CN113410531B - Battery overall temperature detection method, device and computer readable storage medium - Google Patents

Abstract

The invention discloses a battery overall temperature detection method, which comprises the following steps: acquiring ultrasonic detection data of the battery through an ultrasonic detection device arranged on a battery shell; acquiring the electric quantity and the external temperature of the battery; obtaining the calculated internal temperature of the battery according to the ultrasonic detection data and the electric quantity; and calculating the overall temperature of the battery according to the calculated internal temperature and the calculated external temperature. The invention also discloses a battery overall temperature detection device and a computer readable storage medium. The invention makes the battery temperature evaluation and detection more accurate.

Description

Battery overall temperature detection method, device and computer-readable storage medium

technical field

The present invention relates to the technical field of batteries, and in particular, to a method, a device and a computer-readable storage medium for detecting the overall temperature of a battery.

Background technique

Batteries are sensitive to changes in temperature. Temperature affects the activity and charge-discharge performance of battery materials, and affects the safe and stable operation of batteries. Abnormal operating conditions such as battery overheating and thermal runaway can easily lead to safety accidents. In order to ensure the stability and safety of the battery, it is necessary to detect the temperature performance state of the battery.

The traditional battery temperature detection is generally performed by a temperature sensor installed on the surface of the battery, but this detection method detects the temperature outside the battery, which is easily affected by the surrounding environment, resulting in inaccurate detection results.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a method, device and computer-readable storage medium for detecting the overall temperature of a battery, so as to solve the problem of inaccurate battery temperature detection.

In order to achieve the above object, the present invention provides a method for detecting the overall temperature of a battery, and the method for detecting the overall temperature of the battery includes:

Collect the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery casing;

obtain the power and external temperature of the battery;

Obtain the calculated internal temperature of the battery according to the ultrasonic detection data and the power;

According to the calculated internal temperature and the external temperature, the overall temperature of the battery is calculated.

Optionally, the ultrasonic detection data includes first ultrasonic data and second ultrasonic data, and the step of obtaining the calculated internal temperature of the battery according to the ultrasonic detection data and the power level includes:

According to the first ultrasonic flight time and the second ultrasonic flight time and the battery power in the first ultrasonic data and the second ultrasonic data, and calculate the calculated internal temperature of the battery by the following formula:

Among them, t is the calculated internal temperature of the battery; a is the set of coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , a ₈ , a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are constants; D1 _ToF is the first ultrasonic flight time; D2 _ToF is the second ultrasonic flight time; SOC is the battery power.

Optionally, the value of the coefficient a in the formula for calculating the internal temperature can be obtained by fitting and calculating according to multiple groups of real data, and the steps of obtaining the value of the coefficient a in the formula according to the fitting calculation of multiple groups of real data include:

Obtain the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature of the plurality of groups of the batteries;

Calculate the formula according to the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and obtain the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , The values of a ₆ , a ₇ , and a ₈ .

Optionally, the formula is calculated according to the multiple groups of the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and the coefficients a ₀ , a ₁ , a ₂ , a ₃ , and The steps of obtaining the values of a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ include:

Establish the objective function formula for the real battery internal temperature and the stated formula:

Calculate the partial derivative of each coefficient a in the objective function formula, make the value of the partial derivative equal to 0, and obtain the linear equation of the partial derivative of the coefficient a:

Substitute multiple sets of data of the first ultrasonic flight time, the second ultrasonic flight time, electric quantity and real internal temperature into the linear equation, and calculate the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a respectively ₅ , a ₆ , a ₇ , and the values of a ₈ ;

为偏导数符号，n为采样个数，i为采样点，i＝1,2，…，n。Among them, TI is the actual internal temperature of the battery, L is the objective function formula of the actual internal temperature of the battery and the calculated internal temperature of the battery,

is the partial derivative symbol, n is the number of samples, i is the sampling point, i=1, 2, ..., n.

Optionally, by substituting multiple sets of data of the first ultrasonic time of flight, the second ultrasonic time of flight, the amount of electricity and the real internal temperature into the linear equation, the coefficients a ₀ , a ₁ , a ₂ , and a ₃ are obtained by calculation. The steps for obtaining values of , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ also include:

According to the linear equation of the partial derivative of the coefficient a, we get:

Simplify the above equation into matrix form to get XA=Y, where,

The Gaussian elimination method is used to solve A, and the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are calculated respectively.

