阅读说明：本技术 一种动力电池剩余充电时间估算方法、装置及电动汽车 (Power battery residual charging time estimation method and device and electric vehicle ) 是由 陈建行 丁灿 朱骞 牟丽莎 邓承浩 杨辉前 于 2021-09-30 设计创作，主要内容包括：本发明提出一种动力电池剩余充电时间估算方法、装置及电动汽车,该方法包括：基于动力电池进入充电时所采集的电芯单体电压确定动力电池当前所处的目标充电阶数；判断动力电池是否开启预加热功能；若动力电池未开启预加热功能,确定动力电池在目标充电阶数需求的剩余充电时间；对于目标充电阶数之后的剩余各充电阶数,重复执行：计算下一充电阶数对应的电池最高温度和电池最低温度；基于计算出的下一充电阶数对应的电池最高温度和电池最低温度以及下一充电阶数,确定动力电池在下一充电阶数需求的剩余充电时间；将动力电池在目标充电阶数及之后的每一充电阶数各自所需求的剩余充电时间之和确定为未开启预加热功能的动力电池的第一总剩余充电时间。(The invention provides a method and a device for estimating the residual charging time of a power battery and an electric automobile, wherein the method comprises the following steps: determining a current target charging order of the power battery based on the cell voltage acquired when the power battery is charged; judging whether the preheating function of the power battery is started or not; if the preheating function of the power battery is not started, determining the residual charging time required by the power battery at the target charging order; for each remaining charging order after the target charging order, repeatedly performing: calculating the highest temperature and the lowest temperature of the battery corresponding to the next charging order; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order; and determining the sum of the residual charging time required by the power battery in the target charging order and each charging order after the target charging order as the first total residual charging time of the power battery without starting the preheating function.)

1. A method for estimating the residual charging time of a power battery is characterized by comprising the following steps:

determining a current target charging order of the power battery based on the cell voltage acquired when the power battery is charged;

judging whether the preheating function of the power battery is started or not;

if the preheating function of the power battery is not started, determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order which are acquired when the power battery is charged;

for each remaining charging order after the target charging order, repeatedly performing:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

and determining the sum of the residual charging time required by the power battery in the target charging order and each charging order after the target charging order as the first total residual charging time of the power battery without starting the preheating function.

2. The power battery remaining charge time estimation method according to claim 1, further comprising:

if the preheating function of the power battery is started, determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order;

for each remaining charging order after the target charging order, repeatedly performing:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

calculating second total residual charging time of the power battery with the preheating function started based on the lowest temperature of the power battery collected before the preheating function of the power battery is started, the highest temperature of the power battery collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

3. The power battery remaining charge time estimation method according to claim 1,

based on a preset relation table corresponding to the preset battery temperature and the preset charging demand current of the power battery, determining a first charging demand current corresponding to the highest battery temperature acquired when the power battery enters charging and determining a second charging demand current corresponding to the lowest battery temperature acquired when the power battery enters charging;

taking out a smaller one of the first charging demand current and the second charging demand current as a first comparison value;

judging whether the difference value between the charging current of the power battery and the first comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is continuously within the preset range, determining the first comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is not continuously within the preset range, determining the value obtained by reducing the power battery charging current acquired in real time and the first comparison value as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝△SOC_m*△C_apm/I_Reqm

calculating a remaining charging time T of a target charging order_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; deltaC_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmThe charging demand current corresponding to the target charging order is obtained.

4. The method for estimating the remaining charging time of the power battery according to claim 2, wherein a third charging demand current corresponding to the highest battery temperature acquired after the preheating function of the power battery is started and a fourth charging demand current corresponding to the lowest battery temperature acquired before the preheating function of the power battery is started are determined based on a preset relation look-up table corresponding to the preset battery temperature and the charging demand current of the power battery;

taking out a smaller one of the third and fourth charging demand currents as a second comparison value;

judging whether the difference value between the charging current of the power battery and the second comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is continuously within the preset range, determining the second comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is not continuously within the preset range, determining the value obtained by subtracting the second comparison value from the power battery charging current acquired in real time as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝△SOC_m*△C_apm/I_Reqm

calculating the remaining charging time T of the target charging order requirement_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; delta C_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmA charging demand current corresponding to a target charging order。

5. The power battery remaining charge time estimation method according to claim 2, characterized by the formula:

T_Pred＝(T_Tar-T_Min)/T_Rate+T_m+T_m+1+....+T_n

calculating a second total remaining charging time T of the power battery with the preheating function started_PredWherein, T_TarThe maximum temperature T of the battery collected after the preheating function of the power battery is started_MinThe lowest temperature T of the battery collected before the preheating function of the power battery is started_RateFor a predetermined heating rate of the power cell, T_mTo determine the remaining charging time, T, required for the power cell at said target charging order_m+1Determining a remaining charging time, T, required for a next charging order of the power cell after said target charging order_nThe remaining charge time required for the last order charge order.

