Battery multi-source temperature detection method and device

Abstract

The invention relates to the technical field of battery temperature detection, and particularly discloses a battery multi-source temperature detection method and device. According to the method, after a battery management system is awakened through an external controller, a dynamic temperature attenuation model is adopted to predict the initial battery temperature in combination with historical dormancy duration and temperature data, and the initial battery temperature is output before an acquisition board card is ready, so that the problem that the initial temperature of a traditional system is invalid is solved. During the operation period of the system, a three-level temperature source switching strategy is adopted: data of a collection board card is preferentially selected; the sampling probe is switched to when the operation is abnormal; and when the set working duration and the dormancy condition are met, the battery temperature is calculated based on the main control board temperature compensation model. Wherein the temperature attenuation model and the compensation model dynamically update a heat dissipation coefficient and a temperature rise proportion parameter through a recursive algorithm to adapt to battery aging and environment change. According to the method, rapid presumption of the system temperature, multi-source redundant fault tolerance and model self-optimization are realized, and the system reliability and the temperature estimation precision are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery temperature detection, and particularly relates to a battery multi-source temperature detection method and device. Background Art

[0002] In the existing battery management system, the detection of battery temperature is usually achieved by arranging multiple temperature probes in the battery pack. Direct connection to the main control board of the battery management system (BMS) requires a large number of analog-to-digital conversion channels, and the hardware design of the BMS main control board usually cannot meet such a large number of input requirements. Therefore, all temperature probes are connected to a dedicated acquisition board. After the acquisition board is powered on, it centrally acquires and processes temperature data, and then transmits the temperature value to the battery management system (BMS) for processing through an internal communication bus. However, it has the following significant defects:

[0003] 1. Since the acquisition board needs to complete operations such as hardware initialization, multi-channel probe data acquisition, and filtering processing, it cannot immediately output valid temperature values after the system is powered on. During this period, the BMS is forced to be in a waiting state, resulting in an extended overall power-on time of the battery system. More seriously, the initial temperature value sent by the BMS to the external bus during the waiting stage is usually an invalid default value, which may cause misjudgment by downstream controllers and even trigger error protection actions.

[0004] 2. In the prior art, battery temperature detection completely depends on the normal operation of the acquisition board. Once the acquisition board fails due to hardware failure, communication interruption, or software crash, the BMS will immediately lose all temperature information and cannot judge the safety status of the battery, such as over-temperature and low-temperature charging, seriously threatening the operation safety of the battery system.

[0005] Therefore, how to provide effective temperature estimation before the acquisition board is ready and maintain basic temperature detection ability after its failure is an urgent problem to be solved in the current art. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention proposes a battery multi-source temperature detection method and device to solve the technical problem that the battery temperature cannot be obtained before the acquisition board is ready / after the acquisition board fails in the prior art.

[0007] The technical solution adopted by the present invention is a multi-source temperature detection method for batteries. In the first implementable manner, the method includes: waking up the battery management system according to the control signal of an external controller; compensating according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature; outputting the current predicted battery temperature as the battery temperature to the external controller; judging whether the sleep condition of the battery management system is satisfied according to the control signal of the external controller; if the sleep condition is not satisfied, collecting the current battery temperature; outputting the current battery temperature to the external controller; if the sleep condition is satisfied, storing the battery temperature and going to sleep.

[0008] Further, the compensation according to the state of the battery management system before the last sleep includes: obtaining the sleep duration; obtaining the battery temperature at the last sleep; storing the sleep duration and the battery temperature at the last sleep as historical data; dynamically adjusting a preset temperature decay model according to the historical data; inputting the sleep duration and the battery temperature at the last sleep into the temperature decay model to calculate the current predicted battery temperature.

[0009] Preferably, the temperature decay model is:

[0010]

[0011] wherein, T(t) represents the current predicted battery temperature, T env represents the room temperature, T0 represents the battery temperature at the last sleep, P self represents the heat generation power of the battery self-discharge, k represents the heat dissipation coefficient, C represents the heat capacity of the battery pack, and e represents the natural constant.

[0012] Further, the dynamically adjusting the preset temperature decay model according to the historical data includes: establishing a historical data sequence of the sleep duration and the battery temperature at the last sleep according to the historical data; updating the heat dissipation coefficient k in the temperature decay model using a recursive algorithm according to the historical data sequence to obtain a dynamically adjusted temperature decay model.

