Battery low-temperature charging heating control method and management system

Abstract

The invention discloses a battery low-temperature charging heating control method and management system, and relates to the technical field of battery control. The method specifically comprises the following steps: acquiring the initial lowest temperature of the battery pack; judging whether the lowest temperature is within a pulse heating interval or not; the maximum temperature value of the pulse heating interval and the temperature rising rate corresponding to the pulse heating interval are obtained; according to the initial lowest temperature, the maximum temperature value of the pulse heating interval and the temperature rising rate corresponding to the pulse heating interval, first heating time is calculated, and the battery pack is heated according to the first heating time. The invention aims to improve the accuracy of estimating the time required for low-temperature heating of a battery when a dual-system hybrid heating mode combining liquid heating and pulse heating is adopted.

Description

Technical Field

[0001] The present invention relates to the technical field of battery control, and particularly to a battery low-temperature charging and heating control method and management system. Background Art

[0002] With the continuous adjustment of the global energy structure and the increasing requirements for energy conservation and emission reduction, new energy vehicles, as a green and environmentally friendly means of transportation, have obtained rapid development and popularization in recent years. As one of the core components of new energy vehicles, the performance of power batteries largely determines the overall performance of the vehicle. Among them, the charging characteristics and cycle life of batteries in low-temperature environments have become issues of widespread concern to vehicle manufacturers and end customers.

[0003] At present, most new energy vehicles use lithium-ion power batteries as the main carrier for electrical energy storage. The electrochemical characteristics of lithium-ion batteries determine that their charging rate in low-temperature environments will be significantly lower than that at room temperature. This is because low-temperature environments will cause the ion migration speed inside the battery to slow down, the viscosity of the electrolyte to increase, and the polarization phenomenon to intensify, thereby affecting the charging efficiency of the battery. In addition, when charging under low-temperature conditions, lithium dendrites are likely to form on the surface of the battery cathode. Long-term low-temperature charging will cause irreversible damage to the internal structure of the battery, not only shortening the cycle life of the battery, but also reducing the battery's cruising range. Therefore, how to safely and efficiently charge the power batteries of new energy vehicles in low-temperature environments is an important research topic in the current field of battery management.

[0004] In response to the above low-temperature charging problem, the technical solution commonly adopted in the industry at present is to actively heat the power battery, that is, to heat the battery with an external heat source during the low-temperature charging stage, so as to increase the internal temperature of the battery, improve the internal chemical reaction environment of the battery, and then increase the charging rate and protect the battery performance. In the existing low-temperature charging solutions, the charging process is generally divided into three consecutive stages, namely the only heating stage, the charging while heating stage, and the only charging stage. Among them, the only heating stage and the charging while heating stage are collectively referred to as the low-temperature charging stage. The sum of the time lengths of this stage and the subsequent only charging stage constitutes the total remaining charging time required for the battery to be fully charged.

[0005] However, most of the currently widely used battery heating solutions are fixed - power heating methods such as heating with a thermistor (PTC) or heating film. The existing low - temperature charging time estimation models are mainly designed for fixed - power heating methods. This fixed - power heating method has the advantages of simple control and low cost. However, with the development of battery technology, a single fixed - power heating method has gradually become difficult to meet the more flexible and efficient heating requirements. When a dual - system hybrid heating method combining liquid - heat heating and pulse heating is adopted, since its heating power and heating efficiency are jointly affected by multiple factors such as ambient temperature, battery state, fluid medium flow condition, and pulse control parameters, the existing fixed - power heating model is difficult to accurately estimate the time required for low - temperature heating, resulting in a large time error in the actual charging process.

[0006] Therefore, when a dual - system hybrid heating method combining liquid - heat heating and pulse heating is adopted, how to improve the accuracy of estimating the time required for battery low - temperature heating has become a technical problem to be solved urgently. Summary of the Invention

[0007] The main object of the present invention is to provide a battery low - temperature charging heating control method and management system, aiming to improve the accuracy of estimating the time required for battery low - temperature heating when a dual - system hybrid heating method combining liquid - heat heating and pulse heating is adopted.

[0008] To achieve the above object, the present invention proposes a battery low - temperature charging heating control method, including the following steps: Obtain the initial lowest temperature of the battery pack; Judge whether the lowest temperature falls within the pulse heating range. If so; Obtain the maximum temperature value of the pulse heating range and the temperature rise rate corresponding to the pulse heating range; Calculate the first heating time according to the initial lowest temperature, the maximum temperature value of the pulse heating range, and the temperature rise rate corresponding to the pulse heating range, and heat the battery pack according to the first heating time.