6. The method for estimating the remaining charging time of the power battery according to claim 1, wherein the step of calculating the maximum battery temperature and the minimum battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the maximum battery temperature and the minimum battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset threshold of the opening and closing temperature of the thermal management system comprises the steps of:

by the formula:

calculating a first temperature value T_COU1；

By the formula:

calculating a second temperature value T_COU2；

A first temperature value T_COU1And a second temperature value T_COU2The larger value of the first temperature value T is determined as the highest battery temperature corresponding to the next charging order, and the first temperature value T is set_COU1And a second temperature value T_COU2The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_0maxThe maximum temperature of the battery collected when the battery enters a charging state; t is_0minThe minimum temperature of the battery is acquired when the battery enters a charging state; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}The ambient temperature of the environment in which the vehicle is located; t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

7. The method for estimating the remaining charging time of the power battery according to claim 2, wherein the step of calculating the maximum battery temperature and the minimum battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the maximum battery temperature and the minimum battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset threshold of the opening and closing temperature of the thermal management system comprises the steps of:

by the formula:

calculating a third temperature value T_COU3；

By the formula:

calculating a fourth temperature value T_COU4；

A third temperature value T_COU3And a fourth temperature value T_COU4The larger value of the first and second temperature values is determined as the highest battery temperature corresponding to the next charging order, and the third temperature value T is set_COU3And a fourth temperature value T_COU4The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_maxThe maximum temperature of the battery collected after the preheating function of the power battery is started; t is_minThe method comprises the steps of collecting the lowest temperature of a power battery before the preheating function of the power battery is started; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}The ambient temperature of the environment in which the vehicle is located; t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

8. A power battery remaining charge time estimation device, comprising:

the first determination module is used for determining the current target charging order of the power battery based on the acquired cell monomer voltage of the power battery when the power battery is charged;

the judging module is used for judging whether the preheating function of the power battery is started or not;

the second determining module is used for determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order which are acquired when the power battery enters the charging process if the preheating function of the power battery is not started;

a third determining module, configured to repeatedly execute, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

and the fourth determining module is used for determining the sum of the residual charging time required by the power battery in the target charging order and each subsequent charging order as the first total residual charging time of the power battery without starting the preheating function.

9. The power battery remaining charge time estimation apparatus according to claim 8, further comprising:

the fifth determining module is used for determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order if the preheating function of the power battery is started;

a sixth determining module, configured to repeatedly perform, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

the calculation module is used for calculating second total residual charging time of the power battery with the preheating function on the basis of the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

10. An electric vehicle characterized by comprising the power battery remaining charge time estimation device according to claim 8 or 9.

Technical Field

The invention belongs to the field of new energy automobile battery management systems, and particularly relates to a method and a device for estimating the residual charging time of a power battery and an electric automobile.

Background

With the gradual deterioration of global climate, the aggravation of urban atmospheric pollution and the excessive consumption of petroleum resources, more and more people in the automobile field have looked to electric automobiles. The charging time of the power battery of the electric automobile, the estimation of the residual charging time and the like are very important for user experience.

The accurate estimation surplus charge time can provide suitable guidance for the user to use the vehicle, and the user can reasonably arrange the vehicle according to the estimated surplus charge time and the self condition, so that unnecessary waiting is reduced, and the user experience is improved. In addition, accurate estimation surplus charge time still can provide the support for whole car reservation charging function, and the reservation charges can be comparatively accurate control vehicle and charges in the lower period of price of electricity, saves the user expense of charging, promotes user experience.

The conventional method for estimating the remaining charging time is basically obtained by dividing the remaining charging capacity of the battery by the current, the current is obtained by calculating the current from the actual charging current of the battery or the current battery temperature, and the estimation accuracy of the remaining charging time is not high. Such charging methods have several major disadvantages:

1. calculating the residual time according to the real-time current, wherein the estimated value jumps along with the fluctuation of the current;

2. and calculating the charging current according to the temperature of the charging real-time battery without considering the temperature change in the whole charging process, so that the error of the estimated value of the residual charging time is larger.