Optionally, the step of calculating the overall temperature of the battery according to the calculated internal temperature and the external temperature includes:

Calculate the overall temperature of the battery according to the formula T=mTR+(1-m)t;

Among them, T is the overall temperature of the battery, TR is the external temperature of the battery, t is the internal temperature of the battery, m is the weight of the external temperature of the battery, 1-m is the weight of the internal temperature of the battery, 0≤m≤1.

Optionally, after obtaining the step of calculating the internal temperature of the battery by calculating the formula, the method further includes evaluating the formula for calculating the internal temperature according to the following formula to measure the deviation between the calculated value and the real value:

Among them, RESE is the root mean square error, TI is the actual internal temperature of the battery, n is the number of samples, i is the sampling point, i=1,2,...,n.

Optionally, the ultrasonic detection device includes an ultrasonic transmitting end, a first ultrasonic receiving end and a second ultrasonic receiving end, the first ultrasonic receiving end is arranged on the same side of the battery casing as the ultrasonic transmitting end, the second ultrasonic receiving end is The ultrasonic receiving end is arranged on the opposite side of the battery casing and the ultrasonic transmitting end. The step of collecting the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery casing further includes:

Collect the first ultrasonic data of the first ultrasonic receiving end of the battery and the second ultrasonic data of the second ultrasonic receiving end of the battery through the ultrasonic detection device arranged on the battery casing;

Feature extraction is performed on the first ultrasonic data and the second ultrasonic data, and the first ultrasonic time-of-flight and the second ultrasonic time-of-flight are extracted.

In addition, in order to achieve the above object, the present invention also provides an overall battery temperature detection device, the battery overall temperature detection device includes: a memory, a processor, and a device stored in the memory and running on the processor. A battery overall temperature detection program, when the battery overall temperature detection program is executed by the processor, implements the steps of the above-mentioned battery overall temperature detection method.

In addition, in order to achieve the above object, the present invention also provides a computer-readable storage medium on which an overall battery temperature detection program is stored, and when the overall battery temperature detection program is executed by a processor, the above-mentioned method for detecting overall battery temperature is implemented A step of.

The present invention collects the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery shell; at the same time, obtains the electric quantity and external temperature of the battery; and obtains the calculated internal temperature of the battery according to the ultrasonic detection data and electric quantity ; Calculate the overall temperature of the battery according to the calculated internal temperature and the external temperature. Through the above method, the present invention not only considers the external surface temperature of the battery, but also considers the temperature inside the battery, and evaluates the overall temperature of the battery by obtaining the internal temperature of the battery and the external temperature of the battery, so that the battery temperature detection and evaluation is more accurate.

Description of drawings

1 is a schematic diagram of a device structure of a hardware operating environment involved in an embodiment of the present invention;

2 is a schematic flowchart of a first embodiment of a method for detecting the overall temperature of a battery according to the present invention;

FIG. 3 is a schematic diagram of an ultrasonic detection device.

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in FIG. 1 , FIG. 1 is a schematic diagram of a device structure of a hardware operating environment involved in the solution of an embodiment of the present invention.

The device in the embodiment of the present invention may be a PC, or a smart phone, a tablet computer, an e-book reader, an MP3 (Moving Picture Experts Group Audio Layer III) player, and an MP4 (Moving Picture Experts Group Audio Layer III) player. Group Audio Layer IV, moving image expert compression standard audio layer 4) Players, portable computers and other portable terminal devices with display functions.

As shown in FIG. 1 , the apparatus may include: a processor 1001 , such as a CPU, a communication bus 1002 , a user interface 1003 , a network interface 1004 , and a memory 1005 . Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and optionally, the user interface 1003 may also include a standard wired interface and a wireless interface. Optionally, the network interface 1004 may include a standard wired interface and a wireless interface (eg, a WI-FI interface). The memory 1005 may be high-speed RAM memory, or may be non-volatile memory, such as disk memory. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001 .

Optionally, the device may further include a camera, an RF (Radio Frequency, radio frequency) circuit, a sensor, an audio circuit, a WiFi module, and the like. Among them, sensors such as light sensors, motion sensors and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor, wherein the ambient light sensor may adjust the brightness of the display screen according to the brightness of the ambient light, and the proximity sensor may turn off the display screen and/or turn off the display screen when the mobile terminal is moved to the ear. Backlight. As a kind of motion sensor, the gravitational acceleration sensor can detect the magnitude of acceleration in all directions (generally three axes), and can detect the magnitude and direction of gravity when stationary, and can be used for applications that recognize the posture of mobile terminals (such as horizontal and vertical screen switching, related games, magnetometer attitude calibration), vibration recognition related functions (such as pedometer, tapping), etc.; of course, the mobile terminal can also be equipped with other sensors such as gyroscope, barometer, hygrometer, thermometer, infrared sensor, etc. No longer.

