阅读说明：本技术 一种车载动力电池均衡方法、装置及汽车 (Vehicle-mounted power battery equalization method and device and automobile ) 是由 曾勇 闵文骏 王仁蓝 郭思超 于 2018-06-19 设计创作，主要内容包括：本发明提供一种车载动力电池均衡方法、装置及汽车,所述方法首先根据汽车休眠时长及电池充放电电流值确定启动电池均衡；然后确定电压最低的电池单体,获取其它电池单体与所述电压最低的电池单体的压差信息；并根据所述压差信息确定每个电池模组中电池单体的均衡信息；最后根据所述电池单体的均衡信息进行电池均衡。此外,所述装置用于实现所述方法,所述汽车包括所述装置。本发明的方法、装置及汽车解决了整车充电均衡方案不适用于HEV的技术问题,并提高了电池均衡的工作效率。(The invention provides a vehicle-mounted power battery equalization method, a vehicle-mounted power battery equalization device and an automobile, wherein the method comprises the steps of firstly determining to start battery equalization according to automobile dormancy duration and battery charging and discharging current values; then determining the battery monomer with the lowest voltage, and acquiring the pressure difference information of other battery monomers and the battery monomer with the lowest voltage; determining the balance information of the battery monomer in each battery module according to the differential pressure information; and finally, balancing the battery according to the balancing information of the battery monomer. Furthermore, the device is used for implementing the method, and the automobile comprises the device. The method, the device and the automobile solve the technical problem that the charging equalization scheme of the whole automobile is not suitable for the HEV, and improve the working efficiency of battery equalization.)

1. A vehicle-mounted power battery equalization method is characterized by comprising the following steps:

determining to start battery equalization according to the automobile dormancy duration and the battery charging and discharging current value;

determining the battery monomer with the lowest voltage, and acquiring the pressure difference information of other battery monomers and the battery monomer with the lowest voltage;

determining the balance information of the battery monomer in each battery module according to the pressure difference information;

and balancing the battery according to the balancing information of the battery monomer.

2. The vehicle-mounted power battery equalization method according to claim 1, wherein the determining of starting battery cell equalization according to the vehicle sleep time and the battery charge and discharge current value specifically comprises:

if the automobile dormancy duration is greater than a preset first time threshold, starting battery monomer equalization;

if the automobile dormancy duration is less than a preset first time threshold, detecting the charge and discharge current value of the battery; and if the charging and discharging current value of the battery is smaller than the preset current threshold value, and the accumulated time smaller than the preset current threshold value is greater than or equal to a preset second time threshold value, starting the balancing of the single batteries.

3. The vehicle-mounted power battery equalization method according to claim 1, wherein the determining of the battery cell with the lowest voltage and the obtaining of the differential pressure information of the other battery cells and the battery cell with the lowest voltage specifically comprise:

acquiring voltage information of all the battery monomers in real time;

screening out the battery monomer with the lowest voltage;

and comparing the voltage of the battery monomer with the lowest voltage with the voltages of other battery monomers to obtain a plurality of pieces of differential pressure information.

4. The vehicle-mounted power battery equalization method according to claim 1, wherein the determining equalization information of the battery cells in each battery module according to the differential pressure information specifically comprises:

if the pressure difference between a certain battery monomer and the battery monomer with the lowest voltage is larger than a preset pressure difference threshold value, determining that the certain battery monomer is balanced and is about to be started; otherwise, determining that the certain battery monomer is balanced and is about to be closed;

and determining the balanced opening positions and the balanced closing positions of a plurality of battery monomers in the battery module according to the balanced opening and closing conditions of each battery monomer.

5. The vehicle-mounted power battery equalization method according to claim 4, wherein the determining equalization information of the battery cells in each battery module according to the differential pressure information further specifically comprises:

screening out the battery monomer with the shortest balancing time required by each battery module;

the balance time T corresponding to the battery monomer requiring the shortest balance time of the ith battery module is obtained by table look-up_iI is a natural number greater than 0;

if T_iIf the current time is greater than the preset third time threshold, the battery equalization time of the ith battery module is the third time threshold;

if T_iLess than or equal to a preset third time threshold, the battery equalization time of the ith battery module is T_i。

6. The vehicle-mounted power battery balancing method according to claim 5, wherein the battery balancing according to the balancing information of the battery cells specifically comprises:

and performing passive discharge equalization according to the equalization opening positions and the equalization closing positions of a plurality of battery monomers in the battery module and the battery equalization time of each battery module.

