CN101814759A - Energy balance control device and energy balance control method of battery pack - Google Patents

Abstract

The invention relates to the field of the balance control of battery packs, in particular to a balance control device and a balance control method of a battery pack. The device is used for controlling the balance of a battery pack formed by connecting more than one battery in series. The device comprises a judgment module and a balance module, wherein the judgment module is used for judging whether the battery pack needs to be balanced or not; the balance module is used for balancing the battery pack; the battery pack and the judgment module are respectively connected with the balance module; and the judgment module is connected with the balance module, is used for controlling whether the balance module carries out battery balance or not and controls whether the balance module balances the battery or not according to the monitoring of the utilization rate of the energy of the battery pack. The invention adopts the utilization rate of the energy of the battery pack as a quantitative evaluation standard for judging the uniformity of the battery pack, monitors the uniformity of the battery pack at real time by monitoring the utilization rate of the energy of the battery pack and can accurately carry out the battery balance on the battery pack, thereby enhancing the utilization rate of the energy and prolonging the service life of the batteries.

Description

A kind of battery pack power equalising control device and balancing energy control method

Technical field

The present invention relates to battery pack balancing control field, particularly a kind of battery pack balancing control device and balance control method.

Technical background

In order to reach certain voltage, power and energy grade, battery need be connected and be used in groups, as electric automobile, energy-storage system, direct current system etc.Yet in full accord owing to not accomplishing in production and the use, so the consistency between the battery is relative, inconsistent is absolute.Because capacity is little, internal resistance is big, self-discharge rate is high battery is easier in charge and discharge process to be overcharged, overdischarge and overheated, causes the battery performance decrease speed to be accelerated, and presents " positive feedback ", this causes the consistency of battery pack problem to be accelerated amplification.Because the application technology of battery relates to electrochemistry, electricity and calorifics relevant knowledge, and is bigger to the evaluation and the maintaining method difficulty of battery performance.When reality is used,, need carry out quantitatively evaluating to consistency of battery pack, thereby determine whether and to carry out battery balanced to battery pack for the equilibrium and the maintenance of giving battery provides the data support.Prior art is accurate inadequately for how judging whether carrying out battery balanced method to battery pack, thereby causes under unsuitable condition battery pack being carried out battery balanced, and inefficiency has also reduced the life-span of battery simultaneously.

Summary of the invention

The invention provides a kind of battery pack balancing control device and battery pack is carried out battery balanced coarse technical problem to solve in the prior art.

Another one goal of the invention of the present invention is to propose a kind of control method of this control device of application.

The technical scheme that first goal of the invention of the present invention adopts is as follows:

A kind of battery pack balancing control device, described device are used to control to carrying out equilibrium by the battery pack that is composed in series more than a battery, and described device comprises:

Be used to judge whether battery pack needs to carry out balanced judge module;

Be used for battery pack is carried out balanced balance module;

Battery pack and judge module, balance module connects respectively;

Judge module is connected with balance module, be used to control balance module whether carry out battery balanced, described judge module according to the monitoring battery pack capacity usage ratio, control balance module whether battery is carried out equilibrium.

The technical scheme that second goal of the invention of the present invention adopts is as follows:

A kind of battery pack balancing control method, described method comprises:

(21) capacity usage ratio by described judge module monitoring battery pack, when the capacity usage ratio of battery pack is lower than then execution in step (22) of pre-set threshold, otherwise execution in step (21);

(22) balance module battery pack is carried out battery balanced, execution in step (21).

As a kind of preferred version, the concrete steps of the judge module of described step (21) are:

(31) charge and discharge process of monitoring battery pack, the maximum available and the SOC of single battery of measurement;

(32) the battery pack maximum available energy under battery pack maximum available energy and the equilibrium state under the record current state;

(33) the battery pack maximum available energy under the battery pack maximum available energy/equilibrium state under the capacity usage ratio=current state of record battery pack;

(34) if the capacity usage ratio of battery pack is lower than pre-set threshold execution in step (22) balance module battery pack is carried out battery balanced, otherwise execution in step (31).

Wherein step (31) only need be measured before battery pack work and once get final product.