[0013] Further, the step of collecting the current battery temperature includes: receiving the battery temperature collected by the acquisition board card; determining whether the battery temperature collected by the acquisition board card is normal; if so, directly using the temperature collected by the acquisition board card as the battery temperature; if not, receiving the sampled battery temperature; determining whether the sampled battery temperature is normal; if so, using the sampled battery temperature as the battery temperature; if not, obtaining the working duration of the battery management system; determining whether the working duration of the battery management system is less than a first set value; if not, increasing the temperature acquisition failure count by 1; if so, obtaining the sleep duration and determining whether the sleep duration is less than a second set value; if not, returning to the step of increasing the temperature acquisition failure count by 1; if so, receiving the temperature of the main control board of the battery management system; determining whether the temperature of the main control board of the battery management system is normal; if not, returning to the step of increasing the temperature acquisition failure count by 1; if so, using the temperature of the main control board of the battery management system as the battery temperature.

[0014] Further, after the step of increasing the temperature acquisition failure count by 1, it further includes: determining whether the temperature acquisition failure count is greater than a third set value; if so, the battery management system outputs a temperature acquisition failure signal; returning to the step of receiving the battery temperature collected by the acquisition board card; if the temperature acquisition failure count is less than the third set value, returning to the step of receiving the battery temperature collected by the acquisition board card.

[0015] Further, the step of receiving the temperature of the main control board of the battery management system includes: obtaining the temperature of the main control board of the battery management system; inputting the temperature of the main control board of the battery management system into the temperature compensation model to calculate the current compensated battery temperature; using the compensated battery temperature as the battery temperature.

[0016] Preferably, the temperature compensation model is:

[0017] T(t) = T env + r·(T PCB - T env ) + β·t work

[0018] where T(t) represents the compensated battery temperature, T PCB represents the temperature of the main control board of the battery management system, T env represents the room temperature, r represents the temperature rise ratio coefficient, β represents the time accumulation coefficient, and t work represents the working duration of the battery management system.

[0019] Combined with the first implementation method, in the second implementation method, the present invention provides a multi-source temperature detection device for a battery. The device includes: a temperature probe that collects the battery temperature and outputs it to a collection board; the collection board filters the input signal of the temperature probe to generate first temperature data and outputs it to a battery management system; a sampling temperature probe that samples the local battery temperature to generate second temperature data and outputs it to the battery management system; the battery management system obtains the temperature of the main control board of the battery management system to generate third temperature data; the battery management system processes the first temperature data, the second temperature data, and the third temperature data and outputs them to an external controller.

[0020] Furthermore, the power management system includes: a wake-up module for waking up the battery management system according to a control signal from an external controller; a compensation module for compensating according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature as the battery temperature; a sleep module for controlling whether the system sleeps according to a control signal from an external controller; a temperature acquisition module for sequentially determining whether to receive the battery temperature collected by the collection board, the sampled battery temperature, and the temperature of the main control board of the battery management system, and using them as the battery temperature; an output module for outputting the battery temperature to an external controller; and a storage module for storing the sleep duration, the battery temperature, and the working time.

[0021] It can be seen from the above technical solutions that the beneficial technical effects of the present invention are as follows:

[0022] 1. After the BMS is powered on, during the initialization stage of the collection board, the estimated temperature value can be quickly output based on the temperature decay model without waiting for the collection board to be ready. The initial estimated temperature value replaces the invalid default value, ensuring the reliability of the external bus data and preventing the downstream controller from misjudging and causing an emergency shutdown.

[0023] 2. By dynamically updating the heat dissipation coefficient k model parameters and automatically adjusting them according to the thermal characteristics of the battery pack, it adapts to battery aging and environmental changes, further improving the accuracy of temperature estimation.

[0024] 3. The three-level temperature detection source switching strategy of collection board data - sampling probe - main control board temperature compensation can ensure that when the collection board fails due to hardware failure, communication interruption, or software crash, the BMS will not immediately lose all temperature information, improving the fault tolerance of the system. Description of the Drawings

[0025] In order to more clearly illustrate the specific implementation manners of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific implementation manners or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0026] Figure 1 Schematic flow chart of a multi-source battery temperature detection method provided by an embodiment of the present invention;

[0027] Figure 2 Schematic flow chart of collecting the current battery temperature provided by an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of a multi-source battery temperature detection device provided by an embodiment of the present invention. Detailed implementation manners

[0029] Hereinafter, embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and thus are only examples and cannot be used to limit the protection scope of the present invention.

[0030] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those skilled in the art to which the present invention belongs.

