Battery temperature sampling error compensation method

Abstract

The invention discloses a battery temperature sampling error compensation method, and relates to the technical field of batteries, and the compensation method comprises the steps: executing a first temperature compensation strategy under the condition that the sampling temperature of a battery is at a first jump temperature T1, so as to carry out the temperature compensation of the first jump temperature T1; when the sampling temperature of the battery is at a second jump temperature T2, executing a second temperature compensation strategy to perform temperature compensation on the second jump temperature T2; wherein T2 is greater than T1. According to the compensation method, targeted compensation is carried out on the temperature jump point, the temperature sampling precision of the temperature jump point is improved, the accuracy of battery charge and discharge rate calibration of the battery at the temperature jump point is improved, it is guaranteed that the charge and discharge rate of the battery at the temperature jump point is within the battery charge and discharge capacity range, and the battery charge and discharge rate calibration accuracy is improved. The risk that the actual charge-discharge rate exceeds the charge-discharge capacity of the battery due to temperature jump at the critical temperature point of the change of the charge-discharge rate of the battery is effectively avoided.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a battery temperature sampling error compensation method. Background Art

[0002] When single cells are assembled into modules or battery packs, battery temperature monitoring is required for some cells within the pack to assess their operating status and adjust thermal management strategies based on varying temperature conditions. Current battery temperature sampling is typically performed at the window opening of the battery cover's insulation patch. This only represents the local temperature at the sampling location and cannot accurately represent the overall battery temperature. This results in significant errors in overall battery temperature sampling, posing a risk of impacting the battery's charge and discharge capabilities. Summary of the Invention

[0003] Purpose of the invention: The embodiment of the present application provides a battery temperature sampling error compensation method, which aims to solve the problem that the existing battery temperature sampling error is large and affects the battery charging and discharging capacity.

[0004] Technical solution: A battery temperature sampling error compensation method according to an embodiment of the present application includes:

[0005] When the sampled temperature of the battery is at the first transition temperature T1, executing a first temperature compensation strategy to perform temperature compensation on the first transition temperature T1;

[0006] When the sampled temperature of the battery is at the second transition temperature T2, a second temperature compensation strategy is executed to perform temperature compensation on the second transition temperature T2; wherein T2>T1.

[0007] In some embodiments, the first temperature compensation strategy includes:

[0008] Get the first large surface temperature T when the battery sampling temperature is at the first jump temperature T1 大面1 ;

[0009] Get the first jump temperature T1 and the first large surface temperature T 大面1 A first temperature difference ΔT1 between

[0010] Based on the first temperature difference ΔT1, the first compensated temperature T is obtained. 补1 :T 补1 =T1-ΔT1.

[0011] In some embodiments, the second temperature compensation strategy includes:

[0012] Get the second maximum surface temperature T when the battery sampling temperature is at the second jump temperature T2 大面2 ;

[0013] Get the second jump temperature T2 and the second large surface temperature T 大面2 A second temperature difference ΔT2 between

[0014] Based on the second temperature difference ΔT2, the second compensated temperature T is obtained. 补2 :T 补2 =T2+ΔT2.

[0015] In some embodiments, the compensation method further comprises:

[0016] Implement thermal management strategies for batteries;

[0017] The thermal management strategies include: heating strategy, cooling strategy and neither heating nor cooling strategy; the first jump temperature T1 is the sampling temperature when the heating strategy ends; the second jump temperature T2 is the sampling temperature when the cooling strategy starts.

[0018] In some embodiments, the compensation method further comprises:

[0019] Get the maximum temperature T when the battery stops working while executing the cooling strategy max , satisfying, T2<T max ;

[0020] When the battery sampling temperature is in the temperature range (T2, T max ], execute the third temperature compensation strategy.

[0021] In some embodiments, the third temperature compensation strategy includes:

[0022] The temperature interval (T2, T max ] is divided into multiple sub-temperature intervals;

[0023] Obtain the third sampling temperature T3 and the third largest surface temperature T when the battery is charged and discharged in multiple sub-temperature intervals 大面3 ;

[0024] The third sampling temperature T3 in one or more sub-temperature intervals is less than the third large surface temperature T 大面3 In the case of, obtain the third sampling temperature T3 and the third large surface temperature T 大面3 A third temperature difference ΔT3 between

[0025] Based on the third temperature difference ΔT3, the third compensated temperature T is obtained. 补3 :T 补3 =T3+ΔT3.

[0026] In some embodiments, the third temperature compensation strategy further includes:

[0027] The third sampling temperature T3 in one or more sub-temperature intervals is greater than or equal to the third large surface temperature T 大面3 In this case, no temperature compensation is performed.

[0028] In some embodiments, the compensation method further comprises:

[0029] When the sampled temperature of the battery is within the temperature interval ( T1 , T2 ), a neither heating nor cooling strategy is executed, and no temperature compensation is performed.