[0009] By obtaining the initial lowest temperature of the battery pack in real - time and combining with the pre - stored pulse heating parameters, accurately calculate the required first heating time to achieve precise temperature control of the battery pack, thereby effectively improving the charging performance of the battery pack under low - temperature conditions, shortening the waiting time required for battery pack charging, avoiding energy waste caused by over - heating, prolonging the service life of the battery pack, and ensuring stable, safe, and efficient charging performance of the battery pack in a low - temperature environment.

[0010] In an embodiment of the present application, obtaining the temperature rise rate corresponding to the pulse heating range includes the following steps: Construct a correspondence table between different health states of the battery and the confidence level of the battery internal resistance, a fitting coefficient table between different temperatures of the battery and the change of the battery internal resistance, and a correspondence table between different battery power levels and the battery temperature rise coefficient and the first temperature rise rate; Obtain the health state of the current battery, and obtain the corresponding confidence coefficient from the correspondence table between different health states of the battery and the confidence level of the battery internal resistance according to the health state; Obtain the corresponding fitting coefficient from the fitting coefficient table between different temperatures of the battery and the change of the battery internal resistance according to the starting minimum temperature; Obtain the power value of the current battery pack, and obtain the corresponding battery temperature rise coefficient and the first temperature rise rate from the correspondence table between different battery power levels and the battery temperature rise coefficient and the first temperature rise rate according to the power value; Multiply the confidence coefficient, the fitting coefficient, the battery temperature rise coefficient, and the first temperature rise rate to generate the temperature rise rate corresponding to the pulse heating interval.

[0011] By constructing and using the above three correspondence tables to conduct a multi-dimensional comprehensive evaluation of the battery health state, temperature, and power, accurately calculate the actual temperature rise rate of the battery pack during low-temperature charging, make the temperature control more refined, effectively improve the heating accuracy and stability of the battery pack under different low-temperature conditions, avoid energy loss and battery pack performance degradation caused by improper parameter selection, and significantly improve the efficiency of the battery pack during low-temperature charging.

[0012] In an embodiment of the present application, the calculation formula for the first heating time is: ;

[0013] Wherein, represents the confidence coefficient; represents the fitting coefficient; represents the battery temperature rise coefficient; represents the first temperature rise rate; represents the maximum temperature value of the pulse heating interval; represents the starting minimum temperature; represents the first heating time.

[0014] By accurately calculating the first heating time through multi-parameter joint calculation, fully considering various state factors such as the actual health state, temperature, and power of the battery pack, realizing precise heating control during the low-temperature charging process of the battery pack, significantly improving the heating efficiency of the battery pack during charging in a low-temperature environment, effectively shortening the charging waiting time, and reducing the energy consumption loss during the low-temperature charging of the battery pack.

[0015] In an embodiment of the present application, after heating the battery pack according to the first heating time, it further includes: Obtain the current first temperature of the battery pack, and determine whether the first temperature falls within the liquid thermal heating range. If so; Obtain the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid thermal heating range, and the temperature rise rate corresponding to the liquid thermal heating range; According to the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid thermal heating range, and the temperature rise rate corresponding to the liquid thermal heating range, calculate the second heating time, and heat the battery pack according to the second heating time; wherein, the maximum temperature value of the pulse heating range coincides with the minimum temperature value of the liquid thermal heating range.

[0016] By continuously using two different heating methods of pulse heating and liquid thermal heating in combination, efficient, precise, and staged temperature control of the battery pack under low-temperature conditions is achieved. It not only gives play to the advantage of rapid temperature rise of pulse heating in the lower temperature range but also makes full use of the characteristics of fine temperature control and high stability of liquid thermal heating in the medium and high temperature ranges, enabling the temperature of the battery pack to smoothly transition and accurately reach the ideal charging temperature, effectively reducing potential safety hazards caused by temperature fluctuations of the battery pack.

[0017] In an embodiment of the present application, obtaining the temperature rise rate corresponding to the liquid thermal heating range includes the following steps: Construct a corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates, and a corresponding table of different charging currents of the battery and the battery's self-temperature rise rate; Obtain the heating power of the current battery pack, and obtain the corresponding temperature rise influence coefficient and second temperature rise rate from the corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates according to the heating power; Obtain the charging current of the current battery pack, and obtain the corresponding battery self-temperature rise rate from the corresponding table of different charging currents of the battery and the battery's self-temperature rise rate according to the charging current; Multiply the temperature rise influence coefficient, the second temperature rise rate, and the battery self-temperature rise rate to generate the temperature rise rate corresponding to the liquid thermal heating range.

