CN117284105A - Battery segmented charging method and device and vehicle - Google Patents

Abstract

The application relates to the technical field of new energy automobiles, in particular to a battery segmented charging method, a device and a vehicle. The method comprises the following steps: acquiring an initial open-circuit voltage of a battery and a preset first mapping relation when the vehicle is in a charging state, wherein the first mapping relation represents: dividing a total open-circuit voltage interval of the battery into a plurality of sub-open-circuit voltage intervals, wherein each sub-open-circuit voltage interval is associated with a corresponding charging current; obtaining corresponding initial charging current according to the initial open-circuit voltage and the first mapping relation; charging the battery according to the initial charging current, and acquiring the real-time open-circuit voltage of the battery in real time; and changing the charging current in real time when the real-time open-circuit voltage points to one sub-open-circuit voltage interval, so that the battery is fully charged through the charging current after the real-time change. The method can improve the charging speed of the battery.

Description

A battery segmented charging method, device and vehicle

Technical field

This application relates to the technical field of new energy vehicles, and in particular to a battery segmented charging method, device and vehicle.

Background technique

In the field of new energy vehicle technology, especially for pure electric vehicles, battery charging speed is one of the main focuses of users. This is because battery charging speed not only affects users’ anxiety about vehicle battery life, but also greatly affects the transition from the era of fuel vehicles to the era of new energy vehicles.

At present, there are two main methods to solve the problem of slow charging. One is to improve the battery from the material and structure, but this method is difficult and the research progress is slow; the other is to improve the charging method, for example, in charging In the initial stage, constant current charging is performed with a constant large current. After reaching the specified voltage, a small current is used to fully charge the battery.

However, this charging method will result in fast charging speed in the early stage and slow charging speed in the later stage. In the end, the average charging speed and total charging time of the entire charging process do not increase or even decrease.

Contents of the invention

Based on this, a battery segmented charging method, device and vehicle are provided to increase the charging speed of the battery.

In a first aspect, a battery segmented charging method is provided, the method including:

When the vehicle is in a charging state, the initial open circuit voltage of the battery and the preset first mapping relationship are obtained, where the first mapping relationship means: dividing the total open circuit voltage interval of the battery into several sub-open circuit voltage intervals, each Each of the sub-open circuit voltage intervals is associated with a corresponding charging current;

According to the initial open circuit voltage and the first mapping relationship, the corresponding initial charging current is obtained; the battery is charged according to the initial charging current, and the real-time open circuit voltage of the battery is obtained in real time; in the real-time open circuit The charging current is changed in real time every time the voltage points to one of the sub-open circuit voltage intervals, so that the battery is fully charged through the real-time changed charging current.

With reference to the first aspect, in a first implementation manner of the first aspect, before obtaining the preset first mapping relationship, the method further includes:

Obtain several preset sub-open-circuit voltage intervals, and each of the sub-open-circuit voltage intervals is associated with a corresponding charging current;

Wherein, the several sub-open-circuit voltage intervals are obtained by dividing the total open-circuit voltage interval of the battery, and the left endpoint of the total open-circuit voltage interval is the open-circuit voltage corresponding to when the state of charge of the battery is 0, The right endpoint is the open circuit voltage corresponding to when the state of charge of the battery is 1;

Based on the charging current corresponding to each of the sub-open circuit voltage intervals, construct the thermal balance relationship of the battery;

The thermal balance relational expression is discretized, Laplace transformed and inverse Laplace transformed to generate a temperature relational expression of the battery, wherein the temperature relational expression is used to calculate the temperature change of the battery during the charging process. predict;

Optimize the temperature relational expression with the total charging time of the battery and the aging condition of the battery as optimization targets, and obtain a second mapping relationship between the total charging time of the battery and the aging condition of the battery;

The second mapping relationship is evaluated using the superiority and inferiority distance method to obtain the first mapping relationship.

With reference to the first implementation manner of the first aspect, in a second implementation manner of the first aspect, the lengths of the several sub-open-circuit voltage intervals are the same.

In conjunction with the first implementable manner of the first aspect, in a third implementable manner of the first aspect, the step of obtaining several preset sub-open circuit voltage intervals includes:

Obtain the preset low state of charge interval, the stable state of charge interval and the high state of charge interval, wherein the low state of charge interval, the stable state of charge interval and the high state of charge interval are the corresponding It is obtained by dividing the charging process of the battery described above;

Obtain the left end point, right end point, first interval point and second interval point of the total open circuit voltage interval; wherein the first interval point is the turning point from the low state of charge interval to the stable state of charge interval The corresponding open circuit voltage, the second interval point is the open circuit voltage corresponding to the turning point from the stable state of charge interval to the high state of charge interval;

Divide the interval formed by the left end point and the first interval point to obtain several sub-open circuit voltage intervals associated with the low state of charge interval;

Divide the interval formed by the first interval point and the second interval point to obtain several sub-open circuit voltage intervals associated with the stable state of charge interval;

Divide the interval formed by the second interval point and the right end point to obtain several sub-open circuit voltage intervals associated with the high state of charge interval;

Wherein, the length of each of the sub-open-circuit voltage intervals in the low state-of-charge interval and the high-state-of-charge interval is smaller than the length of each of the sub-open-circuit voltage intervals in the stable state-of-charge interval.

Combined with the second implementable manner or the third implementable manner of the first aspect, in the fourth implementable manner of the first aspect, the superiority distance method is used to evaluate the second mapping relationship, and the second mapping relationship is obtained. The steps of the first mapping relationship include:

The second mapping relationship is evaluated using the superiority and inferiority distance method to obtain a third mapping relationship regarding several of the sub-open circuit voltage intervals and the charging current;

In the fast charging mode, balanced charging mode and slow charging mode, different weights are assigned to the total charging time and the aging condition, and the superior and inferior distance method is used to evaluate the third mapping relationship to obtain the Describe the first mapping relationship;

Wherein, in the first mapping relationship, each of the sub-open circuit voltage intervals is associated with corresponding three charging currents, and the three charging currents respectively point to the fast charging mode, the balanced charging mode and the The slow charging mode is used to determine the corresponding charging current according to a preset or user-instructed charging mode when charging the battery.