Those skilled in the art can understand that the device structure shown in FIG. 1 does not constitute a limitation to the device, and may include more or less components than the one shown, or combine some components, or arrange different components.

As shown in FIG. 1, the memory 1005, which is a computer storage medium, may include an operating system, a network communication module, a user interface module, and a battery overall temperature detection program.

In the device shown in FIG. 1 , the network interface 1004 is mainly used to connect to the background server and perform data communication with the background server; the user interface 1003 is mainly used to connect the client (client) and perform data communication with the client; and the processor 1001 can be used to call the battery overall temperature detection program stored in the memory 1005, and perform the following operations:

Collect the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery casing;

obtain the power and external temperature of the battery;

Obtain the calculated internal temperature of the battery according to the ultrasonic detection data and the power;

According to the calculated internal temperature and the external temperature, the overall temperature of the battery is calculated.

Further, the ultrasonic detection data includes the first ultrasonic data and the second ultrasonic data, and the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

According to the first ultrasonic flight time and the second ultrasonic flight time and the battery power in the first ultrasonic data and the second ultrasonic data, and calculate the calculated internal temperature of the battery by the following formula:

Among them, t is the calculated internal temperature of the battery; a is the set of coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , a ₈ , a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are constants; D1 _ToF is the first ultrasonic flight time; D2 _ToF is the second ultrasonic flight time; SOC is the battery power.

Further, the value of the coefficient a in the formula for calculating the internal temperature can be obtained by fitting and calculating according to multiple sets of real data, and the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

Obtain the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature of the plurality of groups of the batteries;

Calculate the formula according to the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and obtain the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , The values of a ₆ , a ₇ , and a ₈ .

Further, the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

Establish the objective function formula of the real battery internal temperature and the calculation formula:

Calculate the partial derivative of each coefficient a in the objective function formula, make the value of the partial derivative equal to 0, and obtain the linear equation of the partial derivative of the coefficient a:

Substitute multiple sets of data of the first ultrasonic flight time, the second ultrasonic flight time, electric quantity and real internal temperature into the linear equation, and calculate the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a respectively ₅ , a ₆ , a ₇ , and the values of a ₈ ;

为偏导数符号，n为采样个数，i为采样点，i＝1,2，…，n。Among them, TI is the actual internal temperature of the battery, L is the objective function formula of the actual internal temperature of the battery and the calculated internal temperature of the battery,

is the partial derivative symbol, n is the number of samples, i is the sampling point, i=1, 2, ..., n.

Further, the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

According to the linear equation of the partial derivative of the coefficient a, we get:

Simplify the above equation into matrix form to get XA=Y, where,

The Gaussian elimination method is used to solve A, and the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are calculated respectively.

Further, the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

Calculate the overall temperature of the battery according to the formula T=mTR+(1-m)t;

Among them, T is the overall temperature of the battery, TR is the external temperature of the battery, t is the internal temperature of the battery, m is the weight of the external temperature of the battery, 1-m is the weight of the internal temperature of the battery, 0≤m≤1.

Further, after obtaining the step of calculating the internal temperature of the battery through formula calculation, the processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

The formula for calculating the internal temperature is evaluated according to the following formula to measure the deviation between the calculated value and the true value:

Among them, RESE is the root mean square error, TI is the actual internal temperature of the battery, n is the number of samples, i is the sampling point, i=1,2,...,n.

Further, the ultrasonic detection device includes an ultrasonic transmitting end, a first ultrasonic receiving end and a second ultrasonic receiving end, the first ultrasonic receiving end is arranged on the same side of the battery casing as the ultrasonic transmitting end, and the second ultrasonic receiving end is The receiving end is arranged on the opposite side of the battery shell and the ultrasonic transmitting end. The processor 1001 can call the battery overall temperature detection program stored in the memory 1005, and also perform the following operations:

Collect the first ultrasonic data of the first ultrasonic receiving end of the battery and the second ultrasonic data of the second ultrasonic receiving end of the battery through the ultrasonic detection device arranged on the battery casing;

Feature extraction is performed on the first ultrasonic data and the second ultrasonic data, and the first ultrasonic time-of-flight and the second ultrasonic time-of-flight are extracted.

The specific embodiments of the device for detecting the overall temperature of a battery according to the present invention are basically the same as the embodiments of the following methods for detecting the overall temperature of a battery, which will not be repeated here.