7. The vehicle-mounted power battery equalization method according to claim 5, characterized by further comprising: before the step of acquiring the differential pressure information of all the battery monomers and the battery monomer with the lowest voltage is executed, the battery equalization time of each battery module is cleared, and the battery equalization parameters are re-confirmed.

8. The vehicle-mounted power battery equalization method according to claim 2, characterized by further comprising the steps of: recording the starting time and the flameout and power-off time of the automobile, and determining the automobile dormancy duration according to the current starting time and the last flameout and power-off time of the automobile.

9. An on-vehicle power battery balancing unit, its characterized in that, the device includes:

the first determining module is used for determining the balance of the starting battery according to the automobile dormancy duration and the battery charging and discharging current value;

the second determining module is used for determining the battery cell with the lowest voltage;

the voltage difference acquisition module is used for acquiring the voltage difference information between other battery monomers and the battery monomer with the lowest voltage;

the third determining module is used for determining the balance information of the single battery in each battery module according to the pressure difference information;

and the battery balancing module is used for balancing the battery according to the balancing information of the single battery.

10. The vehicle-mounted power battery equalization apparatus of claim 9, characterized in that the apparatus further comprises: and the data zero clearing module is used for clearing the battery equalization time of each battery module and reconfirming the battery equalization parameters.

11. The vehicle-mounted power battery equalization apparatus of claim 9, characterized in that the apparatus further comprises:

the time recording module is used for recording the starting time of the automobile and the flameout and power-off time of the automobile;

and the fourth determination module is used for determining the automobile dormancy duration according to the current automobile starting time and the last automobile flameout and power-off time.

12. An automobile, characterized by comprising the on-vehicle power battery equalization apparatus of any one of claims 9 to 11.

Technical Field

The invention relates to the technical field of batteries, in particular to a vehicle-mounted power battery balancing method and device and an automobile.

Background

The vehicle-mounted power Battery comprises a plurality of Battery modules, each Battery module is formed by connecting Battery monomers in series and parallel, voltage can be different in actual use due to the fact that the Battery monomers have consistency problems in the aspects of using bodies, temperature, impedance and the like, the service life of the vehicle-mounted power Battery is shortened due to the fact that the inconsistency occurs, and the Battery Management System (BMS) has the balanced effect of eliminating the voltage difference among the Battery monomers. Then, the prior art selects a charging equalization scheme of the whole vehicle, that is, when a battery management system enters a battery charging mode, the on-off of a discharging circuit is changed according to the real-time voltage condition of a battery monomer.

In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:

1) the Battery equalization scheme in the prior art is only suitable for Plug-in Hybrid Electric vehicles (PHEVs) and pure Electric vehicles (BEVs) which can be charged, but Hybrid Electric Vehicles (HEVs) cannot be charged with batteries, so that the Hybrid Electric vehicles cannot apply the charging equalization scheme in the prior art;

2) the battery equalization scheme in the prior art is limited by the charging time of the whole vehicle, and because the charging operation is relatively troublesome, many vehicle owners of plug-in hybrid electric vehicles do not charge the vehicle frequently, so that the equalization efficiency is not high;

3) in the battery equalization scheme in the prior art, the equalization circuit is switched on and off according to the real-time voltage condition of the battery monomer, the voltage difference performance in a voltage platform area is small, the equalization can be switched off or misjudged (precision influence), and the equalization efficiency and effect are further reduced.

Disclosure of Invention

The invention aims to provide a vehicle-mounted power battery equalization method, a vehicle-mounted power battery equalization device and a vehicle, and aims to overcome the defects that a whole vehicle charging equalization scheme is not suitable for a hybrid vehicle and the equalization efficiency is low due to limitation of the whole vehicle charging time.