Based on the current situation that the existing power battery residual charging time estimation method is insufficient in precision and poor in user experience, optimization of the residual charging time estimation method is particularly important.

Disclosure of Invention

The invention provides a method and a device for estimating the residual charging time of a power battery and an electric vehicle, which can meet the estimation of the residual charging time of different users and different use scenes, can estimate the residual charging time more accurately and provide reasonable reference for the use of the users.

The technical scheme of the invention is as follows:

the invention provides a method for estimating the residual charging time of a power battery, which comprises the following steps:

determining a current target charging order of the power battery based on the cell voltage acquired when the power battery is charged;

judging whether the preheating function of the power battery is started or not;

if the preheating function of the power battery is not started, determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order which are acquired when the power battery is charged;

for each remaining charging order after the target charging order, repeatedly performing:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

and determining the sum of the residual charging time required by the power battery in the target charging order and each charging order after the target charging order as the first total residual charging time of the power battery without starting the preheating function.

Preferably, the method further comprises:

if the preheating function of the power battery is started, determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order;

for each remaining charging order after the target charging order, repeatedly performing:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

calculating second total residual charging time of the power battery with the preheating function started based on the lowest temperature of the power battery collected before the preheating function of the power battery is started, the highest temperature of the power battery collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

Preferably, a first charging demand current corresponding to the highest battery temperature collected when the power battery enters charging and a second charging demand current corresponding to the lowest battery temperature collected when the power battery enters charging are determined based on a preset relation look-up table corresponding to the preset battery temperature and charging demand current of the power battery;

taking out a smaller one of the first charging demand current and the second charging demand current as a first comparison value;

judging whether the difference value between the charging current of the power battery and the first comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is continuously within the preset range, determining the first comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is not continuously within the preset range, determining the value obtained by reducing the power battery charging current acquired in real time and the first comparison value as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝△SOC_m*△C_apm/I_Reqm

calculating a remaining charging time T of a target charging order_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; delta C_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmThe charging demand current corresponding to the target charging order is obtained.

Preferably, based on a preset look-up table of a preset corresponding relation between the battery temperature and the charging demand current of the power battery, determining a third charging demand current corresponding to the highest battery temperature collected after the preheating function of the power battery is started and determining a fourth charging demand current corresponding to the lowest battery temperature collected before the preheating function of the power battery is started;

taking out a smaller one of the third and fourth charging demand currents as a second comparison value;

judging whether the difference value between the charging current of the power battery and the second comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is continuously within the preset range, determining the second comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is not continuously within the preset range, determining the value obtained by subtracting the second comparison value from the power battery charging current acquired in real time as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝ΔSOC_m*ΔC_apm/I_Reqm

calculating the remaining charging time T of the target charging order requirement_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; delta C_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmThe charging demand current corresponding to the target charging order is obtained.

Preferably, by the formula:

T_Pred＝(T_Tar-T_Min)/T_Rate+T_m+T_m+1+....+T_n

calculating a second total remaining charging time T of the power battery with the preheating function started_PredWherein, T_TarThe maximum temperature T of the battery collected after the preheating function of the power battery is started_MinThe lowest temperature T of the battery collected before the preheating function of the power battery is started_RateFor a predetermined heating rate of the power cell, T_mTo determine the remaining charging time, T, required for the power cell at said target charging order_m+1Determining a remaining charging time, T, required for a next charging order of the power cell after said target charging order_nThe remaining charge time required for the last order charge order.

Preferably, the step of calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time, and a preset temperature threshold for switching the thermal management system includes:

by the formula:

calculating a first temperature value T_COU1；

By the formula:

calculating a second temperature value T_COU2；

A first temperature value T_COU1And a second temperature value T_COU2The larger value of the first temperature value T is determined as the highest battery temperature corresponding to the next charging order, and the first temperature value T is set_COU1And a second temperature value T_COU2The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_0maxThe maximum temperature of the battery collected when the battery enters a charging state; t is_0minThe minimum temperature of the battery is acquired when the battery enters a charging state; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}The ambient temperature of the environment in which the vehicle is located; t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

