A battery pack busbar over-temperature detection method, system, application and storage medium

Abstract

The application discloses a kind of battery pack busbar over-temperature detection method, system, application and storage medium.The battery pack busbar over-temperature detection method of the present application includes the steps of obtaining the busbar temperature value corresponding to each battery module in battery pack respectively, non-busbar temperature value;First over-temperature threshold, first threshold, first temperature difference value are set;In a single battery module, the difference between busbar temperature value and the non-busbar temperature value is set as the first temperature difference value;The difference between the first over-temperature threshold and the first temperature difference value of each battery module is compared, whether greater than or equal to the first threshold, if not, the busbar of corresponding battery module is about to over-temperature is judged.The beneficial effects of the present application are that it can be used to detect and predict the problem that busbar is about to over-temperature failure.

Description

Technical Field

[0001] This invention belongs to the technical field of power battery systems, specifically relating to a method, system, application, and storage medium for detecting over-temperature of battery pack busbars. Background Technology

[0002] In a battery management system (BMS), a battery pack contains multiple battery modules, each including one or more busbars to achieve the required output voltage and current characteristics. Therefore, temperature monitoring of the busbars is necessary to ensure the stability of the corresponding output voltage and current. Temperature sensors are typically placed near the bolted connections between the busbars and the modules / cells to collect temperature data. When there is poor contact between the busbar and the cell, the contact resistance increases. Since the heating power of resistance is the square of the current multiplied by the internal resistance, the heat generated by the busbar will increase, causing it to overheat and potentially even melt.

[0003] In existing technologies, to detect whether the temperature of the busbar in a battery pack is abnormal, it is usually determined whether the busbar is overheated by directly comparing the temperature at a certain location or the whole of the detected battery module busbar.

[0004] However, this method of directly comparing the temperature of a certain point on the busbar with a set threshold to determine overheating cannot reflect the overall temperature of the busbar, and can only detect overheating after an abnormal temperature occurs in the busbar. When overheating occurs, it often means that the battery pack may have already failed or been damaged. At this point, adjusting the battery pack voltage cannot avoid the problem of busbar damage. The problem caused by the current technology's inability to predict overheating in advance and adjust the busbar voltage accordingly will further cause more performance loss or failure to the battery pack during charging. Summary of the Invention

[0005] In order to overcome the defects and deficiencies of the existing technology, the first objective of this invention is to provide a method for detecting over-temperature of battery pack busbars, the second objective is to provide a system for detecting over-temperature of battery pack busbars, the third objective is to provide the application of three methods for detecting over-temperature of battery pack busbars, and the fourth objective is to provide a storage medium for predicting in advance whether the busbars of the battery pack will over-temperature.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for detecting over-temperature of a battery pack busbar includes the following steps:

[0008] Obtain the busbar temperature value and non-busbar temperature value for each battery module in the battery pack.

[0009] Set the first over-temperature threshold, the first threshold value, and the first temperature difference value;

[0010] In a single battery module, the difference between the busbar temperature value and the non-busbar temperature value is set as the first temperature difference value;

[0011] Compare the difference between the first over-temperature threshold and the first temperature difference value of each battery module, and determine whether it is greater than or equal to the first threshold value. If not, predict that the busbar of the corresponding battery module will soon over-temperature.

[0012] Preferably, when the difference between the first over-temperature threshold and the first temperature difference value of each battery module is less than the first threshold value, the method further includes the step of:

[0013] Obtain the maximum value of the busbar temperature value among all battery modules, and set the battery module corresponding to the maximum value of the busbar temperature value as the first battery module;

[0014] Obtain the maximum value of the non-busbar temperature value in the battery modules other than the first battery module, and set the battery module corresponding to the maximum value of the busbar temperature value as the second battery module;

[0015] Set a second over-temperature threshold, a second threshold value, and a second temperature difference value;

[0016] The difference between the maximum value of the manifold temperature and the maximum value of the non-manifold temperature is set as the second temperature difference value;

[0017] Compare the difference between the second over-temperature threshold and the second temperature difference value to see if it is greater than or equal to the second threshold value. If not, it is predicted that the bus corresponding to the first battery module will soon over-temperature.

[0018] Furthermore, the second over-temperature threshold is determined based on the difference between the maximum heat generation temperature of the busbar when all battery modules are working normally under the set current range and the maximum heat generation temperature of the non-busbar location when all battery modules are working normally under the set current range.

[0019] The preferred second threshold value is 2 to 4°C.

[0020] Preferably, before comparing whether the difference between the first over-temperature threshold and the first temperature difference value of each battery module is greater than or equal to the first threshold value, the method further includes the following steps:

[0021] Set the third over-temperature threshold, the third threshold value, and the third temperature difference value;

[0022] The difference between the third over-temperature threshold and the bus temperature value of each battery module is set as the third temperature difference value;

[0023] Compare whether the third temperature difference value is greater than or equal to the third threshold value; if so, compare the difference between the first over-temperature threshold and the first temperature difference value of each battery module, and predict whether the busbar of the corresponding battery module is about to over-temperature; if not, predict that the busbar of the corresponding battery module is about to over-temperature.

[0024] Furthermore, the third over-temperature threshold is determined based on the maximum heating temperature of the busbar when all battery modules are working normally within the set current range;

[0025] The preferred value for the third threshold is 3 to 8°C.