[0031] In one embodiment, as Figure 1 shown, it is a schematic flow chart of a multi-source battery temperature detection method provided by an embodiment of the present invention, and the method includes:

[0032] Wake up the battery management system according to the control signal of the external controller; perform compensation according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature; output the current predicted battery temperature to the external controller; judge whether the sleep condition of the battery management system is satisfied according to the control signal of the external controller; if the sleep condition is not satisfied, collect the current battery temperature; output the battery temperature to the external controller; if the sleep condition is satisfied, store the battery temperature and go to sleep.

[0033] Performing compensation according to the state of the battery management system before the last sleep specifically includes the following steps:

[0034] Obtain the sleep duration; obtain the battery temperature at the last sleep; store the sleep duration and the battery temperature at the last sleep as historical data; dynamically adjust the preset temperature decay model according to the historical data; input the sleep duration and the battery temperature at the last sleep into the temperature decay model to calculate the current predicted battery temperature, and the temperature decay model is:

[0035]

[0036] wherein, T(t) represents the current predicted battery temperature, T env represents the room temperature, T0 represents the battery temperature at the last sleep, Pself where \(P\) represents the heat generation power due to self - discharge of the battery, \(k\) represents the heat dissipation coefficient, \(C\) represents the heat capacity of the battery pack, and \(e\) represents the natural constant.

[0037] It should be noted that dynamically adjusting the preset temperature decay model according to the historical data includes establishing a historical data sequence of the dormancy duration and the battery temperature at the previous dormancy according to the historical data.

[0038] Updating the heat dissipation coefficient \(k\) in the temperature decay model using the recursive least - squares method according to the historical data sequence to obtain a dynamically adjusted temperature decay model, and fitting the historical dormancy data using the recursive least - squares method to optimize the parameters of the temperature decay model is prior art, so it will not be elaborated here.

[0039] In this embodiment, the estimated temperature value can be quickly output based on the temperature decay model during the initialization stage of the acquisition board card without waiting for the acquisition board to be ready. The initial estimated temperature value replaces the invalid default value to ensure the reliability of the external bus data and prevent the downstream controller from misjudging and causing an emergency shutdown.

[0040] In this embodiment, as Figure 2 shown, it is a schematic flowchart of a method for acquiring the current battery temperature provided by an embodiment of the present invention, including:

[0041] Receiving the battery temperature collected by the acquisition board card; judging whether the battery temperature collected by the acquisition board card is normal; if so, directly using the temperature collected by the acquisition board card as the battery temperature; if not, receiving the sampled battery temperature.

[0042] Judging whether the sampled battery temperature is normal; if so, using the sampled battery temperature as the battery temperature; if not, obtaining the working duration of the battery management system.

[0043] Judging whether the working duration of the battery management system is less than a first set value; if not, incrementing the temperature acquisition failure count by 1; if so, obtaining the dormancy duration and judging whether the dormancy duration is less than a second set value; if not, returning to the step of incrementing the temperature acquisition failure count by 1; if so, receiving the temperature of the main control board of the battery management system.

[0044] Judging whether the temperature of the main control board of the battery management system is normal; if not, returning to the step of incrementing the temperature acquisition failure count by 1; if so, using the temperature of the main control board of the battery management system as the battery temperature.

[0045] After the step of incrementing the temperature acquisition failure count by 1, the method further includes the following steps:

[0046] Determine whether the number of times of temperature acquisition failure is greater than the third set value; if so, the battery management system outputs a temperature acquisition failure signal; return to the step of receiving the battery temperature collected by the acquisition board.

[0047] If the number of times of temperature acquisition failure is less than the third set value, return to the step of receiving the battery temperature collected by the acquisition board.

[0048] Receive the temperature of the main control board of the battery management system, specifically including the following steps:

[0049] Obtain the temperature of the main control board of the battery management system; input the temperature of the main control board of the battery management system into the temperature compensation model to calculate the current compensated battery temperature; use the compensated battery temperature as the battery temperature.

[0050] The temperature compensation model used in this embodiment is:

[0051] T(t) = T env + r·(T PCB - T env ) + β·t work

[0052] Among them, T(t) represents the compensated battery temperature, T PCB represents the temperature of the main control board of the battery management system, T env represents the room temperature, r represents the temperature rise ratio coefficient, β represents the time accumulation coefficient, t work represents the working duration of the battery management system. Therefore, β·t work is the additional temperature rise generated by the battery operation per unit time.