[0030] In some embodiments,

[0031] The battery also has an initial operating temperature T min ; Compensation methods also include:

[0032] When the battery sampling temperature is in the temperature range (T min , T1), the heating strategy is executed without temperature compensation.

[0033] In some embodiments, the compensation method further comprises:

[0034] When the sampling temperature of the battery is less than or equal to the initial operating temperature T min In this case, the battery does not work and the heating strategy is executed without temperature compensation;

[0035] When the battery sampling temperature is greater than the maximum temperature T max In this case, the battery does not work and the cooling strategy is executed without temperature compensation.

[0036] Beneficial effect: Compared with the prior art, a battery temperature sampling error compensation method in an embodiment of the present application includes: when the sampling temperature of the battery is at a first jump temperature T1, executing a first temperature compensation strategy to perform temperature compensation on the first jump temperature T1; when the sampling temperature of the battery is at a second jump temperature T2, executing a second temperature compensation strategy to perform temperature compensation on the second jump temperature T2; wherein, T2>T1. The compensation method of the present application performs targeted compensation on the temperature jump point, improves the accuracy of temperature sampling at the temperature jump point, and thereby improves the accuracy of battery charge and discharge rate calibration at the temperature jump point, ensuring that the battery charge and discharge rate at the temperature jump point is within the battery charge and discharge capacity range, and effectively avoiding the risk of the actual charge and discharge rate exceeding the battery charge and discharge capacity due to temperature jump at the critical temperature point where the battery charge and discharge rate changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 This is a flow chart of a battery temperature sampling error compensation method according to an embodiment of the present application;

[0039] Figure 2 is a curve showing the relationship between the sampling temperature and the charging speed of the battery in the embodiment of the present application;

[0040] Figure 3 This is a detailed flow chart of a battery temperature sampling error compensation method according to an embodiment of the present application;

[0041] Figure 4 This is a flow chart of a first temperature compensation strategy of a battery temperature sampling error compensation method according to an embodiment of the present application;

[0042] Figure 5 This is a flow chart of a second temperature compensation strategy of a battery temperature sampling error compensation method according to an embodiment of the present application;

[0043] Figure 6 This is a flow chart of a third temperature compensation strategy of a battery temperature sampling error compensation method according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0045] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of this application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle within the range of 80° to 100° is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel, for example, an angle within 10° of completely parallel is considered parallel.

[0046] In the related art, when single cells are assembled into a module or battery pack, it is necessary to perform battery temperature detection on some of the batteries in the battery pack to evaluate the operating status of the batteries in the battery pack, to evaluate the performance and safety status of the battery pack, and to adjust the thermal management strategy according to different temperature conditions. The current temperature collection of batteries in battery packs is based on cost, process complexity, sampling point reliability, and sampling temperature availability. The sampling position of the battery is generally located at the window position of the insulation patch on the top cover of the battery. However, the temperature sampling at the window of the insulation patch on the top cover can only represent the local temperature of the sampling position, and cannot accurately represent the temperature of the battery body. In addition, due to the influence of heat absorption and heat dissipation of other structural parts in the module or battery pack, as well as the influence of overcurrent and heat generation of the aluminum bar of the terminal, the temperature of the sampling position is quite different from the temperature of the battery itself. As a result, when the charge and discharge rate corresponding to the sampling temperature is used for charging and discharging, there is a risk that the actual charge and discharge rate exceeds the charge and discharge capacity of the battery.

[0047] In view of this, an embodiment of the present application provides a battery temperature sampling error compensation method, which aims to solve the above problem.

[0048] Please refer to Figure 1 and Figure 2An embodiment of the present application provides a battery temperature sampling error compensation method, comprising: when the sampling temperature of the battery is at a first transition temperature T1, executing a first temperature compensation strategy to perform temperature compensation on the first transition temperature T1; when the sampling temperature of the battery is at a second transition temperature T2, executing a second temperature compensation strategy to perform temperature compensation on the second transition temperature T2; wherein T2>T1.

[0049] In the embodiment of the present application, the compensation method performs targeted compensation for the temperature jump point, improves the accuracy of temperature sampling at the temperature jump point, and thereby improves the accuracy of the battery charge and discharge rate calibration at the temperature jump point, ensuring that the battery charge and discharge rate at the temperature jump point is within the battery charge and discharge capacity range, and effectively avoids the risk of the actual charge and discharge rate exceeding the battery charge and discharge capacity due to temperature jump at the critical temperature point where the battery charge and discharge rate changes.

[0050] It should be noted that the battery pack or battery module corresponding to the battery of the embodiment of the present application preferably adopts bottom heating and cooling.

[0051] In the embodiments of the present application, the battery has different thermal management strategies at different ambient temperatures. During the battery charging and discharging process, the corresponding charging and discharging operations are also different due to different ambient temperatures. Specifically, as the battery temperature rises, it is considered to gradually increase from low temperature to high temperature. Among them, the embodiments of the present application perform different temperature compensation on the battery based on the battery heating process.