In conjunction with the first implementable manner of the first aspect, in a fifth implementable manner of the first aspect, the step of constructing the thermal balance relationship of the battery based on the charging current corresponding to each of the sub-open circuit voltage intervals, include:

Obtain preset first parameter information, which includes battery quality, battery specific heat capacity, sampling period, electromotive force temperature rise coefficient of the battery, and convective heat transfer coefficient between the battery and the outside world;

Collecting second parameter information, the second parameter information includes battery temperature, external environment temperature, ohmic internal resistance of the battery, polarization internal resistance of the battery, and convection heat exchange area between the battery and the external environment;

According to the first parameter information, the second parameter information and the charging current corresponding to each of the sub-open circuit voltage intervals, the thermal balance relationship is constructed, wherein the thermal balance relationship includes:

m is the mass of the battery, c is the specific heat capacity of the battery, T is the temperature of the battery, is the differential of the battery temperature, I _N is the charging current corresponding to the Nth sub-open circuit voltage interval, R ₀ is the ohmic internal resistance, R ₁ is the polarization internal resistance,/> is the electromotive force temperature rise coefficient, h is the convection heat transfer coefficient, A is the convection heat transfer area, and T _f is the external environment temperature.

In combination with the fifth implementable manner of the first aspect, in a sixth implementable manner of the first aspect, the temperature relational expression includes:

Among them, t ₀ is the initial time, T ₀ is the sampling period, is the battery temperature corresponding to the moment after the sampling period at the initial moment, e is the Euler number,/> is the battery temperature at the initial moment.

In conjunction with the sixth implementable manner of the first aspect, in a seventh implementable manner of the first aspect, the temperature relationship equation is optimized with the total charging time of the battery and the aging condition of the battery as optimization targets. The step of optimizing processing to obtain a second mapping relationship between the total charging time of the battery and the aging condition of the battery includes:

Change the number of sub-open-circuit voltage intervals and the charging current corresponding to each sub-open-circuit voltage interval, and use the number of sub-open-circuit voltage intervals and the charging current corresponding to each sub-open-circuit voltage interval as optimization variables. , taking the total charging time of the battery and the aging condition of the battery as optimization goals, and taking the temperature rise of the battery as a constraint, optimize the temperature relationship to obtain the second mapping relationship, Among them, the temperature rise of the battery is and/> the difference between.

In conjunction with the fourth implementable manner of the first aspect, in an eighth implementable manner of the first aspect, a corresponding initial charging current is obtained according to the initial open circuit voltage and the first mapping relationship; in the real-time The steps of changing the charging current in real time every time the open circuit voltage points to one of the sub-open circuit voltage intervals, so as to fully charge the battery with the real-time changed charging current, include:

Obtain a preset or user-instructed charging mode, wherein the charging mode is one of the fast charging mode, the balanced charging mode and the slow charging mode;

Determine the sub-open-circuit voltage interval that the initial open-circuit voltage points to in the first mapping relationship, and among the three charging currents corresponding to the sub-open-circuit voltage interval that the determined initial open-circuit voltage points to, the current that points to the sub-open-circuit voltage interval is determined. The charging current of the preset or user-instructed charging mode is used as the initial charging current;

The charging current is changed every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so that the battery is fully charged with the real-time changed charging current, wherein the real-time changed charging current points to the preset Or the charging mode indicated by the user.

In a second aspect, a battery segmented charging device is provided, which device includes:

The acquisition unit is used to acquire the initial open circuit voltage of the battery and a preset first mapping relationship when the vehicle is in a charging state, wherein the first mapping relationship represents: dividing the total open circuit voltage range of the battery into several sub-segments. Open circuit voltage interval, each of the sub-open circuit voltage intervals is associated with a corresponding charging current;

An execution unit, configured to obtain the corresponding initial charging current according to the initial open circuit voltage and the first mapping relationship; charge the battery according to the initial charging current, and obtain the real-time open circuit voltage of the battery in real time; The charging current is changed in real time every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so that the battery is fully charged through the real-time changed charging current.

In a third aspect, a vehicle is provided. The vehicle includes a battery segmented charging device as described in the second aspect. The battery segmented charging device is used to perform any of the first aspect or in combination with the first aspect. The steps of the battery segmented charging method described in the embodiment can be implemented.

The above-mentioned battery segmented charging method, device and vehicle, when the vehicle is in a charging state, obtain the initial open circuit voltage of the battery and the preset first mapping relationship, where the first mapping relationship means: dividing the total open circuit voltage range of the battery into Several sub-open-circuit voltage intervals, each sub-open-circuit voltage interval is associated with a corresponding charging current; according to the initial open-circuit voltage and the first mapping relationship, the corresponding initial charging current is obtained; the battery is charged according to the initial charging current, and the real-time data of the battery is obtained in real time Open circuit voltage; when the real-time open circuit voltage points to a sub-open circuit voltage range, the charging current is changed in real time to fully charge the battery through the real-time changed charging current. It can be seen that this application divides the total open circuit voltage range of the battery into several intervals, and each interval uses different current values to charge the battery; while in the prior art, large current is used for fast charging in the early stage, and small current is used for slow charging in the later stage. , in the end the average charging speed of the entire charging process did not increase or even decreased. Therefore, compared with the prior art, the beneficial effect of this application is to increase the battery charging speed.