[0018] By obtaining and comprehensively considering the actual heating power and actual charging current of the current battery pack in real time, accurately calculating the actual temperature rise rate in the liquid thermal heating range makes the temperature control of the battery pack in the liquid thermal heating stage in the medium and high temperature regions more precise, effectively avoiding problems of too fast or too slow temperature rise caused by single-factor calculation, and achieving stable and fine control of the temperature of the battery pack.

[0019] In an embodiment of the present application, the calculation formula for the second heating time is: ;

[0020] Wherein, represents the temperature rise influence coefficient; represents the second temperature rise rate; represents the self - heating rate of the battery; represents the maximum temperature value in the pulse heating interval; represents the maximum temperature value in the liquid - heat heating interval; represents the second heating time.

[0021] By collecting and comprehensively utilizing the actual heating power and actual charging current of the battery pack in real - time, the accurate time required for the second - stage liquid - heat heating of the battery pack is precisely calculated, enabling the battery pack to stably and efficiently complete the temperature rise from the pulse heating stage to the liquid - heat heating stage, and significantly improving the overall efficiency and stability of the battery pack during charging in a low - temperature environment.

[0022] In an embodiment of the present application, it is determined whether the lowest temperature falls within the pulse heating interval. If not; Continue to determine whether the lowest temperature falls within the liquid - heat heating interval. If so, obtain the maximum temperature value in the pulse heating interval, the maximum temperature value in the liquid - heat heating interval, and the temperature rise rate corresponding to the liquid - heat heating interval; According to the maximum temperature value in the pulse heating interval, the maximum temperature value in the liquid - heat heating interval, the temperature rise rate corresponding to the liquid - heat heating interval, and the second heating time, heat the battery pack according to the second heating time.

[0023] It is possible to intelligently determine whether to enter the liquid - heat heating mode based on the lowest temperature of the battery pack, and obtain the corresponding temperature parameters and temperature rise rate to calculate a reasonable heating time, thereby ensuring that the battery pack can reach an appropriate operating temperature within a reasonable time.

[0024] In an embodiment of the present application, continue to determine whether the lowest temperature falls within the liquid - heat heating interval. If not; perform only the charging operation.

[0025] It is possible to intelligently determine the heating strategy based on the lowest temperature of the battery pack to ensure effective heating within an appropriate temperature range.

[0026] In an embodiment of the present application, after heating the battery pack according to the first heating time, it further includes: Obtain the current first temperature of the battery pack, determine whether the first temperature falls within the liquid - heat heating interval. If not; recalculate the first heating time, and then heat the battery according to the updated first heating time.

[0027] It can effectively prevent the battery pack from affecting performance or use safety due to insufficient temperature.

[0028] The present application also discloses a battery management system configured to execute the battery low - temperature charging and heating control method described in any one of the above.

[0029] By adopting the above technical solution, the starting minimum temperature of the battery pack is obtained in real time and combined with the pre-stored pulse heating parameters, and the required first heating time is accurately calculated to achieve precise temperature control of the battery pack, thereby effectively improving the charging performance of the battery pack under low temperature conditions, shortening the waiting time required for charging the battery pack, avoiding energy waste caused by overheating at the same time, prolonging the service life of the battery pack, and ensuring that the battery pack has stable, safe and efficient charging performance in a low temperature environment. Brief Description of the Drawings

[0030] The present invention will be described in detail below with reference to specific embodiments and drawings, wherein: Figure 1 It is a schematic flow structure diagram of the first embodiment of the present invention. Detailed Embodiments

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0032] As Figure 1 shown, in order to achieve the above object, the present invention proposes a battery low-temperature charging and heating control method, including the following steps: Obtain the starting minimum temperature of the battery pack; Judge whether the minimum temperature falls within the pulse heating range. If so; Obtain the maximum temperature value of the pulse heating range and the temperature rise rate corresponding to the pulse heating range; Calculate the first heating time according to the starting minimum temperature, the maximum temperature value of the pulse heating range, and the temperature rise rate corresponding to the pulse heating range, and heat the battery pack according to the first heating time.