[0052] Specifically, such as Figure 1 As shown, the battery temperature sampling error compensation method of the embodiment of the present application includes the following steps:

[0053] S400 : When the sampled temperature of the battery is at a first transition temperature T1 , executing a first temperature compensation strategy to perform temperature compensation on the first transition temperature T1 .

[0054] S600: When the sampled temperature of the battery is at a second transition temperature T2, executing a second temperature compensation strategy to perform temperature compensation on the second transition temperature T2; wherein T2>T1.

[0055] It should be noted that if Figure 3 As shown, before performing S400, the compensation method further includes:

[0056] S100: Executing a thermal management strategy for the battery.

[0057] For step S100, the battery pack or battery module in the embodiment of the present application is generally provided with bottom liquid cooling, and the corresponding thermal management strategy will be executed at this time to heat or cool the battery, thereby improving the battery's charge and discharge capabilities in different temperature ranges. Specific thermal management strategies include: heating strategy, cooling strategy, and neither heating nor cooling strategy. Specifically, as the battery sampling temperature continues to rise, the execution order of the thermal management strategy may be to execute the heating strategy first, and when the battery reaches the optimal charge and discharge state, execute the neither heating nor cooling strategy, and when the battery temperature continues to rise and the battery's charge and discharge capabilities decrease, execute the cooling strategy.

[0058] It should be noted that during the charge and discharge process, the temperature gradually rises. During this process, the battery pack or battery module first undergoes a heating strategy to heat the battery. Then, when the temperature reaches near the first transition temperature T1, heating stops. The batteries in the battery pack will also generate heat during the charge and discharge process. At this time, the battery temperature continues to rise. When it reaches near the second transition temperature T2, the cooling strategy begins to cool the battery. Therefore, the first transition temperature T1 of this application is the sampling temperature when the heating strategy ends and the non-heating and non-cooling strategy begins; the second transition temperature T2 is the sampling temperature when the cooling strategy begins.

[0059] In addition, the temperature of the battery in the embodiment of the present application is not only affected by the thermal management strategy, but also by the battery heat generation, battery heat dissipation, ambient heat generation, and ambient heat dissipation. Therefore, when the thermal management strategy is switched, the corresponding battery temperature will jump. Near the temperature jump point, the battery's charge and discharge capacity (rate) can be adjusted at a certain temperature step. That is, at the first jump temperature T1 and the second jump temperature T2, the corresponding battery charge and discharge rate also jumps. For example, at the first jump temperature T1, the battery stops heating and begins to implement the no heating and no cooling strategy. Although the thermal management component no longer heats, the battery will generate heat during the charge and discharge process. When the battery reaches a certain temperature, the corresponding charge and discharge capacity will also reach the optimal state. At this time, the battery's charge and discharge capacity will jump. At the second jump temperature T2, the battery stops implementing the no heating and no cooling strategy and starts implementing the cooling strategy. However, the temperature continues to rise while the cooling strategy is being implemented, and the battery's charge and discharge capacity will correspondingly jump from the optimal state, reducing the charge and discharge capacity. Because when the battery's charge and discharge capacity changes, the charge and discharge rate calibrated by the sampling temperature is different from the charge and discharge rate that the battery can actually correspond to, charging and discharging the battery at this calibrated charge and discharge rate may affect the battery's charge and discharge capacity, generally exceeding the battery's charge and discharge capacity, which will cause the risk of lithium plating. Charging and discharging the battery beyond its inherent charge and discharge capacity for a long time will cause irreversible damage to battery performance and safety. Therefore, the embodiment of the present application first performs temperature compensation for the battery's temperature jump point, which can effectively protect the battery's charge and discharge capacity and avoid the calibrated charge and discharge rate exceeding the battery's charge and discharge capacity, which affects battery performance and battery safety.

[0060] Regarding step S400: When the battery sampled temperature is at the first transition temperature T1, the first temperature compensation strategy is executed. Based on the above analysis, when the battery sampled temperature is at the first transition temperature T1 and during charge and discharge operations, the battery's initial large surface temperature is relatively low, while the top cover generates heat due to the poles. Therefore, when the battery sampled temperature reaches the first transition temperature T1, the battery is at the critical point where heating stops and the battery is about to reach its peak charge and discharge capacity. At this time, the corresponding large surface temperature of the battery is typically still lower than the sampled temperature at the top cover. Therefore, the corresponding charge and discharge capacity of the battery actually depends on the large surface temperature. The battery charge and discharge rate corresponding to the large surface temperature is actually lower than the charge and discharge rate corresponding to the sampled temperature at the top cover. If the battery is directly calibrated using the sampled temperature at the top cover (the sampled temperature), the charge and discharge rate corresponding to the sampled temperature at the top cover will exceed the battery's actual charge and discharge capacity. This may create a risk of lithium plating in the battery, potentially causing irreversible damage to battery performance and safety. Therefore, in the embodiment of the present application, when the sampled temperature of the battery is at the first transition temperature T1, the first temperature compensation strategy is executed.

