CN105207575A - Hybrid energy storage device - Google Patents

Abstract

The invention relates to an energy storage device, and particularly relates to a hybrid energy storage device using combination of storage batteries and super-capacitors. The hybrid energy storage device comprises a photovoltaic power generation system, a charging controller, a super-capacitor bank, a parallel controller, a storage battery pack and a load. The photovoltaic power generation system, the charging controller, the parallel controller and the load are connected in series in turn. The super-capacitor bank is connected in parallel between the charging controller and the parallel controller. The storage battery pack is connected in parallel between the parallel controller and the load. According to the hybrid energy storage device, the structure of parallel connection of the super-capacitors and the storage batteries is adopted, and the parallel controller is required to be arranged between the super-capacitors and the storage batteries for separation of control voltage. High energy density of the storage batteries and high power density of the super-capacitors can be greatly combined by the device, the disadvantages of the storage batteries and the super-capacitors are compensated and the advantages of the storage batteries and the super-capacitors are enabled to be fully exerted so that the requirement of an independent photovoltaic system for energy management can be more effectively met by the hybrid energy storage system.

Description

A kind of hybrid accumulator

Technical field

The present invention relates to a kind of energy storage device, be specifically related to a kind of hybrid accumulator using storage battery and super capacitor to combine.

Background technology

Modern power systems has multiple demand for energy storage, and the energy storage for ensureing power supply reliability had, as uninterrupted power supply; For ensureing the energy storage of power supply quality, as voltage compensation; The energy storage for improving new energy power generation grid-connection performance had, as stabilized intermittence, the fluctuation of the generation of electricity by new energy power outputs such as wind power generation; Because often kind of energy-storage battery all also exists respective pluses and minuses, if use single energy-storage battery, then can not maximum using photovoltaic system produce rich energy, and use multiple energy-storage battery simultaneously, then can give full play to the advantage of various energy-storage battery, thus the rich energy that photovoltaic system is produced obtains efficiency utilization.Therefore, the hybrid energy-storing in photovoltaic system also starts to come into one's own gradually.

Summary of the invention

The invention provides a kind of hybrid accumulator using super capacitor and storage battery to combine.

To achieve these goals, the present invention adopts following technical scheme: a kind of hybrid accumulator, comprise photovoltaic generating system, charge controller, super capacitor group, parallel controller, batteries and load, described photovoltaic generating system, charge controller, parallel controller and load are connected successively, super capacitor group in parallel between described charge controller and parallel controller, multiple-connected battery group between described parallel controller and load.

Preferably, described batteries comprises lithium battery group and/or lead-acid battery group.Lithium battery has that long service life, power holding capacity are high, lightweight, Acclimation temperature ability is strong, self-discharge rate is low and the advantage such as environmental protection; Lead-acid battery has the advantages such as production technology is simple, cheap.Batteries can select the one in lithium battery group and lead-acid battery group two kinds to use according to concrete requirement, or both be combined.

Preferably, described parallel controller is two-way DC/DC converter.

Preferably, described photovoltaic generating system comprises solar battery group, daylight detection module, daylight tracking module, solar cell state detection module and controller; Described controller is connected with daylight detection module, daylight tracking module, solar cell state detection module respectively, and daylight tracking module is connected with solar panel group, and solar panel group is connected with solar cell state detection module.Controller detects the orientation of the sun according to daylight detection module, then by the orientation of daylight tracking module adjustment solar battery group, makes solar panel group always just to the sun, improves electricity conversion.

The structure that hybrid accumulator of the present invention adopts ultracapacitor in parallel with storage battery, and between ultracapacitor and storage battery, need parallel controller to be separated control voltage, this device power density that the is energy density of storage battery is large and ultracapacitor combines greatly well, make up the shortcoming of the two, the advantage of two parts is not fully exerted, and therefore mixed energy storage system more effectively can meet the demand of angle of solar battery system to energy management.

Accompanying drawing explanation

Fig. 1 is module of the present invention composition schematic diagram;

Fig. 2 is hybrid energy-storing model current constant control voltage curve;

Fig. 3 is hybrid energy-storing model current constant control voltage curve.

Embodiment

Below in conjunction with embodiment, content of the present invention is further described.

As shown in Figure 1, a kind of hybrid accumulator, comprise photovoltaic generating system, charge controller, super capacitor group, parallel controller, batteries and load, described photovoltaic generating system, charge controller, parallel controller and load are connected successively, super capacitor group in parallel between described charge controller and parallel controller, multiple-connected battery group between described parallel controller and load.

Described batteries comprises lithium battery group and/or lead-acid battery group.

Described parallel controller is two-way DC/DC converter.

Photovoltaic generating system through charge controller to super capacitor group, meanwhile, through parallel controller to batteries or load supplying.In this hybrid accumulator, parallel controller plays crucial coordinative role between super capacitor and storage battery.In general, parallel controller can be divided into passive type controller and active controller.In passive type energy storing structure, ultracapacitor is by diode to storage battery or load supplying, and structure is simple, but does not have controllability.In active energy storing structure, ultracapacitor realizes the Energy Transfer to storage battery by DC/DC converter, and therefore hybrid accumulator of the present invention selects active controller.