[0033] Specifically, first, the starting minimum temperature of the battery pack is obtained in real time through a temperature sensor installed in the battery pack, and the starting minimum temperature is transmitted to the battery management system; the battery management system compares the starting minimum temperature with a preset pulse heating range to judge whether the starting minimum temperature falls within the pulse heating range; if the starting minimum temperature is within the pulse heating range, the battery management system reads the maximum temperature value and the temperature rise rate corresponding to the pulse heating range from a pre-stored battery management system parameter table; the battery management system calculates according to the current starting minimum temperature, the maximum temperature value of the pulse heating range, and the temperature rise rate, according to the formula:

[0034] Wherein, Represents the maximum temperature value in the pulse heating interval; Represents the starting minimum temperature; Represents the first heating time; Represents the temperature rise rate corresponding to the pulse heating interval; Calculate the first heating time.

[0035] The battery management system controls the heating execution module to perform pulse heating on the battery pack according to the first heating time, so that the temperature of the battery pack reaches the maximum temperature value in the pulse heating interval, to meet the charging requirements of the battery pack in a low-temperature environment.

[0036] Adopting the above technical solution, by obtaining the starting minimum temperature of the battery pack in real time and combining with the pre-stored pulse heating parameters, accurately calculate the required first heating time, to achieve precise temperature control of the battery pack, thereby effectively improving the charging performance of the battery pack under low-temperature conditions, shortening the waiting time required for charging the battery pack, avoiding energy waste caused by overheating at the same time, prolonging the service life of the battery pack, and ensuring that the battery pack has stable, safe and efficient charging performance in a low-temperature environment.

[0037] In an embodiment of the present application, obtaining the temperature rise rate corresponding to the pulse heating interval includes the following steps: Construct a correspondence table between different battery health states and battery internal resistance confidence levels, a correspondence table between different battery temperatures and battery internal resistance change fitting coefficients, and a correspondence table between different battery power levels and battery temperature rise coefficients and first temperature rise rates; Obtain the health state of the current battery, and obtain the corresponding confidence coefficient from the correspondence table between different battery health states and battery internal resistance confidence levels according to the health state; Obtain the corresponding fitting coefficient from the correspondence table between different battery temperatures and battery internal resistance change fitting coefficients according to the starting minimum temperature; Obtain the power value of the current battery pack, and obtain the corresponding battery temperature rise coefficient and first temperature rise rate from the correspondence table between different battery power levels and battery temperature rise coefficients and first temperature rise rates according to the power value; Multiply the confidence coefficient, fitting coefficient, battery temperature rise coefficient and first temperature rise rate to generate the temperature rise rate corresponding to the pulse heating interval.

[0038] Specifically, through experiments or simulation tests, respectively obtain a correspondence table between different battery health states and battery internal resistance confidence levels, a correspondence table between different battery temperatures and battery internal resistance change fitting coefficients, and a correspondence table between different battery power levels and battery temperature rise coefficients and first temperature rise rates, and pre-store the above three correspondence tables in the battery management system; The following is an example for illustration:

[0039] Corresponding Table of Different Battery Health States and Battery Internal Resistance Confidence Levels: The battery management system obtains the health state of the current battery pack in real time. Based on the health state of the current battery pack, it looks up and obtains the corresponding confidence coefficient in the corresponding table of different battery health states and battery internal resistance confidence levels.

[0040] Corresponding Table of Different Battery Temperatures and Fitting Coefficients of Battery Internal Resistance Changes:

[0041] The battery management system obtains the starting minimum temperature of the battery pack in real time. According to the starting minimum temperature of the current battery pack, it looks up and obtains the corresponding fitting coefficient in the corresponding table of different battery temperatures and fitting coefficients of battery internal resistance changes.

[0042] Corresponding Table of Different Battery Charge Levels, Battery Temperature Rise Coefficients, and First Temperature Rise Rates: The battery management system collects the charge level value of the current battery pack in real time. According to the charge level value of the current battery pack, it looks up and obtains the corresponding battery temperature rise coefficient and the first temperature rise rate in the corresponding table of different battery charge levels, battery temperature rise coefficients, and first temperature rise rates; the battery management system multiplies the confidence coefficient, fitting coefficient, battery temperature rise coefficient, and the first temperature rise rate obtained above in sequence, calculates the temperature rise rate corresponding to the current pulse heating interval, and the battery management system uses the temperature rise rate calculated above to calculate the first heating time of the pulse heating interval, realizing precise heating control of the battery pack under low-temperature conditions.