[0061] like Figure 4 As shown, in some embodiments, the first temperature compensation strategy may specifically include the following steps:

[0062] S410: Obtaining the first large surface temperature T when the sampled temperature of the battery is at the first jump temperature T1 大面1 .

[0063] S420: Obtain the first jump temperature T1 and the first large surface temperature T 大面1 The first temperature difference ΔT1 between them.

[0064] S430: Based on the first temperature difference ΔT1, obtain the first compensated temperature T 补1 :T 补1 =T1-ΔT1.

[0065] In the embodiment of the present application, specifically, when executing the first temperature compensation strategy, the first large surface temperature T when the sampled temperature of the battery is at the first jump temperature T1 is first obtained. 大面1 Since the temperature of the large surface of the battery is lower than the sampling temperature at the top cover of the battery, the corresponding first jump temperature T1 and the first large surface temperature T 大面1 The first temperature difference ΔT1 between the two is: ΔT1 = T1-T 大面1 After obtaining the first temperature difference ΔT1, the sampling temperature, that is, the first jump temperature T1, can be compensated to obtain the first compensated temperature T 补1However, since the first jump temperature T1 is greater than the large surface temperature of the battery at this time, the actual charge and discharge capacity of the battery at this time does not reach the calibrated charge and discharge rate corresponding to the first jump temperature T1, and the charge and discharge of the battery gradually increases before the sampling temperature of the battery reaches the first jump temperature T1. Therefore, the embodiment of the present application needs to compensate for low temperature at the first jump temperature T1 to reduce the calibrated charge and discharge rate and ensure the charge and discharge capacity of the battery. Therefore, after executing the first temperature compensation strategy, the first compensated temperature T 补1 T 补1 =T1-ΔT1.

[0066] Regarding step S600: When the battery sampled temperature is at the second transition temperature T2, the second temperature compensation strategy is executed. Based on the above analysis, when the battery sampled temperature is at the second transition temperature T2, the battery ends the neither heating nor cooling strategy and begins to execute the cooling strategy. At this time, due to the electrochemical reaction within the battery, the temperature continues to rise, the battery's charge and discharge capacity also correspondingly jumps from the optimal state, and the battery's actual applicable charge and discharge rate decreases. When the battery is at the second transition temperature T2, it is the critical point for starting to execute the cooling strategy. The temperature of the battery's large surface is high and has not yet been cooled. The corresponding sampled temperature at the battery's top cover will be lower than the battery's large surface temperature. If the sampled temperature at the top cover, i.e., the second transition temperature T2, is directly used as the calibration temperature and the charge and discharge rate at this temperature is selected for charging, the battery's charge and discharge rate is likely to exceed the battery's charge and discharge capacity. This may also pose a risk of lithium plating in the battery and affect the battery's performance and safety. Therefore, when the battery sampled temperature is near the second transition temperature T2, the second temperature compensation strategy needs to be executed.

[0067] like Figure 5 As shown, in some embodiments, the second temperature compensation strategy includes:

[0068] S610: Obtain the second largest surface temperature T when the sampled temperature of the battery is at the second transition temperature T2 大面2 ;

[0069] S620: Obtain the second jump temperature T2 and the second large surface temperature T 大面2 A second temperature difference ΔT2 between

[0070] S630: Based on the second temperature difference ΔT2, obtain the second compensated temperature T 补2 :T 补2 =T2+ΔT2.

[0071] In the embodiment of the present application, since the sampling temperature of the battery, that is, the second transition temperature T2, needs to be compensated, the temperature of the battery body needs to be obtained at this time. Therefore, when executing the second temperature compensation strategy, the present application first obtains the second large surface temperature T of the battery when the sampling temperature of the battery is at the second transition temperature T2. 大 Noodle 2.

[0072] When obtaining the second largest surface temperature T of the battery 大面2 After that, since the battery has not yet executed the cooling strategy, the battery large surface has not yet cooled down, so the battery large surface temperature at this time (the second large surface temperature T 大面2 ) is actually higher than the sampling temperature at the top cover of the battery (the second transition temperature T2). Therefore, the second transition temperature T2 obtained at this time is consistent with the second large surface temperature T 大面2 The second temperature difference ΔT2 between the two is: ΔT2 = T 大面2 -T2.

[0073] After the battery has experienced the temperature range of the optimal charging state (T1, T2), as the battery temperature rises, the battery charge and discharge capacity decreases. At this time, since the temperature of the large surface of the battery is greater than the sampling temperature at the top cover, the sampling temperature at the top cover (the second jump temperature T2) corresponds to the calibrated charge and discharge rate that actually exceeds the battery's charge and discharge capacity. Therefore, the charge and discharge rate that the battery can actually apply at this time is less than the charge and discharge rate corresponding to the sampling temperature at the top cover. Therefore, it is necessary to compensate the sampling temperature of the top cover to a higher temperature. Therefore, based on the second temperature difference ΔT2, the second compensated temperature T 补2 T 补2 =T2+ΔT2.