Description of drawings

Figure 1 is a schematic flowchart of a battery segmented charging method in one embodiment;

Figure 2 is a structural block diagram of a battery segmented charging device in one embodiment;

Figure 3 is a structural block diagram of a battery segmented charging device in one embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present application in a schematic manner, so the drawings only show the components related to the present application and do not follow the number, shape and number of components in actual implementation. Dimension drawing, in actual implementation, the type, quantity and proportion of each component can be arbitrarily changed, and the component layout type may also be more complex.

The structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to coordinate with the content disclosed in the specification and are for the understanding and reading of those familiar with this technology. They are not used to limit the conditions for the implementation of this application. , it has no technical substantive significance. Any structural modifications, changes in proportions, or adjustments in size, without affecting the effectiveness and purpose of this application, should still fall within the scope of what is disclosed in this application. The technical content must be within the scope of coverage.

References in this specification include "upper", "lower", "left", "right", "middle", "longitudinal", "horizontal", "horizontal", "inner", "outer", "radial" ", "circumferential direction" and other indications of orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation. Specific orientation construction and operation, therefore, should not be construed as limitations on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

In one embodiment, as shown in Figure 1, a battery segmented charging method is provided, including the following steps:

S101: When the vehicle is in the charging state, obtain the initial open circuit voltage of the battery and the preset first mapping relationship, where the first mapping relationship means: dividing the total open circuit voltage interval of the battery into several sub-open circuit voltage intervals. , each of the sub-open circuit voltage intervals is associated with a corresponding charging current;

S102: Obtain the corresponding initial charging current according to the initial open circuit voltage and the first mapping relationship; charge the battery according to the initial charging current, and obtain the real-time open circuit voltage of the battery in real time; in the The charging current is changed in real time every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so that the battery is fully charged through the real-time changed charging current.

In a specific implementation, before the step of obtaining the preset first mapping relationship, it also includes: obtaining several preset sub-open-circuit voltage intervals, and each of the sub-open-circuit voltage intervals is associated with a corresponding charging Current; wherein, the several sub-open-circuit voltage intervals are obtained by dividing the total open-circuit voltage interval of the battery, and the left endpoint of the total open-circuit voltage interval is the open circuit corresponding to when the state of charge of the battery is 0 voltage, the right endpoint is the open circuit voltage corresponding to when the state of charge of the battery is 1; based on the charging current corresponding to each of the sub-open circuit voltage intervals, the thermal balance relationship of the battery is constructed; for the thermal balance relationship Perform discretization, Laplace transformation and inverse Laplace transformation to generate a temperature relational expression of the battery, wherein the temperature relational expression is used to predict the temperature change of the battery during the charging process; using the battery The total charging time of the battery and the aging condition of the battery are used as optimization targets to optimize the temperature relationship, and a second mapping relationship between the total charging time of the battery and the aging condition of the battery is obtained; the superior and inferior distance is used Method evaluates the second mapping relationship to obtain the first mapping relationship.

In the above steps, there are two ways to divide the sub-open-circuit voltage intervals. One is to divide the total open-circuit voltage interval of the battery into several sub-open-circuit voltage intervals with the same interval length. For example, if the total open-circuit voltage interval is expressed as [OCV ₀ , OCV ₁ ], and the number of sub-open-circuit voltage intervals is N, then the N sub-open-circuit voltage intervals are: The charging currents corresponding to N sub-open circuit voltage intervals are: I ₁ , I ₂ ,..., I _N . Among them, through actual vehicle testing and calibration, the number of sub-open circuit voltage intervals is within (0, 30], and _IN will not exceed the maximum allowable charging current of the battery.

Another way of dividing the sub-open-circuit voltage intervals may include the following steps: obtaining several preset sub-open-circuit voltage intervals, including: obtaining the preset low state-of-charge interval, the stable state-of-charge interval, and the high-state-of-charge interval. , wherein the low state of charge interval, the stable state of charge interval and the high state of charge interval are obtained by dividing the charging process of the battery; obtain the left endpoint of the total open circuit voltage interval, The right end point, the first interval point and the second interval point; wherein, the first interval point is the open circuit voltage corresponding to the turning point from the low state of charge interval to the stable state of charge interval, and the second interval point The point is the open circuit voltage corresponding to the turning point from the stable state of charge interval to the high state of charge interval; divide the interval formed by the left end point and the first interval point to obtain the Several sub-open-circuit voltage intervals associated with the electrical state interval; divide the interval formed by the first interval point and the second interval point to obtain several sub-open-circuit voltage intervals associated with the stable charge state interval. ; Divide the interval formed by the second interval point and the right end point to obtain several sub-open circuit voltage intervals associated with the high state of charge interval; wherein, the low state of charge interval and the The length of each of the sub-open-circuit voltage intervals in the high state-of-charge interval is smaller than the length of each of the sub-open-circuit voltage intervals in the stationary state-of-charge interval.

Due to the voltage characteristics of the battery itself, when charging in the high state of charge range and low state of charge range, the voltage changes rapidly, while when charging in the stable state of charge range, the voltage changes relatively gently. Therefore, through the above steps, the entire charging process is divided into three parts, the low state of charge interval, the stable state of charge interval and the high state of charge interval, and then respectively in the low state of charge interval, the stable state of charge interval and the high state of charge interval. The sub-open-circuit voltage intervals are divided under three conditions of the state-of-charge interval.

As an example, in the three situations of low state of charge interval, stable state of charge interval and high state of charge interval, _three sub-open circuit voltage intervals N ₁ , N ₂ and N are divided respectively. Among them, through the actual vehicle Testing and calibration, N ₁ , N ₂ , N ₃ ∈ (0, 10], and N = N ₁ + N ₂ + N ₃ ∈ (0, 30]. If the left endpoint of the total open circuit voltage interval is expressed as OCV ₀ , the right endpoint is represented by OCV ₁ , the first interval point is represented by OCV _a , and the second interval point is represented by OCV _b . The relationship between each sub-open circuit voltage interval and its corresponding charging current can be shown in Table 1.

