Background technique
The utilization of new-energy automobile is affected by temperature, and wherein critical component --- power battery is affected by temperature significantly.Electricity
State-of-charge (State of Charge, SOC), health status (State of Health, SOH) and the battery core service life in pond etc.
Assessment is required to accurate battery temperature with prediction and supports, and this battery temperature is the temperature of inside battery active material.In electricity
Chi Bao utilization during, the temperature sensor for measuring battery temperature can only be arranged in outside batteries, as battery pole at.It is dynamic
Concern is primarily with the operating temperature ranges and temperature difference of battery pack each in battery pack in power battery thermal management field.Likewise,
These temperature values refer both to the temperature of inside battery active material.And if the temperature actually measured with battery external temperature sensor
Value will can generate biggish error as the input of battery thermal management.
In new energy vehicle actual motion, battery temperature is a distribution in battery, at this time measured temperature value and institute
Need to battery temperature there are difference, accurately can estimate inside battery active matter from measured temperature after obtaining this difference
The temperature of matter.
Distribution for internal temperature of battery, existing technology is main, and there are as below methods:
(1) based on the three-dimensional emulation method of Fluid Mechanics Computation
This method mainly analyzes the simplified laggard CFD of actual battery pack physical model.The major advantage of this method
Be know each battery core fever in battery pack, establish opposite fine inside battery model and accurately establish out relevant heat dissipation and
After heating model, the interior temperature distribution of battery can be obtained by Fluid Mechanics Computation and finite element method.But this method
The Temperature Distribution that battery can only be analyzed with offline mode, establishes the simulation model of battery pack, analyzes with being unable to real-time online,
And occupancy resource is more, cannot feed back battery temperature in real time.
(2) the one-dimensional emulation mode of battery-based thermal resistance model
This method is simplified on the basis of above-mentioned three-dimensional emulation method.Simplified model considers heat in battery
Internal generation and transmittance process, each object on transmission path is simplified to after in view of its thermal conductivity and thermal capacitance thermal resistance and
Then thermal capacitance is analyzed the thermal behavior inside battery pack using the method that similar circuit is analyzed.However, simplify after thermal resistance and
Heat capacity ratio is more, and form is more complex, wherein needing scalar quantity more.
(3) temperature estimation based on air hot-fluid method
This method estimates the internal temperature of battery using the energy variation of battery and the energy variation of air.Except initial
Value has been used outside the measurement temperature of battery, and other is estimated value, and the error of estimation is easy accumulation, and does not account for presence
The case where when heating of outside.
Summary of the invention
Technical problem to be solved by the present invention lies in provide the power battery pack that a kind of calculating is simple and accuracy is high
Interior battery temperature calculation method and device.
In order to solve the above technical problem, the present invention provides battery temperature calculation methods in a kind of power battery pack, comprising:
Step S1 at the time of judging that this battery electrode column temperature changes, and is obtained according to the battery electrode column temperature of measurement
Take time interval at the time of changing with last battery electrode column temperature;
Step S2 is calculated separately in the time interval, the calorific value and heat dissipation capacity of inside battery and battery electrode column;
Step S3 is calculated according to the calorific value and heat dissipation capacity of the calculated inside battery and battery electrode column at this
Temperature gap at the time of primary cell pole temperature changes between inside battery and battery electrode column;
Step S4, corresponding battery electrode column temperature at the time of this battery electrode column temperature is changed, with described in institute
State the temperature gap in time interval between inside battery and battery electrode column, at the time of last battery electrode column temperature changes
The influence value of temperature gap between inside battery and battery electrode column is summed, obtain this battery electrode column temperature it is changed when
Carve corresponding internal temperature of battery.
Wherein, the step S1 is specifically included: when the difference for the battery electrode column measured temperature that front and back measures twice is more than
Battery electrode column measures temperature change step-length, and after maintaining setting time, then determines that battery electrode column temperature changes, and record
At the time of changing at the time of at this time as this battery electrode column temperature, then subtracts last battery electrode column temperature and become
At the time of change, time interval at the time of changing with last battery electrode column temperature is obtained.
Wherein, the battery electrode column measurement temperature change step-length is 1 DEG C, and the range of the setting time is 20 seconds to 50
Second.
Wherein, the method also includes:
The measured value of preceding one-shot battery pole temperature is subtracted to the measured value of this battery electrode column temperature, resulting difference multiplies
This battery pole is obtained along with the measured value of preceding one-shot battery pole temperature with the half of battery electrode column temperature change step-length
Corresponding battery electrode column temperature at the time of column temperature changes.
Wherein, in the step S2, the calculation of the battery-heating amount are as follows: open battery ohm heat amount with battery
Heat amount summation when the voltage change of road, multiplied by sample period time step-length, and in the time interval, accumulation is calculated.