[0026] Preferably, the first over-temperature threshold is determined based on the difference between the maximum heat generation temperature of the busbar when a single battery module is working normally under the set current range and the maximum heat generation temperature of the non-busbar location when the battery module is working normally under the set current range.

[0027] The preferred first threshold value is 2 to 4℃.

[0028] Preferably, obtaining the non-manifold temperature value includes the following steps:

[0029] The temperature values ​​at multiple locations outside the busbars in a single battery module are obtained, and then the average value of the temperature values ​​at multiple locations outside the busbars is calculated. This average value is used as the non-busbar temperature value of the battery module.

[0030] A battery pack busbar over-temperature detection system according to any one of the preceding claims includes multiple temperature sensors, a temperature acquisition module, a calculation and processing module, and a first over-temperature prediction module.

[0031] The multiple temperature sensors are respectively located at the bus position and non-bus position of each battery module in the battery pack, and are used to acquire the temperature signals at the bus position and non-bus position;

[0032] The temperature acquisition module is electrically connected to multiple temperature sensors and is used to convert the temperature signal into bus temperature value and non-bus temperature value corresponding to each battery module.

[0033] The calculation and processing module is connected to the temperature acquisition module and is used to calculate the first temperature difference value based on the bus temperature value and the non-bus temperature value of each of the battery modules.

[0034] The first over-temperature prediction module is connected to the calculation and processing module and is used to predict whether the busbar on the corresponding battery module will over-temperature based on whether the difference between the first over-temperature threshold and the first temperature difference is greater than or equal to the first threshold value.

[0035] Preferably, it also includes a second over-temperature prediction module;

[0036] The temperature acquisition module is also used to convert the temperature signal into the maximum value of the bus temperature value corresponding to the first battery module and the maximum value of the non-bus temperature value corresponding to the second battery module.

[0037] The calculation and processing module is also used to calculate the second temperature difference value based on the maximum value of the busbar temperature value corresponding to the first battery module and the maximum value of the non-busbar temperature value corresponding to the second battery module.

[0038] The second over-temperature prediction module is connected to the calculation and processing module and is used to predict whether the busbar corresponding to the busbar temperature value will over-temperature based on whether the difference between the second over-temperature threshold and the second temperature difference value is greater than or equal to the second threshold value.

[0039] Preferably, it also includes a third over-temperature prediction module;

[0040] The third over-temperature prediction module is connected to the temperature acquisition module and is used to predict whether the busbar on the corresponding battery module is about to over-temperature based on whether the third temperature difference value is greater than or equal to the third threshold value.

[0041] Preferably, the calculation processing module is further configured to calculate an average value based on the temperature values ​​at multiple locations outside the busbars in a single battery module, and use the average value as the non-busbar temperature value of the battery module.

[0042] An application of the battery pack bus over-temperature detection method according to any one of the foregoing claims, the application comprising at least one of the following:

[0043] Application of battery pack bus over-temperature detection method in battery pack charging; the application in battery pack charging includes reducing the charging voltage of the battery pack according to a set voltage reduction ratio when it is predicted that the bus will over-temperature.

[0044] Application of the battery pack busbar over-temperature detection method on the battery pack data platform; the application on the battery pack data platform includes sending a prediction record to the data platform when it is predicted that the busbar will over-temperature; when the number of prediction records sent is greater than or equal to a set number, the data platform marks the battery pack as having a faulty state.

[0045] The application of the battery pack busbar over-temperature detection method in battery pack testing and maintenance; the application in battery pack testing and maintenance includes indicating that when the busbar is predicted to over-temperature, it indicates that there is a fault in the busbar in the battery pack, and then the battery pack or busbar is returned for repair.

[0046] A storage medium storing a computer-executable program matching any of the preceding battery pack bus over-temperature detection methods, wherein when the computer-executable program is run, the battery pack bus over-temperature detection method is executed.

[0047] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0048] Compared to existing technologies that directly compare whether the detected busbar temperature exceeds its over-temperature temperature, the battery pack busbar over-temperature detection method of the present invention utilizes the comparison of a first temperature difference value with a first over-temperature threshold and a first threshold value. The first threshold value is used as a lead time to describe the temperature fluctuation range of the busbar when it is within the normal current range and has not approached over-temperature. This avoids the limitation that it can only be detected when the busbar is over-temperature. It achieves higher sensitivity in predicting the phenomenon of obvious abnormal busbar temperature in the battery module that is about to over-temperature (for example, when the busbar connection in a single battery module is obviously loose, the internal resistance of the busbar contact increases sharply but the overall resistance does not change much and the current is still within the normal range, resulting in a significant change in the heat generation of the busbar at the connection, but the internal temperature change of the battery module is small).

[0049] The present invention provides a battery pack busbar over-temperature detection method that utilizes a comparison between a second temperature difference value and a second over-temperature threshold and a second limit value. The second limit value is used as a lead time to describe the temperature fluctuation range of the busbar when it is not close to over-temperature under normal current range. This avoids the limitation that the busbar can only be detected when it is over-temperature. It achieves the effect of predicting in advance the high temperature diffusion phenomenon when a single battery module busbar in the battery pack is about to over-temperature and affect the normal operation of other battery module busbars (for example, when the overall temperature of a certain battery module in the battery pack is high, heat is conducted to the inside of other battery module busbars).