In order to solve the technical problem, the invention provides a vehicle-mounted power battery balancing method, which comprises the following steps:

determining to start battery equalization according to the automobile dormancy duration and the battery charging and discharging current value;

determining the battery monomer with the lowest voltage, and acquiring the pressure difference information of other battery monomers and the battery monomer with the lowest voltage;

determining the balance information of the battery monomer in each battery module according to the pressure difference information;

and balancing the battery according to the balancing information of the battery monomer.

The method for determining and starting the battery monomer equalization according to the automobile dormancy time and the battery charging and discharging current value specifically comprises the following steps:

if the automobile dormancy duration is greater than a preset first time threshold, starting battery monomer equalization;

if the automobile dormancy duration is less than a preset first time threshold, detecting the charge and discharge current value of the battery; and if the charging and discharging current value of the battery is smaller than the preset current threshold value, and the accumulated time smaller than the preset current threshold value is greater than or equal to a preset second time threshold value, starting the balancing of the single batteries.

The determining the battery cell with the lowest voltage and acquiring the differential pressure information of other battery cells and the battery cell with the lowest voltage specifically include:

acquiring voltage information of all the battery monomers in real time;

screening out the battery monomer F with the lowest voltage;

and comparing the voltage of the battery monomer with the lowest voltage with the voltages of other battery monomers to obtain a plurality of pieces of differential pressure information.

Wherein, the determining the balancing information of the battery monomer in each battery module according to the differential pressure information specifically comprises:

if the pressure difference between a certain battery monomer and the battery monomer with the lowest voltage is larger than a preset pressure difference threshold value, determining that the certain battery monomer is balanced and is about to be started; otherwise, determining that the certain battery monomer is balanced and is about to be closed;

and determining the balanced opening positions and the balanced closing positions of a plurality of battery monomers in the battery module according to the balanced opening and closing conditions of each battery monomer.

Wherein, the determining the balancing information of the battery monomer in each battery module according to the differential pressure information specifically further comprises:

screening out the battery monomer with the shortest balancing time required by each battery module;

the balance time T corresponding to the battery monomer requiring the shortest balance time of the ith battery module is obtained by table look-up_iI is a natural number greater than 0;

if T_iIf the current time is greater than the preset third time threshold, the battery equalization time of the ith battery module is the third time threshold;

if T_iLess than or equal to a preset third time threshold, the battery equalization time of the ith battery module is T_i。

The battery equalization according to the equalization information of the battery cells specifically includes:

and performing passive discharge equalization according to the equalization opening positions and the equalization closing positions of a plurality of battery monomers in the battery module and the battery equalization time of each battery module.

Wherein the method further comprises: before the step of acquiring the differential pressure information of all the battery monomers and the battery monomer with the lowest voltage is executed, the battery equalization time of each battery module is cleared, and the battery equalization parameters are re-confirmed.

Wherein the method further comprises the steps of: recording the starting time and the flameout and power-off time of the automobile, and determining the automobile dormancy duration according to the current starting time and the last flameout and power-off time of the automobile.

The invention also provides a vehicle-mounted power battery balancing device, which comprises:

the first determining module is used for determining the balance of the starting battery according to the automobile dormancy duration and the battery charging and discharging current value;

the second determining module is used for determining the battery cell with the lowest voltage;

the voltage difference acquisition module is used for acquiring the voltage difference information between other battery monomers and the battery monomer with the lowest voltage;

the third determining module is used for determining the balance information of the single battery in each battery module according to the pressure difference information;

and the battery balancing module is used for balancing the battery according to the balancing information of the single battery.

Wherein the apparatus further comprises: and the data zero clearing module is used for clearing the battery equalization time of each battery module and reconfirming the battery equalization parameters.

Wherein the apparatus further comprises:

the time recording module is used for recording the starting time of the automobile and the flameout and power-off time of the automobile;

and the fourth determination module is used for determining the automobile dormancy duration according to the current automobile starting time and the last automobile flameout and power-off time.

The invention also provides an automobile which comprises the vehicle-mounted power battery balancing device.

