A correction method and device for characterizing the residual capacity of a vehicle power battery and a vehicle
By setting the normal temperature capacity of the power battery and using the ampere-hour integral algorithm and the capacity decay coefficient MAP table, the SOC display value is calculated in segments, which solves the problem of uneven SOC change of the power battery under low temperature environment and improves the rationality of SOC display and user experience.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GAC AION NEW ENERGY AUTOMOBILE CO LTD
- Filing Date
- 2021-11-04
- Publication Date
- 2026-07-10
AI Technical Summary
In low-temperature environments, errors in the SOC estimation of the power battery cause the discharge to decrease rapidly in the first half and slowly in the second half, resulting in a poor user experience.
By setting the actual remaining capacity of the power battery to the normal temperature capacity, and using the ampere-hour integral algorithm and the capacity decay coefficient MAP table, the remaining capacity display value is calculated in segments, and the SOC inflection point and bottom freeze SOCFrozen value are added to balance the SOC change rate.
It achieves a reasonable and smooth change in SOC during discharge in low-temperature environments, avoiding the problem of a rapid decrease in the first half and a slow decrease in the second half, thus improving the user experience.
Smart Images
Figure CN116068416B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power battery control technology for new energy vehicles, and in particular to a method, device, and vehicle for characterizing the remaining charge of a vehicle power battery. Background Technology
[0002] In new energy vehicles, the State of Charge (SOC) of a battery is a state quantity that represents the battery's remaining capacity. Accurate estimation of the true SOC is crucial for preventing overcharging and over-discharging of the battery and for improving overall vehicle performance. Simultaneously, the SOC display strategy of the power battery system is also critical to user experience. During driving, the most noticeable difference for users is whether the actual driving range matches the range displayed on the instrument panel. Therefore, the SOC display strategy needs to accurately reflect the current SOC state of the power battery system while also considering the user's actual driving experience.
[0003] Current displayed SOC is usually obtained by directly mapping the actual SOC. When there is an estimation error in the actual SOC or when corrections are needed under specific operating conditions, the direct mapping of the displayed SOC to the actual SOC can result in phenomena such as jumps in the displayed SOC and an increase in the displayed SOC during discharge, giving customers an experience of abnormal battery power. When the ambient temperature is low, the usable capacity of the power battery system will shrink compared to that at room temperature, giving customers the experience of shorter battery life. In particular, affected by temperature, capacity decay, SOC estimation accuracy, and driving habits, when driving in low-temperature environments, the battery temperature rises from low to high, and the usable battery capacity also rises from low to high. The rated capacity calculated by SOC changes accordingly, causing the instrument SOC to drop faster in the early stages of driving and slower in the later stages, resulting in a poor customer experience. Summary of the Invention
[0004] The purpose of this invention is to propose a method, device, and vehicle for automatically generating a comprehensive scheduling report that represents the remaining power capacity of a vehicle's power battery. This addresses the technical problem in existing methods where, during low-temperature driving, the State of Charge (SOC) decreases rapidly in the first half of the discharge cycle and slowly in the second half due to capacity decay.
[0005] On the one hand, a correction method for characterizing the remaining charge of a vehicle power battery is provided, including:
[0006] When the power battery is discharging, the actual remaining power capacity of the power battery is set to the normal temperature capacity of the power battery;
[0007] The actual remaining power value is compared with a preset remaining power inflection point threshold; when the actual remaining power value is greater than the preset remaining power inflection point threshold, the remaining power display value is determined by a preset ampere-hour integration algorithm; when the actual remaining power value is less than the preset remaining power inflection point threshold, the remaining power display value is determined by querying a preset capacity decay coefficient MAP table based on the current temperature value of the power battery.
[0008] The remaining power display value is output as the final remaining power value of the power battery.
[0009] Preferably, the room temperature capacity of the power battery is calculated according to the following formula:
[0010]
[0011] Among them, SOC K Indicates the current remaining battery power; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
[0012] Preferably, the preset capacity decay coefficient MAP table is used to record the temperature values of the power battery and the corresponding capacity retention rate of the power battery at each temperature value.
[0013] Preferably, the method further includes: querying the capacity decay coefficient MAP table to determine the lower limit of the actual remaining power value at the corresponding temperature;
[0014] The lower limit of the actual remaining power value at the corresponding temperature is set as the bottom frozen remaining power value of the power battery;
[0015] Set the bottom of the power battery to freeze the remaining power value as the node when the remaining power display value is 0.
[0016] Preferably, it further includes: setting the remaining power inflection point threshold based on the bottom frozen remaining power value of the power battery, so as to calculate the remaining power display value in segments and realize the balanced change of the remaining power display value.