[0050] The present invention provides a battery pack busbar over-temperature detection method. Before predicting whether over-temperature is imminent, it compares a third temperature difference value with a third over-temperature threshold and a third limit value. The third limit value is used as a reserve for over-temperature. By adjusting the third limit value, it can predict over-temperature (drastic temperature change) or predict when the temperature change is not drastic (e.g., when the busbar connection is not obviously loose in a single battery module, the increase in busbar contact internal resistance is small, and the current is still within the normal range, resulting in an insignificant increase in heat generation at the busbar connection). Furthermore, by adjusting the third limit value to a small temperature range (3-8°C) with a certain lead time, it can achieve better sensitivity in predicting whether over-temperature is imminent when the temperature change is not drastic.

[0051] The battery pack busbar over-temperature detection system of the present invention has multiple temperature sensors, temperature acquisition modules, and calculation and processing modules distributed in multiple locations. Utilizing a first over-temperature prediction module, it can predict busbar over-temperature even when the busbar temperature in a single battery module has not reached a high level, effectively identifying obvious abnormal busbar temperature changes that indicate an impending over-temperature phenomenon. The second over-temperature prediction module can predict overall busbar over-temperature in the battery pack in advance, effectively identifying high-temperature diffusion in the busbars of a single battery module. Utilizing a third over-temperature prediction module, it can still determine busbar over-temperature problems even when the busbar connection looseness is not obvious, effectively identifying minor loosening of the busbar connection.

[0052] The application of the battery pack busbar over-temperature detection method of the present invention in battery pack charging can ensure the detection of busbar temperature during the charging and discharging process of the battery pack, thereby improving safety; the application of the battery pack busbar over-temperature detection method of the present invention in battery pack data platform can remotely detect whether there are faults in the battery pack later; the application of the battery pack busbar over-temperature detection method of the present invention in battery pack testing and maintenance can detect busbar connection faults in advance during battery pack testing and maintenance, thereby avoiding safety issues.

[0053] The storage medium of the present invention can execute the method of the present invention to achieve the effect of predicting in advance whether the busbar in the battery pack will overheat. Attached Figure Description

[0054] Figure 1 This is a schematic flowchart of one of the battery pack busbar over-temperature detection methods of the present invention;

[0055] Figure 2 This is a flowchart illustrating another method for detecting over-temperature of battery pack busbars according to the present invention.

[0056] Figure 3 This is a schematic diagram of the framework of one of the battery pack busbar over-temperature detection systems of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0059] Furthermore, the terms "third," "first," and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Similarly, words such as "a," "one," or "the" do not indicate a quantity limitation but rather the presence of at least one. Words such as "including" or "contains" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0060] Example 1

[0061] like Figure 1 As shown. This embodiment 1 provides a method for detecting over-temperature of a battery pack busbar, including the following steps:

[0062] S1. At the same set time point, obtain the busbar temperature value and non-busbar temperature value corresponding to each battery module in the battery pack.

[0063] The total number of battery modules in the battery pack is N, and the busbar temperature value of each battery module is marked as follows: n represents the nth battery module, and i represents the nth position on the busbar within the battery module; the non-busbar temperature value corresponding to each battery module is marked as follows. k represents the nth non-bus position; (Note: k is the position of the non-bus system) (x is any number other than n);

[0064] This embodiment further optimizes the acquisition of the non-busbar temperature value of the nth battery module. The steps are as follows: Obtain temperature values ​​at multiple locations outside the busbar in a single battery module. (k = 1, ..., K, where K is the total number of locations where temperature values ​​are obtained on a single battery module), and then calculate the average value of the temperature values ​​of the battery module at multiple locations outside the busbar. and the average value As the non-manhole temperature value

[0065] S2. Calculate the busbar temperature value for each battery module separately. With their respective non-manifold temperature values The difference is recorded as the first temperature difference value ΔT1;

[0066] Compare the first over-temperature threshold T set for each battery module. t1Is the difference between the first temperature difference value ΔT1 and the first temperature difference value ΔT1 greater than or equal to the set first threshold value a, i.e., T? t1 Does -ΔT1≥a hold true?

[0067] If the first temperature difference ΔT1 has exceeded the threshold of the corresponding over-temperature alarm, the bus contact internal resistance will increase significantly, resulting in a significant increase in temperature and obvious loosening of the bus contact. In order to ensure that the bus operates within the normal current range, a small advance threshold value a is used to relatively sensitively predict the over-temperature problem of the corresponding bus on the corresponding battery module.

[0068] Among them, the first over-temperature threshold T t1 The difference between the maximum heat generation temperature of the busbar when each battery module is working normally under a set charging or discharging current range and the maximum heat generation temperature of the non-busbar location when the battery module is working normally under a set current range is determined; the value of the first threshold value a is in the range of 2 to 4℃, and in this embodiment, the first threshold value a is preferably 2℃;

[0069] If so, it means that the first temperature difference value ΔT1 has not exceeded the threshold of the corresponding over-temperature alarm, and there is no obvious poor contact in the busbar. Then proceed to the next step.

[0070] S3. Obtain the maximum busbar temperature value of all battery modules in the battery pack, denoted as T. max1 The corresponding battery module is designated as the first battery module; the maximum non-busbar temperature value of other battery modules besides the first battery module is obtained and denoted as T. max2 The corresponding battery module is designated as the second battery module, and one or more of the remaining battery modules can be designated as the second battery module.

