Battery soc value correction method and device, and battery pack

Abstract

The application discloses a battery SOC value correction method and device and a battery pack. The method comprises the following steps: obtaining a real-time SOC value of a battery when the battery is powered on and in a charging and discharging state; if the real-time SOC value is in a preset interval, determining a corresponding relationship between the SOC value and a charging and discharging voltage of the battery according to a current charging and discharging current; calculating the SOC value according to the corresponding relationship and the charging and discharging voltage, and correcting the real-time SOC value based on the SOC value. Through the application, the accuracy of SOC value calculation can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic power, in particular to a battery SOC value correction method and device and a battery pack. BACKGROUND

[0002] At present, the calculation method of the residual capacity value (SOC value) of the battery mostly adopts the ampere-hour metering method. The ampere-hour metering method has errors, and the cumulative error will become larger and larger with the increase of the use time. Therefore, the calculation of the SOC value of the battery by using the ampere-hour metering method alone has a large error, and the calculation result has low accuracy.

[0003] In view of the problem that the calculation of the SOC value of the battery by using the ampere-hour metering method alone in the prior art has a large error and the calculation result has low accuracy, no effective solution has been proposed at present. SUMMARY

[0004] The battery SOC value correction method, device and battery pack provided in the embodiments of the present application solve the problem that the calculation of the SOC value of the battery by using the ampere-hour metering method alone in the prior art has a large error and the calculation result has low accuracy.

[0005] To solve the above technical problem, the present application provides a battery SOC value correction method, wherein the method comprises:

[0006] When the battery is powered on and in a charging and discharging state, obtaining a real-time SOC value of the battery;

[0007] If the real-time SOC value is in a preset interval, determining a corresponding relationship between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current;

[0008] calculating the SOC value according to the corresponding relationship and the charging and discharging voltage, and correcting the real-time SOC value based on the SOC value.

[0009] Further, the determination of the corresponding relationship between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current comprises:

[0010] calculating a charging and discharging rate according to the current charging and discharging current;

[0011] obtaining a deviation amount of the charging and discharging voltage corresponding to the same SOC value under the current charging and discharging rate and under a reference charging and discharging rate;

[0012] determining the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under the current charging and discharging rate according to the deviation amount and the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under the reference charging and discharging rate.

[0013] Further, when the battery is powered on and in the charging and discharging state, the real-time SOC value of the battery is obtained, comprising:

[0014] At the moment when the battery is powered on, the initial SOC value of the battery is obtained according to the open circuit voltage table lookup;

[0015] According to the initial SOC value, the charging and discharging current and the charging and discharging time length, the real-time SOC value of the battery is calculated.

[0016] Further, in the battery charging state, the real-time SOC value is corrected based on the SOC value, comprising:

[0017] Determine the size relationship between the SOC value and the real-time SOC value;

[0018] If the SOC value is greater than the real-time SOC value, the real-time SOC value is corrected to the SOC value at a preset speed;

[0019] If the SOC value is less than or equal to the real-time SOC value, the real-time SOC value is controlled to remain the current value until the SOC value is greater than the real-time SOC value, and then the real-time SOC value is triggered to be corrected to the SOC value at a preset speed.

[0020] Further, in the battery discharging state, the real-time SOC value is corrected based on the SOC value, comprising:

[0021] Determine the size relationship between the SOC value and the real-time SOC value;

[0022] If the SOC value is less than the real-time SOC value, the real-time SOC value is corrected to the SOC value at a preset speed;

[0023] If the SOC value is greater than or equal to the real-time SOC value, the real-time SOC value is controlled to remain the current value until the SOC value is less than the real-time SOC value, and then the real-time SOC value is triggered to be corrected to the SOC value at a preset speed.

[0024] Further, in the battery charging state, the method further comprises:

[0025] If the SOC value reaches the upper limit value of the preset interval, the corresponding relationship between the SOC value and the charging and discharging voltage of the battery is re-determined according to the current SOC value, the charging and discharging voltage value corresponding to the current SOC value, and the overvoltage protection threshold of the battery;

[0026] According to the re-determined corresponding relationship between the SOC value and the charging and discharging voltage of the battery and the charging and discharging voltage, the SOC value is calculated, and the real-time SOC value is corrected based on the SOC value.

[0027] Further, in the battery discharging state, the method further comprises:

[0028] If the SOC value reaches the lower limit value of the preset interval, the correspondence between the SOC value and the charging and discharging voltage of the battery is re-determined according to the current SOC value, the charging and discharging voltage value corresponding to the current SOC value, and the undervoltage protection threshold of the battery.