[0053] The time accumulation coefficient β is used to represent the temperature rise rate per unit time of the battery due to internal heat generation in the working state:

[0054]

[0055] The time accumulation coefficient β can be obtained by recording the temperature and time data of the battery during constant current charge and discharge under experimental conditions and through linear regression analysis and calculation, which will not be elaborated here.

[0056] The temperature rise ratio coefficient r represents the ratio of the temperature rise rates of the main control board of the battery management system and the battery under the same conditions, that is, the correlation between the temperature rise rates of the main control board and the battery:

[0057]

[0058] The temperature rise ratio coefficient r can be obtained by simultaneously recording the temperature and time data of the main control board and the battery during constant current charge and discharge under experimental conditions and calculating through linear regression fitting. It should be noted that the temperature rise ratio coefficient r is only applicable when the working duration of the battery management system is less than the first set value and the sleep duration is greater than the second set value. In this embodiment, the first set value is 10 seconds and the second set value is 8 hours.

[0059] If the system has been in a long-term sleep state (the second set value), the battery and the main control board have cooled to the ambient temperature. After being awakened again, the two start to heat up synchronously from the same temperature. At this time, within a short period (the working duration of the system is less than the first set value), the temperature rise rates of the two can be approximately considered linearly related. After the system has been working for a period of time, the battery generates significant self-heating due to high-current operation, and its temperature rise rate accelerates. The temperature rise of the main control board mainly comes from the chip power consumption, and the correlation between the temperature rises of the two decreases. Moreover, indirectly reflecting the temperature of the battery through the temperature of the main control board by the power management system is itself a redundant fault-tolerant design and does not require measuring the temperature in this way during the long operation of the system. Therefore, the role of the first set value is to exit the indirect measurement mode based on the temperature of the main control board after this time node to avoid cumulative errors caused by differences in the temperature rise curves.

[0060] If the sleep duration of the system is too short, and any one of the battery and the main control board is in a different temperature reduction stage, it will cause the deviation of the temperature rise curves of the two from the critical point, resulting in the inapplicability of the temperature compensation model. Further, if the temperature compensation model is introduced to describe the temperature of the battery and the main control board at this time, it will be seriously interfered by the residual heat during sleep, significantly increasing the error of temperature judgment. Therefore, it is necessary to set the second set value according to the heat capacity characteristics of the battery pack so that it is not less than the time required for the battery pack to naturally cool from the working temperature to the ambient temperature.

[0061] Further, the third set value determines the number of cycles for the system to switch the three-level temperature detection source. For example, in this embodiment, the third set value is set to 100 times. After exceeding 100 times, it is determined as a failure and a maintenance signal is triggered to avoid the system falling into an infinite retry loop and delaying control decisions.

[0062] In one embodiment, a device for multi-source temperature detection of a battery provided by the present invention, as Figure 3 shown, includes:

[0063] Multiple groups of temperature probes are used to collect battery temperatures and output them to the acquisition board. Each group of temperature probes is connected to its corresponding acquisition board through a temperature acquisition line and outputs temperature information. The acquisition board filters the temperature information to generate first temperature data and outputs it to the battery management system. In this embodiment, a sampling temperature probe is further included. Limited by the limited number of I / O ports on the main control board of the power management system, a total of 2 sampling temperature probes are set to sample the local battery temperature, generate second temperature data and output it to the battery management system. The battery management system obtains the temperature of the main control board of the battery management system, generates third temperature data, and processes the first temperature data, the second temperature data, and the third temperature data and outputs them to an external controller.

[0064] In this embodiment, the system specifically includes: a wake-up module for waking up the battery management system according to the control signal of the external controller; a compensation module for compensating according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature as the battery temperature; a sleep module for controlling whether to sleep according to the control signal of the external controller; a temperature acquisition module for sequentially determining to receive the temperatures of the acquisition board, the sampling interface of the battery management system, and the battery management system as the battery temperature; an output module for outputting the battery temperature to the external controller; and a storage module for storing the sleep duration, the battery temperature, and the working time.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A multi-source temperature detection method for a battery, characterized in that, It includes: Wake up the battery management system according to the control signal of the external controller; Compensate according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature; Output the current predicted battery temperature to the external controller as the battery temperature; Judge whether the sleep condition of the battery management system is satisfied according to the control signal of the external controller; If the sleep condition is not satisfied, collect the current battery temperature; Output the current battery temperature to the external controller; If the sleep condition is satisfied, store the battery temperature and go to sleep.