[0071] In this embodiment, each battery module preferably has a positive bus and a negative bus, with each bus corresponding to a bus temperature value. The maximum value T of the bus temperature value of the first battery module is... max1 This refers to the highest temperature value among multiple locations on the positive and negative busbars of the first battery module; in other embodiments, each battery module may also have other busbars, in which case the maximum temperature value T of the busbars of the first battery module is... max1 This refers to the highest temperature value among multiple locations across all busbars in the first battery module;

[0072] S4, when the first over-temperature threshold T in the battery module t1When the difference between the current and the first temperature difference value ΔT1 is greater than or equal to the first threshold value, it is possible that the busbar of a single battery module is about to overheat. However, the heat does not cause the temperature of the non-busbar location of that battery module to rise. Instead, the heat is conducted to the non-busbar locations in other battery modules. Therefore, step S4 performs the following process to supplement the prediction of the busbar overheating:

[0073] Calculate the maximum value T of the busbar temperature of the first battery module. max1 The maximum value T of the non-busbar temperature of the second battery module max2 The difference is recorded as the second temperature difference value ΔT2, which is ΔT2 = T. max1 -T max2 ;

[0074] Compare the second over-temperature threshold T set in the battery pack t2 Subtract the second temperature difference value ΔT2 from the difference, and check if the difference is greater than or equal to the set second threshold value b, which is T. t2 Does -ΔT2≥b hold true?

[0075] If the second temperature difference ΔT2 has exceeded the over-temperature alarm threshold, the corresponding busbar of the first battery module will experience over-temperature problems, and the heat will be conducted to other battery modules and affect the busbars of other modules. In this case, a smaller advance second threshold value b is used to more sensitively predict that the corresponding busbar on the first battery module will experience over-temperature problems, and the heat conduction has already affected the normal operation of the second battery module.

[0076] Among them, the second over-temperature threshold T t2 The difference between the maximum heat generation temperature of the busbar in all battery modules when they are working normally under the set charging or discharging current range and the maximum heat generation temperature of the non-busbar location in all battery modules when they are working normally under the set charging or discharging current range is determined; the value of the second threshold value b is in the range of 2 to 4℃, and in this embodiment, the second threshold value b is preferably 2℃;

[0077] If the second temperature difference value ΔT2 does not exceed the threshold of the corresponding over-temperature alarm, and the busbars of each battery module in the battery pack do not show signs of being about to over-temperature, then proceed to the next time point to continue over-temperature detection of the battery pack busbars.

[0078] In this embodiment, the first over-temperature threshold T is preferred. t1 First threshold value a, second over-temperature threshold T t2The second threshold value b is an empirical value obtained by statistically analyzing data from charging or discharging temperature tests of at least 50 battery modules of the same specification within at least 3 consecutive hours at one or more set normal operating charging and discharging current ranges. When it is necessary to perform over-temperature detection on the busbar in a battery pack of a different specification, another battery pack of the same specification as the one being tested must be selected to perform busbar charging or discharging temperature tests, and another set of first over-temperature thresholds T is obtained accordingly. t1 First threshold value a, second over-temperature threshold T t2 The second threshold value b, the values ​​of each parameter may be the same as or different from the results of the previous tests.

[0079] In this embodiment, multiple temperature sensors are preferably used to acquire the corresponding temperature signals, and a temperature acquisition module is used to convert the corresponding temperature signals into relevant temperature value data. The battery pack contains multiple battery modules. In this embodiment, each battery module preferably has a temperature sensor on its positive and negative busbars, and multiple additional temperature sensors are evenly distributed in each battery module outside of the positive and negative busbars. Each temperature sensor transmits its respective temperature signal to the temperature acquisition module, which then converts it into a temperature value.

[0080] Compared with the prior art, the advantages of this embodiment 1 are as follows:

[0081] The obtained busbar temperature values ​​for each battery module in the battery pack. Non-manifold temperature value Based on this, in this embodiment 1, the first temperature difference value ΔT1 and the first over-temperature threshold T are used. t1 The comparison of the first threshold value 'a' is used to describe the temperature fluctuation range of the busbar when it is not close to overheating under normal current range. This avoids the limitation that it can only be detected when the busbar is overheating. It enables higher sensitivity to predict the phenomenon of obvious abnormal busbar temperature in the battery module that is about to overheat (for example, when the busbar connection is obviously loose in a single battery module, the internal resistance of the busbar contact increases sharply but the overall resistance does not change much and the current is still within the normal range, resulting in a significant change in the heat generation of the busbar at the connection, but the internal temperature of the battery module changes little).

[0082] In this embodiment 1, the second temperature difference ΔT2 and the second over-temperature threshold T are used. t2The comparison of the second threshold value b uses the second threshold value b as a lead time to describe the temperature fluctuation range of the busbar when it is not close to overheating under normal current range. This avoids the limitation that it can only be detected when the busbar is overheated. It achieves the effect of predicting the high temperature diffusion phenomenon when a single battery module busbar in the battery pack is about to overheat and affect the normal operation of other battery module busbars (for example, when the overall temperature of a certain battery module in the battery pack is high, heat is conducted to the inside of other battery module busbars).

