CN202210762U - Staggered piezo-electricity double-chip-beam type energy-harvesting system - Google Patents

Abstract

The utility model discloses a staggered piezo-electricity double-chip-beam type energy-harvesting system, which has higher practical power density, comprises an external support and piezo-electricity double-chip beams in the external support, and is characterized in that the two adjacent piezo-electricity double-chip beams are respectively arranged on two sides of the external support. Compared with a conventional piezo-electricity energy-harvesting device, the system provided by the utility model has the advantages that under the premise of identical material, the practical output power density is greatly improved under all excitation frequencies and improved by one time especially at the area near the most remarkable resonance vibration area.

Description

A kind of staggered piezoelectric bimorph beam type prisoner can system

Technical field

The utility model relates to a kind of prisoner can system, is specifically related to a kind ofly be converted into electric energy through the vibrational energy in the absorbing environmental through piezoelectric and come the staggered piezoelectric bimorph beam type prisoner with higher actual power density that microelectronic component is supplied power can system.

Background technology

Internet of Things is the important component part of generation information technology, and the element of formation Internet of Things most critical is the sensor device that is placed in the various items.Traditional mode for these transducer power supplies is wired power supply or electrochemical cell power supply.Though wired power supply can guarantee the normal supply of device institute energy requirement, because the One's name is legion of sensing unit in the sensing network, make difficult wiring.As time goes on and gradually the amount of power supply of traditional electrical chemical cell can weaken; Therefore can only guarantee the operate as normal of micro element within a short period of time; Its traditional battery-powered mode can not satisfy its growth requirement gradually, can come more and more to receive publicity for the method that such device is supplied power through vibration and the noise of drawing in the environment.Wherein, piezoelectric harvester is because output of its higher and more stable energy and energy absorption efficiency become the energy accumulator spare of being praised highly most.

Therefore other be one of the most frequently used structure in the piezoelectric harvester design more near the frequency of ambient vibration to piezoelectric bimorph beam type structure relatively owing to its resonance frequency.Yet what the piezoelectric bimorph beam in traditional energy accumulator design all adopted is that homonymy distributes or cross direction profiles, or does not provide more concrete spatial distribution scheme.The use of piezoelectric harvester is to liking very little all kinds of microelectronic components and the sensing equipment of volume, and therefore under the prerequisite that satisfies the output demand, its shared space should be as far as possible little.Therefore, scholar such as Roundy is with the important performance indexes of output energy density as piezoelectric harvester.The output energy density is the power that the piezoelectric harvester of unit volume is exported, yet the piezoelectricity prisoner can structure not be static device, need take certain space during its work.If it is too small that this working space is provided with, just might bump between two adjacent piezoelectrics, make the prisoner system to break down, power output reduces, even scraps fully.

One side of the piezoelectric bimorph of typical piezoelectric prisoner ability system embeds in the exterior support wall, and the other end is in free state, forms the piezoelectric bimorph girder construction.What the piezoelectric bimorph beam all adopted in the design of energy accumulator system is that homonymy distributes or cross direction profiles; And for guarantee between each piezoelectric device can operate as normal and do not bump each other; Just must guarantee to have certain space between the piezoelectric element, for tradition prisoner ability system, its safe space demand is bigger; Reduce the prisoner's energy efficiency in the unit space, promptly reduced its actual power density.Yet actual power density is considerable index for the energy source of this microelectronic component of piezoelectricity prisoner ability system, therefore is badly in need of a kind of prisoner's ability system that higher actual power density is arranged.

The utility model content

The purpose of the utility model is to provide a kind of staggered piezoelectric bimorph beam type with higher actual power density to capture can system.

The index of reasonably passing judgment on the output performance of a piezoelectric system should be real output density, and promptly the volume of prisoner's ability system should comprise piezoelectrics itself and trouble free service gap simultaneously.This patent is based on this theory, and having proposed a kind of cross-distribution piezoelectric bimorph beam type prisoner with higher real output density can system.Numerical simulation result shows, can significantly improve the actual power density that the prisoner can system through the piezoelectric bimorph beam being carried out cross-distribution.

The utility model is achieved in that

A kind of staggered piezoelectric bimorph beam type with higher actual power density is captureed the ability system, comprises exterior support and piezoelectric bimorph beam; The effect of exterior support is that the vibrational energy in the ambient vibration source is incorporated in prisoner's ability system, lets whole prisoner make the vertical vibrating perpendicular to horizontal plane by device, also plays the effect of enhanced system stability of vibration and encapsulation simultaneously.