The embodiment of the invention has the beneficial effects that:

(1) the embodiment of the invention determines whether to start the battery equalization of the battery management system according to the automobile dormancy duration and the battery charging and discharging current value, so that compared with the charging equalization mode in the prior art, the embodiment of the invention does not depend on the battery equalization in the charging mode, and can be popularized to a hybrid electric vehicle model without external charging;

(2) the embodiment of the invention obtains the pressure difference information of all the battery monomers of the vehicle-mounted power battery and the battery monomer with the lowest voltage in real time, timely judges which battery monomers need to be subjected to battery equalization according to the pressure difference information, and then performs battery equalization on the battery monomers needing to be equalized; therefore, the pressure difference between the single batteries of the battery is reduced, so that the usable capacity of a battery system can be increased, and good vehicle endurance index can be kept; meanwhile, the reduction of the pressure difference can also increase the available power of a battery system, so that good power indexes of the whole vehicle can be maintained;

(3) the embodiment of the invention overcomes the defect that the charging equalization mode in the prior art is limited by the charging time of the whole vehicle, effectively improves the equalization effect of a battery management system, is beneficial to reliably reducing the use pressure difference of the battery and realizes the consistency self-repair of single batteries; particularly for the plug-in hybrid electric vehicle, the embodiment of the invention has important positive significance, and can avoid the problem that the plug-in hybrid electric vehicle cannot achieve good balance effect because the plug-in hybrid electric vehicle is not charged frequently;

(4) the embodiment of the invention sets the differential pressure threshold value, determines that a certain battery monomer needs to be balanced under the condition that the differential pressure between the certain battery monomer and the battery monomer with the lowest voltage is greater than the preset differential pressure threshold value, sets the differential pressure threshold value to be a variable value, is determined by the residual electric quantity SOC, has smaller voltage difference performance corresponding to the voltage platform area, and sets the differential pressure threshold value of the voltage platform area to be a smaller value matched with the voltage difference performance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a vehicle-mounted power battery balancing method according to an embodiment of the invention.

Fig. 2 is a sub-flowchart of step S100 according to an embodiment of the present invention.

Fig. 3 is a sub-flowchart of step S200 according to an embodiment of the present invention.

Fig. 4 is a sub-flowchart of step S300 according to an embodiment of the present invention.

Fig. 5 is a block diagram of a vehicle-mounted power battery balancing device according to a second embodiment of the present invention.

Detailed Description

The following description of the embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments in which the invention may be practiced.

Fig. 1 is a flowchart of a vehicle-mounted power battery equalization method according to an embodiment of a first aspect of the present invention, where the method includes the following steps:

s100, determining to start battery equalization according to the automobile dormancy duration and the battery charge and discharge current value;

s200, determining the battery monomer with the lowest voltage, and acquiring the pressure difference information of other battery monomers and the battery monomer with the lowest voltage;

s300, determining the balance information of the single batteries in each battery module according to the differential pressure information;

and S400, balancing the battery according to the balancing information of the battery monomer.

Specifically, on-vehicle power battery includes a plurality of battery module, and each battery module includes a plurality of battery monomer, and this embodiment the balanced information indicates which battery monomer needs the equilibrium in each battery module, and which battery monomer does not need the equilibrium. The automobile sleep duration in the embodiment refers to the period from when the automobile is turned off to when the re-ignition is started.

It should be particularly noted that the starting of the battery equalization in step S100 includes a startup equalization and a small current equalization, where the startup equalization is detected when the entire vehicle is started, and the equalization is started once the vehicle dormancy duration satisfies a condition; the small current balance is to detect the charging and discharging current value of the battery when the whole vehicle is in normal use, and comprises the scenes of driving, idling, slow charging, battery heat preservation and the like, and once the charging and discharging current value of the battery meets the conditions, the balance is started.

In the embodiment, whether the battery equalization function is started or not is determined according to the automobile dormancy duration and the battery charging and discharging current value, so that compared with a traditional whole automobile charging equalization mode, the battery equalization function is started without depending on battery equalization in a charging mode, and the embodiment is suitable for various automobile types such as plug-in hybrid electric vehicles, pure electric vehicles and hybrid electric vehicles.

