

$Z=\frac{V_o}{I_s}=\frac{V_o\∠{\mathrm{\α}}_o}{I_s\∠{\mathrm{\α}}_i}\text{=}\frac{V_o}{I_s}\∠{\mathrm{\α}}_o-{\mathrm{\α}}_i=\left|Z\right|\∠\mathrm{\α}=\left|Z\right|(\cos \mathrm{\α}+j\sin \mathrm{\α})$

$=\left|Z\right|\cos \mathrm{\α}+j\left|Z\right|\sin \mathrm{\α}$

Wherein, V _oAnd I _sBe effective value, also can be maximal value V _{O max}And I _{S max}, because effective value and maximal value are only poor one

Multiple, again because Z=r+jX, so have: r=|Z|cos α, r are exactly the internal resistance of cell that we need obtain.

In ac-current inject method, do not need accumulator to discharge, can realize the online detection internal resistance of cell of safety, so can the performance of accumulator not impacted, the defective of ac-current inject method is to measure the phase differential between ac current signal and voltage responsive signal and the voltage and current, need in MCU, realize trigonometric function calculating etc., so the hardware circuit and the algorithm more complicated that adopt, need the extrinsic motivated signal source circuit in addition, increased the complexity of hardware, and and be subjected to extraneous interference easily, influenced measuring accuracy.

Summary of the invention

The purpose of this utility model is to overcome above-mentioned defective and provides a kind of measuring accuracy high and apparatus for measuring battery internal resistance simple in structure.

Goal of the invention of the present utility model is achieved through the following technical solutions:

A kind of internal resistance of cell proving installation, comprise battery unit, described battery unit is made up of controller, on-off circuit and battery cell or electric battery, and described on-off circuit and battery cell or electric battery constitute the loop, and described controller is connected on the control end of described on-off circuit; Sampling unit, described sampling unit are used to gather the electric current of the voltage at battery two ends and the cell circuit of flowing through; Control module, described control module is according to the current value of sampling unit output and the internal resistance of magnitude of voltage counting cell monomer or electric battery.

The utility model internal resistance of cell proving installation, in battery unit, be provided with controller and on-off circuit, utilize the disconnection and the closure of controller gauge tap circuit period property, make electric battery self produce excitation source signal, need not the extrinsic motivated source circuit, reduced the complexity of hardware, reduced cost, save the space, reduced extraneous interference simultaneously, improved measuring accuracy and reliability effectively.

Description of drawings

Fig. 1 is the utility model embodiment internal resistance of cell proving installation general structure block diagram;

Fig. 2 is the utility model embodiment internal resistance of cell proving installation concrete structure synoptic diagram.

Embodiment

With reference to the accompanying drawings the utility model is described in further detail below:

According to Fig. 1 to Fig. 2, a kind of internal resistance of cell proving installation of the utility model, comprise battery unit, sampling unit and control module, described battery unit is made up of controller, on-off circuit and battery cell or electric battery, described on-off circuit and battery cell or electric battery constitute the loop, described controller is connected on the control end of described on-off circuit, described sampling unit is used to gather the electric current of the voltage at battery two ends and the cell circuit of flowing through, and described control module is according to the current value of sampling unit output and the internal resistance of magnitude of voltage counting cell monomer or electric battery.

Described on-off circuit can be selected switching tubes such as triode, field effect transistor for use, controller can be selected oscillatory circuit or single-chip microcomputer for use, the control that output signal is added in switching tube is extremely gone up, and makes the switch change of on-off circuit generating period, makes circuit produce the exciting current signal.

Described battery unit also comprises sampling resistor, and described sampling resistor is connected on the loop of on-off circuit and battery cell or electric battery formation, and the two ends of described sampling resistor are connected to the input end of described sampling unit.The two ends of described sampling resistor R1 are connected to the input end of described sampling unit and constitute first sampling channel, the two ends of described battery cell B1 are connected to the input end of described sampling unit and constitute second sampling channel, described battery cell just, be respectively equipped with the first capacitance C1 and the second capacitance C2 between the input end of negative pole and described sampling unit, described sampling unit is by the exciting current signal of the first sampling channel acquisition stream through sampling resistor R1, and battery cell correspondent voltage signal enters sampling unit through second sampling channel of the first capacitance C1 and second capacitance C2 composition simultaneously.

