CN-121978552-A - Battery discharge power determining method and system

CN121978552ACN 121978552 ACN121978552 ACN 121978552ACN-121978552-A

Abstract

The invention discloses a method and a system for determining battery discharge power, wherein a current state of charge value, a current temperature and a first discharge power value of a battery are obtained, corresponding discharge power values are firstly inquired in a preset power mapping table according to the current state of charge value and the current temperature to obtain a second discharge power value, then the first target discharge power value and an overpower energy integral value are obtained by combining the first discharge power value and the second discharge power value, finally the overpower energy integral value is compared with a preset threshold value, and the first target discharge power is selected to be regulated or not to be regulated according to the comparison result, so that final discharge power is obtained, the deviation of the battery to external output power is effectively reduced, and the use safety of the battery is ensured.

Inventors

ZHENG LINXIN
FAN XIAOMENG

Assignees

欣旺达动力科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260119

Claims (10)

1. A battery discharge power determination method, comprising: Acquiring a current state of charge value, a current temperature and a first discharge power value of a battery; Inquiring a corresponding discharge power value in a preset power mapping table according to the current state of charge value and the current temperature to obtain a second discharge power value; comparing the first discharge power value with the second discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the second discharge power value to obtain an overpower energy integration value; And judging whether the overpower energy integration value is larger than a preset threshold value, if so, adjusting the first target discharge power value to obtain a second target discharge power value, determining that the second target discharge power value is the final discharge power of the battery, and if so, determining that the first target discharge power value is the final discharge power of the battery.
2. The battery discharge power determination method according to claim 1, wherein the obtaining the second discharge power value further includes: acquiring the current battery voltage of the battery; Judging whether the current battery voltage is smaller than a first preset voltage threshold value, and if so, adjusting the second discharge power value according to a preset adjusting method to obtain a third discharge power value; Comparing the first discharge power value with the third discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the third discharge power value to obtain an overpower energy integration value.
3. The method for determining the discharge power of a battery according to claim 2, wherein said adjusting the second discharge power value according to a preset adjustment method to obtain a third discharge power value comprises: if the current battery voltage is smaller than a second preset voltage threshold, the second discharge power value is adjusted according to a first preset slope, and a third discharge power value is obtained; and if the current battery voltage is greater than or equal to a second preset voltage threshold and less than a first preset voltage threshold, adjusting the second discharge power value according to a second preset slope to obtain a third discharge power value, wherein the second preset voltage threshold is less than the first preset voltage threshold, and the first preset slope is greater than the second preset slope.
4. The battery discharge power determination method of claim 1, wherein comparing the first discharge power value and the second discharge power value to obtain a first target discharge power value comprises: The minimum discharge power value of the first discharge power value and the second discharge power value is selected as a first target discharge power value.
5. The battery discharge power determination method according to claim 1, wherein the integrating based on the first discharge power value and the second discharge power value to obtain the overpower energy integration value includes: Calculating the difference value of the first discharge power value and the second discharge power value to obtain a power difference value; and integrating the power difference value to obtain an overpower energy integral.
6. The battery discharge power determination method according to claim 1, wherein when a corresponding discharge power value is queried in a preset power map according to the current state of charge value and the current temperature, further comprising: When the corresponding discharge power value is not inquired in the preset power mapping table according to the current state of charge value and the current temperature, acquiring the current internal resistance value of the battery; and carrying out power prediction according to the current internal resistance value to obtain the second discharge power value.
7. The battery discharge power determination method according to claim 6, wherein said performing power prediction based on said current internal resistance value to obtain said second discharge power value includes: and constructing a power prediction model according to the emergency derating coefficient and the performance parameter of the battery, wherein the expression of the power prediction model is as follows: In the formula, For the first initial power value in question, For the open circuit voltage of the battery, For the cut-off voltage of the battery, Is the actual internal resistance of the battery; And inputting the current internal resistance value into the power prediction model to perform power prediction, so as to obtain the second discharge power value.
8. The method for determining the discharge power of a battery according to claim 1, wherein the preset power map is determined by dynamically calibrating the test battery, and comprises: Discharging the test batteries respectively in different state of charge values under each temperature working condition according to a preset calibration method to obtain the corresponding discharge power of the test batteries in different state of charge values under each temperature working condition; Testing the corresponding discharge power of the battery according to different charge state values under the temperature working conditions to obtain an initial power mapping table; Performing nonlinear interpolation on the initial power mapping table to obtain a preset power mapping table, wherein the preset calibration method comprises the following steps: dividing the temperature working conditions according to the discharge temperature range of the test battery, and determining a plurality of charge state values corresponding to each temperature working condition, wherein the discharge temperature range is determined according to the actual use situation of the test battery; And gradually increasing the discharge power of the test battery under different charge state values under each temperature working condition according to a first preset speed until the voltage of the test battery is smaller than or equal to a cut-off voltage, gradually reducing the discharge power of the test battery according to a second preset speed until the voltage is not changed along with the reduction of the discharge power, stopping discharging, and recording the current discharge power of the test battery.
9. A battery discharge power determination system, comprising: the first acquisition module is used for acquiring the current state of charge value, the current temperature and the first discharge power value of the battery; the discharging power determining module is used for inquiring the corresponding discharging power value in the preset power mapping table according to the current state of charge value and the current temperature to obtain a second discharging power value; The overpower energy integration value calculation module is used for comparing the first discharge power value and the second discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the second discharge power value to obtain an overpower energy integration value; The judging module is used for judging whether the overpower energy integration value is larger than a preset threshold value, if so, the first target discharge power value is adjusted to obtain a second target discharge power value, the second target discharge power value is determined to be the final discharge power of the battery, and if so, the first target discharge power value is determined to be the final discharge power of the battery.
10. The battery discharge power determination system of claim 9, further comprising: The second acquisition module is used for acquiring the current battery voltage of the battery; The second judging module is used for judging whether the current battery voltage is smaller than a first preset voltage threshold value or not, and if so, adjusting the second discharge power value according to a preset adjusting method to obtain a third discharge power value; And the calculation module is used for comparing the first discharge power value with the third discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the third discharge power value to obtain an overpower energy integration value.