Table 1 Schematic representation of the relationship between sub-open circuit voltage range and charging current

Further, based on the charging current corresponding to each of the sub-open circuit voltage intervals, the step of constructing the thermal balance relationship of the battery includes: obtaining preset first parameter information, the first parameter information includes battery quality, battery Specific heat capacity, sampling period, electromotive force temperature rise coefficient of the battery and convective heat transfer coefficient between the battery and the outside world; collecting second parameter information, the second parameter information includes battery temperature, external environment temperature, ohm of the battery The internal resistance, the polarization internal resistance of the battery, and the convection heat exchange area between the battery and the outside world; according to the first parameter information, the second parameter information, and each of the sub-open circuit voltage intervals. charging current to construct the thermal balance relationship, where the thermal balance relationship includes:

m is the mass of the battery, c is the specific heat capacity of the battery, T is the temperature of the battery, is the differential of the battery temperature, I _N is the charging current corresponding to the Nth sub-open circuit voltage interval, R ₀ is the ohmic internal resistance, R ₁ is the polarization internal resistance,/> is the electromotive force temperature rise coefficient, h is the convection heat transfer coefficient, A is the convection heat transfer area, and T _f is the external environment temperature.

It should be noted that the above electromotive force temperature rise coefficient changes with the change of the battery's state of charge, and both the ohmic internal resistance and the polarization internal resistance change with the changes of the battery temperature, the battery's state of charge and the battery current. These three Parameters can be obtained experimentally through battery hybrid power pulse characteristics.

The thermal balance relationship is discretized, Laplace transformed and inverse Laplace transformed to generate the temperature relationship of the battery including:

Among them, t ₀ is the initial time, T ₀ is the sampling period, is the battery temperature corresponding to the moment after the sampling period at the initial moment, e is the Euler number,/> is the battery temperature at the initial moment.

Furthermore, the temperature relational expression is optimized with the total charging time of the battery and the aging condition of the battery as optimization targets, and a third equation regarding the total charging time of the battery and the aging condition of the battery is obtained. 2. The steps of mapping relationship include:

Change the number of sub-open-circuit voltage intervals and the charging current corresponding to each sub-open-circuit voltage interval, and use the number of sub-open-circuit voltage intervals and the charging current corresponding to each sub-open-circuit voltage interval as optimization variables. , taking the total charging time of the battery and the aging condition of the battery as optimization goals, and taking the temperature rise of the battery as a constraint, optimize the temperature relationship to obtain the second mapping relationship, Among them, the temperature rise of the battery is and/> the difference between.

Specifically, the second mapping relationship is a Pareto curve regarding the total charging time of the battery and the aging condition of the battery, wherein the total charging time and the aging condition are based on the total number of state-of-charge intervals. It is determined by the charging current corresponding to each state-of-charge interval. The total charging time is the sum of the charging time corresponding to N open circuit voltage intervals, which can be expressed as: Among them, Target ₁ is the total charging time, N is the total number of sub-open-circuit voltage intervals, n is the index of the sub-open-circuit voltage interval,/> is the charging capacity corresponding to the nth state-of-charge interval of the battery, and _tn is the charging time corresponding to the nth sub-open circuit voltage interval.

The method of obtaining the aging condition includes: obtaining the preset battery discharge rate and gas constant; collecting the battery temperature and the charging capacity of the charging current within the corresponding time; according to the battery discharge rate, the gas constant, the The battery temperature and the current state of charge are used to obtain the aging situation, where the mathematical expression for obtaining the aging situation includes:

Tar get ₂ is the aging condition, C _rate is the battery discharge rate, e is Euler's number, R is the gas constant, T is the battery temperature, is the charging capacity.

The above charging capacity can be calculated based on the charging current and charging time corresponding to N open circuit voltage intervals, and can be expressed as: Among them, N is the total number of sub-open-circuit voltage intervals, n is the index of the sub-open-circuit voltage interval, I _n is the charging current corresponding to the n-th sub-open-circuit voltage interval, t _n is the charging corresponding to the n-th sub-open-circuit voltage interval duration.

Since the total charging time and aging of the battery are both functions of the total number of state-of-charge intervals N _and the charging current In corresponding to each state-of-charge interval, the total number of state-of-charge intervals N and The charging current I _n corresponding to each state-of-charge interval is the optimization variable, and the total charging time and aging condition of the battery are continued to be the optimization goals. After evaluating the second mapping relationship through the superior and inferior distance method, we can obtain both The Pareto curve of N open-circuit voltage intervals and N charging currents for the total charging time and aging conditions is the first mapping relationship.

It should be noted that if the state of charge is not distinguished when dividing the sub-open-circuit voltage intervals, in the first mapping relationship obtained after optimization, the change amplitudes of the charging currents corresponding to each sub-open-circuit voltage interval will be almost the same, and there will be no The difference is more obvious; if the state of charge is distinguished when dividing the sub-open-circuit voltage intervals, then in the first mapping relationship obtained after optimization, the corresponding sub-open-circuit voltage intervals in the low-state-of-charge interval and the high-state-of-charge interval The charging current is smaller than the charging current corresponding to each sub-open circuit voltage interval in the equilibrium state of charge interval.

After the first mapping relationship is obtained through the above steps, in the first mapping relationship, each of the sub-open circuit voltage intervals is associated with a corresponding charging current. When using the first mapping relationship, the charging current corresponding to the sub-open-circuit voltage range pointed by the determined initial open-circuit voltage can be used as the initial charging current according to the sub-open-circuit voltage range pointed by the initial open-circuit voltage in the first mapping relationship.