The piezoelectric bimorph beam is the main prisoner's ability element in prisoner's ability system, and mechanical vibrational energy is converted into electric energy.The piezoelectric bimorph beam is by the two-layer a pair of piezoelectric patches that identical physical dimension is arranged from the thickness direction polarization up and down, and middlely forms in order to strengthen integrally-built metal level.The upper and lower surfaces of piezoelectric patches is coated with electrode, and electrode is selected the silver-colored preferably material of electric conductivity usually for use.

In use; The prisoner who floats in the ability system can structure be in series by a plurality of piezoelectric bimorph beams; The important difference of itself and traditional energy accumulator battle array is; Two adjacent piezoelectric bimorph beams are arranged in the left and right sides of exterior support in prisoner's ability structure, rather than picture tradition prisoner can be distributed in the same side in the system.

Promptly an end of m piezoelectric bimorph beam embeds the left side wall of exterior support, and an end of m+1 piezoelectric bimorph beam embeds the right side wall of exterior support.

The piezoelectric bimorph beam can be cascaded through lead, and connects with load impedance.Also can adopt other circuit connecting mode; As connecting with load impedance again after the parallel connection of piezoelectric bimorph beam; Perhaps at single piezoelectric bimorph beam with parallelly connected with other single piezoelectric bimorph beams again after single load impedance is connected with the series circuit of single load impedance, and other circuit connecting mode.

Therefore the energy supply of piezoelectric harvester when requiring it that big as far as possible power output is provided, save space hold to liking very little all kinds of microelectronic components and the sensing equipment of volume as far as possible.Therefore scholar such as Roundy is with the important performance indexes of output energy density as piezoelectric harvester.The power density of traditional piezoelectric harvester is defined as:

$\mathrm{\γ}=\frac{P_{\mathrm{OUT}}}{V_D}---\left(1\right)$

Wherein, P _OUTBe the power output of energy accumulator, V _DVolume for the piezoelectric device body.Yet to piezoelectricity prisoner ability system, wherein each parts not all are static devices, need take certain space during its work.If it is too small that this working space is provided with, just might bump between two adjacent piezoelectrics, make the prisoner system to break down, power output reduces, even scraps fully.Therefore the index of rationally passing judgment on the output performance of a piezoelectric system should be real output density γ _R, promptly the volume of prisoner's ability system should comprise the V of piezoelectrics own simultaneously _DWith trouble free service gap V _S

${\mathrm{\γ}}_R=\frac{P_{\mathrm{OUT}}}{V_D+V_S}---\left(2\right)$

Connected by homonymy piezoelectric bimorph beam by n, outer load is simple impedance Z _LPiezoelectricity prisoner can system, wherein adjacent m and m+1 piezoelectric bimorph beam are as shown in Figure 1.Their respective piezoelectric layer and a metal layer thickness was

two piezoelectric bimorph beam vertical gap between security

According to the right end of the outer wall of the respective security clearance is

and

around the end of the maximum absolute value of

and

The geometry of each piezoelectric bimorph beam is only had any different on thickness in the supposing the system, and establishes and then the trouble free service gap of this system do

$V_S=\mathrm{\α}\underset{k=1}{\overset{n}{\mathrm{\Σ}}}2b(L+L_S)w_L^{\left(k\right)}---\left(3\right)$

Wherein, L, b are the length and the width of piezoelectric bimorph beam.α＞1 is the safety clearance coefficient, can choose according to space requirements such as practical wiring.Then real output density does

${\mathrm{\&gamma;}}_R=\frac{P_{\mathrm{OUT}}}{\underset{k=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000092936180000011.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}2\mathrm{bL}(h_c^{\left(k\right)}+h_p^{\left(k\right)})+\mathrm{\&alpha;}\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}2b(L+L_S)w_L^{\left(k\right)}}---\left(4\right)$

The utility model is compared with existing piezoelectric harvester and had the following advantages: this prisoner can system can system compare with traditional homonymy prisoner; In full accord even draw materials; Its actual output power density can under each driving frequency, all having significantly of system improve than the tradition prisoner; Especially near the resonance region that energy accumulator merits attention most, its actual output power density has improved nearly one times.