Referring to FIG. 2, FIG. 2 is a schematic flowchart of the first embodiment of the method for detecting the overall temperature of the battery according to the present invention. The method for detecting the overall temperature of the battery includes:

Step S10, collecting ultrasonic detection data of the battery through an ultrasonic detection device disposed on the battery casing;

Due to the characteristics of the battery layered structure, the battery temperature can be divided into the battery surface temperature and the battery internal temperature. There are two factors that affect the battery temperature change, one is the battery working environment temperature, and the other is the charge and discharge current during the battery operation. The battery working environment temperature mainly affects the battery surface temperature, and the heat conduction direction is transferred from the battery surface to the battery interior. The charging and discharging current of the battery mainly affects the internal temperature of the battery, and the heat conduction direction is transferred from the inside of the battery to the outside of the battery. Inaccurate detection of battery temperature performance status may lead to abnormal conditions such as overheating or even thermal runaway of the battery, resulting in unstable battery operation, unsafe operation and even fire. In general, the surface temperature of the battery is inconsistent with the internal temperature of the battery. The battery temperature detection of the present invention is to evaluate the overall temperature performance of the battery in combination with the external temperature and the internal temperature of the battery.

As a new type of high-energy battery successfully developed in the 20th century, power lithium battery has the advantages of high energy, high battery voltage, wide operating temperature range, and long storage life. It has entered a large-scale practical stage and is widely used in electronics, artificial satellites, Aerospace, new energy vehicles and energy storage. Large-capacity lithium batteries have been tried in electric vehicles and become one of the main power sources of electric vehicles in the 21st century. The detection of the temperature performance status of power lithium batteries is an important part of the battery management system. Due to the layered structure of the power lithium battery, the battery temperature affects the diffusion of lithium ions and the transfer process of the charge. During the charging and discharging process of the lithium battery, the lithium intercalation states of the internal electrode materials of the battery are different, resulting in changes in battery parameters and elastic modulus. According to the elastic wave The theory of propagation in saturated porous media states that this change will produce different acoustic propagation characteristics. Since the ultrasonic detection parameters are directly related to the internal material properties of the battery, and the internal material properties of the battery are directly related to the temperature, these parameters are related to the internal temperature of the battery, and are also related to the battery power (SOC) and battery capacity (SOH). There is a certain correlation between them. Therefore, the internal temperature value of the battery can be estimated by applying the ultrasonic detection parameters. In the specific embodiment of the present invention, a power lithium-ion battery (hereinafter referred to as battery) can be selected as the detection object of the overall temperature detection method, and the internal temperature of the battery is detected based on the ultrasonic transmission detection technology. It can be understood that other battery types, such as nickel-cadmium batteries, lead-acid batteries, etc., may also be used in specific embodiments.

Further, in order to detect the internal changes of the battery and facilitate the detection of the internal temperature of the battery, as an embodiment, an ultrasonic detection device is designed in this embodiment, as shown in FIG. 3 . The ultrasonic transmitting end is attached to one side of the battery to be tested. The first ultrasonic receiving end is attached to the same side of the battery to be detected as the transmitting end and is spaced apart at a certain distance, and is parallel to the transmitting end. The second ultrasonic receiving end is attached to the opposite side of the transmitting end and is aligned with the center at the same time, so that the ultrasonic model component in the horizontal direction of the battery and the ultrasonic signal component data in the vertical direction passing through the battery can be detected respectively. . The shape of the battery may be cylindrical or square, and the present invention does not limit the shape of the battery to be tested. Detection characteristic parameters such as time-of-flight, maximum amplitude and intensity can be extracted through the ultrasonic signals of the ultrasonic transmitter and receiver. -R, resonant frequency 9khz). A single-pulse sinusoidal excitation signal with a frequency range of 25-30kHz is given to the ultrasonic transmitter. Due to the different lithium intercalation states of the electrode materials inside the battery at different temperatures, the battery parameters and elastic modulus change, thus affecting the ultrasonic wave inside the battery. The propagation speed and amplitude will be attenuated to some extent. The ultrasonic signal reflected back after passing through the battery to be tested is received on the side of the first ultrasonic receiving end. At the same time, the ultrasonic signal transmitted through the battery to be tested is collected by the second ultrasonic receiving end on the opposite side. The transmitted ultrasonic signal passing through the battery to be tested and the reflected ultrasonic signal reflected back are collected comprehensively, and the ultrasonic signal carrying the temperature and battery state of the battery to be detected is collected to the greatest extent possible. The ultrasonic signals received by the two ultrasonic receiving ends are amplified by the signal amplifier and then input to the microcontroller, and the received acoustic data is sent to the battery overall temperature detection device through the microcontroller, wherein the received acoustic data is simply passed through the battery overall temperature detection device. After processing, acoustic data including ultrasonic time-of-flight (ToF), maximum amplitude and intensity are obtained. In this embodiment, the ultrasonic data is extracted by feature extraction, and the time-of-flight of the first ultrasonic receiving end and the flight time of the second ultrasonic receiving end are extracted as the internal temperature of the battery. reference data. Those skilled in the art can understand that the detection data of one or more ultrasonic receiving ends can also be selected, and even other ultrasonic parameters or combinations of other ultrasonic parameters can be selected as the reference data of the internal temperature of the battery. specific restrictions.