After the battery is charged according to the initial charging current, the real-time open circuit voltage of the battery is obtained in real time, and every time the real-time open circuit voltage reaches a sub-open-circuit voltage interval, the charging current is changed, and the charging voltage corresponding to the sub-open-circuit voltage interval reached by the real-time open circuit voltage is The current charges the battery, and the step of changing the charging current according to the real-time open circuit voltage continues until the battery is fully charged.

It should be noted that since the second way of dividing the sub-open-circuit intervals takes into account the impact of different state-of-charge intervals on the battery voltage, in the case of high and low state-of-charge intervals, the sub-state-of-charge intervals will be divided into: To be more detailed, in the first mapping relationship obtained after optimization, the charging current of each sub-open circuit voltage interval in the high and low state of charge intervals will also be smaller than the charging current of each sub-open circuit voltage interval in the stationary state of charge interval, so by The first mapping relationship obtained in this way is applied to the battery charging process to further increase the battery charging speed.

Among them, during the charging process, the open circuit voltage can be calculated using the following mathematical expression: OCV=EI·(R ₀ +R ₁ ), OCV is the open circuit voltage during the charging process, E is the potential difference inside the battery, and I is the charging process The charging current, R ₀ is the ohmic internal resistance of the battery, and R ₁ is the polarization internal resistance of the battery.

This application also provides a third implementation manner, that is, based on the above two ways of generating the first mapping relationship, the division of charging modes is added, that is, the superiority and inferiority distance method is used to evaluate the second mapping relationship, and we obtain The step of the first mapping relationship includes: using the superiority and inferiority distance method to evaluate the second mapping relationship to obtain a third mapping relationship about several of the sub-open circuit voltage intervals and the charging current; In charging mode, balanced charging mode and slow charging mode, different weights are assigned to the total charging time and the aging condition, and the superiority distance method is used to evaluate the third mapping relationship to obtain the first Mapping relationship; wherein, in the first mapping relationship, each of the sub-open circuit voltage intervals is associated with corresponding three charging currents, and the three charging currents respectively point to the fast charging mode, the balanced charging mode and the slow charging mode, so that when charging the battery, the corresponding charging current is determined according to the preset or user-instructed charging mode.

The third mapping relationship in this embodiment has the same meaning as the first mapping relationship in the above-mentioned embodiment, and is a Pareto curve regarding N sub-open circuit voltage intervals and N charging currents. After obtaining the third mapping relationship, according to the different weight values of the total charging time of the battery and the aging condition of the battery, and using the merit distance method for evaluation, the first mapping relationship can be obtained. In the first mapping relationship, each charge There are three charging currents corresponding to the state interval, and each charging current corresponds to three different charging modes, namely fast charging mode, balanced charging mode and slow charging mode.

In the fast charging mode, the weight allocated to the total charging time is higher than the weight allocated to the aging condition, that is, the total charging time is considered to a higher degree than the aging condition. Preferably, on the premise of considering battery aging, maximize the consideration The total charging time, that is, the ratio of the weight allocated to the total charging time and the weight allocated to the aging condition is at the highest 0.9:0.1 and at the lowest 0.5:0.4; in balanced charging mode, the weight allocated to the total charging time is equal to the weight allocated to the aging condition. The weight of , that is, considering the total charging time and the aging condition to the same extent, the ratio of the weights assigned to the two is 0.5:0.5; similarly, in the slow charging mode, the weight assigned to the total charging time is smaller than the weight assigned to the aging condition. The weight, that is, the degree of considering the aging situation is higher than the degree of considering the total charging time. Preferably, on the premise of considering the total charging time, the aging situation is considered to the maximum, that is, the weight assigned to the total charging time and the weight assigned to the aging situation. The lowest ratio is 0.1:0.9, and the highest ratio is 0.4:0.5.

Generally, as shown in Table 2, the schematic table of the weight ratio of the three charging modes, in the same weight allocation method, the ratio of the weight allocated to the total charging time in the fast charging mode and the weight allocated to the aging condition (referred to as the weight ratio in Table 2 below), the ratio between the weight assigned to the total charging time in the slow charging mode and the weight assigned to the aging condition should be reciprocal of each other.

Table 2 Schematic table of the weight ratio of the three charging modes

Charging mode Quick charge mode Balanced charging mode Slow charging mode weight ratio 0.9:0.1 0.5:0.5 0.1:0.9

Through the first mapping relationship obtained in this implementation, when using the first mapping relationship, a preset or user-instructed charging mode is obtained, wherein the charging mode is the fast charging mode, the balanced charging mode and one of the slow charging modes; determine the sub-open-circuit voltage interval pointed by the initial open-circuit voltage in the first mapping relationship, and determine the sub-open-circuit voltage interval pointed by the determined initial open-circuit voltage. Among the corresponding three charging currents, the charging current pointing to the preset or user-instructed charging mode is used as the initial charging current.

The battery is charged according to the initial charging current, and the real-time open circuit voltage of the battery is obtained in real time; when the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, the charging current is changed, and the real-time open circuit voltage reaches the sub-open circuit voltage interval. Among the corresponding three charging currents, the charging current pointing to the preset or user-instructed charging mode charges the battery, and the step of changing the charging current according to the real-time open circuit voltage is continued to charge the battery through the real-time changed charging current. Fully charged, wherein the real-time changed charging current points to the preset or user-instructed charging mode. It can be seen that the first mapping relationship obtained through this embodiment can not only change the charging current according to the real-time open circuit voltage of the battery, but also select a specific charging mode according to specific scene requirements, which improves scene adaptability.

Among them, the preset charging mode can be any one of fast charging mode, balanced charging mode and slow charging mode. Generally, in order to take into account the total charging time and aging condition, the preset charging mode can be balanced charging mode. .