[0029] The SOC value is calculated according to the re-determined correspondence between the SOC value and the charging and discharging voltage of the battery and the charging and discharging voltage, and the real-time SOC value is corrected based on the SOC value.

[0030] The application also provides a battery SOC value correction device, which comprises:

[0031] The acquisition module is configured to acquire a real-time SOC value of the battery when the battery is powered on and in a charging and discharging state.

[0032] The determination module is configured to determine the correspondence between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current when the real-time SOC value is in a preset interval.

[0033] The correction module is configured to calculate the SOC value according to the correspondence and the charging and discharging voltage, and correct the real-time SOC value based on the SOC value.

[0034] The application also provides a battery pack comprising the above-mentioned battery SOC value correction device.

[0035] The application also provides a computer readable storage medium having a computer program stored thereon, wherein the program is executed by a processor to implement the above-mentioned battery SOC value correction method.

[0036] The application provides a technical solution, which acquires a real-time SOC value of a battery when the battery is powered on and in a charging and discharging state, determines the correspondence between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current when the real-time SOC value is in a preset interval, calculates the SOC value according to the correspondence and the charging and discharging voltage, and corrects the real-time SOC value based on the SOC value. That is, the SOC value is determined based on the detected charging and discharging voltage and the correspondence between the SOC value and the charging and discharging voltage of the battery. The SOC value determined in this way has higher accuracy than the real-time SOC value obtained by the ampere-hour metering method, and can effectively improve the accuracy of SOC value calculation. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A flowchart of the battery SOC value correction method according to an embodiment of the application;

[0038] Figure 2 a corresponding relationship curve between the voltage across the battery and the SOC value at different charging rates;

[0039] Figure 3 a corresponding relationship curve between the voltage across the battery and the SOC value at different discharging rates;

[0040] Figure 4 a flow chart of a battery SOC value correction method according to another embodiment of the present application;

[0041] Figure 5 a structure block diagram of a battery SOC value correction device according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall into the protection scope of the present application.

[0043] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0044] It should be understood that the term "and / or" used herein only describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0045] Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (a stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detecting (a stated condition or event)" or "in response to detecting (a stated condition or event)".

[0046] It is also to be noted that the terms "comprising", "including", and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0047] Optional embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0048] Embodiment 1

[0049] The present embodiment provides a battery SOC value correction method, Figure 1 A flowchart of the battery SOC value correction method according to the present embodiment is shown in FIG. 1, which includes the following steps. Figure 1

[0050] S101, when the battery is powered on and in a charging and discharging state, obtaining a real-time SOC value of the battery.

[0051] In a specific implementation, the open-circuit voltage lookup table method can be used to obtain the initial SOC value according to the voltage across the single battery at the power-on time. After the battery is in a charging and discharging state, the open-circuit voltage lookup table method is no longer applicable. At this time, the ampere-hour metering method is more suitable for calculating the SOC value. Since the initial SOC value has been determined, the charging and discharging current and the charging and discharging time length can be detected to calculate the increase or consumption of the battery capacity. Based on the initial SOC value, the real-time SOC value can be obtained.

[0052] S102, if the real-time SOC value is within a preset interval, determining the corresponding relationship between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current.

[0053] Figure 2 The corresponding relationship curve between the voltage across the battery and the SOC value under different charging rates, i.e., the OCV curve, is shown in FIG. 2, where the arrow direction is the change direction of the SOC value. Figure 2 The charging process is only used as an example for illustration. In fact, the voltage across the battery includes the charging voltage and the discharging voltage, i.e., the charging and discharging voltage. As shown in FIG. 3, the OCV curve of the battery can be basically divided into three sections. Figure 2

[0054] In the first stage, when the SOC value < first threshold SOC1, the OCV curve increases approximately linearly, and the slope is different under different rates. The greater the rate, the higher the slope.

[0055] ​​In the second stage, when the first threshold SOC1≤SOC value≤the second threshold SOC2, the OCV curve tends to be flat, and the slope is basically unchanged, but the intercept with the vertical axis will increase with the rate;

[0056] In the third stage, when the SOC value>the second threshold SOC2, the OCV curve presents an approximately linear growth, and the greater the rate, the lower the slope.

[0057] Based on the above characteristics, it is considered that the OCV curve of a certain reference charge and discharge rate can be fitted to other charge and discharge rates as a reference for SOC value calculation. Assuming that the curve of the reference charge and discharge rate (for example, the discharge rate is 1C) is fitted as Table[SOC value, V 1C ]; define a calibration parameter array b to store the offset of the charge and discharge voltage of other charge and discharge rates based on the reference rate of 1C [b(1), b(2), b(3), …] when the first threshold SOC1≤SOC value≤the second threshold SOC2. According to the above offset, the OCV curve under any discharge rate can be obtained based on the OCV curve under the reference charge and discharge rate.