[0074] Of course, the ambient temperature range in which the battery is charged and discharged can span a wide range, and the temperature range in which charging and discharging can actually be performed can range from more than 20 degrees below zero to more than 60 degrees Celsius. Therefore, the temperature error compensation method of the embodiment of the present application can also cover the entire temperature range in which the battery can perform charging and discharging.

[0075] Specifically, the temperature sampled at the window position of the battery top cover can be divided into five stages. Among them, the external environment in which the battery is located has basically the same effect on the increase and decrease of heat in the local area of the battery. At the same time, the battery module or battery pack where the battery is located adopts the bottom heating and cooling method to implement the thermal management strategy. The minimum temperature of the battery operation (i.e., battery charging and discharging) is T min The maximum temperature of the battery operation (i.e. battery charging and discharging) is T max , that is, the lower limit temperature of the battery is T min , the upper limit temperature of the battery is T max , where T min <T1<T2<T maxWhen the sampling temperature is ≤ T1, the heating strategy is executed and the heating circuit of the thermal management component in the battery pack starts to heat the battery. When the sampling temperature is ≥ T2, the cooling strategy is executed and the cooling circuit of the thermal management component in the battery pack starts to cool the battery.

[0076] like Figure 3 As shown, in some embodiments, the compensation method further includes:

[0077] S700: Obtaining the maximum temperature T when the battery stops working while the cooling strategy is executed max , satisfying, T2<T max .

[0078] S800: When the battery sampling temperature is within the temperature range (T2, T max ], execute the third temperature compensation strategy.

[0079] In an embodiment of the present application, after the sampling temperature of the battery exceeds the second jump temperature T2, the cooling strategy is implemented. At this time, the thermal management component of the battery pack first cools the bottom of the battery, and the low temperature is gradually transferred to the top cover of the battery. Therefore, there may be a situation where the sampling temperature of the top cover is inconsistent with the large surface temperature of the battery itself. In this case, the third temperature compensation strategy is implemented for the sampling temperature of the battery, which can further protect the battery charging and discharging performance and improve the battery safety.

[0080] Further, such as Figure 6 As shown, in some embodiments, the third temperature compensation strategy includes:

[0081] S810: Set the temperature range (T2, T max ] is divided into multiple sub-temperature intervals.

[0082] S820: Obtaining the third sampling temperature T3 and the third large surface temperature T when the battery is charged and discharged in multiple sub-temperature intervals 大面3 .

[0083] S830: The third sampling temperature T3 in one or more sub-temperature intervals is less than the third large surface temperature T 大面3 In the case of, obtain the third sampling temperature T3 and the third large surface temperature T 大面3 A third temperature difference ΔT3 between

[0084] S840: Based on the third temperature difference ΔT3, obtain a third compensated temperature T 补3 :T 补3 =T3+ΔT3.

[0085] In the embodiments of the present application, the higher the temperature in this temperature range, the lower the corresponding battery's charge and discharge capacity. Under normal circumstances within this temperature range, the sampled temperature on the battery cover will be higher than the battery's large surface temperature. However, there is no guarantee that the sampled temperature on the battery cover will always be higher than the battery's large surface temperature throughout the entire temperature range.

[0086] Therefore, the embodiment of the present application first sets the temperature interval (T2, T max ] is divided into multiple sub-temperature intervals. There can be n sub-temperature intervals, where the actual size of n can be adjusted according to the accuracy requirements. At this time, the temperature interval will be divided into (T max -T2) / n sub-temperature intervals. Then, step S820 is executed. Within these temperature intervals, a temperature point in each temperature interval is taken to perform a 0-100% charge and discharge cycle, and the large surface temperature of the battery itself (the third large surface temperature T 大面3 ) and the sampled temperature of the battery top cover (the third sampled temperature T3). Then, step S830 is executed. If, within one or more sub-temperature intervals, the third sampled temperature T3 is less than the third large surface temperature T 大面3 At this time, the charge and discharge rate of the battery corresponding to the sampling temperature is actually greater than the charge and discharge rate that the battery itself can achieve, that is, the charge and discharge rate corresponding to the sampling temperature exceeds the charge and discharge capacity of the battery. At this time, the third temperature difference ΔT3 is obtained, ΔT3 = T 大面3 -T3. At this time, based on the third temperature difference ΔT3, the sampled temperature of the battery is compensated to obtain the third compensated temperature T 补3 :T 补3 =T3+ΔT3.

[0087] like Figure 6 As shown, in some embodiments, the third temperature compensation strategy further includes:

[0088] S850: The third sampling temperature T3 in one or more sub-temperature intervals is greater than or equal to the third large surface temperature T 大面3 In this case, no temperature compensation is performed.

[0089] Based on the above steps, the third large surface temperature T of the battery in the present application is obtained within multiple sub-temperature intervals. 大面3 and the third sampling temperature T3 of the battery top cover, if the third sampling temperature T3 in one or more sub-temperature intervals is greater than or equal to the third large surface temperature T 大面3In this case, the calibrated battery charge and discharge rate corresponding to the third sampling temperature T3 is less than or equal to the battery's own charge and discharge capacity. In this case, even if the optimal charge and discharge rate of the battery cannot be achieved, the battery charge and discharge performance can be guaranteed not to be affected, and the battery safety will not be affected. Therefore, in this case, no temperature compensation is performed.