Wherein, in the step S2, the calculation of the battery electrode column calorific value are as follows: battery operating current square multiplies
With the contact resistance value of battery electrode column, and accumulation calculates in the time interval.
Wherein, if at a time opening heating, the step S2 further includes the accumulative heating for calculating heating process
Amount, calculation are as follows: heating finish time subtracts heating initial time, multiplied by heating power.
Wherein, the step S3 is specifically included: by the sum of inside battery calorific value and heat dissipation capacity in the time interval with
The ratio of the thermal capacitance of battery in the time interval, and in the time interval battery electrode column calorific value and heat dissipation capacity it
With the ratio of the thermal capacitance with battery electrode column in the time interval, obtain at the time of this battery electrode column temperature changes
Temperature gap between inside battery and battery electrode column.
Wherein, the step S3 is specifically included: by inside battery calorific value, heat dissipation capacity and heating in the time interval
The ratio of the sum of accumulative heating amount of process and the thermal capacitance of battery in the time interval, in addition electric in the time interval
The ratio of the sum of pond pole calorific value and heat dissipation capacity with the thermal capacitance of battery electrode column in the time interval is obtained in this primary cell
Temperature gap at the time of pole temperature changes between inside battery and battery electrode column.
The present invention also provides battery temperature computing devices in a kind of power battery pack, comprising:
Acquiring unit, for the battery electrode column temperature according to measurement, when judging that this battery electrode column temperature is changed
It carves, and obtains time interval at the time of changing with last battery electrode column temperature;
Computing unit, for calculating separately in the time interval, the calorific value of inside battery and battery electrode column and
Heat dissipation capacity;And according to the calorific value and heat dissipation capacity of the calculated inside battery and battery electrode column, calculate in this primary cell
Temperature gap at the time of pole temperature changes between inside battery and battery electrode column;And by this battery electrode column temperature
Corresponding battery electrode column temperature at the time of changing, with described in the time interval between inside battery and battery electrode column
Temperature gap, last battery electrode column temperature temperature gap at the time of change between inside battery and battery electrode column
Influence value summation, obtains corresponding internal temperature of battery at the time of this battery electrode column temperature changes.
The beneficial effect of the embodiment of the present invention is:
The present invention can be integrated into existing battery management system, pass through the battery pole obtained to actual measurement in engineering
The mutation analysis of column temperature is battery life predicting, battery pack heat pipe at the time of judging to change internal temperature of battery predicted value
The more accurate temperature parameter input of the offers such as reason;
Temperature value based on battery electrode column measurement can not directly represent the internal temperature of battery, but battery is one whole
Body, regardless of the type of cooling, the variation of temperature can go out inside battery variation, institute of the present invention at battery electrode column with indirect reaction
It is proposed that analysis battery electrode column is suitable for the cooling and air-cooled different operating conditions of liquid from internal temperature of battery difference method for distinguishing, for battery
When group does not work, i.e., battery, which is in radiating state, can also relatively accurately predict the temperature of inside battery;
Update not instead of each sampling period of internal temperature of battery is updated, determines, subtracts by actual conditions
Resource occupation is lacked.
Specific embodiment
The explanation of following embodiment be with reference to attached drawing, can be to the specific embodiment implemented to the example present invention.
It please refers to shown in Fig. 1, the embodiment of the present invention one provides battery temperature calculation method in a kind of power battery pack, packet
It includes:
Step S1 at the time of judging that this battery electrode column temperature changes, and is obtained according to the battery electrode column temperature of measurement
Take time interval at the time of changing with last battery electrode column temperature;
Step S2 is calculated separately in the time interval, the calorific value and heat dissipation capacity of inside battery and battery electrode column;
Step S3 is calculated according to the calorific value and heat dissipation capacity of the calculated inside battery and battery electrode column at this
Temperature gap at the time of primary cell pole temperature changes between inside battery and battery electrode column;
Step S4, corresponding battery electrode column temperature at the time of this battery electrode column temperature is changed, with described in institute
State the temperature gap in time interval between inside battery and battery electrode column, at the time of last battery electrode column temperature changes
The influence value of temperature gap between inside battery and battery electrode column is summed, obtain this battery electrode column temperature it is changed when
Carve corresponding internal temperature of battery.
The embodiment of the present invention measures temperature change value by battery electrode column to judge the variation moment of battery electrode column temperature, and
Thus to obtain the time interval with the last battery electrode column measurement temperature change moment, then to the battery in this time interval
The fever of pole and inside battery, heat dispersal situations are for statistical analysis, obtain the inside battery and battery pole at aforementioned variation moment
The changing value of column temperature difference.