[0043] By adopting the above technical solution, through constructing and using the above three corresponding tables to conduct multi-dimensional comprehensive evaluation of the battery health state, temperature, and charge level, accurately calculating the actual temperature rise rate of the battery pack during low-temperature charging, making the temperature control more refined, effectively improving the heating accuracy and stability of the battery pack under different low-temperature conditions, avoiding energy loss and battery pack performance degradation caused by improper parameter selection, and significantly improving the efficiency of the battery pack during low-temperature charging.

[0044] In an embodiment of the present application, the calculation formula for the first heating time is: ;

[0045] Wherein, represents the confidence coefficient; represents the fitting coefficient; represents the battery temperature rise coefficient; represents the first temperature rise rate; represents the maximum temperature value of the pulse heating interval; represents the starting minimum temperature; represents the first heating time.

[0046] Specifically, the battery management system collects the starting minimum temperature of the battery pack in real time through a temperature sensor . The battery management system determines whether the battery pack is within the pulse heating range according to the current starting minimum temperature of the battery pack . When the starting minimum temperature of the battery pack falls within the pulse heating range, the battery management system obtains the maximum temperature value of the pulse heating range . The battery management system collects the current health state of the battery pack, the starting minimum temperature of the battery pack , and the current power value of the battery pack in real time, and respectively obtains the confidence coefficient , the fitting coefficient , the battery temperature rise coefficient , and the first temperature rise rate according to the pre-stored correspondence table between different health states of the battery and the confidence level of the battery internal resistance, the fitting coefficient table of the change of the battery internal resistance corresponding to different temperatures of the battery, and the correspondence table between different battery powers and the battery temperature rise coefficient and the first temperature rise rate; the battery management system substitutes the above parameters into the formula:

[0047] to calculate the first heating time ; the battery management system controls the heating execution module to perform pulse heating on the battery pack according to the calculated first heating time so that the temperature of the battery pack accurately rises to the maximum temperature value of the pulse heating range .

[0048] By adopting the above technical solution, the first heating time is calculated through precise multi-parameter joint calculation, fully considering various state factors such as the actual health state, temperature, and power of the battery pack, realizing precise heating control during the low-temperature charging process of the battery pack, significantly improving the temperature rise efficiency during the charging process of the battery pack in a low-temperature environment, effectively shortening the charging waiting time, and reducing the energy consumption loss during the low-temperature charging of the battery pack.

[0049] In an embodiment of the present application, after heating the battery pack according to the first heating time, it further includes: Obtaining the current first temperature of the battery pack, and judging whether the first temperature falls within the liquid heating range. If so; Obtaining the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid heating range, and the temperature rise rate corresponding to the liquid heating range; According to the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heating interval, and the temperature rise rate corresponding to the liquid heating interval and the second heating time, the battery pack is heated according to the second heating time; wherein, the maximum temperature value of the pulse heating interval coincides with the minimum temperature value of the liquid heating interval.

[0050] Specifically, after the battery management system completes the pulse heating of the battery pack according to the first heating time, it continues to obtain the current first temperature of the battery pack in real time through the temperature sensor inside the battery pack. The battery management system determines whether the current first temperature of the battery pack falls within a preset liquid heating interval; if the current first temperature of the battery pack is within the liquid heating interval, the battery management system further obtains the pre-stored maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heating interval, and the temperature rise rate corresponding to the liquid heating interval; wherein, the maximum temperature value of the pulse heating interval is the minimum temperature value of the liquid heating interval, and the two intervals are seamlessly connected. The battery management system calculates the second heating time of the battery pack according to the obtained maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heating interval, and the temperature rise rate corresponding to the liquid heating interval, based on the formula:

[0051] wherein, represents the maximum temperature value of the pulse heating interval; represents the maximum temperature value of the liquid heating interval; represents the second heating time; represents the temperature rise rate corresponding to the liquid heating interval. After calculating the second heating time of the battery pack, the battery management system controls the liquid heating execution module to perform liquid heating on the battery pack according to the second heating time, further accurately raising the temperature of the battery pack to the maximum temperature value of the liquid heating interval, so that the battery pack finally reaches a suitable temperature range for charging.

