CN-117783883-B - Method for rapidly estimating reference temperature of all single batteries in battery pack

Abstract

A rapid estimation method for reference temperature of all single batteries in a battery pack relates to the technical field of lithium ion batteries. The method comprises the steps of calculating the distance between the terminal voltage of the single battery without the temperature sensor and the terminal voltage of all the single batteries with the temperature sensor based on the Euclidean distance, obtaining a battery index with the smallest distance difference as a target battery, taking the obtained measured temperature of the target battery as the reference temperature of the single battery without the temperature sensor, taking the obtained reference temperature as data, designing an on-line deployment and temperature estimation strategy for embedded deployment and application, and taking the storage space capacity of an embedded system into consideration. The reference temperature is obtained based on the minimum Euclidean distance between the measurable voltage parameter and the voltage of the single battery terminal provided with the temperature sensor, an embedded deployment strategy is set, limited temperature sensing measurable information is fully utilized, and the temperature estimation of all the single batteries in the battery pack is rapidly and effectively realized.

Inventors

• ZHAO LINHUI
• Qin Pengliang

Assignees

• 哈尔滨工业大学

Dates

Publication Date

20260512

Application Date

20231229

Claims (1)

1. 1. A method for rapidly estimating the reference temperature of all single batteries in a battery pack is characterized by comprising the following steps: step one, selecting a target battery with measurable temperature information based on a distance index between measurable voltage parameters For the battery pack with the temperature sensors arranged in key positions, the temperature can influence the terminal voltage of the single battery, the higher the temperature is, the larger the terminal voltage is, and for measuring the difference between the terminal voltages of the single battery, the distance between the terminal voltage of each single battery without the temperature sensors and the terminal voltage of all single batteries with the temperature sensors is calculated based on Euclidean distance, and the following is expressed: where ED represents the calculation of the Euclidean distance, Indicating that the terminal voltage of the unit cell of the temperature sensor is not set, The terminal voltage of the single battery provided with the temperature sensor is represented, M represents the number of the single battery not provided with the temperature sensor, and omega represents the number of the single battery provided with the temperature sensor; The battery Index Best with the smallest distance difference is obtained based on the calculated distance as follows: the single battery provided with the temperature sensor, which is found by the battery index with the smallest distance difference, is used as a target battery; obtaining a reference temperature based on the obtained target battery with the measurable temperature information Taking the acquired measured temperature of the target battery as the reference temperature of the single battery without the temperature sensor, and adopting the following formula: Wherein T n represents the temperature of the battery cell where the temperature sensor is not provided, and T s represents the temperature of the battery cell where the temperature sensor is provided; Setting a sliding window, designing an online temperature estimation strategy, and carrying out online deployment and application The obtained reference temperature is used as data, and for embedded deployment and application, an on-line deployment and temperature estimation strategy is designed in consideration of the storage space capacity of an embedded system, and is as follows: 3.1, setting a fixed sliding window according to the storage space capacity of the embedded system, and when the stored data capacity is smaller than or equal to the sliding window, calculating the distance between the single battery with the temperature sensor and the terminal voltage of each single battery with the temperature sensor through a formula (5) under the condition of a current window, and acquiring the reference temperature of the single battery at the current moment through a formula (6) and a formula (7); 3.2, when the stored data capacity is larger than the sliding window size, deleting the stored data according to the odd number bit or the even number bit based on the sliding window length sequence, wherein the formula is as follows: Z(1:2:N w )=[] (8) Where N w denotes the sliding window size and Z denotes a window storage sequence having a data length of N w ; After the data is deleted, the data is stored continuously based on 3.1 until the reference temperature is obtained for all the single batteries without temperature sensors in the battery pack.

Description

Method for rapidly estimating reference temperature of all single batteries in battery pack Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a method for rapidly estimating the reference temperature of all single batteries in a battery pack. Background The cells in the battery pack are numerous and subject to cost, space, and wiring, only a limited number of temperature sensors are placed on the cell surface with critical locations in the internal battery pack, while the temperature of other cells cannot be effectively monitored. Therefore, in order to ensure the performance of the battery, monitor and prevent the occurrence of thermal runaway of the battery, the method has important significance for accurately estimating the temperature of each single battery in the battery pack. Most of the current temperature estimation methods of the battery are temperature estimation methods for single batteries, including a direct measurement method, an electrochemical impedance spectroscopy (Electrochemical Impedance Spectroscopy, EIS) based method, a model based method and a data driving based method, and the temperature estimation method of the single battery is the basis of battery pack temperature estimation. The method based on the EIS requires special test equipment and a test circuit, cannot be applied to the actual battery pack on line, the method based on the EIS requires to build a thermal model of the battery, such as a lumped battery thermal model, a two-state battery thermal model and the like and a temperature estimation model, a heat transfer mechanism inside the battery is considered, the precision and the complexity of the battery thermal model are balanced, the working condition applicability of the battery thermal model and the temperature estimation model is poor, model parameters are required to be continuously adjusted and updated, the existing method is used for simulating a small battery pack, a high-order temperature estimation model is built based on the position of the limited temperature sensor, but for a plurality of battery packs inside the single battery, the method based on the EIS is difficult to deploy and apply in an embedded battery management system, the heat transfer mechanism of the battery is not required to be considered, only the data driving is used for building a voltage, current, a state of charge and other parameters and the temperature are required to be balanced, the heat transfer mechanism of the battery is not required to be built, but the temperature of the data driving model is not consistent with the temperature estimation model is not required to be built, and the temperature of the single battery is poor in the heat transfer mechanism is not built due to the fact that the temperature is not consistent with the temperature of the temperature estimation model is required to be built. In summary, the existing battery temperature estimation method has the problems of poor working condition applicability, failure to consider the actual battery pack structure, failure to fully utilize measurable parameter information, difficulty in embedded deployment and application, and failure to meet the effective estimation of the battery temperature in the form of a battery pack. Disclosure of Invention In order to solve the defects in the prior art, the invention provides a rapid estimation method of the reference temperature of all the single batteries in a battery pack, which obtains the reference temperature based on the minimum Euclidean distance between the measurable voltage parameter and the voltage of the single battery terminal provided with a temperature sensor, and sets an embedded deployment strategy, thereby fully utilizing limited temperature sensing measurable information and rapidly and effectively realizing the temperature estimation of all the single batteries in the battery pack. In order to achieve the purpose, the invention adopts the following technical scheme that the method for rapidly estimating the reference temperature of all the single batteries in the battery pack comprises the following steps: step one, selecting a target battery with measurable temperature information based on a distance index between measurable voltage parameters For the battery pack with the temperature sensors arranged in key positions, the temperature can influence the terminal voltage of the single battery, the higher the temperature is, the larger the terminal voltage is, and for measuring the difference between the terminal voltages of the single battery, the distance between the terminal voltage of each single battery without the temperature sensors and the terminal voltage of all single batteries with the temperature sensors is calculated based on Euclidean distance, and the following is expressed: where ED represents the calculation of the Euclidean distance, Indicating that the terminal voltage of the unit cell of th