As the battery ages, the chemical reaction speed inside the battery slows down, and the internal resistance of the battery increases, resulting in a decrease in charging current. That is, battery aging will cause the charging speed to slow down; and the aging of the battery is strongly related to the charging current; and because Battery temperature during charging will affect battery life. Therefore, in the step of generating the first mapping relationship in the above three embodiments, this application takes the total charging time and aging condition of the battery as the optimization target, and uses the temperature rise of the battery as the limiting condition, and the total open circuit voltage interval is The number of batteries and the charging current corresponding to each interval are optimized, so that the first mapping relationship obtained not only takes into account the aging of the battery, but also limits the temperature rise of the battery, which can ensure as many aspects as possible How quickly the battery charges.

When specifically applying the battery charging method of this application, since the current emitted by the charging pile and the charging gun is usually fixed, this application obtains the ideal charging current through the first mapping relationship when obtaining the current emitted by the charging pile and charging gun. , and then process the current emitted by the charging pile and charging gun so that the processed current is consistent with the charging current obtained through the first mapping relationship, and then charge the battery according to the processed charging current.

To sum up, this application divides the total open circuit voltage range of the battery into several intervals, and each interval uses different current values to charge the battery; while in the prior art, large current is used for fast charging in the early stage, and small current is used in the later stage. With slow charging, the average charging speed of the entire charging process does not increase or even decreases. Therefore, compared with the prior art, the beneficial effect of this application is to increase the battery charging speed.

It should be understood that although various steps in the flowchart of FIG. 1 are shown in sequence as indicated by arrows, these steps are not necessarily executed in the order indicated by arrows. Unless otherwise specified in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in Figure 1 may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution of these sub-steps or stages The sequence is not necessarily sequential, but may be performed in turn or alternately with other steps or sub-steps of other steps or at least part of stages.

In one embodiment, as shown in Figure 2, a battery segmented charging device is provided, including:

The acquisition unit is used to acquire the initial open circuit voltage of the battery and a preset first mapping relationship when the vehicle is in a charging state, wherein the first mapping relationship represents: dividing the total open circuit voltage range of the battery into several sub-segments. Open circuit voltage interval, each of the sub-open circuit voltage intervals is associated with a corresponding charging current;

An execution unit, configured to obtain the corresponding initial charging current according to the initial open circuit voltage and the first mapping relationship; charge the battery according to the initial charging current, and obtain the real-time open circuit voltage of the battery in real time; The charging current is changed in real time every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so that the battery is fully charged through the real-time changed charging current.

In a specific implementation, as shown in Figure 3, the device further includes a preprocessing unit, which is configured to: obtain several preset sub-open circuit voltage intervals before obtaining the preset first mapping relationship. , and each of the sub-open-circuit voltage intervals is associated with a corresponding charging current; wherein, the plurality of sub-open-circuit voltage intervals are obtained by dividing the total open-circuit voltage interval of the battery, and the left end of the total open-circuit voltage interval The point is the open circuit voltage corresponding to when the battery's state of charge is 0, and the right endpoint is the open circuit voltage corresponding to when the battery's state of charge is 1; based on the charging current corresponding to each of the sub-open circuit voltage intervals , construct the thermal balance relationship of the battery; perform discretization, Laplace transformation and inverse Laplace transformation on the heat balance relationship to generate the temperature relationship of the battery, where the temperature relationship is used in the charging process The temperature change of the battery is predicted in The second mapping relationship of the aging condition of the battery; the second mapping relationship is evaluated using the superiority and inferiority distance method to obtain the first mapping relationship.

Further, the lengths of the several sub-open-circuit voltage intervals are consistent.

In another embodiment, the preprocessing unit is used to obtain several preset sub-open circuit voltage intervals, including: obtaining the preset low state of charge interval, the stable state of charge interval and the high state of charge interval, wherein , the low state of charge interval, the stable state of charge interval and the high state of charge interval are obtained by dividing the charging process of the battery; obtain the left endpoint and right endpoint of the total open circuit voltage interval , the first interval point and the second interval point; wherein, the first interval point is the open circuit voltage corresponding to the turning point from the low state of charge interval to the stable state of charge interval, and the second interval point is The open circuit voltage corresponding to the turning point from the stable state of charge interval to the high state of charge interval; divide the interval formed by the left end point and the first interval point to obtain the low state of charge several sub-open-circuit voltage intervals associated with the interval; divide the interval formed by the first interval point and the second interval point to obtain several sub-open-circuit voltage intervals associated with the stable state-of-charge interval; The interval formed by the second interval point and the right end point is divided to obtain several sub-open circuit voltage intervals associated with the high state of charge interval; wherein, the low state of charge interval and the high charge state interval are The length of each of the sub-open-circuit voltage intervals in the electrical state interval is smaller than the length of each of the sub-open-circuit voltage intervals in the stationary state-of-charge interval.

Furthermore, the preprocessing unit is used to evaluate the second mapping relationship using the superiority distance method, and the step of obtaining the first mapping relationship includes: using the superiority distance method to evaluate the second mapping relationship. , obtain a third mapping relationship between several of the sub-open circuit voltage intervals and the charging current; in fast charging mode, balanced charging mode and slow charging mode, allocate the total charging time and the aging condition respectively Different weights are used, and the superiority distance method is used to evaluate the third mapping relationship to obtain the first mapping relationship; wherein, in the first mapping relationship, each of the sub-open circuit voltage intervals is associated with a corresponding Three charging currents, and the three charging currents are respectively directed to the fast charging mode, the balanced charging mode and the slow charging mode, so that when charging the battery, according to the preset or user instructions The charging mode determines the corresponding charging current.