Preferably, the step of calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time, and a preset temperature threshold for switching the thermal management system includes:

by the formula:

calculating a third temperature value T_COU3；

By the formula:

calculating a fourth temperature value T_COU4；

A third temperature value T_COU3And a fourth temperature value T_COU4The larger value of the first and second temperature values is determined as the highest battery temperature corresponding to the next charging order, and the third temperature value T is set_COU3And a fourth temperature value T_COU4The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_maxThe maximum temperature of the battery collected after the preheating function of the power battery is started; t is_minThe method comprises the steps of collecting the lowest temperature of a power battery before the preheating function of the power battery is started; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}The ambient temperature of the environment in which the vehicle is located; t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

The invention also provides a device for estimating the residual charging time of the power battery, which comprises:

the first determination module is used for determining the current target charging order of the power battery based on the acquired cell monomer voltage of the power battery when the power battery is charged;

the judging module is used for judging whether the preheating function of the power battery is started or not;

the second determining module is used for determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order which are acquired when the power battery enters the charging process if the preheating function of the power battery is not started;

a third determining module, configured to repeatedly execute, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

and the fourth determining module is used for determining the sum of the residual charging time required by the power battery in the target charging order and each subsequent charging order as the first total residual charging time of the power battery without starting the preheating function.

Preferably, the apparatus further comprises:

the fifth determining module is used for determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order if the preheating function of the power battery is started;

a sixth determining module, configured to repeatedly perform, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

the calculation module is used for calculating second total residual charging time of the power battery with the preheating function on the basis of the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

The invention also provides an electric automobile which comprises the power battery residual charging time estimation device.

The invention has the beneficial effects that:

the charging system can adapt to working conditions such as direct current charging, alternating current charging, charging heating and different charging target battery state of charge (SOC), can be suitable for power battery packs provided with cooling systems and not provided with cooling systems, and has redundancy estimation capability when the output current of the charging pile is abnormal.

The charging method and the charging system can adapt to various charging working conditions, accurately estimate the residual charging time, provide accurate reference for a user to use the vehicle, and improve user experience.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention.

Detailed Description

Referring to fig. 1, the present invention provides a method for estimating a remaining charging time of a power battery, the method comprising the following steps:

step S101, determining a current target charging order of the power battery based on the cell voltage acquired when the power battery is charged.

In this embodiment, the power battery is charged by inserting the charging gun into the charging port of the power battery. The collection of the cell individual voltage of the power battery belongs to the existing mode in this embodiment.

Dividing the voltage into n steps according to the cell single voltage of the power battery, wherein each step corresponds to a cell single voltage range V_n-1To V_n. Selecting the cell single highest voltage CellU based on the actually acquired cell single voltage, and determining the charging order corresponding to the cell single highest voltage CellU. And if the charging order is determined to be the first order, selecting the lowest voltage of the single battery cell to re-determine the charging order, and determining the charging order to be the target charging order required in the scheme. If the determined charging order is the other order after the first order, the determined charging order is taken as the target charging order required in the scheme.

And step S102, judging whether the power battery starts a preheating function or not.

And step S103, if the preheating function of the power battery is not started, determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order acquired when the power battery is charged.

Specifically, the step S103 includes:

based on a preset relation table corresponding to the preset battery temperature and the preset charging demand current of the power battery, determining a first charging demand current corresponding to the highest battery temperature acquired when the power battery enters charging and determining a second charging demand current corresponding to the lowest battery temperature acquired when the power battery enters charging;

taking out a smaller one of the first charging demand current and the second charging demand current as a first comparison value;

judging whether the difference value between the charging current of the power battery and the first comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is continuously within the preset range, determining the first comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the first comparison value is not continuously within the preset range, determining the value obtained by reducing the power battery charging current acquired in real time and the first comparison value as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝△SOC_m*△C_apm/I_Reqm

calculating a remaining charging time T of a target charging order_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; delta C_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmThe charging demand current corresponding to the target charging order is obtained.

Step S104, for each remaining charging order after the target charging order, repeatedly performing:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; and determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order.

In this embodiment, the specific steps of calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time, and the preset temperature threshold for switching the thermal management system include:

by the formula:

calculating a first temperature value T_COU1；

By the formula:

calculating a second temperature value T_COU2；

A first temperature value T_COU1And a second temperature value T_COU2The larger value of the first temperature value T is determined as the highest battery temperature corresponding to the next charging order, and the first temperature value T is set_COU1And a second temperature value T_COU2The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_0maxThe maximum temperature of the battery collected when the battery enters a charging state; t is_0minThe minimum temperature of the battery is acquired when the battery enters a charging state; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}The ambient temperature of the environment in which the vehicle is located; t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

After the calculation of the battery maximum and minimum temperatures for the next charge order is completed, the above steps are repeated until the remaining charge time required for all remaining charge orders is determined.