[0017] On the other hand, a correction device for characterizing the remaining charge of a vehicle power battery is also provided, for implementing the aforementioned correction method for characterizing the remaining charge of a vehicle power battery, comprising:
[0018] An initialization module is used to set the actual remaining charge value of the power battery to the normal temperature capacity of the power battery when the power battery is discharging.
[0019] The calculation module compares the actual remaining battery power value with a preset remaining battery power inflection point threshold. When the actual remaining battery power value is greater than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined by a preset ampere-hour integration algorithm. When the actual remaining battery power value is less than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined by querying a preset capacity decay coefficient MAP table based on the current temperature value of the power battery. The remaining battery power display value is then output as the final remaining battery power value.
[0020] Preferably, the initialization module is further configured to calculate the room-temperature capacity of the power battery according to the following formula:
[0021]
[0022] Among them, SOC K Indicates the current remaining battery power; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
[0023] Preferably, the calculation module is further used to record the temperature values of the power battery and the corresponding capacity retention rate of the power battery at each temperature value, and outputs a capacity decay coefficient MAP table.
[0024] Preferably, the calculation module is further configured to query the capacity decay coefficient MAP table to determine the lower limit of the actual remaining power value at the corresponding temperature; set the lower limit of the actual remaining power value at the corresponding temperature as the bottom frozen remaining power value of the power battery; and set the bottom frozen remaining power value of the power battery as the node when the remaining power display value is 0.
[0025] The remaining power inflection point threshold is set based on the remaining power value frozen at the bottom of the power battery to calculate the remaining power display value in segments and achieve a balanced change in the remaining power display value.
[0026] On the other hand, a car is also provided in which the remaining charge value of the power battery is corrected during discharge by means of the correction device for characterizing the remaining charge of the vehicle power battery.
[0027] In summary, implementing the embodiments of the present invention has the following beneficial effects:
[0028] The present invention provides a method, device, and vehicle for correcting the remaining capacity of a vehicle power battery. The capacity calculated using the actual State of Charge (SOC) is fixed as the capacity at room temperature. At the end of the discharge, the actual SOC is mapped to the instrument SOC based on the capacity coefficient of the discharge at each temperature. An SOC inflection point is added during discharge to balance the SOC change rate in the first and second halves of the discharge, making the instrument SOC change more reasonable throughout the entire discharge process. An SOC inflection point threshold judgment and a bottom-freezing SOC are also added. Frozen This value ensures that the instrument's SOC changes more smoothly and reasonably throughout the entire discharge process, avoiding the problem of a rapid drop in SOC in the first half and a slower drop in the second half when driving at low temperatures, which leads to a poor user experience. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.
[0030] Figure 1 This is a schematic diagram of the main process of a method for correcting the remaining power of a vehicle power battery according to an embodiment of the present invention.
[0031] Figure 2 This is a logical schematic diagram of a correction method for characterizing the remaining power of a vehicle power battery in an embodiment of the present invention.
[0032] Figure 3 This is a schematic diagram of a correction device for characterizing the remaining charge of a vehicle power battery in an embodiment of the present invention.
[0033] Figure 4 This is a schematic diagram showing the slope of the change in SOC in an embodiment of the present invention. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.
[0035] like Figure 1 and Figure 2 The diagram shown is a schematic representation of an embodiment of a method for characterizing the remaining charge of a vehicle power battery provided by the present invention. In this embodiment, the method includes the following steps:
[0036] When the power battery is discharging, the actual remaining capacity of the power battery is set to its normal temperature capacity; that is, when the power battery is determined to be in a discharging state, the actual SOC value (actual remaining capacity value) is set to the actual SOC value.Act The rated capacity is fixed as the room temperature capacity C1, that is, the ampere-hour integral accuracy is set to be unaffected by temperature.
[0037] In a specific embodiment, the room temperature capacity is calculated according to the following formula:
[0038]
[0039] Among them, SOC K Indicates the current remaining battery level; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
[0040] Furthermore, the actual remaining battery power value is compared with a preset remaining battery power inflection point threshold; when the actual remaining battery power value is greater than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined using a preset ampere-hour integration algorithm; when the actual remaining battery power value is less than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined by querying a preset capacity decay coefficient MAP table based on the current temperature value of the power battery; that is, as... Figure 4 As shown, the SOC inflection point value is increased. 拐点 (Remaining battery power inflection point threshold), when SOC Act SOC 拐点 In Zone 1, the instrument's State of Charge (SOC) is calculated using an ampere-hour integration algorithm; when the SOC... Act <SOC 拐点 At time (zone two), the instrument's SOC (remaining battery level) is checked via MAP. Cdecr (Capacity decay coefficient MAP table) calculation. Among these, the ampere-hour integration algorithm has been widely applied in the lithium battery industry and in various fields, and the estimation of battery state of charge (SOC) has become a crucial aspect of battery management. It can be used for all electric vehicle batteries; if current measurement is accurate and sufficient data for estimating the initial state is available, it is a simple and reliable SOC estimation method. Compared to the open-circuit voltage method, which relies on long-term storage or resting to obtain the open-circuit voltage, the ampere-hour integration method is more reliable.
