CN102866360A - Power battery pack allowable discharging power estimation method - Google Patents

Abstract

The invention relates to a power battery pack allowable discharging power estimation method, which is characterized in that an allowable discharging power value Pset under each temperature T and corresponding system-on-chip (SOC) value when a battery pack is in work is previously measured, a discharging power reference table MAP is formed, and the data is prestored in a battery management system database; and then the allowable discharging power value is obtained by adopting different calculation methods according to the SOC values. By comprehensively considering factors such as internal resistance of the battery pack, the lowest voltage, consistency of the battery pack and the like and segmenting the SOC, the estimation of the battery pack allowable discharging power is more accurate. Moreover, a battery management system can better control the discharging of the battery pack according to the acquired allowable discharging power, the over discharge possibility is reduced, and the battery pack is better protected.

Description

A kind of power battery pack allows the discharge power predictor method

Technical field

The present invention relates to the improvement of electric battery control method.

Background technology

The permission discharge power predictor method of current battery group is more single, mainly is that temperature T by electric battery and SOC carry out power and estimate.This method is not considered the factors such as each monomer battery voltage, internal resistance, consistance in the electric battery, when SOC exists that error, the internal resistance of cell increase, when the battery inconsistency increases, might cause the part battery to be crossed putting and damage battery.

Summary of the invention

In view of this, the technical problem to be solved in the present invention provides and has a kind ofly considered electric battery, temperature, SOC value, voltage, internal resistance, each battery cell consistance factor, estimates that power battery pack allows the discharge power predictor method accurately.

In order to solve the problems of the technologies described above, this technical matters adopts following solution:

A kind of power battery pack allows the discharge power predictor method, and the method comprises the steps:

1). pre-estimation goes out the permission discharge power Pset value under each temperature T of electric battery work and corresponding each SOC value, formation discharge power table of comparisons MAP, and with this data pre-storage in the battery management system database;

2). when the SOC value more than or equal to 40% the time, according to the permission discharge power Pset value of directly obtaining this moment in real time temperature T and the SOC value battery management system database;

When the SOC value less than 40% more than or equal to 10% the time, according to current minimum monomer voltage value Vmin in the default discharge lower voltage limit value Vo of electric battery and the electric battery, adopt following formula to obtain current permission discharge power Pset value:

Pset=MAP(SOC, T) * Kp* (Vmin-Vo)/Vo, wherein, the Kp value is scale parameter;

When the SOC value less than 10% and 0＜Vmin-Vo＜0.1 the time, current permission discharge power Pset value is: Pset=U*I, wherein U is current assembled battery total voltage, I is current electric battery total current.

Compared with prior art, the present invention has following advantage:

1. this method has considered the factors such as electric battery internal resistance, minimum voltage, consistency of battery pack, and the SOC segmentation is considered, it is more accurate to make electric battery allow discharge power to estimate.

2. battery management is the discharge that can better control electric battery according to the permission discharge power of the method acquisition, has reduced to cross the possibility of putting, and has better protected electric battery.

Embodiment

For the ease of it will be appreciated by those skilled in the art that below in conjunction with embodiment the present invention is described in further detail:

In the electric automobile during traveling process, battery management system and each parameter of car load control module Real-time Collection electric battery, and adopt the designed method estimation power battery pack of present embodiment to allow discharge power pre-.Particularly, the method comprises the steps:

At first, pre-estimation goes out the permission discharge power Pset value under each temperature T of electric battery work and corresponding each SOC value, formation discharge power table of comparisons MAP, and with this data pre-storage in the battery management system database; MAP is as shown in the table for this discharge power table of comparisons:

SOC/T	-35℃	-30℃	-20℃	-10℃	0℃	10℃	20℃	40℃	55℃
										5%	0	0	0	0	0	0	0	0	0
10%	0	0	20	40	60	90	120	120	120
										20%	0	0	20	50	70	105	200	200	200
30%	0	0	20	60	90	135	400	400	400
										40%	0	0	20	80	120	180	500	500	500
50%	0	0	20	110	150	240	600	630	630
										60%	0	0	40	120	160	300	600	630	630
70%	0	0	40	140	220	300	600	630	630
										80%	0	0	70	140	220	450	630	630	630
90%	0	0	70	160	270	450	630	630	630
										100%	0	0	70	160	270	450	630	630	630

In the electric automobile operational process, the current SOC value of battery management system Real-time Obtaining, when the SOC value is decided according to battery behavior more than or equal to this value of 40%() time, directly obtain to allow discharge power Pset value according to the discharge power table of comparisons MAP in the upper table, namely, Pset=MAP (SOC, T).

When the SOC value less than 40% more than or equal to 10% the time, the expression electric battery has been used a period of time, minimum monomer voltage value Vmin, the internal resistance of cell, SOC and the temperature T of electric battery this moment accounts for major influence factors to the permission discharge power of electric battery.Because minimum monomer voltage is near the sparking voltage lower limit at this moment, the battery that internal resistance is large caused easily low-voltage variation or crossed and put, so must limit this moment to discharge power because the pressure drop in its internal resistance causes its voltage lower if any high power discharge this moment.Conversely, this moment, electric battery allowed the discharge power value to be determined by above-mentioned factor.According to current minimum monomer voltage value Vmin in the default discharge lower voltage limit value Vo of electric battery and the electric battery, adopt following formula to obtain current permission discharge power Pset value:

Pset=MAP(SOC, T) * Kp* (Vmin-Vo)/Vo, wherein, the Kp value is scale parameter, is the data statistics value.

When the SOC value less than 10% and 0＜Vmin-Vo＜0.1 the time, the dump energy of electric battery is very low, large discharge power was easy to make voltage to reach lower limit and protected this moment, therefore need to limit in advance discharge power.At this moment, the total voltage U of battery management system Real-time Collection electric battery, electric battery total current I, then, current permission discharge power Pset value is: Pset=U*I.Otherwise, the Pset value according to the SOC value less than 40% more than or equal to 10% the time value, i.e. Pset=MAP(SOC, T) * Kp* (Vmin-Vo)/Vo, wherein, the Kp value is scale parameter, is the data statistics value.

The present invention has considered the factors such as electric battery internal resistance, minimum voltage, consistency of battery pack, and the SOC segmentation is considered, it is more accurate to make electric battery allow discharge power to estimate.The permission discharge power that battery management system obtains according to the method can better be controlled the discharge of electric battery, has reduced to cross the possibility of putting, and has better protected electric battery.

Above-described embodiment only is wherein specific implementation of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to claim of the present invention.Should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these apparent replacement forms all belong to protection scope of the present invention.

Claims (1)

1. a power battery pack allows the discharge power predictor method, it is characterized in that the method comprises the steps:

1). pre-estimation goes out the permission discharge power Pset value under each temperature T of electric battery work and corresponding each SOC value, formation discharge power table of comparisons MAP, and with this data pre-storage in the battery management system database;

2). when the SOC value more than or equal to 40% the time, according to the permission discharge power Pset value of directly obtaining this moment in real time temperature T and the SOC value battery management system database;

When the SOC value less than 40% more than or equal to 10% the time, according to current minimum monomer voltage value Vmin in the default discharge lower voltage limit value Vo of electric battery and the electric battery, adopt following formula to obtain current permission discharge power Pset value:

Pset=MAP(SOC, T) * Kp* (Vmin-Vo)/Vo, wherein, the Kp value is scale parameter;

When the SOC value less than 10% and 0＜Vmin-Vo＜0.1 the time, current permission discharge power Pset value is: Pset=U*I, wherein U is current assembled battery total voltage, I is current electric battery total current.