[0058] That is, within the interval of the first threshold SOC1≤SOC value≤the second threshold SOC2, as long as the actual charge and discharge rate and the deviation of the charge and discharge voltage corresponding to the same SOC value under the actual charge and discharge rate and the reference charge and discharge rate are obtained, the relationship curve between each SOC value and the charge and discharge voltage of the battery under different charge and discharge rates can be obtained. Therefore, if the real-time SOC value is within the preset interval, the charge and discharge rate can be determined according to the current charge and discharge current, and then the corresponding relationship between the SOC value and the charge and discharge voltage of the battery under the current charge and discharge rate can be determined.

[0059] S103, calculate the SOC value according to the above corresponding relationship and the charge and discharge voltage, and correct the real-time SOC value based on the SOC value.

[0060] The battery SOC value correction method of the embodiment, by acquiring the real-time SOC value of the battery when the battery is powered on and in the charge and discharge state, if the real-time SOC value is within the preset interval, the corresponding relationship between the SOC value and the charge and discharge voltage of the battery is determined according to the current charge and discharge current, the SOC value is calculated according to the above corresponding relationship and the charge and discharge voltage, and the real-time SOC value is corrected based on the SOC value. That is, the SOC value is determined based on the corresponding relationship between the SOC value and the charge and discharge voltage of the battery through the detected charge and discharge voltage. The SOC value determined in this way has higher accuracy than the real-time SOC value obtained by the ampere-hour metering method, and can effectively improve the accuracy of SOC value calculation.

[0061] Specifically, the correspondence between the SOC value and the charge-discharge voltage of the battery according to the current charge-discharge current is determined by: calculating the charge-discharge rate according to the current charge-discharge current, wherein the charge-discharge rate = charge-discharge current / rated capacity; obtaining the deviation of the charge-discharge voltage corresponding to the same SOC value under the current charge-discharge rate and under the reference charge-discharge rate; and determining the correspondence between the SOC value and the charge-discharge voltage of the battery under the current charge-discharge rate according to the above deviation and the correspondence between the SOC value and the charge-discharge voltage of the battery under the reference charge-discharge rate.

[0062] The above correspondence can be embodied by the following table:

[0063] Table 1: Correspondence between SOC value and charge-discharge voltage under reference charge-discharge rate

[0064]

[0065]

[0066] Based on the above Table 1 and the deviation of the charge-discharge voltage corresponding to the same SOC value under the current charge-discharge rate and under the reference charge-discharge rate, the correspondence between the SOC value and the charge-discharge voltage of the battery under the current charge-discharge rate can be obtained:

[0067] Table 2: Correspondence between SOC value and charge-discharge voltage under current charge-discharge rate

[0068] SOC value (%) Charge / discharge voltage 0％ V1+b 5％ V2+b 10％ V3+b … … n％ Vn+b

[0069] As can be seen from the above Table 1 and Table 2, the correspondence between the SOC value and the charge-discharge voltage of the battery under the current charge-discharge rate can be determined according to the deviation of the charge-discharge voltage corresponding to the same SOC value under the current charge-discharge rate and under the reference charge-discharge rate and the correspondence between the SOC value and the charge-discharge voltage of the battery under the reference charge-discharge rate. Only the deviation of the charge-discharge voltage corresponding to the same SOC value under different charge-discharge rates and under the reference charge-discharge rate needs to be obtained in advance through experiments. By analogy, the correspondence between the SOC value and the charge-discharge voltage of the battery under any charge-discharge rate can be obtained.

[0070] As described above, at the power-on time, the open-circuit voltage lookup table method can be used to obtain the initial SOC value according to the voltage across the single battery at the power-on time. After the battery is in the charging and discharging state, the open-circuit voltage lookup table method is no longer applicable. At this time, the ampere-hour metering method is more suitable for calculating the SOC value. Since the initial SOC value has been determined, the battery capacity can be calculated by detecting the charging and discharging current and the charging and discharging time. Based on the initial SOC value, the real-time SOC value can be obtained. Therefore, when the battery is powered on and in the charging and discharging state, the real-time SOC value of the battery is obtained, including: at the power-on time of the battery, obtaining the initial SOC value of the battery according to the open-circuit voltage lookup table; calculating the real-time SOC value of the battery according to the initial SOC value, the charging and discharging current, and the charging and discharging time. The correspondence between the open-circuit voltage and the SOC value is shown in the following table:

[0071] Table 3 Correspondence between open-circuit voltage and SOC value

[0072] SOC (%) Voltage across single cell Battery pack voltage 0％ 2.582 38.73 5％ 3.142 47.13 10％ 3.221 48.31 15％ 3.242 48.63 … … …

[0073] The open-circuit voltage is the voltage across the single battery at the power-on time.