Furthermore, the step of the preprocessing unit used to construct the thermal balance relationship of the battery based on the charging current corresponding to each of the sub-open circuit voltage intervals includes: obtaining preset first parameter information, the first parameter The information includes battery quality, battery specific heat capacity, sampling period, electromotive force temperature rise coefficient of the battery and convective heat transfer coefficient between the battery and the outside world; second parameter information is collected, and the second parameter information includes battery temperature, external environment temperature , the ohmic internal resistance of the battery, the polarization internal resistance of the battery, and the convection heat exchange area between the battery and the outside world; according to the first parameter information, the second parameter information and each of the The charging current corresponding to the sub-open circuit voltage interval is used to construct the thermal balance relationship, where the thermal balance relationship includes:

m is the mass of the battery, c is the specific heat capacity of the battery, T is the temperature of the battery, is the differential of the battery temperature, I _N is the charging current corresponding to the Nth sub-open circuit voltage interval, R ₀ is the ohmic internal resistance, R ₁ is the polarization internal resistance,/> is the electromotive force temperature rise coefficient, h is the convection heat transfer coefficient, A is the convection heat transfer area, and T _f is the external environment temperature.

Wherein, the temperature relational expression includes:

Among them, t ₀ is the initial time, T ₀ is the sampling period, is the battery temperature corresponding to the moment after the sampling period at the initial moment, e is the Euler number,/> is the battery temperature at the initial moment.

Furthermore, the preprocessing unit is used to optimize the temperature relational expression with the total charging time of the battery and the aging condition of the battery as optimization targets, and obtain information about the total charging time of the battery and the aging condition of the battery. The step of the second mapping relationship of the aging situation includes: changing the number of the sub-open-circuit voltage intervals and the charging current corresponding to each of the sub-open-circuit voltage intervals. The charging current corresponding to the sub-open circuit voltage interval is an optimization variable, the total charging time of the battery and the aging condition of the battery are used as optimization targets, and the temperature rise of the battery is used as a constraint. The temperature relationship is The formula is optimized to obtain the second mapping relationship, where the temperature rise of the battery is and/> the difference between.

Specifically, the execution unit is configured to obtain the corresponding initial charging current according to the initial open circuit voltage and the first mapping relationship; and change the charging current in real time every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so as to The step of filling the battery with a real-time changed charging current includes: obtaining a preset or user-instructed charging mode, wherein the charging mode is the fast charging mode, the balanced charging mode and the slow charging mode. One of the fast charging modes determines the sub-open-circuit voltage interval that the initial open-circuit voltage points to in the first mapping relationship, and in the three corresponding sub-open-circuit voltage intervals that the determined initial open-circuit voltage points to. In the charging current, the charging current pointing to the preset or user-instructed charging mode is used as the initial charging current; the charging current is changed every time the real-time open circuit voltage points to one of the sub-open circuit voltage intervals, so that after the real-time change, The battery is fully charged with a charging current, wherein the real-time changed charging current points to the preset or user-instructed charging mode.

For specific limitations on the battery segmented charging device, please refer to the above limitations on the battery segmented charging method, which will not be described again here. Each module in the above-mentioned battery segmented charging device can be implemented in whole or in part by software, hardware and combinations thereof. Each of the above modules may be embedded in or independent of the processor of the computer device in the form of hardware, or may be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

In one embodiment, a vehicle is provided. The vehicle includes a battery segmentation charging device as described in the above embodiment, and the battery segmentation charging device is used to perform battery segmentation as described in the previous embodiment. Charging method.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage. In the media, when executed, the computer program may include the processes of the above method embodiments. Any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and/or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain Synchlink DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

The technical features of the above embodiments can be combined in any way. To simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, all possible combinations should be used. It is considered to be within the scope of this manual.

The above-described embodiments only express several implementation modes of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims (11)

1. A battery segment charging method, comprising:

acquiring an initial open-circuit voltage of a battery and a preset first mapping relation when the vehicle is in a charging state, wherein the first mapping relation represents: dividing a total open-circuit voltage interval of the battery into a plurality of sub-open-circuit voltage intervals, wherein each sub-open-circuit voltage interval is associated with a corresponding charging current;

Obtaining corresponding initial charging current according to the initial open-circuit voltage and the first mapping relation; charging the battery according to the initial charging current, and acquiring the real-time open-circuit voltage of the battery in real time; and changing the charging current in real time when the real-time open-circuit voltage points to one sub-open-circuit voltage interval, so that the battery is fully charged through the charging current after the real-time change.

2. The battery segment charging method according to claim 1, wherein before acquiring the preset first map, the method further comprises:

acquiring a plurality of preset sub-open-circuit voltage intervals, wherein each sub-open-circuit voltage interval is respectively associated with a corresponding charging current;

the plurality of sub-open circuit voltage intervals are obtained by dividing the total open circuit voltage interval of the battery, wherein the left end point of the total open circuit voltage interval is the open circuit voltage corresponding to the state of charge of the battery being 0, and the right end point is the open circuit voltage corresponding to the state of charge of the battery being 1;

constructing a heat balance relation of the battery based on the charging current corresponding to each sub-open-circuit voltage interval;

Discretizing, law transformation and reverse Law transformation are carried out on the thermal balance relation to generate a temperature relation of the battery, wherein the temperature relation is used for predicting the temperature change condition of the battery in the charging process;

optimizing the temperature relation by taking the total charging time length of the battery and the aging condition of the battery as optimization targets to obtain a second mapping relation of the total charging time length of the battery and the aging condition of the battery;

and evaluating the second mapping relation by adopting a good-bad distance method to obtain the first mapping relation.

3. The battery segment charging method of claim 2, wherein the lengths of the plurality of sub-open circuit voltage intervals are uniform.