Wherein, described photovoltaic generating system comprises solar battery group, daylight detection module, daylight tracking module, solar cell state detection module and controller; Described controller is connected with daylight detection module, daylight tracking module, solar cell state detection module respectively, and daylight tracking module is connected with solar panel group, and solar panel group is connected with solar cell state detection module.

Mixed energy storage system of the present invention is applied in 48V independent photovoltaic direct current micro-grid system, and namely whole angle of solar battery system adopts 48V DC bus, and generating, energy storage and load are all connected with this 48V DC bus.

Hybrid accumulator according to the present invention sets up hybrid energy-storing model below, and to hybrid energy-storing model be used in ultracapacitor and storage battery in parallel time performance analyze.Mainly to the performance evaluation of constant voltage, constant current, invariable power discharge and recharge in analysis in parallel.Therefore, the performance of the hybrid energy-storing model below under brief analysis under these three kinds of charge and discharge systems.Because ultracapacitor and the primary condition of storage battery parallel connection are that the two voltage is identical, thus when analyzing hybrid energy-storing model electromotive force E in accumulator internal resistance model _bequal with the initial voltage of electric capacity C in ultracapacitor equivalence RC model, i.e. E _b=U _c0.In addition, ultracapacitor and the storage battery voltage when parallel connection is not 0, considers that the rated voltage of hybrid energy-storing power supply in the present invention is 24V, and the initial voltage here both setting during parallel connection is 18V.

The charging/discharging thereof all relatively commonly used for ultracapacitor and storage battery is constant voltage and current constant control mode, below with regard to the performance of hybrid energy-storing model under these two kinds of patterns of brief analysis.In order to quantitative analysis, setting E _bfor 18V, R _bbe 0.1 Ω, R _cbe 0.05 Ω, C be 50F.

Under constant pressure control system, setting voltage is U, then can calculate electric current now.

$I\left(s\right)=\frac{U(U-E_b)(R_b+R_c)}{R_b{R}_c}\frac{s+1/\[(R_b+R_c)C\]}{s^2\[s+1/\left(R_{c}C\right)\]}---\left(1-1\right)$

Carry out Laplace inverse transformation according to formula 1-1, thus obtain the time-domain expression (1-2) of now electric current.

$i\left(t\right)=\frac{U(U-E_b)}{R_b}(R_{b}C-R_b{\mathrm{Ce}}^{-t/\left(R_{c}C\right)}+t)---(1-2)$

During setting Isobarically Control, constant input voltage is 18.1V, therefore can be obtained the change curve of hybrid energy-storing model electric current under constant pressure control system by formula (1-2), as shown in Figure 2.Under can finding out constant pressure control system, when voltage is slightly higher than hybrid energy-storing model initial voltage, input current can sharply increase (substantially linearly increasing) at short notice, therefore under this kind of control mode, should note the harm that overcurrent causes.

Under current constant control mode, setting electric current is I, then can calculate the voltage at now hybrid energy-storing model two ends.

$U\left(s\right)=\frac{E_b}{s}+\frac{{\mathrm{IR}}_b{R}_c}{R_b+R_c}\frac{s+1/\left(R_{c}C\right)}{s+1/\[(R_b+R_c)C\]}---(1-3)$

Carry out Laplace inverse transformation according to formula (1-3), thus obtain the time-domain expression (1-4) of now model terminal voltage.

$u\left(t\right)=E_b+\frac{{\mathrm{IR}}_b{R}_c}{R_b+R_c}\[\mathrm{\δ}\left(t\right)+\frac{R_b}{R_c(R_b+R_c)C}{e}^{-t/\[(R_b+R_c)C\]}\]---(1-4)$

During setting current constant control, constant input current is 20A, therefore can obtain the change curve of hybrid energy-storing model in current constant control mode drag terminal voltage by formula (1-4), as shown in Figure 3.Under can finding out current constant control mode, starting stage input voltage only produces a small peak voltage, and reaches rapidly a stationary value at short notice.

According to the analysis to hybrid energy-storing model constant voltage and current constant control mode, can find out, when ultracapacitor and storage battery parallel connection (middle without parallel controller effect) are charged, adopt constant voltage charge control can produce huge electric current at short notice, easily damage energy storage device.And adopting constant current charge control mode, input voltage can not produce larger peak voltage in the starting stage, and can reach a stable value within a short period of time.Therefore, when ultracapacitor and storage battery parallel connection (middle without parallel controller effect), constant current should be adopted to charge at that time.

Claims (4)

1. a hybrid accumulator, it is characterized in that: comprise photovoltaic generating system, charge controller, super capacitor group, parallel controller, batteries and load, described photovoltaic generating system, charge controller, parallel controller and load are connected successively, super capacitor group in parallel between described charge controller and parallel controller, multiple-connected battery group between described parallel controller and load.

2. hybrid accumulator according to claim 1, is characterized in that: described batteries comprises lithium battery group and/or lead-acid battery group.

3. hybrid accumulator according to claim 1, is characterized in that: described parallel controller is two-way DC/DC converter.

4. hybrid accumulator according to claim 1, is characterized in that: described photovoltaic generating system comprises solar battery group, daylight detection module, daylight tracking module, solar cell state detection module and controller; Described controller is connected with daylight detection module, daylight tracking module, solar cell state detection module respectively, and daylight tracking module is connected with solar panel group, and solar panel group is connected with solar cell state detection module.