In another possible embodiment, as shown in fig. 2, the step S100 of determining to start cell balancing according to the vehicle sleep time and the battery charging and discharging current value specifically includes the following sub-steps:

s101, presetting a first time threshold A;

the first time threshold value A needs to be actually calibrated according to the electrochemical characteristics of the single battery, and is generally not less than 1 hour;

s102, comparing the automobile sleeping time with a first time threshold A, and determining whether the battery sleeping time is enough to eliminate polarization or not according to the size;

if the automobile dormancy duration is greater than a preset first time threshold A, judging that the battery voltage polarization elimination is completed, and starting a battery monomer balancing function;

if the automobile sleeping time is less than a preset first time threshold A, judging that the battery voltage polarization elimination is not completed, and executing a step S103;

s103, detecting the absolute value I of the charge and discharge current of the battery; in the normal use process of the vehicle-mounted power battery, the embodiment monitors the magnitude of charge and discharge current in real time;

s104, setting a current threshold D, and comparing the absolute value I of the charging and discharging current of the battery with the current threshold D;

if the absolute value I of the charging and discharging current of the battery is smaller than the preset current threshold D, the battery is considered to enter a quasi-steady state stage, and step S105 is executed;

after a period of time in the quasi-steady state stage, it can be considered that the battery is stable and can be subjected to equalization judgment, and it needs to be particularly noted that the battery rate and the actual use condition need to be considered for the size of the D value in this embodiment, the battery equalization judgment error is large when the D value is too large, and the battery with too small D value is difficult to meet the quasi-steady state condition, and is generally not greater than 0.1C.

S105, calculating the accumulated time M of the absolute value I of the charging and discharging current of the battery, which is smaller than a preset current threshold D, and setting a second time threshold E;

and if the accumulated time M is greater than or equal to the second time threshold value E, the battery is considered to be stable and balance judgment can be carried out, and then the battery monomer balance is started.

It should be particularly noted that the battery with too small E value has large equalization judgment error, and the battery with too large E value is difficult to meet the quasi-steady state condition, generally not more than 10 min; D. and E is a parameter restricted by mutual matching, and can be calibrated to form a D-E value look-up table.

In another possible embodiment, as shown in fig. 3, the step S200 determines the battery cell with the lowest voltage, and acquiring the differential pressure information between the other battery cells and the battery cell with the lowest voltage specifically includes:

s201, acquiring voltage information of all battery monomers in real time;

for example, in this embodiment, the number of battery cells of the power battery is defined as n, where n is a natural number greater than 1, and the voltage of the battery cells is monitored by the monitoring unit, so as to obtain voltage parameters of the n battery cells in real time;

s202, screening out the battery cell with the lowest voltage, defining the battery cell as F, and setting the voltage as V_F；

S203 respectively connecting the voltage of the other n-1 battery cells except the battery cell F with the voltage V of the battery cell F_FComparing to obtain n-1 pieces of differential pressure information;

in another possible embodiment, as shown in fig. 4, the step S300 of determining the balancing information of the battery cells in each battery module according to the differential pressure information specifically includes:

s301, setting a differential pressure threshold value B, and acquiring all differential pressure information G in the vehicle-mounted power battery_jThen, G is compared_jAnd magnitude of differential pressure threshold B;

wherein G is_jRepresenting jth differential pressure information, j being a natural number greater than 0;

s302, determining whether the battery monomer is balanced to be opened or closed according to the comparison result;

if the voltage difference G between a certain battery cell and the battery cell with the lowest voltage_jIf the voltage difference is greater than a preset voltage difference threshold value B, determining that the certain battery monomer is balanced and is about to be started; otherwise, determining the certain batteryClosing the monomer in a balanced mode;

here, it should be noted that the differential pressure threshold B is determined according to a remaining power (SOC), since the remaining power is a dynamic value, that is, the differential pressure threshold B is also a dynamic value; the differential pressure B needs to consider the actual condition calibration of the battery SOC, the BMS detection and the precision of the equalizing circuit, and meanwhile, the start-up equalization and the small current equalization can be separately calibrated to form an SOC-differential pressure B value lookup table. And judging the balance condition according to different B values under different SOCs, for example, the B value of the platform area is small, and paying attention to the fact that the balance is not started when the SOC is too low.