[0074] In the battery charging state, the real-time SOC value of the battery increases with the extension of the charging time. Therefore, in the charging state, the real-time SOC value can only increase, and cannot decrease, otherwise it will violate the change rule of the SOC value corresponding to the current battery state. Therefore, the real-time SOC value is corrected based on the SOC value, including: judging the size relationship between the SOC value and the real-time SOC value; if the SOC value is greater than the real-time SOC value, it indicates that the real-time SOC value is too small, and the real-time SOC value needs to be corrected to the SOC value at a predetermined speed; if the SOC value is less than or equal to the real-time SOC value, it indicates that the real-time SOC value is too large or accurate. If the real-time SOC value is too large, since it is in the charging state, the real-time SOC value cannot be decreased. Therefore, the real-time SOC value is controlled to remain at the current value until the SOC value determined according to the voltage across the battery is greater than the real-time SOC value after the voltage across the battery increases, triggering the real-time SOC value to be corrected to the SOC value at a predetermined speed. If the real-time SOC value is accurate, no correction is needed, and the real-time SOC value is still controlled to remain at the current value until the SOC value determined according to the voltage across the battery is greater than the real-time SOC value after the voltage across the battery increases, triggering the real-time SOC value to be corrected to the SOC value at a predetermined speed.

[0075] In the battery discharge state, the real-time SOC value of the battery decreases with the extension of the discharge time, therefore, in the discharge state, the real-time SOC value can only decrease, and cannot increase, otherwise it will violate the change rule of the SOC value corresponding to the current battery state, therefore, the real-time SOC value is corrected based on the SOC value, including: judging the size relationship between the SOC value and the real-time SOC value; if the SOC value is less than the real-time SOC value, it indicates that the actual real-time SOC value is too large, and the real-time SOC value needs to be corrected to the SOC value at a preset speed; if the SOC value is greater than or equal to the real-time SOC value, it indicates that the real-time SOC value is too small or accurate, if it is the case that the real-time SOC value is too small, since it is in the discharge state, the real-time SOC value cannot increase, therefore, the real-time SOC value is controlled to remain at the current value until the SOC value is less than the real-time SOC value, then the real-time SOC value is triggered to be corrected to the SOC value at a preset speed, if it is the case that the real-time SOC value is accurate, the real-time SOC value does not need to be corrected, and is still controlled to remain at the current value until the SOC value is less than the real-time SOC value, then the real-time SOC value is triggered to be corrected to the SOC value at a preset speed.

[0076] As mentioned above Figure 2 As shown in the above-mentioned OCV curve of the battery charging stage can be basically divided into three stages, in the third stage, when the SOC value > second threshold SOC2, the OCV curve increases approximately linearly, the greater the rate, the lower the slope, therefore, the OCV curve of the third stage can be approximately regarded as a straight line segment, but the corresponding relationship between the SOC value and the charging and discharging voltage in this stage is different from the above-mentioned corresponding relationship in the preset interval, since the corresponding relationship between the SOC value and the charging and discharging voltage under the current charging and discharging rate has been determined, the SOC value and the voltage value of the point SOC2= second threshold SOC2, which is the junction point of the second stage and the third stage, can be obtained, and the coordinates of this point on the OCV curve are (SOC2, V ( nC, SOC2) ), since the battery has an overvoltage protection threshold A1, for example, the overvoltage protection threshold of a lithium iron phosphate battery is 3.6V, which is the voltage across the battery when the SOC value is equal to 100%, therefore, the coordinates of the second point of the third stage of the OCV curve (100, A1) can be obtained. According to the coordinates of the above-mentioned two points, the corresponding relationship between the voltage V nC and the SOC value in the third stage of the OCV curve during charging can be obtained:

[0077]

[0078] After the above correspondence is obtained, the SOC value can be determined according to the voltage across the battery obtained thereafter and the correspondence, and then the real-time SOC value is corrected, and therefore, in the battery charging state, the above method further comprises: if the SOC value reaches the upper limit value of the preset interval, the correspondence between the SOC value and the charging / discharging voltage of the battery is re-determined according to the current SOC value, the charging / discharging voltage value corresponding to the current SOC value, and the overvoltage protection threshold of the battery;

[0079] The SOC value is calculated according to the re-determined correspondence between the SOC value and the charging / discharging voltage of the battery and the charging / discharging voltage, and the real-time SOC value is corrected based on the SOC value.