As a kind of preferred version, the method that the judge module of described step (21) is monitored the capacity usage ratio of the battery pack that is in series by n battery is:

(41) maximum discharge capacity of counting cell group

The maximum charge capacity

And maximum available

(42) the SOC operation interval [SOC of single battery is filled in the process of putting entirely in calculating entirely in battery pack _{Dch_end}, SOC _{Ch_end}];

(43) maximum available energy of counting cell group under current state

With the maximum available energy after the equilibrium

(44) capacity usage ratio of counting cell group

(45) when

Be lower than pre-set threshold then execution in step (22) call balance module battery pack is carried out battery balanced, otherwise execution in step (41).

The present invention adopts the battery pack power utilance as the quantitatively evaluating standard of judging consistency of battery pack, by the battery pack power utilance is monitored, monitor the consistency of battery pack in real time, can carry out battery balanced to battery pack accurately, thereby improve the battery pack power utilance, extending battery life.

Description of drawings

Fig. 1 is a workflow of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in more detail.

The maximum available energy of 1 battery pack

N maximum available is respectively Q _Max[1] ..., Q _Max[n], state-of-charge is respectively SOC ₀[1] ..., SOC ₀After the battery strings of [n] was unified into group, the major parameter of battery pack was as follows:

(1) maximum discharge capacity

I=1 wherein ..., n;

(2) maximum charge capacity

J=1 wherein ..., n;

(3) maximum available

(4) maximum available energy

M=1 wherein ..., n.

${\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}\left[m\right]={\mathrm{SOC}}_0\left[m\right]-\frac{Q_{\mathrm{rem}}^B}{Q_{\max }\left[m\right]},$ ${\mathrm{SOC}}_{\mathrm{ch}\_\mathrm{end}}\left[m\right]={\mathrm{SOC}}_0\left[m\right]+\frac{Q_{\mathrm{ch}\_\max }^B}{Q_{\max }\left[m\right]}.$

As seen, after the series connection in groups, the maximum available energy of battery pack is relevant with the maximum available and the SOC of living in of a single battery in the group.For the maximization that realizes that battery pack power is utilized, need the capacity of battery pack to make full use of on the one hand; On the other hand, every battery all is in higher SOC and has great importance equally for the stored energy that improves battery pack.That is to say, in order to realize that stored energy reaches maximization, the equilibrium of battery pack not only needs being full of electricity and having put electric (be the capacity of battery reach make full use of) of the minimum battery of realization capacity, to make that also the state-of-charge of all batteries reaches high as far as possible in the battery pack, promptly guarantee that all batteries all are full of electricity when charging finishes, this is the basis for estimation that whether needs to carry out equilibrium from the angle battery pack of energy.

The capacity usage ratio of 2 battery pack

Suppose that cell p is the battery of capacity minimum in the battery pack that is composed in series of n battery, when then battery pack was full of electricity, all single batteries all were filled electricity in the group, and promptly the SOC of all single batteries reaches 100%.When battery pack was discharged, the maximum discharge capacity of battery pack was exactly the maximum available after its equilibrium

Equal the maximum available (Q of cell p _Max[p]), that is:

$Q_{\max }^{\mathrm{eq}\_B}=Q_{\max }\left[p\right]\·\·\·\·\·\·\left(1\right)$

When so discharge finishes, the residual capacity of any battery m in the battery pack

For:

$Q_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\left[m\right]=Q_{\max }\left[m\right]-Q_{\max }\left[p\right]\·\·\·\·\·\·\left(2\right)$

At this moment, the state-of-charge of this battery

For:

${\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\left[m\right]=\frac{Q_{\max }\left[m\right]-Q_{\max }\left[p\right]}{Q_{\max }\left[m\right]}\×100\%=\frac{Q_{\max }\left[m\right]-Q_{\max }^{\mathrm{eq}\_B}}{Q_{\max }\left[m\right]}\×100\%\·\·\·\·\·\·\left(3\right)$

So in charge and discharge process, the maximum available energy of battery m

For:

$E_{\max }^{\mathrm{eq}}\left[m\right]=Q_{\max }^{\mathrm{eq}\_B}\×U_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\right[m],100\%]}\·\·\·\·\·\·\left(4\right)$

The maximum available energy of battery pack

For:

$E_{\max }^{\mathrm{eq}\_B}=Q_{\max }^{\mathrm{eq}\_B}\×\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{U}_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\right[k],100\%]},$ k＝1，...，n.....................(5)

So capacity usage ratio of battery For:

${\mathrm{\η}}_E^B=\frac{E_{\max }^B}{E_{\max }^{\mathrm{eq}\_B}}=\frac{Q_{\max }^B\×\underset{m=1}{\overset{n}{\mathrm{\Σ}}}{U}_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}\right[m],{\mathrm{SOC}}_{\mathrm{ch}\_\mathrm{end}}[m\left]\right]}}{Q_{\max }^{\mathrm{eq}\_B}\×\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{U}_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\right[k],100\%]}}$

$={\mathrm{\η}}_C^B\×\frac{\underset{m=1}{\overset{n}{\mathrm{\Σ}}}{U}_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}\right[m],{\mathrm{SOC}}_{\mathrm{ch}\_\mathrm{end}}[m\left]\right]}}{\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{U}_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\right[k],100\%]}}\·\·\·\·\·\·\left(6\right)$

Owing to after the equilibrium,, have for any battery:

$Q_{\max }^{\mathrm{eq}\_B}\×U_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}^{\mathrm{eq}}\right[k],100\%]}\≥Q_{\max }^B\×U_{\mathrm{SOC}=\left[{\mathrm{SOC}}_{\mathrm{dch}\_\mathrm{end}}\right[k],{\mathrm{SOC}}_{\mathrm{ch}\_\mathrm{end}}[k\left]\right]}\·\·\·\·\·\·\left(7\right)$

So

Always smaller or equal to 1, in the process of using, the consistency of battery pack is poor more like this,

Just more little, so the capacity usage ratio of battery pack is the quantitatively evaluating index of consistency of battery pack and whether needs balanced basis for estimation.

As shown in Figure 1, concrete workflow of the present invention is as follows:

(S1) maximum discharge capacity of counting cell group The maximum charge capacity

And maximum available

(S2) the SOC operation interval [SOC of single battery is filled in the process of putting entirely in calculating entirely in battery pack _{Dch_end}, SOC _{Ch_end}];

(S3) maximum available energy of counting cell group under current state

With the maximum available energy after the equilibrium

(S4) capacity usage ratio of counting cell group

(S5) when

Be lower than pre-set threshold then execution in step (S6) call balance module battery pack is carried out battery balanced, otherwise execution in step (S1);

(S6) calling balance module carries out battery balanced to battery pack.

Claims (4)

1. one kind is utilized maximized battery pack balancing control device based on energy, and described device is used for carrying out equilibrium more than the battery pack of a battery series connection, and described device comprises:

Be used to judge whether battery pack needs to carry out balanced judge module;

Be used for battery pack is carried out balanced balance module;

Battery pack is connected with balance module respectively with judge module;

Whether judge module is connected with balance module, be used to control balance module and carry out battery balancedly, it is characterized in that: described judge module is according to the capacity usage ratio of monitoring battery pack, and whether the control balance module carries out equilibrium to battery.

2. one kind is utilized maximized battery pack balancing control method based on energy, adopts the described device of claim 1, it is characterized in that described method comprises:

(21) capacity usage ratio by described judge module monitoring battery pack, when the capacity usage ratio of battery pack is lower than then execution in step (22) of pre-set threshold, otherwise execution in step (21);

(22) balance module battery pack is carried out battery balanced, execution in step (21).

3. balance control method according to claim 2 is characterized in that, the concrete steps of the judge module of described step (21) are:

(31) charge and discharge process of monitoring battery pack, the maximum available and the SOC of single battery of measurement;

(32) the battery pack maximum available energy under battery pack maximum available energy and the equilibrium state under the record current state;

(33) the battery pack maximum available energy under the battery pack maximum available energy/equilibrium state under the capacity usage ratio=current state of record battery pack;

(34) if the capacity usage ratio of battery pack is lower than pre-set threshold execution in step (22) balance module battery pack is carried out battery balanced, otherwise execution in step (31).

4. balance control method according to claim 2 is characterized in that, the method that the judge module of described step (21) is monitored the capacity usage ratio of the battery pack that is in series by n battery is:

(41) maximum discharge capacity of counting cell group

, the maximum charge capacity

And maximum available

(42) the SOC operation interval [SOC of single battery is filled in the process of putting entirely in calculating entirely in battery pack _{Dch_end}, SOC _{Ch_end}];

(43) maximum available energy of counting cell group under current state

With the maximum available energy after the equilibrium

(44) capacity usage ratio of counting cell group

(45) when

Be lower than pre-set threshold then execution in step (22) call balance module battery pack is carried out battery balanced, otherwise execution in step (41).

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