[0083] Example 2

[0084] like Figure 2 As shown. This embodiment 2 provides a method for detecting over-temperature of a battery pack busbar, including the following steps:

[0085] S1. At the same set time point, obtain the busbar temperature value and non-busbar temperature value corresponding to each battery module in the battery pack; preferably, further obtain the maximum value T of the busbar temperature values ​​of all battery modules in the battery pack. max1 And the corresponding battery module is designated as the first battery module;

[0086] This embodiment further optimizes the acquisition of the non-busbar temperature value of the nth battery module. The steps are as follows: Obtain temperature values ​​at multiple locations outside the busbar in a single battery module. (k = 1, ..., K, where K is the total number of locations where temperature values ​​are obtained on a single battery module), and then calculate the average value of the temperature values ​​of the battery module at multiple locations outside the busbar. and the average value As the non-manhole temperature value

[0087] S2, Calculate the set third over-temperature threshold T t3 Subtract the individual bus temperature values ​​of each battery module The difference is set as the third temperature difference value ΔT3. Then, it is compared whether the third temperature difference value ΔT3 is greater than or equal to the set third threshold value c, that is, whether ΔT3≥c holds true.

[0088] Otherwise, it indicates the bus temperature value in the corresponding battery module. The temperature has exceeded the corresponding over-temperature alarm threshold. At this point, the increase in bus contact resistance is small, resulting in a negligible increase in heat generation. To ensure the bus operates within the normal current range, a larger advance third threshold value c is used to provide sufficient redundancy for predicting the bus temperature in advance. The corresponding busbar will experience overheating issues;

[0089] Among them, the third overtemperature threshold T t3To determine the maximum heating temperature of the busbar when all battery modules are working normally under the set charging or discharging current range; the value of the third threshold c is in the range of 3 to 8℃, and in this embodiment, the third threshold c is preferably 5℃;

[0090] If so, it indicates the busbar temperature value. If the over-temperature alarm threshold is not exceeded and there is no loose connection on the bus causing over-temperature, proceed to the next step.

[0091] In this preferred embodiment, due to the busbar temperature value With maximum value T max1 Therefore, the third overtemperature threshold T can be set directly. t3 The maximum value T of the manifold temperature max1 The difference is the third temperature difference value ΔT3, and then it is compared whether the third temperature difference value ΔT3 is greater than or equal to the third threshold value c;

[0092] If so, then the busbar temperature value T of the first battery module max1 The corresponding over-temperature alarm threshold was not exceeded, and the busbar did not overheat due to slight connection looseness. It can be further inferred that the busbars in all battery modules did not overheat due to slight connection looseness, and then proceed to the next step.

[0093] S3. Calculate the bus temperature value for each battery module separately. With their respective non-manifold temperature values The difference is recorded as the first temperature difference value ΔT1;

[0094] Compare the first over-temperature threshold T set for each battery module. t1 Is the difference between the first temperature difference value ΔT1 and the first temperature difference value ΔT1 greater than or equal to the set first threshold value a, i.e., T? t1 Does -ΔT1≥a hold true?

[0095] If the first temperature difference ΔT1 has exceeded the threshold of the corresponding over-temperature alarm, the bus contact internal resistance will increase significantly, resulting in a significant increase in temperature and obvious loosening of the bus contact. In order to ensure that the bus operates within the normal current range, a small advance threshold value a is used to relatively sensitively predict the over-temperature problem of the corresponding bus on the corresponding battery module.

[0096] Among them, the first over-temperature threshold T t1The difference between the maximum heat generation temperature of the busbar when each battery module is working normally under a set charging or discharging current range and the maximum heat generation temperature of the non-busbar location when the battery module is working normally under a set current range is determined; the value of the first threshold value a is in the range of 2 to 4℃, and in this embodiment, the first threshold value a is preferably 2℃;

[0097] If so, it means that the first temperature difference value ΔT1 has not exceeded the threshold of the corresponding over-temperature alarm, and there is no obvious abnormal temperature change in the bus. Then proceed to the next step.

[0098] S4. Obtain the maximum value T of the non-busbar temperature value in the battery modules other than the first battery module. max2 And the corresponding battery module is recorded as the second battery module;

[0099] S5, when the first over-temperature threshold T in the battery module t1 When the difference between the current and the first temperature difference value ΔT1 is greater than or equal to the first threshold value, it is possible that the busbar of a single battery module is about to overheat. However, the heat does not cause the temperature of the non-busbar location of that battery module to rise. Instead, the heat is conducted to the non-busbar locations in other battery modules. Therefore, step S5 performs the following process to supplement the prediction of the busbar overheating:

[0100] Calculate the maximum value T of the busbar temperature of the first battery module. max1 The maximum value T of the non-busbar temperature of the second battery module max2 The difference is recorded as the second temperature difference value ΔT2, which is ΔT2 = T. max1 -T max2 ;

[0101] Compare the second over-temperature threshold T set in the battery pack t2 Subtract the second temperature difference value ΔT2 from the difference, and check if the difference is greater than or equal to the set second threshold value b, which is T. t2 Does -ΔT2≥b hold true?

[0102] If the second temperature difference ΔT2 has exceeded the over-temperature alarm threshold, the corresponding busbar of the first battery module will experience over-temperature problems, and the heat will be conducted to other battery modules and affect the busbars of other modules. In this case, a smaller advance second threshold value b is used to more sensitively predict that the corresponding busbar on the first battery module will experience over-temperature problems, and the heat conduction has already affected the normal operation of the second battery module.