Step S20, obtaining the power and external temperature of the battery;

The state of charge (SOC, State of Charge) of the battery is the state of charge, also known as the remaining power. It is a parameter that reflects the percentage of the current battery capacity to the total available capacity. It is numerically defined as the ratio of the remaining capacity to the total battery capacity, commonly expressed as a percentage , and its value range is 0 to 1. When SOC=0, it means that the battery is fully discharged, and when SOC=1, it means that the battery is fully charged. When the SOC state is high, the reactivity of the positive and negative electrode materials will increase and the thermal stability will decrease. Therefore, while detecting the internal temperature of the battery according to the ultrasonic data, the present invention also considers the influence of the battery power, and the battery The capacity is used as a reference factor for evaluating the internal temperature of the battery. The method of collecting battery power can be to use a charge and discharge tester, or to obtain the battery SOC value by open circuit voltage method, ampere-hour integration method, internal resistance method, Kalman filter method or neural network method. In the present invention, the external temperature of the battery refers to the temperature of the external surface of the battery, not the temperature of the surrounding environment outside the battery, which can be obtained directly from an infrared thermal imager or through a temperature sensor attached to the surface of the battery.

Step S30, obtaining the calculated internal temperature of the battery according to the ultrasonic detection data and the power;

There is a nonlinear relationship between the ultrasonic detection data and the internal temperature of the battery. By building a mathematical model of the ultrasonic acoustic data and the internal temperature of the battery, the model can be used to directly detect the internal temperature of the battery in the actual application process. In this embodiment, the ultrasonic flight time and battery power are used as input data, and the calculated internal temperature of the battery is obtained by the following calculation formula according to the first ultrasonic flight time and the second flight time and the battery power:

t=f(D1 _ToF , D2 _ToF , SOC; a)

=a ₀ +a ₁ D1 _ToF +a ₂ D2 _ToF +a ₃ SOC+a ₄ D1 _ToF SOC+a ₅ D2 _ToF SOC+a ₆ D1 _ToF ² +a ₇ D2 _ToF ² +a ₈ SOC ²

Among them, t is the calculated internal temperature of the battery; a is the set of coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , a ₈ , a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are constants; D1 _ToF is the first ultrasonic flight time; D2 _ToF is the second ultrasonic flight time; SOC is the battery power.

The above calculation formula is a ternary quadratic function of the internal temperature of the battery with respect to the first ultrasonic flight time, the second flight time and the battery power. It can be understood that in specific embodiments, other parameters can also be selected to construct a functional formula of the internal temperature. The function formula Not limited to ternary nor limited to quadratic.

The value of the coefficient a can be obtained by fitting according to the real sampling data of the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the internal temperature of the battery with a sufficient sample size. It is specially reminded that the sampled data should be as rich and comprehensive as possible, covering as much as possible ultrasonic data of different power levels and different temperatures. At the same time, when sampling experiments, it is necessary to pay attention to the rationality of the temperature to prevent battery failure due to excessive temperature. Even security incidents. For example, by adjusting the incubator to change the ambient temperature of the experimental battery, thereby indirectly changing the internal temperature and external temperature of the experimental battery, and using the charge and discharge tester to make the experimental battery at different SOC values, obtain the actual internal temperature of the experimental battery at this time. , external temperature, battery level, and ultrasonic flight time. Since the experimental battery is not in working state at this time, by placing the experimental battery in the incubator for a sufficient time, the temperature set by the incubator can be used as the actual internal temperature and external temperature of the battery, or the battery can be measured by a temperature sensor. true temperature. In this way, the ultrasonic detection data and battery surface temperature data of the battery at different internal temperatures and different SOC values can be obtained. According to multiple sets of real data, the nonlinear least squares method is used to fit the calculation formula of the internal temperature, so as to obtain the formula of The value of the coefficient a.