[0041] In a specific embodiment, the preset capacity decay coefficient MAP table is used to record the various temperature values of the power battery and the corresponding capacity retention rate of the power battery at each temperature value. That is, the capacity decay coefficient MAP table (MAP) is derived based on the capacity retention rate of the power battery at different temperatures. Cdecr Bottom frozen SOC Frozen Values are determined by MAP Cdecr Obtained. SOC FrozenThis is the usable lower limit of the true SOC at that temperature.
[0042] Specifically, bottom-frozen SOC Frozen Values are determined by MAP Cdecr The process involves querying the capacity decay coefficient MAP table to determine the lower limit of the actual remaining battery capacity at the corresponding temperature; setting this lower limit as the bottom-frozen remaining battery capacity value; and setting this bottom-frozen remaining battery capacity value as the node where the remaining battery capacity display value is 0. Frozen The value is the point at which the instrument's SOC is mapped to 0, and this value changes according to the battery temperature.
[0043] More specifically, the remaining power inflection point threshold is set based on the frozen remaining power value at the bottom of the power battery, in order to calculate the remaining power display value in segments and achieve a balanced change in the remaining power display value. That is, as... Figure 4 As shown, it can be based on SOC Frozen Select a reasonable SOC size 拐点 This is to balance the slope of SOC changes shown in the first and second halves of the chart. During the upward movement at low temperatures, SOC... Frozen At this point, the SOC is relatively high, so increase the SOC. 拐点 After the value, when SOC Act SOC 拐点 In Zone 1 (high SOC segment), the slope of the SOC decrease is determined by the ampere-hour integral and is not affected by the SOC. Frozen The actual SOC decline rate at this point is consistent with the displayed SOC decline rate. When SOC... Act <SOC 拐点 In Zone 2 (low SOC range), due to battery discharge and vehicle heating, the battery temperature rises, and the SOC... Frozen The actual SOC decrease rate is relatively low, and the displayed SOC decrease rate is quite consistent with the actual SOC decrease rate. Throughout the entire driving process, the displayed SOC changes relatively smoothly, avoiding the experience of inaccurate mileage in the first half of the trip.
[0044] The remaining power display value is output as the final remaining power value of the power battery. That is, the remaining power display value calculated in the above segments is the final remaining power value. In this way, the instrument's SOC changes more reasonably and smoothly throughout the entire discharge process, avoiding the problem of a poor user experience caused by a rapid drop in SOC in the first half and a slower drop in the second half when driving in low temperatures.
[0045] like Figure 3The diagram shown is a schematic representation of an embodiment of a correction device for characterizing the remaining charge of a vehicle power battery provided by the present invention. In this embodiment, the device is used to implement the correction method for characterizing the remaining charge of a vehicle power battery, including:
[0046] An initialization module is used to set the actual remaining charge value of the power battery to its room temperature capacity when the power battery is discharging; specifically, the initialization module is also used to calculate the room temperature capacity of the power battery according to the following formula:
[0047]
[0048] Among them, SOC K Indicates the current remaining battery level; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
[0049] The calculation module compares the actual remaining battery capacity with a preset remaining battery capacity inflection point threshold. When the actual remaining battery capacity is greater than the preset threshold, a preset ampere-hour integration algorithm is used to determine the displayed remaining battery capacity. When the actual remaining battery capacity is less than the preset threshold, a preset capacity decay coefficient MAP table is consulted based on the current temperature of the battery to determine the displayed remaining battery capacity. The displayed remaining battery capacity is then output as the final remaining battery capacity. Specifically, the calculation module also records the temperature values of the battery and the corresponding capacity retention rate at each temperature value, outputting a capacity decay coefficient MAP table. The calculation module is also used to query the capacity decay coefficient MAP table to determine the lower limit of the actual remaining power value at the corresponding temperature; set the lower limit of the actual remaining power value at the corresponding temperature as the bottom frozen remaining power value of the power battery; set the bottom frozen remaining power value of the power battery as the node when the remaining power display value is 0; and set the remaining power inflection point threshold according to the bottom frozen remaining power value of the power battery to calculate the remaining power display value in segments and achieve a balanced change in the remaining power display value.
[0050] The present invention also provides a vehicle in which the remaining charge value of the power battery during discharge is corrected by the aforementioned correction device for characterizing the remaining charge of the vehicle power battery.