[0103] Among them, the second over-temperature threshold T t2The difference between the maximum heat generation temperature of the busbar in all battery modules when they are working normally under the set charging or discharging current range and the maximum heat generation temperature of the non-busbar location in all battery modules when they are working normally under the set charging or discharging current range is determined; the value of the second threshold value b is in the range of 2 to 4℃, and in this embodiment, the second threshold value b is preferably 2℃;

[0104] If so, end the current over-temperature test of the busbar or perform the busbar over-temperature test at the next time point.

[0105] In this embodiment, the first over-temperature threshold T is preferred. t1 Second over-temperature threshold T t2 The third over-temperature threshold T t3 The first threshold value a, the second threshold value b, and the third threshold value c are all empirical values ​​obtained by statistically analyzing data from charging or discharging temperature tests of at least 50 battery modules of the same battery pack specifications for at least 3 consecutive hours under one or more set normal operating charging or discharging current ranges. When it is necessary to perform over-temperature detection on the busbar in a battery pack of a different specification, another battery pack of the same specification as the one being tested must be selected to perform busbar charging or discharging temperature tests, and another set of first over-temperature thresholds T must be obtained. t1 Second over-temperature threshold T t2 The third over-temperature threshold T t3 The values ​​of the first threshold value a, the second threshold value b, and the third threshold value c may be the same as or different from the results of the previous tests.

[0106] In this embodiment, multiple temperature sensors are preferably used to acquire the corresponding temperature signals, and a temperature acquisition module is used to convert the corresponding temperature signals into relevant temperature value data. The battery pack contains multiple battery modules. In this embodiment, each battery module preferably has a temperature sensor on its positive and negative busbars, and multiple additional temperature sensors are evenly distributed in each battery module outside of the positive and negative busbars. Each temperature sensor transmits its respective temperature signal to the temperature acquisition module, which then converts it into a temperature value.

[0107] Compared with the prior art, the advantages of this embodiment 2 are as follows:

[0108] In this embodiment 2, the first temperature difference ΔT1 and the first over-temperature threshold T are used. t1The comparison of the first threshold value 'a' is used to describe the temperature fluctuation range of the busbar when it is not close to overheating under normal current range. This avoids the limitation that it can only be detected when the busbar is overheating. It enables higher sensitivity to predict the phenomenon of obvious abnormal busbar temperature in the battery module that is about to overheat (for example, when the busbar connection is obviously loose in a single battery module, the internal resistance of the busbar contact increases sharply but the overall resistance does not change much and the current is still within the normal range, resulting in a significant change in the heat generation of the busbar at the connection, but the internal temperature of the battery module changes little).

[0109] In this embodiment 2, the second temperature difference value ΔT2 and the second over-temperature threshold T are used. t2 The comparison of the second threshold value b is used to describe the temperature fluctuation range of the busbar when it is not close to overheating under normal current range. This avoids the limitation that it can only be detected when the busbar is overheated. It can achieve the effect of predicting the high temperature diffusion phenomenon when a single battery module busbar in the battery pack is about to overheat and affect the normal operation of other battery module busbars (for example, when the overall temperature of a certain battery module in the battery pack is high, heat is conducted to the inside of other battery module busbars).

[0110] In this embodiment 2, the third temperature difference value ΔT3 and the third over-temperature threshold T are utilized. t3 The comparison of the third threshold value c shows that the third threshold value c is used as a reserve for over-temperature. By adjusting the third threshold value c, the prediction of over-temperature (drastic temperature change) or the prediction of when the temperature change is not drastic (e.g., when the bus connection is not obviously loose in a single battery module, the increase in bus contact internal resistance is small and the current is still within the normal range, resulting in an insignificant increase in heat generation at the bus connection). Furthermore, by adjusting the third threshold value to a small temperature range with a certain lead time, the prediction of whether over-temperature is imminent when the temperature change is not drastic can be achieved with better sensitivity.

[0111] Example 3

[0112] like Figure 3 As shown. This embodiment 3 provides a battery pack busbar over-temperature detection system, which can be used to execute the battery pack busbar over-temperature detection methods in Embodiments 1 and / or 2. The battery pack busbar over-temperature detection system of this embodiment includes multiple temperature sensors, a temperature acquisition module, a calculation and processing module, a first over-temperature prediction module, and a second over-temperature prediction module.

[0113] Multiple temperature sensors are respectively located at the busbar and non-busbar positions of each battery module in the battery pack. The multiple temperature sensors are used to detect and acquire temperature signals at the busbar and non-busbar positions, and then transmit the multiple temperature signals to the temperature acquisition module. In this embodiment, preferably, in each battery module of the battery pack, a temperature sensor is provided on the positive busbar and the negative busbar of each battery module, and multiple other temperature sensors are evenly distributed in each battery module outside the positive busbar and the negative busbar.

[0114] The temperature acquisition module is electrically connected to multiple temperature sensors. This module processes the multiple temperature signals as needed, converting them into busbar temperature values ​​corresponding to each battery module. Non-manifold temperature value And determine the maximum value T of the busbar temperature of the first battery module. max1 The maximum value T of the non-busbar temperature of the second battery module max2 A single battery module often has temperature values ​​obtained from multiple locations on the busbar. In this case, the maximum busbar temperature T of the first battery module is... max1 Pick The largest one.