Specifically, establish the real battery internal temperature and the objective function formula of the calculation formula:

为偏导数符号；n为采样个数；i为采样点；i＝1,2，…，n；

为第i次采样时根据采样的第一超声波飞行时间D1_ToFi、第二超声波飞行时间D2_ToFi、电量SOC_i计算得到的内部温度；TI_i为第i次采样时真实的电池内部温度。Among them, TI is the actual internal temperature of the battery; L is the objective function formula of the actual internal temperature of the battery and the calculated internal temperature of the battery,

is the partial derivative symbol; n is the number of samples; i is the sampling point; i=1,2,...,n;

is the internal temperature calculated according to the sampled first ultrasonic flight time D1 _ToFi , second ultrasonic flight time D2 _ToFi , and power SOC _i during the ith sampling; TI _i is the actual internal temperature of the battery during the ith sampling.

Calculate the partial derivative of each coefficient a in the objective function formula. In order to optimize the objective function, make the partial derivative value equal to 0, and obtain the linear equation of the partial derivative of the coefficient a:

Substitute multiple sets of data of the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature into the linear equation, and then the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ can be calculated respectively. The values of , a ₅ , a ₆ , a ₇ , and a ₈ .

Further, simplify the above linear equation to get:

Written in matrix form to get XA=Y, where,

Using the Gaussian elimination method to solve A, the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ can be obtained.

Further, after obtaining the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ into the formula for calculating the internal temperature, it is also necessary to calculate the internal temperature according to the following formula is evaluated by the formula to measure the deviation between the calculated value and the true value:

Among them, RESE is the root mean square error, TI is the actual internal temperature of the battery, n is the number of samples, i is the sampling point, i=1,2,...,n.

If the calculated RESE value, that is, the deviation between the calculated value and the actual value, is small and meets the specified range, it is considered that the value of the coefficient a is reasonable and the internal temperature calculation formula is valid; if the deviation between the calculated value and the real value is large , exceeding the specified deviation range, it means that the internal temperature calculated by the formula is very different from the real internal temperature, and the value of a is unreasonable. You can obtain more sample data or change the sampling method and sampling data. The fitting calculation is performed by taking the value until the specified deviation range is met.

Step S40, calculating the overall temperature of the battery according to the calculated internal temperature and the external temperature

Through step S30, this embodiment establishes the relationship between the internal temperature of the battery, the ultrasonic data and the battery power, and obtains the value of the coefficient in the relationship by fitting the real data. In practical applications, it can be directly calculated by using the functional relationship. The internal temperature of the battery is combined with the external temperature of the battery obtained in step S20 to evaluate the overall temperature of the battery.

Further, in this embodiment, the external temperature and internal temperature of the battery are calculated according to the formula T=mTR+(1-m)t to obtain the overall temperature of the battery; where T is the overall temperature of the battery, TR is the external temperature of the battery, and t is the battery. Internal temperature, m is the weight of the external temperature of the battery, 1-m is the weight of the internal temperature of the battery, 0≤m≤1, m can be evaluated and formulated based on expert opinions. In a specific embodiment, other algorithms may also be selected to obtain the overall temperature of the battery, which will not be repeated here.

In this embodiment, the internal temperature of the battery is calculated by collecting the ultrasonic data of the battery, and the overall temperature of the battery is comprehensively evaluated in combination with the collected external temperature of the battery. Both the external temperature of the battery and the internal temperature of the battery are considered, so that the battery temperature evaluation is more comprehensive and accurate. An important basis for improving battery thermal runaway warning. This embodiment also provides a mathematical model of the quadratic equation of the internal temperature with respect to the ultrasonic flight time and battery power, and obtains the formula coefficient by fitting the internal temperature formula with real data, and then uses the root mean square error formula to compare the internal temperature formula Evaluate and optimize the formula algorithm to make the algorithm more accurate.

In addition, an embodiment of the present invention also provides a computer-readable storage medium. The computer-readable storage medium stores a battery overall temperature detection program. When the battery overall temperature detection program is executed by a processor, the following operations are implemented:

Collect the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery casing;

obtain the power and external temperature of the battery;

Obtain the calculated internal temperature of the battery according to the ultrasonic detection data and the power;

According to the calculated internal temperature and the external temperature, the overall temperature of the battery is calculated.

Further, the ultrasonic detection data includes the first ultrasonic data and the second ultrasonic data, and when the overall temperature detection program of the battery is executed by the processor, the following operations are also implemented:

According to the first ultrasonic flight time and the second ultrasonic flight time and the battery power in the first ultrasonic data and the second ultrasonic data, and calculate the calculated internal temperature of the battery by the following formula:

Among them, t is the calculated internal temperature of the battery; a is the set of coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , a ₈ , a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are constants; D1 _ToF is the first ultrasonic flight time; D2 _ToF is the second ultrasonic flight time; SOC is the battery power.