4. The battery segment charging method according to claim 2, wherein the step of obtaining a predetermined number of sub-open circuit voltage intervals comprises:

acquiring a preset low-state-of-charge interval, a steady-state-of-charge interval and a high-state-of-charge interval, wherein the low-state-of-charge interval, the steady-state-of-charge interval and the high-state-of-charge interval are obtained by dividing a charging process of the battery;

Acquiring a left end point, a right end point, a first interval point and a second interval point of the total open circuit voltage interval; the first interval point is an open circuit voltage corresponding to a turning point from the low charge state interval to the stable charge state interval, and the second interval point is an open circuit voltage corresponding to a turning point from the stable charge state interval to the high charge state interval;

dividing a section formed by the left end point and the first section point to obtain a plurality of sub-open-circuit voltage sections associated with the low-charge state section;

dividing a section formed by the first section point and the second section point to obtain a plurality of sub-open-circuit voltage sections associated with the stable state-of-charge section;

dividing a section formed by the second section point and the right end point to obtain a plurality of sub-open-circuit voltage sections associated with the high-charge-state section;

the length of each sub-open-circuit voltage interval in the low state-of-charge interval and the high state-of-charge interval is smaller than the length of each sub-open-circuit voltage interval in the steady state-of-charge interval.

5. The battery segment charging method according to claim 3 or 4, wherein the step of evaluating the second mapping relation by using a good-bad distance method to obtain the first mapping relation comprises:

evaluating the second mapping relation by adopting a good-bad distance method to obtain a third mapping relation about a plurality of sub-open-circuit voltage intervals and the charging current;

different weights are distributed to the total charging duration and the aging condition in a fast charging mode, a balanced charging mode and a slow charging mode respectively, and the third mapping relation is evaluated by adopting a good-bad distance method to obtain the first mapping relation;

in the first mapping relationship, each sub-open-circuit voltage interval is associated with three corresponding charging currents, and the three charging currents respectively point to the fast charging mode, the balanced charging mode and the slow charging mode, so that when the battery is charged, the corresponding charging currents are determined according to a preset charging mode or a charging mode indicated by a user.

6. The battery segment charging method according to claim 2, wherein the step of constructing a heat balance relation of the battery based on the charging current corresponding to each of the sub-open-circuit voltage intervals comprises:

Acquiring preset first parameter information, wherein the first parameter information comprises battery quality, battery specific heat capacity, sampling period, electromotive force temperature rise coefficient of the battery and convective heat transfer coefficient of the battery and the outside;

collecting second parameter information, wherein the second parameter information comprises battery temperature, external environment temperature, ohmic internal resistance of the battery, polarization internal resistance of the battery and convection heat exchange area of the battery and the external environment;

constructing the thermal balance relation according to the first parameter information, the second parameter information and the charging current corresponding to each sub-open-circuit voltage interval, wherein the thermal balance relation comprises:

m is the mass of the battery, c is the specific heat capacity of the battery, T is the temperature of the battery,i is the differentiation of the battery temperature _N For the charging current corresponding to the Nth sub-open-circuit voltage interval, R ₀ For the ohmic internal resistance, R ₁ For the internal resistance of the polarization,for the electromotive force temperature rise coefficient, h is the convection heat transfer coefficient, A is the convection heat transfer area, T _f Is the ambient temperature.

7. The battery segment charging method of claim 6, wherein the temperature relationship comprises:

Wherein t is ₀ For the initial time, T ₀ In order to sample the period of time,for the battery temperature corresponding to the moment when the initial moment passes the sampling period, e is Euler number, < >>Is the battery temperature at the initial time.

8. The method for sectionally charging a battery according to claim 7, wherein the step of optimizing the temperature relation with respect to the total length of time of charging the battery and the aging condition of the battery as an optimization target to obtain the second mapping relation between the total length of time of charging the battery and the aging condition of the battery comprises:

changing the number of the sub open-circuit voltage intervals and the charging current corresponding to each sub open-circuit voltage interval, taking the number of the sub open-circuit voltage intervals and the charging current corresponding to each sub open-circuit voltage interval as optimization variables, taking the total charging time length of the battery and the aging condition of the battery as optimization targets, taking the temperature rise condition of the battery as constraint conditions, and optimizing the temperature relation to obtain the second mapping relation, wherein the temperature rise condition of the battery is thatAnd->Difference between them.

9. The battery segment charging method according to claim 5, wherein a corresponding initial charging current is obtained according to the initial open-circuit voltage and the first map; a step of changing a charging current in real time when the real-time open circuit voltage is directed to each of the sub-open circuit voltage intervals to charge the battery with the real-time changed charging current, comprising:

Acquiring a preset or user-indicated charging mode, wherein the charging mode is one of the fast charging mode, the balanced charging mode and the slow charging mode;

determining a sub-open-circuit voltage interval pointed by the initial open-circuit voltage in the first mapping relation, and taking charging current pointed by the preset or user-pointed charging mode as initial charging current in three charging currents corresponding to the determined sub-open-circuit voltage interval pointed by the initial open-circuit voltage;

and changing the charging current when the real-time open-circuit voltage points to one sub-open-circuit voltage interval, so as to fully charge the battery through the charging current after the real-time change, wherein the charging current after the real-time change points to the preset or user-indicated charging mode.

10. A battery segment charging apparatus, the apparatus comprising:

the system comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring an initial open-circuit voltage of a battery and a preset first mapping relation when a vehicle is in a charging state, and the first mapping relation represents: dividing a total open-circuit voltage interval of the battery into a plurality of sub-open-circuit voltage intervals, wherein each sub-open-circuit voltage interval is associated with a corresponding charging current;

The execution unit is used for obtaining corresponding initial charging current according to the initial open-circuit voltage and the first mapping relation; charging the battery according to the initial charging current, and acquiring the real-time open-circuit voltage of the battery in real time; and changing the charging current in real time when the real-time open-circuit voltage points to one sub-open-circuit voltage interval, so that the battery is fully charged through the charging current after the real-time change.

11. A vehicle, characterized in that the vehicle comprises a battery segment charging device according to claim 9 for performing the steps of the battery segment charging method according to any one of claims 1-8.