[0052] By adopting the above technical solution, through the continuous combined use of two different heating methods, namely pulse heating and liquid heating, efficient, precise, and staged temperature control of the battery pack under low-temperature conditions is achieved. It not only gives play to the advantage of rapid temperature rise of pulse heating in the lower temperature range but also makes full use of the characteristics of fine temperature control and high stability of liquid heating in the medium and high temperature ranges, enabling the temperature of the battery pack to smoothly transition and accurately reach the ideal charging temperature, effectively reducing potential safety hazards caused by temperature fluctuations of the battery pack.

[0053] In an embodiment of the present application, obtaining the temperature rise rate corresponding to the liquid heating interval includes the following steps: Construct a correspondence table between different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates, and a correspondence table between different charging currents of the battery and the self-temperature rise rate of the battery; Obtain the heating power of the current battery pack, and obtain the corresponding temperature rise influence coefficient and the second temperature rise rate from the corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates; Obtain the charging current of the current battery pack, and obtain the corresponding self-temperature rise rate of the battery from the corresponding table of different charging currents of the battery and the self-temperature rise rate of the battery; Multiply the temperature rise influence coefficient, the second temperature rise rate, and the self-temperature rise rate of the battery to generate the temperature rise rate corresponding to the liquid heat heating interval.

[0054] Specifically, pre-construct the corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates, and the corresponding table of different charging currents of the battery and the self-temperature rise rate of the battery through experiments or simulations, and pre-store the above corresponding tables in the battery management system; The following is an example: Corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates: The battery management system obtains the actual heating power of the current battery pack in real time, and searches and obtains the corresponding temperature rise influence coefficient and the second temperature rise rate from the pre-stored corresponding table of different heating powers of the battery, temperature rise influence coefficients, and second temperature rise rates.

[0055] Corresponding table of different charging currents of the battery and the self-temperature rise rate of the battery:

[0056] The battery management system collects the actual charging current of the current battery pack in real time, and searches and obtains the corresponding self-temperature rise rate of the battery from the pre-stored corresponding table of different charging currents of the battery and the self-temperature rise rate of the battery.

[0057] The battery management system multiplies the temperature rise influence coefficient, the second temperature rise rate, and the self-temperature rise rate of the battery obtained in the above steps in sequence to calculate the temperature rise rate corresponding to the liquid heat heating interval under the current working condition. The battery management system uses the obtained temperature rise rate corresponding to the liquid heat heating interval to calculate the accurate second heating time, and controls the liquid heat heating execution module accordingly to complete the liquid heat heating in the second stage of the battery pack, further realizing the precise temperature control of the battery pack.

[0058] Adopting the above technical solution, by obtaining and comprehensively considering the actual heating power and the actual charging current of the current battery pack in real time, accurately calculating the actual temperature rise rate in the liquid heat heating interval, making the temperature control in the liquid heat heating stage of the battery pack in the medium and high temperature regions more precise, effectively avoiding the problem of too fast or too slow temperature rise caused by single-factor calculation, and realizing the stable and fine control of the battery pack temperature.

[0059] In an embodiment of the present application, the calculation formula for the second heating time is: ;

[0060] Wherein, represents the temperature rise influence coefficient; represents the second temperature rise rate; represents the self - heating rate of the battery; represents the maximum temperature value in the pulse heating interval; represents the maximum temperature value in the liquid - heat heating interval; represents the second heating time.

[0061] Specifically, the battery management system collects the current first temperature of the battery pack after pulse heating in real time through a temperature sensor, and determines whether the current first temperature is within the liquid - heat heating interval; if the current first temperature is within the liquid - heat heating interval, the battery management system obtains the maximum temperature value and the maximum temperature value of the pulse heating interval stored in advance, where the maximum temperature value of the pulse heating interval coincides with the minimum temperature value of the liquid - heat heating interval. The battery management system obtains the temperature rise influence coefficient and the second temperature rise rate in real time according to the actual heating power of the battery pack, and obtains the self - heating rate of the battery from the pre - constructed corresponding table of different charging currents of the battery and the self - heating rate of the battery according to the actual charging current. The battery management system calculates the second heating time

[0062] through the formula: ; Finally, the battery management system controls the liquid - heat heating execution module to perform liquid - heat heating on the battery pack according to the calculated second heating time so that the temperature of the battery pack is accurately increased to the maximum temperature value of the liquid - heat heating interval.