Since battery electrode column temperature is the physical quantity of an actual measurement, there is measurement fluctuation and measurement essence during actual measurement
Degree problem such as fluctuates between 0.001~0.002 DEG C, this value is made approximation by the present embodiment, i.e., sets to battery electrode column measurement temperature
Set change step Tstep, general change step TstepCan meet the requirements for 1 DEG C (be briefly exactly the pole temperature measured is with 1
DEG C be change interval).After having set change step, the precision of measured battery electrode column temperature also will do it corresponding circle
It is whole.
When the battery electrode column temperature surveyed is from Tbar(i-1) it is changing into Tbar(i), the T and after setting timebar(i)≠
Tbar(i-1) it still sets up, then judges that battery electrode column temperature changes, record this moment t1_end.Tbar(i-1) and Tbar(i) divide
Not Wei front and back battery electrode column temperature twice measured value, temperature change step-length T is measured according to the battery electrode column of aforementioned settingstep
(the present embodiment is set as 1 DEG C), then Tbar(i-1) and Tbar(i) difference between is more than 1 DEG C, and when the maintenance setting of this difference
Between after, i.e., judgement battery electrode column temperature change.The purpose that setting time is arranged is to ensure that the temperature of measurement is stablized, without
It is because accidental fluctuation causes error in judgement.In general, the range of setting time can be set between 20 seconds to 50 seconds.
At the time of this battery electrode column temperature changes before t1_end, the last time is judged by the measured value of battery electrode column temperature
Battery electrode column temperature is denoted as t0_end at the time of changing, then front and back at the time of battery electrode column temperature changes twice when
Between interval of delta t=t1_end-t0_end.Certainly, if the t1_end moment is that battery electrode column temperature changes for the first time, Δ
At the time of t=t1_end-t_start, t_start are under original state, to need t_start=convenient for calculating next time
T1_end resets initial time.
T1_end is denoted as k, k moment battery electrode column temperature T at the time of this battery electrode column temperature is changedbar(k) by
Following formula (1) calculate:
Tbar(k)=Tbar(i-1)+[Tbar(i-1)-Tbar(i)]×Tstep×0.5 (1)
The measured value of preceding one-shot battery pole temperature is subtracted to the measured value of this battery electrode column temperature, resulting difference
K moment battery can be arrived along with the measured value of preceding one-shot battery pole temperature multiplied by the half of battery electrode column temperature change step-length
Pole temperature Tbar(k).It should be noted that the measured value of aforementioned battery electrode column temperature is mainly used for judging battery electrode column temperature
The variation moment, in the battery electrode column temperature T at the variation momentbar(k) it is then calculated by formula (1) to substitute observed temperature, a side
The influence fluctuated when face is to eliminate measurement, be on the other hand it is accurate as far as possible under the temperature accuracy of consideration, temperature is rigid after all
Temperature is the average value for approaching the temperature of bounce front and back at the time of bounce.
After step S1 obtains the time interval Δ t of battery electrode column temperature change twice, battery hair is calculated in step s 2
Heat Qinner, battery electrode column calorific value Qbar, while considering the heat dissipation capacity Q of the two in this time intervalbar_dis、
Qinner_dis。
Wherein, battery-heating amount QinnerCalculation it is as follows:
Wherein, OCV andBattery open circuit voltage under a certain temperature and SOC and open-circuit voltage are respectively corresponded to temperature
Variation susceptibility, tsampleFor sample period time step-length, what (OCV-U) × I was indicated is battery ohm heat amount (for not
Can backheating), andIndicate heat amount when battery open circuit voltage variation (for can backheating).Sample period time step
Long tsampleIt is traditionally arranged to be 1 second.
Battery electrode column calorific value QbarCalculation it is as follows:
Qbar=Qbar+I2×Rcontact×Δt (3)
Wherein, RcontactFor the contact resistance value of battery electrode column.
It should be noted that battery-heating amount QinnerAnd battery electrode column calorific value QbarIt is within each sampling period
What accumulation calculated, after step S1 obtains the time interval Δ t of battery electrode column temperature change twice, it can be obtained and passed through in Δ t
Accumulate the battery-heating amount Q calculatedinnerAnd battery electrode column calorific value Qbar.Certainly, it is calculated according to formula (2), (3), needs to remember
Record t_start, the battery electrode column temperature T surveyed at the time of under lower original statebar_ 0, the SOC of battery, operating voltage U, battery
Operating current I, environment temperature TambEtc. information, calculating be all based on the value of last moment and be iterated.