Further, the value of the coefficient a in the formula for calculating the internal temperature can be obtained by fitting according to multiple groups of real data, and the steps of calculating and obtaining the value of the coefficient a in the calculation formula according to the multiple groups of real data include:

Obtain the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature of the plurality of groups of the batteries;

Calculate the formula according to the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and obtain the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , The values of a ₆ , a ₇ , and a ₈ .

Further, when the battery overall temperature detection program is executed by the processor, the following operations are also implemented:

Establish the objective function formula for the real battery internal temperature and the stated formula:

Calculate the partial derivative of each coefficient a in the objective function formula, make the value of the partial derivative equal to 0, and obtain the linear equation of the partial derivative of the coefficient a:

Substitute multiple sets of data of the first ultrasonic flight time, the second ultrasonic flight time, electric quantity and real internal temperature into the linear equation, and calculate the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a respectively ₅ , a ₆ , a ₇ , and the values of a ₈ ;

为偏导数符号，n为采样个数，i为采样点，i＝1,2，…，n。Among them, TI is the actual internal temperature of the battery, L is the objective function formula of the actual internal temperature of the battery and the calculated internal temperature of the battery,

is the partial derivative symbol, n is the number of samples, i is the sampling point, i=1, 2, ..., n.

Further, when the battery overall temperature detection program is executed by the processor, the following operations are also implemented:

According to the linear equation of the partial derivative of the coefficient a, we get:

Simplify the above equation into matrix form to get XA=Y, where,

The Gaussian elimination method is used to solve A, and the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are calculated respectively.

Further, when the battery overall temperature detection program is executed by the processor, the following operations are also implemented:

Calculate the overall temperature of the battery according to the formula T=mTR+(1-m)t;

Among them, T is the overall temperature of the battery, TR is the external temperature of the battery, t is the internal temperature of the battery, m is the weight of the external temperature of the battery, 1-m is the weight of the internal temperature of the battery, 0≤m≤1.

Further, when the battery overall temperature detection program is executed by the processor, the following operations are also implemented:

The formula for calculating the internal temperature is evaluated according to the following formula to measure the deviation between the calculated value and the true value:

Among them, RESE is the root mean square error, TI is the actual internal temperature of the battery, n is the number of samples, i is the sampling point, i=1,2,...,n.

Further, the ultrasonic detection device includes an ultrasonic transmitting end, a first ultrasonic receiving end and a second ultrasonic receiving end, the first ultrasonic receiving end is arranged on the same side of the battery casing as the ultrasonic transmitting end, and the second ultrasonic receiving end is The receiving end is arranged on the opposite side of the battery shell and the ultrasonic transmitting end. When the battery overall temperature detection program is executed by the processor, the following operations are also implemented:

Collect the first ultrasonic data of the first ultrasonic receiving end of the battery and the second ultrasonic data of the second ultrasonic receiving end of the battery through the ultrasonic detection device arranged on the battery casing;

Feature extraction is performed on the first ultrasonic data and the second ultrasonic data, and the first ultrasonic time-of-flight and the second ultrasonic time-of-flight are extracted.

The specific embodiments of the computer-readable storage medium of the present invention are basically the same as the above-mentioned embodiments of the method for detecting the overall temperature of the battery, and are not repeated here.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or system comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or system. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article or system that includes the element.

The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages or disadvantages of the embodiments.

From the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus a necessary general hardware platform, and of course hardware can also be used, but in many cases the former is better implementation. Based on this understanding, the technical solutions of the present invention can be embodied in the form of software products in essence or the parts that make contributions to the prior art. The computer software products are stored in a storage medium (such as ROM/RAM) as described above. , magnetic disk, optical disk), including several instructions to make a terminal device (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the methods described in the various embodiments of the present invention.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields , are similarly included in the scope of patent protection of the present invention.

Claims (7)

1. A method for detecting the overall temperature of a battery, wherein the method for detecting the overall temperature of the battery comprises: Collect the ultrasonic detection data of the battery through the ultrasonic detection device arranged on the battery casing; obtain the power and external temperature of the battery; Obtain the calculated internal temperature of the battery according to the ultrasonic detection data and the power; Calculate the overall temperature of the battery according to the calculated internal temperature and the external temperature; The ultrasonic detection data includes first ultrasonic data and second ultrasonic data, and the step of obtaining the calculated internal temperature of the battery according to the ultrasonic detection data and the power level includes: According to the first ultrasonic flight time and the second ultrasonic flight time and the battery power in the first ultrasonic data and the second ultrasonic data, and the calculated internal temperature of the battery is calculated by the following formula:

Among them, t is the calculated internal temperature of the battery; a is the set of coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , a ₈ , a ₀ , a ₁ , a ₂ , a3, _{a4, a5, a6, a7, a8 are constants; D1 ToF is the first ultrasonic flight time; D2 ToF is the second ultrasonic flight time ;} SOC is the battery power; The value of the coefficient a in the formula for calculating the internal temperature can be obtained by fitting and calculating according to multiple groups of real data, and the steps of calculating and obtaining the value of the coefficient a in the formula according to the multiple groups of real data include: Obtain the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature of the plurality of groups of the batteries; Calculate the formula according to the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and obtain the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , The values of a ₆ , a ₇ , and a ₈ ; The formula is calculated according to the multiple groups of the first ultrasonic flight time, the second ultrasonic flight time, the electric quantity and the real internal temperature, and the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , and a are obtained respectively. The steps of obtaining values of ₅ , a ₆ , a ₇ , and a ₈ include: Establish the objective function formula for the real battery internal temperature and the stated formula:

Calculate the partial derivative of each coefficient a in the objective function formula, make the value of the partial derivative equal to 0, and obtain the linear equation of the partial derivative of the coefficient a:

Substitute multiple sets of data of the first ultrasonic flight time, the second ultrasonic flight time, electric quantity and real internal temperature into the linear equation, and calculate the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a respectively ₅ , a ₆ , a ₇ , and the values of a ₈ ; Among them, TI is the actual internal temperature of the battery, L is the objective function formula of the actual internal temperature of the battery and the calculated internal temperature of the battery,

is the partial derivative symbol, n is the number of samples, i is the sampling point, i=1, 2, ..., n. 2. The battery temperature detection method according to claim 1, wherein the data of the first ultrasonic time-of-flight, the second ultrasonic time-of-flight, electric quantity and true internal temperature of multiple groups are substituted into the linear equation, The steps of calculating the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ respectively include: According to the linear equation of the partial derivative of the coefficient a, we get:

Simplify the above equation into matrix form to get XA=Y, where,

A=(a ₀ a ₁ ...a ₈ ) ^T ,

The Gaussian elimination method is used to solve A, and the values of the coefficients a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , a ₆ , a ₇ , and a ₈ are calculated respectively. 3. The battery temperature detection method according to claim 1, wherein the step of calculating the overall temperature of the battery according to the calculated internal temperature and the external temperature comprises: Calculate the overall temperature of the battery according to the formula T=mTR+(1-m)t; Among them, T is the overall temperature of the battery, TR is the external temperature of the battery, t is the internal temperature of the battery, m is the weight of the external temperature of the battery, 1-m is the weight of the internal temperature of the battery, 0≤m≤1. 4. The battery temperature detection method according to claim 1, wherein after the step of obtaining the calculated internal temperature of the battery by formula calculation, the method further comprises evaluating the formula for calculating the internal temperature according to the following formula, To measure the deviation between the calculated value and the true value:

Among them, RESE is the root mean square error, TI is the actual internal temperature of the battery, n is the number of samples, i is the sampling point, i=1,2,...,n. 5. The battery temperature detection method according to claim 1, wherein the ultrasonic detection device comprises an ultrasonic transmitting end, a first ultrasonic receiving end and a second ultrasonic receiving end, and the first ultrasonic receiving end is arranged on the battery. The outer casing is on the same side as the ultrasonic transmitting end, the second ultrasonic receiving end is arranged on the opposite side of the battery casing and the ultrasonic transmitting end, and the ultrasonic detection device of the battery casing is used to collect the ultrasonic detection of the battery. The data steps also include: Collect the first ultrasonic data of the first ultrasonic receiving end of the battery and the second ultrasonic data of the second ultrasonic receiving end of the battery through the ultrasonic detection device arranged on the battery casing; Feature extraction is performed on the first ultrasonic data and the second ultrasonic data, and the first ultrasonic time-of-flight and the second ultrasonic time-of-flight are extracted. 6. A battery overall temperature detection device, characterized in that, the battery overall temperature detection device comprises: a memory, a processor, and a battery overall temperature detection program stored on the memory and running on the processor, When the overall temperature detection program of the battery is executed by the processor, the steps of the method for detecting the overall temperature of the battery according to any one of claims 1 to 5 are implemented. 7. A computer-readable storage medium on which a battery overall temperature detection program is stored, characterized in that, when the battery overall temperature detection program is executed by a processor, the battery according to any one of claims 1 to 5 is implemented. Steps of the overall temperature detection method.

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