[0063] By adopting the above - mentioned technical solution, by collecting and comprehensively using the actual heating power and actual charging current of the battery pack in real time, the accurate time required for the second - stage liquid - heat heating of the battery pack is accurately calculated, enabling the battery pack to stably and efficiently complete the temperature rise from the pulse heating stage to the liquid - heat heating stage, and significantly improving the overall efficiency and stability of the battery pack during charging in a low - temperature environment.

[0064] In an embodiment of the present application, it is determined whether the lowest temperature falls within the pulse heating range. If not; Continue to determine whether the lowest temperature falls within the liquid heating range. If so, obtain the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid heating range, and the temperature rise rate corresponding to the liquid heating range; According to the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid heating range, and the temperature rise rate corresponding to the liquid heating range, calculate the second heating time, and heat the battery pack according to the second heating time.

[0065] Specifically, obtain the measurement data of the lowest temperature, and compare the lowest temperature with the preset temperature range of the pulse heating range. If the lowest temperature is within the temperature range of the pulse heating range, no subsequent judgment is required; if the lowest temperature does not fall within the temperature range of the pulse heating range, continue to determine whether the lowest temperature is within the temperature range of the liquid heating range.

[0066] If the lowest temperature is within the temperature range of the liquid heating range, obtain the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid heating range, and the temperature rise rate corresponding to the liquid heating range. Then, calculate the second heating time according to the maximum temperature value of the pulse heating range, the maximum temperature value of the liquid heating range, and the temperature rise rate corresponding to the liquid heating range, and heat the battery pack according to the second heating time.

[0067] By adopting the above technical solution, it is possible to intelligently determine whether to enter the liquid heating mode according to the lowest temperature of the battery pack, obtain the corresponding temperature parameters and temperature rise rate, calculate a reasonable heating time, so as to ensure that the battery pack can reach a suitable working temperature within a reasonable time.

[0068] In an embodiment of the present application, continue to determine whether the lowest temperature falls within the liquid heating range. If not; perform only charging operation.

[0069] Specifically, obtain the measurement data of the lowest temperature, and compare the lowest temperature with the preset temperature range of the pulse heating range. If the lowest temperature is within the temperature range of the pulse heating range, no subsequent judgment is required; if the lowest temperature does not fall within the temperature range of the pulse heating range, continue to determine whether the lowest temperature is within the temperature range of the liquid heating range.

[0070] If the lowest temperature is within the temperature range of the liquid heating interval, obtain the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heating interval, and the temperature increase rate corresponding to the liquid heating interval. Then, calculate the second heating time based on the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heating interval, and the temperature increase rate corresponding to the liquid heating interval, and heat the battery pack according to the second heating time.

[0071] If the lowest temperature does not fall within the temperature range of the liquid heating interval, perform the operation of only charging without heating.

[0072] By adopting the above technical solution, the heating strategy can be intelligently judged according to the lowest temperature of the battery pack, ensuring effective heating within a suitable temperature range.

[0073] In an embodiment of the present application, after heating the battery pack according to the first heating time, it further includes: Obtain the current first temperature of the battery pack, and judge whether the first temperature falls within the liquid heating interval. If not, recalculate the first heating time, and then heat the battery according to the updated first heating time.

[0074] Specifically, heat the battery pack according to the first heating time. After heating is completed, obtain the current first temperature of the battery pack, and compare the first temperature with the temperature range of the liquid heating interval.

[0075] If the first temperature falls within the temperature range of the liquid heating interval, it indicates that the battery pack has achieved a suitable heating effect, and the current heating process ends. If the first temperature does not fall within the temperature range of the liquid heating interval, recalculate the first heating time, and then heat the battery according to the updated first heating time to ensure that the battery pack gradually warms up until it meets the requirements of the liquid heating interval.

[0076] By adopting the above technical solution, it can effectively avoid the battery pack from affecting its performance or use safety due to insufficient temperature.

[0077] The present application also discloses a battery management system configured to execute the battery low-temperature charging and heating control method described in any one of the above.

[0078] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A battery low temperature charging heating control method, characterized in that: The following steps are involved: Get the minimum starting temperature of the battery pack; determining whether the minimum temperature falls within the pulse heating interval, and if so; Obtain the maximum temperature value of the pulse heating interval and the temperature increase rate corresponding to the pulse heating interval; A first heating time is calculated according to the starting minimum temperature, the maximum temperature value of the pulse heating interval, and the temperature increase rate corresponding to the pulse heating interval, and the battery pack is heated according to the first heating time.