[0080] Figure 3 The corresponding relationship curves between the voltage across the battery and the SOC value under different discharge rates are similar, and the arrow direction is the change direction of the SOC value, as shown in Figure 3 As shown in the figure, the OCV curve of the battery during discharging can be basically divided into three stages, and in the third stage (i.e., the first stage of the charging process), when the SOC value < first threshold SOC1, the OCV curve decreases approximately linearly, and the slope is different under different rates, and the greater the rate, the higher the slope, and therefore, the OCV curve of the third stage of the OCV curve during discharging of the battery is approximately regarded as a straight line segment, but the correspondence between the SOC value and the charging / discharging voltage in this stage is different from the above-mentioned correspondence in the preset interval, and since the correspondence between the SOC value and the charging / discharging voltage under the current charging / discharging rate has been determined, the SOC value and the voltage value of the point SOC1 = second threshold SOC1, which is the junction point of the second stage and the third stage, can be obtained, and the coordinates of the point on the OCV curve are (SOC1, V (nC,SOC1) ), and since the battery has an under-voltage protection threshold A2, for example, the under-voltage protection threshold of a lithium iron phosphate battery is 2V, which is the voltage across the battery when the SOC value is equal to 0, and therefore, the coordinates of the second point of the third stage of the OCV curve (0, A2) can be obtained. According to the coordinates of the above two points, the correspondence between the voltage V nC and the SOC value in the third stage of the OCV curve during discharging can be obtained.

[0081]

[0082] After the above correspondence is obtained, the SOC value can be determined according to the voltage across the battery obtained later and the correspondence, and then the real-time SOC value is corrected, therefore, in the battery discharge state, the above method further comprises: if the SOC value reaches the lower limit value of the preset interval, the correspondence between the SOC value and the charge-discharge voltage of the battery is re-determined according to the current SOC value, the charge-discharge voltage corresponding to the current SOC value, and the undervoltage protection threshold of the battery; the SOC value is calculated according to the re-determined correspondence between the SOC value and the charge-discharge voltage of the battery and the charge-discharge voltage, and the real-time SOC value is corrected based on the SOC value.

[0083] Figure 4 The flow chart of the battery SOC value correction method in the charging state according to another embodiment of the application is shown in FIG. 2, which comprises the following preferred steps: Figure 4

[0084] S1, reading the initial SOC value after the battery is powered on.

[0085] S2, detecting the charging current and obtaining the real-time SOC value after the battery is in the charging state.

[0086] In the specific implementation, the initial power SOC0 is obtained by open circuit lookup table, the battery capacity consumed in a period of time SOC3 is obtained by current*time (unit Ah), and the real-time SOC value = SOC0-SOC3.

[0087] S3, determining the relationship between the charging voltage and the SOC value according to the charging current.

[0088] S4, calculating the SOC value according to the charging voltage and the relationship between the charging voltage and the SOC value.

[0089] S5, judging whether the real-time SOC value ≥ SOC value is true, if yes, executing step S6, and if no, executing step S7.

[0090] S6, keeping the current real-time SOC value unchanged, and then returning to step S5.

[0091] S7, correcting the real-time SOC value to the SOC value at a preset speed, and then returning to step S5.

[0092] For example, the real-time SOC value is increased by 1% every 30S, and the interval time can be determined according to the battery capacity and the commonly used charge-discharge rate. For example, the rated charge-discharge rate of a 10AH battery is 1C, and the interval is set to 10S and the real-time SOC value is increased by 1%.

[0093] Embodiment 2

[0094] The embodiment provides a battery SOC value correction device, Figure 5 ​As shown in a structural block diagram of the battery SOC value correction device according to the embodiment of the present application, Figure 5 the device comprises:

[0095] An acquisition module 10 is configured to acquire a real-time SOC value of the battery when the battery is powered on and in a charging and discharging state.

[0096] In a specific implementation, the power-on time can be determined by using an open-circuit voltage lookup table method, according to the voltage between the single battery at the power-on time, and the initial SOC value is obtained by looking up the table. After the battery is in the charging and discharging state, the open-circuit voltage lookup table method is no longer applicable, and at this time, the ampere-hour metering method is more suitable for calculating the SOC value. Since the initial SOC value has been determined, the charging and discharging current and the charging and discharging time can be detected to calculate the increase or consumption of the battery capacity, and based on the initial SOC value, the real-time SOC value can be obtained.

[0097] A determination module 20 is configured to determine a corresponding relationship between the SOC value and the charging and discharging voltage of the battery according to the current charging and discharging current when the real-time SOC value is in a preset interval.