In addition, if at a time opening heating, then heating initial time t is recordedheat_s, and at the end of heating
Record heating finish time theat_e, calculate the accumulative heating amount Q of heating processheat.Calculation is as follows:
Qheating=P × (theat_e-theat_s) (4)
Battery electrode column heat dissipation capacity Qbar_disIt is calculated by following formula:
Qbar_dis={ [Tbar(k-1)-Tamb]×hbar+[Tbar(k-1)4-Ta 4 mb]×kradi}×Δt (5)
Wherein, TambFor environment temperature, hbarFor at battery electrode column with the cross-ventilation coefficient of heat transfer, kradiFor battery electrode column
Heat emissivity coefficient.
Inside battery heat dissipation capacity Qinner_disMainly consider it is thermally conductive lead raw heat loss, be calculated as follows:
Qinner_dis=[Tinner(k-1)-Tamb]×hcell×Δt (6)
According to the calorific value and heat dissipation capacity of the step S2 inside battery obtained and battery electrode column, it is calculated as follows at this
Temperature gap at the time of battery electrode column temperature changes between inside battery and battery electrode column:
Wherein, cpcell、cpbarThe respectively specific heat of battery and pole, mcell、mbarThe respectively quality of battery and pole.
That is, the meter of temperature gap at the time of this battery electrode column temperature changes between inside battery and battery electrode column
Calculation mode are as follows: by the heat of the sum of inside battery calorific value and heat dissipation capacity and battery in the time interval in the time interval
The ratio of appearance, in addition the sum of battery electrode column calorific value and heat dissipation capacity and battery in the time interval in the time interval
The ratio of the thermal capacitance of pole.
If there is heating process as the aforementioned, then at the time of this battery electrode column temperature changes inside battery with
The calculation of temperature gap between battery electrode column are as follows: by inside battery calorific value in the time interval, heat dissipation capacity and
The ratio of the sum of accumulative heating amount of heating process and the thermal capacitance of battery in the time interval, in addition in the time interval
The ratio of the sum of interior battery electrode column calorific value and heat dissipation capacity with the thermal capacitance of battery electrode column in the time interval.
The internal temperature of the battery at current time is finally calculated by following formula:
Wherein, TinnerIt (k) is k moment internal temperature of battery, TbarIt (k) is k moment battery electrode column temperature, Δ T (k-1) is
The temperature gap of k-1 moment battery electrode column calculated and inside battery, k1、k2It changes for last battery electrode column temperature
At the time of influence coefficient of the temperature difference to this temperature difference, by calibration.
That is the calculation of the internal temperature of battery are as follows: corresponding electricity at the time of this battery electrode column temperature changes
Pond pole temperature, with the temperature gap between inside battery and battery electrode column in the time interval, last battery
The influence value of temperature gap at the time of pole temperature changes between inside battery and battery electrode column is summed.
Corresponding to battery temperature calculation method in a kind of power battery pack of the embodiment of the present invention one, the embodiment of the present invention two is mentioned
For battery temperature computing device in a kind of power battery pack, comprising:
Acquiring unit, for the battery electrode column temperature according to measurement, when judging that this battery electrode column temperature is changed
It carves, and obtains time interval at the time of changing with last battery electrode column temperature;
Computing unit, for calculating separately in the time interval, the calorific value of inside battery and battery electrode column and
Heat dissipation capacity;And according to the calorific value and heat dissipation capacity of the calculated inside battery and battery electrode column, calculate in this primary cell
Temperature gap at the time of pole temperature changes between inside battery and battery electrode column;And by this battery electrode column temperature
Corresponding battery electrode column temperature at the time of changing, with described in the time interval between inside battery and battery electrode column
Temperature gap, last battery electrode column temperature temperature gap at the time of change between inside battery and battery electrode column
Influence value summation, obtains corresponding internal temperature of battery at the time of this battery electrode column temperature changes.
It is by above description it is found that implementing bring beneficial effect of the present invention:
The present invention can be integrated into existing battery management system, pass through the battery pole obtained to actual measurement in engineering
The mutation analysis of column temperature is battery life predicting, battery pack heat pipe at the time of judging to change internal temperature of battery predicted value
The more accurate temperature parameter input of the offers such as reason;
Temperature value based on battery electrode column measurement can not directly represent the internal temperature of battery, but battery is one whole
Body, regardless of the type of cooling, the variation of temperature can go out inside battery variation, institute of the present invention at battery electrode column with indirect reaction
It is proposed that analysis battery electrode column is suitable for the cooling and air-cooled different operating conditions of liquid from internal temperature of battery difference method for distinguishing, for battery
When group does not work, i.e., battery, which is in radiating state, can also relatively accurately predict the temperature of inside battery;
Update not instead of each sampling period of internal temperature of battery is updated, determines, subtracts by actual conditions
Resource occupation is lacked.
The above disclosure is only the preferred embodiments of the present invention, cannot limit the right model of the present invention with this certainly
It encloses, therefore equivalent changes made in accordance with the claims of the present invention, is still within the scope of the present invention.