[0115] The calculation and processing module is connected to the temperature acquisition module. The calculation and processing module is used to calculate the maximum value T of the busbar temperature of the first battery module. max1 The maximum value T of the non-busbar temperature of the second battery module max2 Calculate the second temperature difference value ΔT3, which is used based on the bus temperature values ​​of each battery module. With their respective non-manifold temperature values Calculate the first temperature difference value ΔT2. In this preferred embodiment, the calculation module is also used to calculate the non-busbar temperature values ​​of each battery module. Let it be the average of K temperatures at its non-busbar locations. And calculated Then, the non-manifold temperature value is simultaneously transmitted. The specific value is returned to the temperature acquisition module, which facilitates the expansion and application of the temperature value in other implementation methods.

[0116] The first over-temperature prediction module is connected to the calculation and processing module. The first over-temperature prediction module is used to determine the first over-temperature threshold T corresponding to each battery module. t1 By subtracting the first temperature difference value ΔT1 from the first temperature difference value, it is determined whether the busbar on the corresponding battery module will overheat. In this embodiment, the first overheat threshold T is preferred. t1 The first threshold value 'a' is preset in the first over-temperature prediction module. When T is not met... t1When -ΔT1≥a, it is predicted that the corresponding busbar will experience overheating problems.

[0117] The second over-temperature prediction module is connected to the calculation and processing module. The second over-temperature prediction module is used to predict the temperature based on the second over-temperature threshold T. t2 By subtracting the second temperature difference value ΔT2 from the value of the second temperature difference value, it is determined whether the busbar on the battery module corresponding to the maximum busbar temperature value of the first battery module will overheat. In this embodiment, the second overheat threshold T is preferred. t2 The second threshold value b is preset in the third over-temperature prediction module. When T is not met... t2 When -ΔT2≥b, it is predicted that the busbar will experience an overheating problem.

[0118] When the battery pack busbar over-temperature detection method in Embodiment 2 needs to be executed, the battery pack busbar over-temperature detection system in Embodiment 3 also adds a third over-temperature prediction module. The third over-temperature prediction module is connected to the temperature acquisition module. The third over-temperature prediction module is used to determine the over-temperature threshold T based on the temperature. t1 Subtract the busbar temperature value The third temperature difference value ΔT3 is determined to be greater than or equal to the third threshold value c, indicating whether the busbar corresponding to the given temperature value is overheated. This embodiment preferably uses the third overheat threshold value T. t3 The third threshold value c is preset in the third over-temperature prediction module. When the threshold is not met... At that time, it was predicted that the corresponding busbar would experience overheating issues.

[0119] In this embodiment, it is preferable to integrate the temperature acquisition module, the calculation and processing module, the first over-temperature prediction module, the second over-temperature prediction module, and the third over-temperature prediction module (if any) into the same computer.

[0120] Compared with the prior art, the advantages of this embodiment 3 are as follows:

[0121] This embodiment utilizes multiple distributed temperature sensors, temperature acquisition modules, and calculation processing modules. The first over-temperature prediction module predicts busbar over-temperature even before the busbar temperature in a single battery module reaches a high level, effectively identifying obvious abnormal busbar temperature changes that indicate impending over-temperature. The second over-temperature prediction module predicts overall busbar over-temperature in the battery pack, effectively identifying high-temperature diffusion in individual battery module busbars. The third over-temperature prediction module can still determine busbar over-temperature even when busbar connection loosening is not obvious, effectively identifying minor loosening of busbar connections.

[0122] Example 4

[0123] This embodiment 4 provides an application of the battery pack bus over-temperature detection method in embodiment 1 and / or embodiment 2, specifically the application of the battery pack bus over-temperature detection method in battery pack charging.

[0124] The application of the battery pack bus over-temperature detection method in battery pack charging includes reducing the battery pack charging voltage according to a set voltage drop ratio when the bus is predicted to overheat. In this embodiment, the preferred charging scenario for the battery pack is fast charging and / or supercharging. Furthermore, this embodiment further preferably uses an initial charging voltage that is an integer multiple of the set voltage drop ratio.

[0125] Compared with the prior art, the beneficial effect of this embodiment 4 is that it can detect and predict the bus overheating when the battery pack is charging, and immediately reduce the charging voltage of the battery pack to reduce the heat generation power of the bus, thus avoiding the temperature abnormality problem caused by continuing to maintain a high voltage.

[0126] Example 5

[0127] This embodiment 5 provides an application of the battery pack bus over-temperature detection method in embodiment 1 and / or embodiment 2, specifically the application of the battery pack bus over-temperature detection method on a battery pack data platform.

[0128] The application of the battery pack busbar over-temperature detection method on the battery pack data platform includes: when it is predicted that the busbar will over-temperature, a prediction record of busbar over-temperature is sent to the data platform at certain time intervals within a set time period. When the number of prediction records sent is greater than or equal to the set number, it indicates that the temperature rise trend of the busbar has not been controlled in time within the set time period, and the data platform marks the battery pack as having a fault state.

[0129] Compared with the prior art, the beneficial effect of this embodiment 5 is that by predicting whether the busbar will overheat, after the battery pack is assembled into the electric vehicle, it can remotely detect whether there is a fault in the battery pack in the later stage before ensuring that the busbar has not overheated, and the battery pack data platform can mark the fault in time to play an alarm function.