2. The battery low temperature charging heating control method according to claim 1, characterized in that: Obtaining the temperature rise rate corresponding to the pulse heating interval includes the following steps: Construct a table of battery health status and battery internal resistance confidence, a table of battery temperature and battery internal resistance change fitting coefficient, and a table of battery power and battery temperature rise coefficient and first temperature rise rate. Obtaining a current health state of the battery, and obtaining a corresponding confidence coefficient from a corresponding table of different health states of the battery and confidence levels of battery internal resistance according to the health state; According to the starting minimum temperature, a corresponding fitting coefficient is obtained from the fitting coefficient table of the battery at different temperatures and the battery internal resistance change; Obtaining a current power value of the battery pack, and obtaining a corresponding battery temperature rise coefficient and a first temperature rise rate from a corresponding table of different battery power values, battery temperature rise coefficients, and first temperature rise rates according to the power value; The confidence coefficient, the fitting coefficient, the battery temperature rise coefficient and the first temperature rise rate are multiplied to generate a temperature rise rate corresponding to the pulse heating interval.

3. The battery low temperature charging heating control method according to claim 2, characterized in that: The calculation formula for the first heating time is: ； in, represents the confidence coefficient; represents the fitting coefficient; Indicates the battery temperature rise coefficient; Indicates the first temperature rise rate; Indicates the maximum temperature value of the pulse heating interval; Indicates the minimum starting temperature; Indicates the first heating time.

4. The battery low temperature charging heating control method according to any one of claims 1 to 3, characterized in that: After heating the battery pack according to the first heating time, the method further includes: Obtaining a current first temperature of the battery pack, and determining whether the first temperature falls within a liquid-heat heating interval, if so; Obtain the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heat heating interval, and the temperature increase rate corresponding to the liquid heat heating interval; According to the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heat heating interval, and the second heating time of the temperature rise rate corresponding to the liquid heat heating interval, the battery pack is heated according to the second heating time; wherein the maximum temperature value of the pulse heating interval and the minimum temperature value of the liquid heat heating interval coincide.

5. The battery low temperature charging heating control method according to claim 4, characterized in that: Obtaining the temperature increase rate corresponding to the liquid thermal heating interval includes the following steps: Construct a table of correspondence between different heating powers of batteries and temperature rise influence coefficients and second temperature rise rates, and a table of correspondence between different charging currents of batteries and battery self-heating rates; Obtain the heating power of the current battery pack, and according to the heating power, obtain the corresponding temperature rise influence coefficient and the second temperature rise rate from the corresponding table of different heating powers of the battery and the temperature rise influence coefficient and the second temperature rise rate; Obtaining the current charging current of the battery pack, and obtaining the corresponding battery self-heating rate from the corresponding table of different battery charging currents and battery self-heating rates according to the charging current; The temperature rise influence coefficient, the second temperature rise rate, and the battery self-heating rate are multiplied to generate a temperature rise rate corresponding to the liquid thermal heating interval.

6. The battery low temperature charging heating control method according to claim 5, characterized in that: The calculation formula for calculating the second heating time is: ； in, Indicates the temperature rise influence coefficient; Indicates the second temperature rise rate; Indicates the battery self-heating rate; Indicates the maximum temperature value of the pulse heating interval; Indicates the maximum temperature value of the liquid heat heating interval; Indicates the second heating time.

7. The battery low temperature charging heating control method according to claim 1, characterized in that: determining whether the minimum temperature falls within the pulse heating interval, if not; Continue to determine whether the minimum temperature falls within the liquid heat heating interval, and if so, obtain the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heat heating interval, and the temperature increase rate corresponding to the liquid heat heating interval; According to the maximum temperature value of the pulse heating interval, the maximum temperature value of the liquid heat heating interval, and the second heating time of the temperature rise rate corresponding to the liquid heat heating interval, the battery pack is heated according to the second heating time.

8. The battery low temperature charging heating control method according to claim 7, characterized in that: Continue to determine whether the minimum temperature falls within the liquid heat heating interval, if not; perform a charging-only operation.

9. The battery low temperature charging heating control method according to claim 4, characterized in that: After heating the battery pack according to the first heating time, the method further includes: Obtain the current first temperature of the battery pack, determine whether the first temperature falls within the liquid-heating heating interval, and if not; recalculate the first heating time, and then heat the battery according to the updated first heating time.

10. A battery management system, characterized in that: The method is configured to execute the battery low temperature charging heating control method as described in any one of claims 1 to 9.

Images