Description of drawings

Fig. 1 is the utility model structural representation;

Fig. 2 is the utility model external load circuit sketch map;

Fig. 3 is the utility model piezoelectric bimorph girder construction sketch map;

Fig. 4 is the graph of a relation between the utility model real output density and the driving frequency.

Embodiment

Further specify the embodiment of the utility model below in conjunction with accompanying drawing.

Shown in accompanying drawing 1; The utility model said staggered piezoelectric bimorph beam type prisoner with higher actual power density can respectively capture and can place on the sidewall of exterior support 4 according to interlace mode by element piezoelectric bimorph beam in the system; Exterior support is along with external environment vibration source 5 is done vertical vibration with Asin2 π ft, each piezoelectric bimorph beam 6 through lead to be connected as electricity like the series system of accompanying drawing 2 and load impedance 7.Be depicted as the structure of piezoelectric bimorph beam like accompanying drawing 3, comprise two piezoelectric patches 1 up and down,, be coated with argent on the upper and lower surface of piezoelectric patches and do electrode 3 being provided with metal level 2 to strengthen piezoelectric bimorph beam vibration fatigue durability between two piezoelectric patches 1 up and down.

The material PZT-5H that chooses piezoelectric patches is an example, its density p ₀=7500kg/m ³, material parameter is following:

s ₁₁＝16.5×10 ^-12m ²/N，d ₃₁＝-274×10 ^-12C/N，

ε ₃₃＝3400ε ₀，ε ₀＝8.854×10 ^-12farads/m

Intermediate metal layer is an aluminium alloy, its Young's modulus E=70GPa, density p=2700kg/m ³A is the vibration amplitude of piezoelectricity stiff end, angular frequency ₀=2 π f, f are ambient vibration source forcing frequency.Get the acceleration amplitude

of excitation.In calculating, choose the width b=10mm of piezoelectric patches, piezoelectric patches length l=70mm, the intermetallic metal layer thickness is 0.8 with the thickness ratio of piezoelectric patches.For forced vibration,, use s for the Considering Damping effect ₁₁(1-iQ ^-1) alternative s ₁₁, Q is the quality factor of material, gets Q=50 in the calculating.Load resistance is anti-outside in calculating, getting is Z _L=iZ ₀, get horizontal safety clearance L _S=0.1L, safety clearance alpha=11.

The real output density comparison diagram of the tradition prisoner ability system that is in series for different driving frequency lower piezoelectric twin lamella beams shown in Figure 4 and the utility model prisoner ability system.Its prisoner separately can structure be respectively 3.05,3.10,3.15,3.20 by 5 piezoelectric patches thickness h p, and the piezoelectric bimorph beam of 3.25mm is formed, i.e. n=5.Obviously; In full accord though draw materials; But captureing the ability system, cross-distribution piezoelectric bimorph beam type significantly raising is all arranged under each driving frequency than traditional real output density of captureing the ability system; Especially near the resonance region that energy accumulator merits attention most, its actual output power density has improved nearly one times.In addition, this piezoelectricity prisoner can system the form that is electrically connected on the advantage on the structure distribution and prisoner can the unit irrelevant, therefore in other electrical connection form, it is effective equally to capture in the ability system this method like the piezoelectricity of parallel form and series-parallel connection form.

Claims (5)

1. a staggered piezoelectric bimorph beam type is captureed the ability system, comprises the piezoelectric bimorph beam that exterior support is inner with being positioned at exterior support, and it is characterized in that: two adjacent piezoelectric bimorph beams are arranged in the both sides of exterior support.

2. can system according to the said prisoner of claim 1, it is characterized in that: said piezoelectric bimorph beam is by the two-layer a pair of piezoelectric patches that identical physical dimension is arranged from the thickness direction polarization up and down, and middlely forms in order to strengthen integrally-built metal level.

3. according to the said prisoner's ability of claim 2 system, it is characterized in that: the upper and lower surfaces of said piezoelectric patches is coated with electrode.

4. according to the said prisoner's ability of claim 3 system, it is characterized in that: said electrode is selected silver-colored material for use.

5. according to the said prisoner's ability of the arbitrary claim of claim 1 to 4 system, it is characterized in that: said piezoelectric bimorph beam is cascaded through lead, and connects with load impedance.

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