Described sampling unit calculates current effective value and voltage effective value according to the current instantaneous value in the loop of flowing through that collects and the instantaneous voltage of battery, described sampling unit is exported to described control module simultaneously with current instantaneous value, instantaneous voltage and the current effective value that calculates, the voltage effective value gathered, and described sampling unit is signals collecting chip commonly used such as CS5460 etc.

Described control module calculates the internal resistance of cell according to current effective value, voltage effective value and current instantaneous value, the instantaneous voltage of input through integral operation, and described control module is preferably single-chip microcomputer, as adopting LPC2194 etc.

Be the utility model examples measure battery cell internal resistance concrete structure synoptic diagram as shown in Figure 2, at first carry out periodic switch change by controller gauge tap circuit, make circuit produce the exciting current signal, described sampling unit CS5460 is by the exciting current signal i of the first sampling channel acquisition stream through sampling resistor R1, gather the corresponding instantaneous voltage signal of battery cell u through entering sampling unit CS5460 by second sampling channel of forming by the first capacitance C1 and the second capacitance C2 simultaneously, described sampling unit CS5460 calculates current effective value Irms and voltage effective value Urms according to the current instantaneous value i in the loop of flowing through that collects and the instantaneous voltage u of battery, described sampling unit is with the current instantaneous value i that gathers, instantaneous voltage u and the current effective value Irms that calculates, voltage effective value Urms exports to described control module LPC2194 simultaneously, described control module LPC2194 draws active energy PE and apparent electric energy SE according to described current value and magnitude of voltage by integral operation, and active energy is $\mathrm{PE}=\frac{1}{T}{\∫}_0^T\mathrm{pd}\left(t\right)=\frac{1}{T}{\∫}_0^T\mathrm{uid}\left(t\right),$ Wherein u, i are instantaneous voltage and electric current, and the apparent electric energy is SE=Urms*Irms, and wherein Urms and Irms are the effective value of voltage, electric current, and θ=(Urms/Irms) * (PE/SE) draws the internal resistance of cell according to formula internal resistance of cell R=(Urms/Irms) * cos.

The utility model internal resistance of cell proving installation can also be measured the resistance of batteries in battery set monomer, between sampling unit and electric battery, switches set is set, switch between the different monomer in electric battery by controller gauge tap group, make sampling unit form the loop with the battery cell of electric battery, collecting unit is gathered the voltage and the current in loop of battery cell in each loop, adopts the internal resistance of battery cell in the method counting cell group same as described above.

The embodiment of the above is a better embodiment of the present utility model; be not to limit concrete practical range of the present utility model with this, the equivalence variation that all shapes according to the utility model, structure are done all is included in the protection domain of the present utility model.

Claims (5)

1, a kind of internal resistance of cell proving installation is characterized in that:

Comprise battery unit, described battery unit is made up of controller, on-off circuit and battery cell or electric battery, and described on-off circuit and battery cell or electric battery constitute the loop, and described controller is connected on the control end of described on-off circuit;

Sampling unit, described sampling unit are used to gather the electric current of the voltage at battery two ends and the cell circuit of flowing through;

Control module, described control module is according to the current value of sampling unit output and the internal resistance of magnitude of voltage counting cell monomer or electric battery.

2, internal resistance of cell proving installation according to claim 1, it is characterized in that: described battery unit also comprises sampling resistor, described sampling resistor is connected on the loop of on-off circuit and battery cell or electric battery formation, and the two ends of described sampling resistor are connected to the input end of described sampling unit.

3, internal resistance of cell proving installation according to claim 2 is characterized in that: the two ends of described battery cell or electric battery are connected to the input end of described sampling unit.

4, internal resistance of cell proving installation according to claim 3 is characterized in that: be respectively equipped with capacitance between the positive and negative electrode of described battery cell or electric battery and the input end of described sampling unit.

5, internal resistance of cell proving installation according to claim 1, it is characterized in that: described control module is a single-chip microcomputer.

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