2. The battery multi-source temperature detection method according to claim 1, characterized in that The compensation according to the state of the battery management system before the last sleep includes: Obtain the sleep duration; Obtain the battery temperature at the last sleep; Store the sleep duration and the battery temperature at the last sleep as historical data; Dynamically adjust the preset temperature decay model according to the historical data; Input the sleep duration and the battery temperature at the last sleep into the temperature decay model to calculate the current predicted battery temperature.

3. The method for detecting the multi-source temperature of a battery according to claim 2, characterized in that, The temperature decay model is: Where T(t) represents the current predicted battery temperature, T env represents the room temperature, T0 represents the battery temperature during the last sleep state, P self represents the heat power generated by battery self-discharge, k represents the heat dissipation coefficient, C represents the heat capacity of the battery pack, and e represents the natural constant.

4. A battery multi-source temperature detection method according to any one of claims 2 or 3, characterized in that The dynamically adjusting the preset temperature decay model according to the historical data includes: Establish a historical data sequence of the sleep duration and the battery temperature at the last sleep according to the historical data; Update the heat dissipation coefficient k in the temperature decay model using a recursive algorithm according to the historical data sequence to obtain a dynamically adjusted temperature decay model.

5. A battery multi-source temperature detection method according to claim 1, characterized in that, The collecting the current battery temperature includes: Receive the battery temperature collected by the acquisition board; Judge whether the battery temperature collected by the acquisition board is normal; If it is, directly use the temperature collected by the acquisition board as the battery temperature; If not, receive the sampled battery temperature; Judge whether the sampled battery temperature is normal; If it is, use the sampled battery temperature as the battery temperature; If not, obtain the working duration of the battery management system; Judge whether the working duration of the battery management system is less than the first set value; If not, increment the temperature acquisition failure count by 1; If it is, obtain the sleep duration and judge whether the sleep duration is less than the second set value; If not, return to the step of incrementing the temperature acquisition failure count by 1; If it is, receive the temperature of the main control board of the battery management system; Judge whether the temperature of the main control board of the battery management system is normal; If not, return to the step of incrementing the temperature acquisition failure count by 1; If it is, use the temperature of the main control board of the battery management system as the battery temperature.

6. A method for multi-source temperature detection of a battery according to claim 5, characterized in that After the step of incrementing the temperature acquisition failure count by 1, it further includes: Judge whether the temperature acquisition failure count is greater than the third set value; If it is, the battery management system outputs a temperature acquisition failure signal; Return to the step of receiving the battery temperature collected by the acquisition board; If the temperature acquisition failure count is less than the third set value, return to the step of receiving the battery temperature collected by the acquisition board.

7. A multi-source temperature detection method for a battery according to claim 5, characterized in that, The receiving the temperature of the main control board of the battery management system includes: Obtain the temperature of the main control board of the battery management system.

8. Input the temperature of the main control board of the battery management system into the temperature compensation model to calculate the current compensated battery temperature; Use the compensated battery temperature as the battery temperature. A battery multi-source temperature detection method according to claim 7, wherein the temperature compensation model is: T(t) = T env + r·(T PCB - T env ) + β·t work Among them, T(t) represents the compensated battery temperature, T PCB represents the temperature of the main control board of the battery management system, T env represents the room temperature, r represents the temperature rise ratio coefficient, β represents the time accumulation coefficient, and t work represents the working duration of the battery management system.

9. A multi-source temperature detection device for a battery, characterized in that The device includes: A temperature probe that collects the battery temperature and outputs it to the acquisition board; The acquisition board filters the input signal of the temperature probe, generates first temperature data and outputs it to the battery management system; A sampling temperature probe that samples the local battery temperature, generates second temperature data and outputs it to the battery management system; The battery management system obtains the temperature of the main control board of the battery management system and generates third temperature data; the battery management system processes the first temperature data, the second temperature data and the third temperature data and outputs them to an external controller.

10. The device for multi-source temperature detection of a battery according to claim 9, characterized in that, The power management system includes: A wake-up module for waking up the battery management system according to the control signal of the external controller; A compensation module for compensating according to the state of the battery management system before the last sleep to obtain the current predicted battery temperature as the battery temperature; A sleep module for controlling whether the system sleeps according to the control signal of the external controller; A temperature acquisition module for sequentially determining whether to receive the battery temperature collected by the acquisition board, the sampled battery temperature and the temperature of the main control board of the battery management system, and using them as the battery temperature; An output module for outputting the battery temperature to an external controller; A storage module for storing the sleep duration, the battery temperature and the working time.

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