Description

Battery discharge power determining method and system Technical Field The present invention relates to the field of battery management systems, and in particular, to a method and a system for determining battery discharge power. Background The power battery is used as a core power source of the electric automobile, and the power performance of the power battery directly determines the acceleration capacity, the endurance stability and the driving experience of the whole automobile, so that the power battery is a key component for influencing the core competitiveness of the automobile. The power switching strategy is a control logic and an execution rule for dynamically adjusting the external output power or the received power of the Battery according to the real-time state of the power Battery by the BMS (Battery management system), the traditional power switching strategy generally relies on a discretized power mapping table to construct the control logic, and the mode has basic control capability in early application, but the set fixed threshold cannot adapt to the dynamic characteristics of the Battery, such as low-temperature polarization and aging internal resistance increase, so that the external output power or the received power of the Battery is easy to deviate, and the safety problem is caused. Disclosure of Invention In order to solve the technical problems, the embodiment of the invention provides a method and a system for determining battery discharge power, which are used for solving the technical problems that a power switching strategy in the prior art cannot adapt to the dynamic change characteristics of a battery, so that the external output power of the battery is deviated. A first aspect of an embodiment of the present invention provides a method for determining a battery discharge power, including: Acquiring a current state of charge value, a current temperature and a first discharge power value of a battery; Inquiring a corresponding discharge power value in a preset power mapping table according to the current state of charge value and the current temperature to obtain a second discharge power value; Comparing the first discharge power value with the second discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the second discharge power value to obtain an overpower energy integration value; Judging whether the overpower energy integration value is larger than a preset threshold value, if so, adjusting the first target discharge power value to obtain a second target discharge power value, determining the second target discharge power value as the final discharge power of the battery, and if so, determining the first target discharge power value as the final discharge power of the battery. In a possible implementation manner of the first aspect, when obtaining the second discharge power value, the method further includes: Acquiring the current battery voltage of the battery; Judging whether the current battery voltage is smaller than a first preset voltage threshold value, and if so, adjusting the second discharge power value according to a preset adjustment method to obtain a third discharge power value; And comparing the first discharge power value with the third discharge power value to obtain a first target discharge power value, and integrating according to the first discharge power value and the third discharge power value to obtain an overpower energy integration value. In a possible implementation manner of the first aspect, the adjusting the second discharge power value according to the preset adjusting method to obtain a third discharge power value includes: If the current battery voltage is smaller than the second preset voltage threshold, the second discharge power value is adjusted according to the first preset slope, and a third discharge power value is obtained; And if the current battery voltage is greater than or equal to a second preset voltage threshold and less than the first preset voltage threshold, adjusting the second discharge power value according to a second preset slope to obtain a third discharge power value, wherein the second preset voltage threshold is less than the first preset voltage threshold, and the first preset slope is greater than the second preset slope. In a possible implementation manner of the first aspect, comparing the first discharge power value and the second discharge power value to obtain a first target discharge power value includes: The minimum discharge power value of the first discharge power value and the second discharge power value is selected as the first target discharge power value. In a possible implementation manner of the first aspect, integrating according to the first discharge power value and the second discharge power value to obtain the overpower energy integration value includes: calculating the difference value of the first discharge pow