[0090] like Figure 3 As shown, in some embodiments, the compensation method further includes:

[0091] S500: When the sampled temperature of the battery is within the temperature interval (T1, T2), a neither heating nor cooling strategy is executed, and no temperature compensation is performed.

[0092] In the embodiments of the present application, when the battery's sampled temperature is within the temperature range (T1, T2), the battery's charge and discharge capabilities are at their optimal state. The battery requires neither heating nor cooling, and can operate normally. The battery's heat is generated by self-generated heat. This self-generated heat is primarily due to the internal resistance of the battery during the charge and discharge process, and therefore primarily occurs on the battery's large surface. From a battery structural perspective, the positive and negative current collectors are welded beneath the battery's top cover, and the positive and negative terminals are located around the top cover. These three locations are where self-generated heat is most pronounced. Due to the heat dissipation from the positive and negative terminals, the top cover temperature sample cannot be considered to represent the battery's lowest temperature. For example, for a prismatic lithium iron phosphate battery, the heating termination point (the first transition temperature T1) and the cooling start point (the second transition temperature T2) generally represent the peaks of the battery's charge and discharge capabilities. In other words, within the temperature range (T1, T2), the battery's charge and discharge rate from 0% to 100% charge is constant, and the battery's charge and discharge rate is at its maximum within this temperature range. That is, when the sampling temperature falls within the range of (T1, T2), the battery's charge and discharge capacity is constant. In this scenario, the battery operation will not be at risk due to the calibrated charge and discharge rate exceeding the battery's actual charge and discharge capacity. Therefore, when the sampling temperature falls within the range of (T1, T2), there is no need to compensate for the battery's sampling temperature.

[0093] In some embodiments, the battery also has an initial operating temperature T min ;like Figure 3 As shown, the compensation method also includes:

[0094] S300: When the battery sampling temperature is within the temperature range (T min , T1), the heating strategy is executed without temperature compensation.

[0095] In the embodiment of the present application, when the sampling temperature of the battery is within the temperature range (T min, T1), due to the low battery temperature, it is necessary to implement a heating strategy for the battery to increase the battery temperature. At this time, the battery can charge and discharge normally, and the heat of the battery comes from the heating of the bottom thermal management component and the heat generated by the battery itself. According to the thermal conductivity characteristics, the temperature sampled at the top cover of the battery is still the lowest temperature of the battery itself. Because in this temperature range, as the battery sampling temperature increases, the charge and discharge rate of the battery also increases, and the sampling temperature at the top cover is lower than the temperature of the battery itself, so when the battery sampling temperature is in the temperature range (T min , T1), the actual sampling temperature at the battery top cover is the lowest temperature of the battery itself, and the battery charge and discharge rate calibrated by this sampling temperature will not exceed the actual charge and discharge rate level of the battery under the current working conditions. Therefore, using the sampling temperature at the top cover as the calibration temperature of the battery's charge and discharge rate does not risk exceeding the battery's charging capacity. Therefore, when the battery's sampling temperature is within the temperature range (T min , T1), no temperature compensation is performed.

[0096] like Figure 3 As shown, in some embodiments, the compensation method further includes:

[0097] S200: When the sampling temperature of the battery is less than or equal to the initial operating temperature T min In this case, the battery does not work and the heating strategy is executed without temperature compensation.

[0098] S900: The battery sampling temperature is greater than the maximum temperature T max In this case, the battery does not work and the cooling strategy is executed without temperature compensation.

[0099] In the embodiment of the present application, when the sampling temperature of the battery is less than or equal to the initial operating temperature T min In this case, because the temperature is too low, the battery cannot perform charge and discharge and does not generate heat by itself. The heat of the battery comes from the heating of the bottom thermal management component (the surrounding environment also transfers heat to the battery, but all batteries are in the same environment and the environmental impact of different positions of a single battery is not much different, so the heat exchange of the environment is not studied in depth). At this time, the bottom of the battery is closest to the heating point, and the top cover is farthest from the heating point. According to the principle of thermal conduction, the temperature at the bottom of the battery is the highest, and the heat gradually decreases from the bottom to the top cover of the battery. At this time, the temperature collected at the sampling point of the top cover is the temperature of the lowest temperature of the battery itself, and when the actual sampling temperature is equal to the initial operating temperature T min When the temperature of the battery itself is greater than the initial operating temperature T min However, in a low temperature environment, the battery does not work. In this scenario, there is no risk of the battery operating under low temperature conditions. Therefore, when the sampling temperature of the battery is less than or equal to the initial operating temperature T minIn this case, there is no need to compensate for the sampled temperature of the battery.