S303, determining the balanced opening positions and the balanced closing positions of a plurality of battery monomers in the battery module according to the balanced quasi-opening and quasi-closing conditions of each battery monomer;

in one example, one battery module includes 12 battery cells, and then the definition in this embodiment is as follows:

monomer equalization intended to start: judging whether the battery cell balance needs to be started, and defining the battery cell balance as 1;

monomer equilibrium is about to be turned off: judging whether the battery monomer is balanced and not started, and defining the battery monomer as 0;

it is therefore possible to obtain a case where the equilibrium open position of the battery module in this example may be 101010101010, 000111000111, 001100110011, or the like.

It should be noted that the equalization position of the battery module is kept fixed in the subsequent equalization until the equalization is finished, and is not changed along with the real-time cell pressure difference of the battery. The embodiment can show less to the voltage difference in voltage platform district, and the pressure difference threshold value in voltage platform district also can set to a less value that matches with the voltage difference performance, carries out the balanced scheme of equalizer circuit switching for prior art according to the real-time voltage condition of battery monomer, can avoid the balanced condition of closing or erroneous judgement to further improve balanced efficiency and effect.

In another possible embodiment, as shown in fig. 4, the step S300 of determining the balancing information of the battery cells in each battery module according to the differential pressure information specifically further includes:

s301 screening out eachCell S with shortest equalization time required by each cell module_i；

Wherein S is_iThe battery cell which represents the ith battery module and has the shortest balancing time is the lowest voltage in the cells needing to be balanced in the ith battery module, and i is a natural number which is greater than 0;

s302, looking up a table to obtain the balancing time T corresponding to the battery monomer requiring the shortest balancing time of the ith battery module_i(ii) a It should be noted that the time-voltage lookup table should be a corresponding lookup table difference value between the balanced minimum voltage of the battery module and the minimum voltage of the battery system;

wherein if T_iIf the battery equalization time is larger than a preset third time threshold C, selecting the battery equalization time of the ith battery module as the third time threshold;

wherein if T_iIf the current value is less than or equal to a preset third time threshold value C, the battery equalization time of the ith battery module is selected as T_i。

It should be particularly pointed out that, for the case that the equalization time is too long, the multi-segment equalization design is performed, the selection of the C time only needs to be performed between two equalization starts, if too short, the efficiency is too long, and if too short, the efficiency is not necessary, and the equalization error is reduced by the multi-segment equalization, which is generally not less than 6 hours; of course, the startup equalization and the small current equalization can be considered and also can be separately calibrated, wherein the small current equalization time is shorter, and the influence of judgment errors is reduced.

In another possible embodiment, the step S400 of performing battery balancing according to balancing information of the battery cells specifically includes:

discharging equalization is carried out according to the equalization opening positions and the equalization closing positions of the plurality of battery monomers in each battery module and the battery equalization time of each battery module;

the discharge equalization mode can be passive equalization; the passive equalization is discharging of the monomer with higher voltage; specifically, in the passive equalization described in this embodiment, an equalization circuit is designed on the acquisition board, so that a discharge resistor is connected in parallel to each Battery cell, and the discharge equalization is implemented by opening and closing a control circuit of a Battery Management System (BMS).

It should be noted that, a balance starting snapshot mode is adopted to replace the real-time detection and judgment in the prior art, increase the balance time and avoid the dynamic judgment error, and the snapshot mode refers to that the battery cell which needs to be balanced and is detected after balance starting is stopped after the balance is finished; and the charging and discharging current and voltage change conditions of the battery are ignored during the balancing period, the balancing parameters are not cleared after the battery management system is dormant after the whole vehicle is powered off, and the balancing is continued after the next starting.

In one exemplary embodiment, the method further comprises: after step S100 is executed, before step S200 is executed, the following steps are executed:

and clearing the battery equalization time of each battery module and reconfirming the battery equalization parameters. The original balance counting time of the battery management system is cleared, and the balance parameters are confirmed again, so that the error accumulation caused by the software and hardware calculation of the battery management system can be avoided.