[0098] As mentioned above Figure 2 , the OCV curve of the battery can be basically divided into three stages:

[0099] In the first stage, when the SOC value is less than a first threshold SOC1, the OCV curve increases approximately linearly, and the slope is different at different rates, and the greater the rate, the higher the slope.

[0100] In the second stage, when the first threshold SOC1 is less than or equal to the SOC value and less than or equal to a second threshold SOC2, the OCV curve tends to be flat, and the slope is basically unchanged, but the intercept with the vertical axis will increase with the rate.

[0101] In the third stage, when the SOC value is greater than the second threshold SOC2, the OCV curve increases approximately linearly, and the greater the rate, the lower the slope.

[0102] Based on the above characteristics, it is considered that the OCV curve of a certain reference charging and discharging rate can be fitted to approximately fit the curve of other charging and discharging rates as a reference for SOC value calculation and calibration. It is assumed that the curve of the reference charging and discharging rate (for example, the discharge rate is 1C) is fitted as Table [SOC value, V 1C ] after fitting; a calibration parameter array b is defined to store the offset of the charging and discharging voltage of other charging and discharging rates based on the reference charging and discharging rate (1C) when the first threshold SOC1 is less than or equal to the SOC value and less than or equal to the second threshold SOC2 [b(1), b(2), b(3), …]. According to the above offset, the OCV curve under any discharge rate can be obtained based on the OCV curve under the reference charging and discharging rate.

[0103] That is, in the interval of the first threshold SOC1≤SOC value≤the second threshold SOC2, as long as the actual charge-discharge rate is obtained, and the deviation amount of the charge-discharge voltage corresponding to the same SOC value under the actual charge-discharge rate and under the reference charge-discharge rate, the relationship curve between each SOC value and the charge-discharge voltage of the battery under different charge-discharge rates can be obtained. Therefore, the real-time SOC value is in the preset interval, and the charge-discharge rate can be determined according to the current charge-discharge current, and then the corresponding relationship between the SOC value and the charge-discharge voltage of the battery under the current charge-discharge rate is determined.

[0104] The correction module 30 is configured to calculate the SOC value according to the above-mentioned corresponding relationship and the charge-discharge voltage, and correct the real-time SOC value based on the SOC value.

[0105] The battery SOC value correction device of the embodiment, through the obtaining module 10, obtains the real-time SOC value of the battery when the battery is powered on and in the charge-discharge state, through the determination module 20, when the real-time SOC value is in the preset interval, determines the corresponding relationship between the SOC value and the charge-discharge voltage of the battery according to the current charge-discharge current, through the correction module 30, calculates the SOC value according to the above-mentioned corresponding relationship and the charge-discharge voltage, and corrects the real-time SOC value based on the SOC value. That is, through the detected charge-discharge voltage, the SOC value is determined based on the corresponding relationship between the SOC value and the charge-discharge voltage of the battery. The SOC value determined in this way has higher accuracy than the real-time SOC value obtained by the ampere-hour metering method, and can effectively improve the accuracy of the SOC value calculation.

[0106] The determination module 20 is specifically configured to: calculate the charge-discharge rate according to the current charge-discharge current, wherein the charge-discharge rate = charge-discharge current / rated capacity; obtain the deviation amount of the charge-discharge voltage corresponding to the same SOC value under the current charge-discharge rate and under the reference charge-discharge rate; and determine the corresponding relationship between the SOC value and the charge-discharge voltage of the battery under the current charge-discharge rate according to the above-mentioned deviation amount and the corresponding relationship between the SOC value and the charge-discharge voltage of the battery under the reference charge-discharge rate.

[0107] As described above, at the power-on moment, the open-circuit voltage table lookup method can be used to obtain the initial SOC value according to the voltage across the single battery at the power-on moment. After the battery is in the charge-discharge state, the open-circuit voltage table lookup method is no longer applicable. At this time, the ampere-hour metering method is more suitable for calculating the SOC value. Since the initial SOC value has been determined, the battery capacity can be calculated by detecting the charge-discharge current and the charge-discharge time length, and the real-time SOC value can be obtained based on the initial SOC value. Therefore, the obtaining module 10 is specifically configured to: at the power-on moment of the battery, obtain the initial SOC value of the battery according to the open-circuit voltage table lookup; and calculate the real-time SOC value of the battery according to the initial SOC value, the charge-discharge current and the charge-discharge time length.