[0100] In the embodiment of the present application, when the sampling temperature of the battery is greater than the maximum temperature T max In this case, the battery cannot work because the temperature exceeds the maximum temperature at which the battery can operate. However, in order to ensure the safety of the battery, a cooling strategy is implemented and the thermal management component cools the battery. The heat of the battery comes from the ambient heat minus the cooling heat dissipation. The bottom of the battery contacts the thermal management component, but the temperature sampling position is on the battery top cover. According to the principle of thermal conductivity, the temperature at the battery top cover is the highest temperature of the battery itself. Moreover, when the sampling temperature of the battery is greater than the maximum temperature T max In this case, the battery does not work, so there is no need to compensate for the sampling temperature.

[0101] It should be noted that the embodiments of the present application can use fresh batteries to form a battery module or battery pack for charge and discharge tests. Simulate the working environment of different temperature ranges within the entire temperature range in which the battery can perform charge and discharge operations, so as to obtain the sampling temperature of the battery top cover and the temperature of the large surface of the battery. Based on the obtained test data, the sampling temperature of the battery is compensated using the compensation method of the present application, and the compensated temperature is remapped to the corresponding battery charge and discharge rate in the battery charging map (Mapping, mapping, atlas) diagram for charge and discharge. This can prevent the battery's calibrated charge and discharge rate from exceeding the battery's actual charge and discharge capacity, thereby protecting the battery's performance and safety.

[0102] It should also be noted that the battery pack or battery module of the embodiment of the present application extends from the total positive and total negative to connect the load to form a complete circuit. When sampling the temperature of the battery top cover, it is necessary to pay attention to the large overcurrent of the aluminum bar and copper bar at the total positive and total negative. Assuming that the cross-sectional area of the aluminum bar at the total positive is S, the length is L, the resistivity is ρ, the current of a single battery is I, and the voltage is U, then the current at the total positive aluminum bar is 2I, and the heat generated at the aluminum bar at the same time is: Q 产热 =4I 2 ρL t / Theoretically, the heat generated by the aluminum bars at the positive and negative locations is four times that of the aluminum bars at other locations. Furthermore, although the copper busbars connected to the positive and negative locations have a resistivity 0.6 times that of aluminum, their cross-sectional area is much smaller than that of the aluminum bars, significantly affecting the temperatures at the positive and negative locations. Therefore, it is important to avoid these two areas when locating temperature sampling points.

[0103] It should also be noted that the charging rate of the battery in the embodiment of the present application can be set according to the actual charging and discharging capacity of the battery itself, and the maximum charging and discharging rate of the battery can be 1SOC (State of Charge, state of charge or power), 2SOC or 4SOC, etc. Please refer to Table 1. The embodiment of the present application takes the battery with a charging rate of 1SOC as an example to divide the temperature range and briefly explain it. Table 1 shows the battery charging map with a maximum charging and discharging rate of 1SOC (the parameter in the table is the rate, such as 1.00 means the charging current is 1× the rated capacity of the battery, the horizontal axis is the battery charging state, and the vertical axis is the battery temperature).

[0104] Table 1

[0105]

[0106] In Table 1, -20°C corresponds to the initial operating temperature T of the battery in the embodiment of the present application. min , 15 ℃ can correspond to the first jump temperature T1 of the embodiment of the present application, 40 ℃ can correspond to the second jump temperature T2 of the embodiment of the present application, and 60 ℃ can correspond to the first jump temperature T max , (40°C, 60°C) can correspond to the third sampling temperature T3 of the embodiment of the present application. min In the temperature range (T1, T2), as the temperature increases, the charge and discharge rate of the battery increases; in the temperature range (T1, T2), as the temperature increases, the charge and discharge rate of the battery remains constant at the optimal state; in the temperature range (T2, T max ) temperature range, as the temperature increases, the battery's charge and discharge rate decreases.

[0107] The compensation method of the embodiment of the present application also includes: further correcting the compensated temperature difference. Specifically, the battery can be charged according to the battery charging map in Table 1, and the thermal management strategy (heating when required and cooling when required) is executed at the same time. The temperature difference between the battery top cover and the large surface of the battery is measured in the SOC range corresponding to the maximum charging rate of the battery in different temperature ranges, and the maximum temperature difference between the battery top cover and the large surface of the battery in different temperature ranges, charging rates, and SOC ranges is obtained, as shown in Figure 2 below.

[0108] Table 2

[0109]

[0110] Table 2 shows the maximum temperature difference between the battery cover and the large surface temperature of the battery itself in different temperature ranges, charge rates, and SOC charging ranges. Of course, the maximum temperature difference can be measured specifically according to the specific implementation. Table 2 of this application is only used as an example to indicate in which temperature range, at the corresponding maximum charge and discharge rate, the SOC range in which the maximum temperature difference will exist. The specific value of this temperature difference is not shown. The corresponding temperature difference value is the actual compensation value between the battery sampling temperature and the actual temperature in different temperature ranges, different charge and discharge rates, and different SOC ranges.