In another exemplary embodiment, the method further comprises: recording the automobile starting time, and determining the automobile dormancy duration according to the current automobile starting time and the last automobile flameout and power-off time;

specifically, before step S100 is executed, the following steps are executed:

igniting and starting the whole vehicle, and initializing;

after the initialization is finished, reading the current time, namely the starting time of the automobile;

and when the automobile is flamed out and powered off, reading and recording the flamed out and powered off time of the automobile as a judgment parameter of the next balanced starting condition.

As shown in fig. 5, a schematic block structure diagram of an onboard power battery balancing apparatus is provided in an embodiment of a second aspect of the present invention, specifically, the apparatus includes:

the first determining module 1 is used for determining the balance of the starting battery according to the automobile dormancy duration and the battery charging and discharging current value;

the second determining module 2 is used for determining the battery cell with the lowest voltage;

the voltage difference acquisition module 3 is used for acquiring the voltage difference information between other battery monomers and the battery monomer with the lowest voltage;

the third determining module 4 is used for determining the balance information of the single battery in each battery module according to the pressure difference information;

and the battery balancing module 5 is used for balancing the battery according to the balancing information of the single battery.

In another possible embodiment, the apparatus further comprises: and the data zero clearing module 6 is used for clearing the battery equalization time of each battery module and reconfirming the battery equalization parameters.

In another possible embodiment, the apparatus further comprises:

the time recording module 7 is used for recording the starting time of the automobile and the flameout and power-off time of the automobile;

and the fourth determination module 8 is used for determining the automobile dormancy duration according to the current automobile starting time and the last automobile flameout power-off time.

It should be noted that the apparatus according to the embodiments of the second aspect may be at least partially integrated in a Battery Management System (BMS).

For the device embodiment, since it corresponds to the method embodiment described above, the relevant points may be referred to the partial description of the method embodiment.

In an embodiment of a third aspect of the invention, an automobile is provided, which comprises the vehicle-mounted power battery balancing device according to the embodiment of the second aspect.

As can be seen from the above description of the embodiments, the method and apparatus of the embodiments of the present invention have the following advantages:

(1) the embodiment of the invention determines whether to start the battery equalization of the battery management system according to the automobile dormancy duration and the battery charging and discharging current value, so that compared with the charging equalization mode in the prior art, the embodiment of the invention does not depend on the battery equalization in the charging mode, and can be popularized to a hybrid electric vehicle model without external charging;

(2) the embodiment of the invention obtains the pressure difference information of all the battery monomers of the vehicle-mounted power battery and the battery monomer with the lowest voltage in real time, timely judges which battery monomers need to be subjected to battery equalization according to the pressure difference information, and then performs battery equalization on the battery monomers needing to be equalized; therefore, the pressure difference between the single batteries of the battery is reduced, so that the usable capacity of a battery system can be increased, and good vehicle endurance index can be kept; meanwhile, the reduction of the pressure difference can also increase the available power of a battery system, so that good power indexes of the whole vehicle can be maintained;

(3) the embodiment of the invention overcomes the defect that the charging equalization mode in the prior art is limited by the charging time of the whole vehicle, effectively improves the equalization effect of a battery management system, is beneficial to reliably reducing the use pressure difference of the battery and realizes the consistency self-repair of single batteries; particularly for the plug-in hybrid electric vehicle, the embodiment of the invention has important positive significance, and can avoid the problem that the plug-in hybrid electric vehicle cannot achieve good balance effect because the plug-in hybrid electric vehicle is not charged frequently;

(4) the embodiment of the invention is provided with the differential pressure threshold value B, when the differential pressure between a certain battery monomer and the battery monomer with the lowest voltage is larger than the preset differential pressure threshold value B, the certain battery monomer is determined to be balanced, the differential pressure threshold value B is set to be a variable value, the voltage difference performance corresponding to the voltage platform area is smaller, and the differential pressure threshold value B of the voltage platform area can also be set to be a value matched with the voltage difference performance.

The undeployed portions of the embodiments of the present invention may be referred to the corresponding portions of the above embodiments, and are not expanded in detail.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.