[0108] In the battery charging state, the real-time SOC value of the battery increases with the prolonging of the charging time, and therefore, in the charging state, the real-time SOC value can only increase, and cannot decrease, otherwise it will violate the change rule of the SOC value corresponding to the current battery state, and therefore, in the charging state, the above-mentioned correction module 30 is specifically configured to: determine the size relationship between the SOC value and the real-time SOC value; if the SOC value is greater than the real-time SOC value, it indicates that the real-time SOC value is too small, and the real-time SOC value needs to be corrected to the SOC value at a preset speed; if the SOC value is less than or equal to the real-time SOC value, it indicates that the real-time SOC value is too large or accurate, if the real-time SOC value is too large, since it is in the charging state, the real-time SOC value cannot decrease, and therefore, the real-time SOC value is controlled to remain at the current value until the SOC value determined according to the voltage across the battery is greater than the real-time SOC value after the voltage across the battery increases, and then the real-time SOC value is corrected to the SOC value at a preset speed, if the real-time SOC value is accurate, no correction is needed, and the real-time SOC value is still controlled to remain at the current value until the SOC value determined according to the voltage across the battery is greater than the real-time SOC value after the voltage across the battery increases, and then the real-time SOC value is corrected to the SOC value at a preset speed.

[0109] In the battery discharging state, the real-time SOC value of the battery decreases with the prolonging of the discharging time, and therefore, in the discharging state, the real-time SOC value can only decrease, and cannot increase, otherwise it will violate the change rule of the SOC value corresponding to the current battery state, and therefore, in the discharging state, the above-mentioned correction module 30 is specifically configured to: determine the size relationship between the SOC value and the real-time SOC value; if the SOC value is less than the real-time SOC value, it indicates that the real-time SOC value is too large, and the real-time SOC value needs to be corrected to the SOC value at a preset speed; if the SOC value is greater than or equal to the real-time SOC value, it indicates that the real-time SOC value is too small or accurate, if the real-time SOC value is too small, since it is in the discharging state, the real-time SOC value cannot increase, and therefore, the real-time SOC value is controlled to remain at the current value until the SOC value is less than the real-time SOC value, and then the real-time SOC value is corrected to the SOC value at a preset speed, if the real-time SOC value is accurate, no correction is needed, and the real-time SOC value is still controlled to remain at the current value until the SOC value is less than the real-time SOC value, and then the real-time SOC value is corrected to the SOC value at a preset speed.

[0110] The OCV curve of the battery charging stage can be divided into three stages basically. In the third stage, when the SOC value > the second threshold SOC2, the OCV curve increases approximately linearly, and the greater the rate, the lower the slope. Therefore, the OCV curve of the third stage can be approximately regarded as a straight line segment. However, the correspondence between the SOC value and the charging / discharging voltage in this stage is different from the correspondence in the preset interval. Therefore, in the battery charging state, the determination module 20 is further configured to: when the SOC value reaches the upper limit value of the preset interval, determine the correspondence between the SOC value and the charging / discharging voltage of the battery again according to the current SOC value, the charging / discharging voltage value corresponding to the current SOC value, and the overvoltage protection threshold of the battery; and the correction module 30 is further configured to: calculate the SOC value according to the determined correspondence between the SOC value and the charging / discharging voltage of the battery and the charging / discharging voltage, and correct the real-time SOC value based on the SOC value.

[0111] Similarly, the OCV curve of the battery discharging stage can be divided into three stages basically. In the third stage (i.e., the first stage of the charging process), when the SOC value < the first threshold SOC1, the OCV curve decreases approximately linearly, and the greater the rate, the higher the slope. Therefore, the OCV curve of the third stage of the OCV curve of the battery discharging stage can be approximately regarded as a straight line segment. However, the correspondence between the SOC value and the charging / discharging voltage in this stage is different from the correspondence in the preset interval. Therefore, in the battery discharging state, the determination module 20 is further configured to: when the SOC value reaches the lower limit value of the preset interval, determine the correspondence between the SOC value and the charging / discharging voltage of the battery again according to the current SOC value, the charging / discharging voltage value corresponding to the current SOC value, and the undervoltage protection threshold of the battery; and the correction module 30 is further configured to: calculate the SOC value according to the determined correspondence between the SOC value and the charging / discharging voltage of the battery and the charging / discharging voltage, and correct the real-time SOC value based on the SOC value.

[0112] Embodiment 3

[0113] The embodiment provides a battery pack including the battery SOC value correction device in the above embodiment, which is configured to determine the SOC value based on the correspondence between the SOC value and the charging / discharging voltage of the battery by the detected charging / discharging voltage. The SOC value determined in this way has higher accuracy than the real-time SOC value obtained by the ampere-hour meter method, and can effectively improve the accuracy of the SOC value calculation.

[0114] Embodiment 4

[0115] The embodiment provides a computer readable storage medium having a computer program stored thereon, and the program is executed by a processor to implement the battery SOC value correction method.

[0116] The apparatus embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purposes of the embodiments.