Step S105, determining a sum of remaining charging times required by the power battery in the target charging order and each subsequent charging order as a first total remaining charging time of the power battery without starting the preheating function.

Specifically, by the formula: t is_Pred＝T_m+T_m+1+...+T_n

Calculating the first total remaining charge time T_predWherein, T_mResidual charging time, T, required for a target charging order_mThe remaining charging time, T, required for the next charging order after the target charging order_nThe remaining charging time required for the last charging order.

Through the above steps S101 to S105, prediction of the remaining charging time of the power battery whose pre-heating function is not turned on can be realized.

In this embodiment, a method for predicting the remaining charging time of a power battery with a preheating function is also provided, and the method further includes:

step S106, if the preheating function of the power battery is started, determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order;

step S107, for each remaining charging order after the target charging order, repeatedly performs:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

step S108, calculating second total residual charging time of the power battery with the preheating function on the basis of the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

Wherein, the step S106 includes:

determining a third charging demand current corresponding to the highest battery temperature acquired after the preheating function of the power battery is started and a fourth charging demand current corresponding to the lowest battery temperature acquired before the preheating function of the power battery is started based on a preset relation look-up table corresponding to the preset battery temperature and the charging demand current of the power battery;

taking out a smaller one of the third and fourth charging demand currents as a second comparison value;

judging whether the difference value between the charging current of the power battery and the second comparison value, which is acquired in real time within a preset time length, is continuously within a preset range;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is continuously within the preset range, determining the second comparison value as the charging demand current corresponding to the target charging order;

if the difference value between the power battery charging current acquired in real time within the preset time length and the second comparison value is not continuously within the preset range, determining the value obtained by subtracting the second comparison value from the power battery charging current acquired in real time as the charging demand current corresponding to the target charging order;

by the formula:

T_m＝ΔSOC_m*ΔC_apm/I_Reqm

calculating remaining charge for a target charge order requirementTime T_mWherein, Δ SOC_mThe difference value between the SOC calibration point corresponding to the target charging order and the current SOC of the power battery is obtained; delta C_apmFor the battery full pack charge capacity, I, corresponding to the target charge order_ReqmThe charging demand current corresponding to the target charging order is obtained.

In step S107, the step of calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the remaining charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time, and a preset thermal management system switching temperature threshold includes:

by the formula:

calculating a third temperature value T_COU3；

By the formula:

calculating a fourth temperature value T_COU4；

A third temperature value T_COU3And a fourth temperature value T_COU4The larger value of the first and second temperature values is determined as the highest battery temperature corresponding to the next charging order, and the third temperature value T is set_COU3And a fourth temperature value T_COU4The lower value of the voltage is determined as the lowest temperature of the battery corresponding to the next charging order;

wherein, C₀、C₁、C₂And C₃Are all temperature calculated coefficients, C₀、C₁、C₂And C₃Is a constant; t is_maxThe maximum temperature of the battery collected after the preheating function of the power battery is started; t is_minThe method comprises the steps of collecting the lowest temperature of a power battery before the preheating function of the power battery is started; t is_{Water (W)}The temperature of the outlet water of the thermal management system; t is_{Ring (C)}For the environment of the vehicleThe ambient temperature of (a); t is_COU1' is the highest temperature of the battery corresponding to the last charging order; t is_COU2' is the lowest temperature of the battery corresponding to the last charging order; t is the current charged time of the vehicle; k is the starting state of the thermal management system, k is 1 when the thermal management system is started, and k is 0 when the thermal management system is closed; i is the charging demand current required by the last charging order; and R is the internal resistance of the power battery.

In step S108, by the formula:

T_Pred＝T_Heat+T_Chrg＝(T_Tar-T_Min)/T_Rate+T_m+T_m+1+....+T_n

calculating a second total remaining charging time T of the power battery with the preheating function started_PredWherein, T_TarThe maximum temperature T of the battery collected after the preheating function of the power battery is started_MinThe lowest temperature T of the battery collected before the preheating function of the power battery is started_RateFor a predetermined heating rate of the power cell, T_mTo determine the remaining charging time, T, required for the power cell at said target charging order_m+1Determining a remaining charging time, T, required for a next charging order of the power cell after said target charging order_nThe remaining charge time required for the last order charge order.