[0051] For details regarding the correction device for characterizing the remaining charge of a vehicle's power battery and the specific implementation process of the vehicle, please refer to the specific implementation process of the correction method for characterizing the remaining charge of a vehicle's power battery described above, which will not be repeated here.
[0052] In summary, implementing the embodiments of the present invention has the following beneficial effects:
[0053] The present invention provides a method, device, and vehicle for correcting the remaining capacity of a vehicle power battery. The capacity calculated using the actual State of Charge (SOC) is fixed as the capacity at room temperature. At the end of the discharge, the actual SOC is mapped to the instrument SOC based on the capacity coefficient of the discharge at each temperature. An SOC inflection point is added during discharge to balance the SOC change rate in the first and second halves of the discharge, making the instrument SOC change more reasonable throughout the entire discharge process. The invention also includes SOC inflection point judgment and bottom-freezing of the SOC. Frozen This value ensures that the instrument's SOC changes more smoothly and reasonably throughout the entire discharge process, avoiding the problem of a rapid drop in SOC in the first half and a slower drop in the second half when driving at low temperatures, which leads to a poor user experience.
[0054] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.
Claims
1. A correction method for characterizing the remaining charge of a vehicle power battery, characterized in that, include: When the power battery is discharging, the actual remaining power capacity of the power battery is set to the normal temperature capacity of the power battery; The actual remaining battery power value is compared with a preset remaining battery power inflection point threshold; when the actual remaining battery power value is greater than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined by a preset ampere-hour integration algorithm; When the actual remaining power value is less than the preset remaining power inflection point threshold, the remaining power display value is determined by querying the preset capacity decay coefficient MAP table based on the current temperature value of the power battery. The remaining power display value is output as the final remaining power value of the power battery; The method further includes: The lower limit of the actual remaining power value at the corresponding temperature is determined by querying the capacity decay coefficient MAP table; The lower limit of the actual remaining power value at the corresponding temperature is set as the bottom frozen remaining power value of the power battery; Set the bottom of the power battery to freeze the remaining power value as the node when the remaining power display value is 0; The method further includes: The remaining power inflection point threshold is set based on the remaining power value frozen at the bottom of the power battery to calculate the remaining power display value in segments and achieve a balanced change in the remaining power display value.
2. The method as described in claim 1, characterized in that, The room temperature capacity of the power battery is calculated according to the following formula: ； Among them, SOC K Indicates the current remaining battery power; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
3. The method as described in claim 2, characterized in that, The preset capacity decay coefficient MAP table is used to record the temperature values of the power battery and the corresponding capacity retention rate of the power battery at each temperature value.
4. A correction device for characterizing the remaining charge of a vehicle power battery, used to implement the correction method for characterizing the remaining charge of a vehicle power battery as described in any one of claims 1-3, characterized in that, include: An initialization module is used to set the actual remaining charge value of the power battery to the normal temperature capacity of the power battery when the power battery is discharging. The calculation module is used to compare the actual remaining power value with a preset remaining power inflection point threshold. When the actual remaining battery power value is greater than the preset remaining battery power inflection point threshold, the remaining battery power display value is determined by the preset ampere-hour integration algorithm; When the actual remaining power value is less than the preset remaining power inflection point threshold, the remaining power display value is determined by querying the preset capacity decay coefficient MAP table based on the current temperature value of the power battery. The remaining power display value is then output as the final remaining power value of the power battery. The calculation module is further configured to query the capacity decay coefficient MAP table to determine the lower limit of the actual remaining power value at the corresponding temperature; set the lower limit of the actual remaining power value at the corresponding temperature as the bottom frozen remaining power value of the power battery; and set the bottom frozen remaining power value of the power battery as the node when the remaining power display value is 0. The calculation module is also used to set the remaining power inflection point threshold based on the bottom frozen remaining power value of the power battery, so as to calculate the remaining power display value in segments and realize the balanced change of the remaining power display value.
5. The apparatus as described in claim 4, characterized in that, The initialization module is also used to calculate the room temperature capacity of the power battery according to the following formula: ； Among them, SOC K Indicates the current remaining battery power; SOC K-1 dt represents the remaining charge value at the previous moment; I represents the rate of temperature change of the power battery; C1 represents the current value of the power battery; and C1 represents the fixed capacity of the power battery at room temperature.
6. The apparatus as claimed in claim 5, characterized in that, The calculation module is also used to record the temperature values of the power battery and the corresponding capacity retention rate of the power battery at each temperature value, and outputs a capacity decay coefficient MAP table.
7. A car, characterized in that, The remaining charge value of the power battery during discharge is corrected using the correction device for characterizing the remaining charge of the vehicle power battery as described in any one of claims 4-6.