[0117] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be implemented by means of software plus necessary universal hardware platforms, and of course can also be implemented by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0118] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of correcting a battery SOC value, characterized by, The method comprises: acquiring a real-time SOC value of the battery when the battery is powered on and in a charging and discharging state; if the real-time SOC value is in a preset interval, determining a corresponding relationship between the SOC value and a charging and discharging voltage of the battery according to a current charging and discharging current; wherein, the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under different charging and discharging rates is preset; the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under different charging and discharging rates is determined according to the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under a reference charging and discharging rate and a deviation amount of the charging and discharging voltage corresponding to the same SOC value under different charging and discharging rates; the deviation amount and the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under the reference charging and discharging rate are used to determine the corresponding relationship between the SOC value and the charging and discharging voltage of the battery under different charging and discharging rates; calculating the SOC value according to the corresponding relationship and the charging and discharging voltage, and correcting the real-time SOC value based on the SOC value.

2. The method of claim 1, wherein, acquiring a real-time SOC value of the battery when the battery is powered on and in a charging and discharging state, comprising: obtaining an initial SOC value of the battery according to an open circuit voltage at a time when the battery is powered on; calculating the real-time SOC value of the battery according to the initial SOC value, a charging and discharging current and a charging and discharging duration.

3. The method of claim 1, wherein, correcting the real-time SOC value based on the SOC value in a charging state of the battery, comprising: judging a size relationship between the SOC value and the real-time SOC value; if the SOC value is greater than the real-time SOC value, correcting the real-time SOC value to the SOC value at a preset speed; if the SOC value is less than or equal to the real-time SOC value, controlling the real-time SOC value to keep a current value until the SOC value is greater than the real-time SOC value, and then triggering the real-time SOC value to be corrected to the SOC value at a preset speed.

4. The method of claim 1, wherein, correcting the real-time SOC value based on the SOC value in a discharging state of the battery, comprising: judging a size relationship between the SOC value and the real-time SOC value; if the SOC value is less than the real-time SOC value, correcting the real-time SOC value to the SOC value at a preset speed; if the SOC value is greater than or equal to the real-time SOC value, controlling the real-time SOC value to keep a current value until the SOC value is less than the real-time SOC value, and then triggering the real-time SOC value to be corrected to the SOC value at a preset speed.

5. The method of claim 1, wherein, in a charging state of the battery, the method further comprises: if the SOC value reaches an upper limit value of the preset interval, re-determining a corresponding relationship between the SOC value and a charging and discharging voltage of the battery according to a current SOC value, a charging and discharging voltage value corresponding to the current SOC value and an overvoltage protection threshold of the battery; calculating the SOC value according to the re-determined corresponding relationship between the SOC value and the charging and discharging voltage of the battery and the charging and discharging voltage, and correcting the real-time SOC value based on the SOC value.

6. The method of claim 1, wherein, In the battery discharging state, the method further comprises: if the SOC value reaches the lower limit value of the preset interval, determining the correspondence between the SOC value and the charging / discharging voltage of the battery according to the current SOC value, the charging / discharging voltage corresponding to the current SOC value, and the undervoltage protection threshold of the battery; calculating the SOC value according to the re-determined correspondence between the SOC value and the charging / discharging voltage of the battery and the charging / discharging voltage, and correcting the real-time SOC value based on the SOC value.

7. A battery SOC value correction device characterized by comprising: The device comprises: an acquisition module, configured to acquire a real-time SOC value of a battery when the battery is powered on and in a charging / discharging state; a determination module, configured to determine the correspondence between the SOC value and the charging / discharging voltage of the battery according to a current charging / discharging current when the real-time SOC value is in a preset interval; the determination module is specifically configured to: calculate a charging / discharging rate according to the current charging / discharging current; determine the correspondence between the SOC value and the charging / discharging voltage of the battery according to the charging / discharging rate; wherein, the correspondence between the SOC value and the charging / discharging voltage of the battery under different charging / discharging rates is preset; the correspondence between the SOC value and the charging / discharging voltage of the battery under different charging / discharging rates comprises: acquiring a deviation amount of the charging / discharging voltage corresponding to the same SOC value under different charging / discharging rates and under a reference charging / discharging rate; determining the correspondence between the SOC value and the charging / discharging voltage of the battery under different charging / discharging rates according to the deviation amount and the correspondence between the SOC value and the charging / discharging voltage of the battery under the reference charging / discharging rate; a correction module, configured to calculate the SOC value according to the correspondence and the charging / discharging voltage, and correct the real-time SOC value based on the SOC value.

8. A battery pack characterized by comprising: The battery SOC value correction device of claim 7 is included.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method of any one of claims 1 to 6.

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