In the embodiment, for a direct current or alternating current charging process which is low in battery temperature and needs preheating, the whole charging process can be simplified into 2 stages of a heating process-a charging process; the charging process with pre-heating has a residual charging time which is determined by the pre-heating time T_HeatAnd a charging time T_ChrgSumming to obtain; heating time T_HeatIs (preheating target temperature T)_TarMinimum temperature T of the battery_Min) Cell heating Rate T_Rate(ii) a Charging time T_ChrgAccording to the heating target temperature T_TarAnd calculating the charging time of each stage of charging according to the corresponding required current.

Through the above steps S106 to S108, the prediction of the remaining charging time of the power battery for starting the preheating function can be realized.

Because most of the existing methods for estimating the residual charging time obtain charging current of each step according to the current battery temperature and then calculate the charging time, the error of the residual charging time is large under the condition that the deviation between the calculated temperature and the actual temperature is large.

According to the method, factors such as battery charging temperature rise, battery thermal management function (heating or cooling), ambient temperature and the like are considered according to a battery temperature rise model, the battery highest temperature and the battery lowest temperature corresponding to each charging order are estimated according to the battery highest temperature and the battery lowest temperature of the battery at the current charging order, and then the residual charging time required by each charging order can be calculated according to the estimated battery highest temperature and battery lowest temperature of each charging order.

In this embodiment, the first total remaining charging time determined in step S105 or the second total remaining charging time determined in step S108 needs to be displayed on a display screen to prompt a user, in this embodiment, a filtering process is performed on a calculated value of the first remaining charging time or the second remaining charging time, and except the following cases, the calculated value is filtered at a rate of p minutes/second and then sent to an output interface. When the charging target SOC is adjusted, the power battery enters q seconds after charging, and when the power battery is fully charged, the filtering output is not carried out according to the rate of p minutes/second, but when the information of the types is adjusted, the filtering output is carried out immediately.

By the method, the residual charging time of the preheating function of the power battery can be predicted when the power battery is started or not started.

The invention also provides a device for estimating the residual charging time of the power battery, which comprises:

the first determination module is used for determining the current target charging order of the power battery based on the acquired cell monomer voltage of the power battery when the power battery is charged;

the judging module is used for judging whether the preheating function of the power battery is started or not;

the second determining module is used for determining the residual charging time required by the power battery at the target charging order based on the highest temperature of the battery, the lowest temperature of the battery and the target charging order which are acquired when the power battery enters the charging process if the preheating function of the power battery is not started;

a third determining module, configured to repeatedly execute, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

and the fourth determining module is used for determining the sum of the residual charging time required by the power battery in the target charging order and each subsequent charging order as the first total residual charging time of the power battery without starting the preheating function.

Preferably, the apparatus further comprises:

the fifth determining module is used for determining the residual charging time required by the power battery at the target charging order based on the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started and the target charging order if the preheating function of the power battery is started;

a sixth determining module, configured to repeatedly perform, for each remaining charging order after the target charging order:

calculating the highest battery temperature and the lowest battery temperature corresponding to the next charging order according to the residual charging time of the previous charging order, the highest battery temperature and the lowest battery temperature corresponding to the previous charging order, the power battery charging current collected in real time and a preset switching temperature threshold of the thermal management system; determining the residual charging time required by the power battery at the next charging order based on the calculated highest temperature and lowest temperature of the battery corresponding to the next charging order and the next charging order;

the calculation module is used for calculating second total residual charging time of the power battery with the preheating function on the basis of the lowest battery temperature collected before the preheating function of the power battery is started, the highest battery temperature collected after the preheating function of the power battery is started, and residual charging time required by the power battery in a target charging order and each subsequent charging order;

the maximum temperature of the battery collected after the preheating function of the power battery is started is the preheating target temperature of the power battery.

The invention also provides an electric automobile which comprises the power battery residual charging time estimation device.

The device and the automobile have the same technical effects as the method, can adapt to working conditions such as direct current charging, alternating current charging, charging heating, different charging target battery states of charge (SOC) and the like, can be suitable for power battery packs provided with cooling systems and not provided with cooling systems, and have redundancy estimation capability when the output current of the charging pile is abnormal.