[0111] It should be noted that the battery temperature sampling error compensation method of the embodiment of the present application can ensure that the above-mentioned compensation strategy is compensated for the actual sampling temperature under different temperature conditions. The battery charge and discharge rate set by the battery management system in the battery pack is within the charge and discharge capacity of the battery itself. This avoids the battery charge and discharge rate set by the battery management system exceeding the charge and discharge capacity of the battery itself under different temperature environments, reducing the risk of lithium plating in the short-term use of the battery and the risk of loss of electrical performance and safety performance in long-term use.

[0112] It should also be noted that the battery temperature sampling error compensation method of the embodiment of the present application is a conservative strategy, the main purpose of which is to reduce the safety risks of battery use. At the same time, when the compensation strategy intervenes, the impact on the battery charge and discharge rate is relatively small, which can ensure normal charging and discharging of the battery.

[0113] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0114] The above is a detailed introduction to a battery temperature sampling error compensation method provided in an embodiment of the present application, and a specific example is used to illustrate the principles and implementation methods of the present application. The description of the above embodiment is only used to help understand the technical solution and core idea of the present application; ordinary technicians in this field should understand that: it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of each embodiment of the present application.

Claims

1. A battery temperature sampling error compensation method, characterized in that: include: When the sampled temperature of the battery is at a first transition temperature T1, executing a first temperature compensation strategy to perform temperature compensation on the first transition temperature T1; When the sampled temperature of the battery is at a second transition temperature T2, a second temperature compensation strategy is executed to perform temperature compensation on the second transition temperature T2, wherein T2>T1.

2. The battery temperature sampling error compensation method according to claim 1, characterized in that: The first temperature compensation strategy includes: Obtain the first large surface temperature T when the sampling temperature of the battery is at the first jump temperature T1 大面1 ; Obtain the first jump temperature T1 and the first large surface temperature T 大面1 A first temperature difference ΔT1 between Based on the first temperature difference ΔT1, a first compensated temperature T is obtained. 补1 :T 补1 =T1-ΔT1.

3. The battery temperature sampling error compensation method according to claim 1, characterized in that: The second temperature compensation strategy includes: Obtain the second largest surface temperature T when the sampling temperature of the battery is at the second jump temperature T2 大面2 ; Get the second jump temperature T2 and the second large surface temperature T 大面2 A second temperature difference ΔT2 between Based on the second temperature difference ΔT2, the second compensated temperature T is obtained. 补2 :T 补2 =T2+ΔT2.

4. The battery temperature sampling error compensation method according to claim 1, characterized in that: The compensation method further includes: executing a thermal management strategy on the battery; The thermal management strategies include: heating strategy, cooling strategy and neither heating nor cooling strategy; the first jump temperature T1 is the sampling temperature when the heating strategy ends; the second jump temperature T2 is the sampling temperature when the cooling strategy starts.

5. The battery temperature sampling error compensation method according to claim 4, characterized in that: The compensation method further comprises: Get the maximum temperature T of the battery when it stops working under the execution of the cooling strategy max , satisfying, T2<T max ; When the sampling temperature of the battery is in the temperature range (T2, T max ], execute the third temperature compensation strategy.

6. The battery temperature sampling error compensation method according to claim 5, characterized in that: The third temperature compensation strategy includes: The temperature interval (T2, T max ] is divided into multiple sub-temperature intervals; Obtain the third sampling temperature T3 and the third large surface temperature T3 when the battery is charged and discharged in multiple sub-temperature intervals 大面3 ; The third sampling temperature T3 in one or more of the sub-temperature intervals is lower than the third large surface temperature T 大面3 In the case of, obtaining the third sampling temperature T3 and the third large surface temperature T 大面3 A third temperature difference ΔT3 between Based on the third temperature difference ΔT3, a third compensated temperature T is obtained. 补3 :T 补3 =T3+ΔT3.

7. The battery temperature sampling error compensation method according to claim 6, characterized in that: The third temperature compensation strategy further includes: The third sampling temperature T3 in one or more of the sub-temperature intervals is greater than or equal to the third large surface temperature T 大面3 In this case, no temperature compensation is performed.

8. The battery temperature sampling error compensation method according to claim 4, characterized in that: The compensation method further includes: When the sampled temperature of the battery is within the temperature interval (T1, T2), the neither heating nor cooling strategy is executed, and no temperature compensation is performed.

9. The battery temperature sampling error compensation method according to claim 5, characterized in that: The battery also has an initial operating temperature T min The compensation method further comprises: When the sampling temperature of the battery is in the temperature range (T min , T1), the heating strategy is executed without temperature compensation.

10. The battery temperature sampling error compensation method according to claim 9, characterized in that: The compensation method further comprises: When the sampling temperature of the battery is less than or equal to the initial operating temperature T min In the case of , the battery does not work, and the heating strategy is executed without temperature compensation; When the sampling temperature of the battery is greater than the maximum temperature T max In this case, the battery does not work and the cooling strategy is executed without temperature compensation.

Images