[0130] Example 6

[0131] This embodiment 6 provides an application of the battery pack busbar over-temperature detection method in embodiment 1 and / or embodiment 2, specifically the application of the battery pack busbar over-temperature detection method in battery pack testing and maintenance.

[0132] The application of the battery pack busbar over-temperature detection method in battery pack testing and maintenance includes: when it is predicted that the busbar will over-temperature, it indicates that there is a loose connection fault at the busbar connection position in the battery pack, and then the battery pack or busbar is returned for repair.

[0133] Compared with the prior art, the beneficial effects of this embodiment 6 are: it can effectively detect busbar connection faults in advance during battery pack testing and maintenance, avoid further damage to the battery pack due to busbar overheating, and ensure the safety of the battery pack testing and maintenance process.

[0134] Example 7

[0135] This embodiment 7 provides a storage medium storing a computer-executable program that matches the battery pack bus over-temperature detection method in Embodiment 1 and / or Embodiment 2. When the computer-executable program runs, the battery pack bus over-temperature detection method is executed.

[0136] Compared with the prior art, the beneficial effect of this embodiment 7 is that when the computer executable program is run in the computer, it executes the relevant steps of the battery pack bus over-temperature detection method in embodiment 1 and / or embodiment 2, and realizes the function of predicting whether the battery pack bus is over-temperature.

[0137] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for detecting over-temperature of a battery pack busbar, characterized in that, The steps include the following: Obtain the busbar temperature value and non-busbar temperature value for each battery module in the battery pack. Set the first over-temperature threshold, the first threshold value, and the first temperature difference value; In a single battery module, the difference between the busbar temperature value and the non-busbar temperature value is set as the first temperature difference value; Compare the difference between the first over-temperature threshold and the first temperature difference value of each battery module, and determine whether it is greater than or equal to the first threshold value. Otherwise, predict that the busbar of the corresponding battery module will soon over-temperature. When the difference between the first over-temperature threshold and the first temperature difference value of each battery module is less than the first threshold value, the following steps are also included: Obtain the maximum value of the busbar temperature value among all battery modules, and set the battery module corresponding to the maximum value of the busbar temperature value as the first battery module; Obtain the maximum value of the non-busbar temperature value in the battery modules other than the first battery module, and set the battery module corresponding to the maximum value of the non-busbar temperature value as the second battery module; Set a second over-temperature threshold, a second threshold value, and a second temperature difference value; The difference between the maximum value of the manifold temperature and the maximum value of the non-manifold temperature is set as the second temperature difference value; Compare the difference between the second over-temperature threshold and the second temperature difference value to see if it is greater than or equal to the second threshold value. If not, it is predicted that the bus corresponding to the first battery module will soon over-temperature.

2. The battery pack busbar over-temperature detection method according to claim 1, characterized in that, The second over-temperature threshold is determined based on the difference between the maximum heat generation temperature of the busbar in all battery modules when they are working normally under the set current range and the maximum heat generation temperature of the non-busbar location in all battery modules when they are working normally under the set current range. The second threshold value is 2~4℃.

3. The battery pack busbar over-temperature detection method according to claim 1, characterized in that, Before comparing whether the difference between the first over-temperature threshold and the first temperature difference value of each battery module is greater than or equal to the first threshold value, the following steps are also included: Set the third over-temperature threshold, the third threshold value, and the third temperature difference value; The difference between the third over-temperature threshold and the bus temperature value of each battery module is set as the third temperature difference value; Compare whether the third temperature difference value is greater than or equal to the third threshold value; if so, compare the difference between the first over-temperature threshold and the first temperature difference value of each battery module, and predict whether the busbar of the corresponding battery module is about to over-temperature; if not, predict that the busbar of the corresponding battery module is about to over-temperature.

4. The battery pack busbar over-temperature detection method according to claim 3, characterized in that, The third over-temperature threshold is determined based on the maximum heating temperature of the busbar when all battery modules are working normally within the set current range. The third threshold value is 3~8℃.

5. The battery pack busbar over-temperature detection method according to claim 1, characterized in that, The first over-temperature threshold is determined based on the difference between the maximum heat generation temperature of the busbar when a single battery module is working normally under the set current range and the maximum heat generation temperature of the non-busbar location when the battery module is working normally under the set current range. The first threshold value is 2~4℃.

6. The battery pack busbar over-temperature detection method according to claim 1, characterized in that, Obtaining the non-manifold temperature value involves the following steps: The temperature values ​​at multiple locations outside the busbars in a single battery module are obtained, and then the average value of the temperature values ​​at multiple locations outside the busbars is calculated. This average value is used as the non-busbar temperature value of the battery module.

7. A battery pack busbar over-temperature detection system according to any one of claims 1-6, characterized in that, It includes multiple temperature sensors, a temperature acquisition module, a calculation and processing module, and a first over-temperature prediction module; The multiple temperature sensors are respectively located at the bus position and non-bus position of each battery module in the battery pack, and are used to acquire the temperature signals at the bus position and non-bus position; The temperature acquisition module is electrically connected to multiple temperature sensors and is used to convert the temperature signal into bus temperature value and non-bus temperature value corresponding to each battery module. The calculation and processing module is connected to the temperature acquisition module and is used to calculate the first temperature difference value based on the bus temperature value and the non-bus temperature value of each of the battery modules. The first over-temperature prediction module is connected to the calculation and processing module and is used to predict whether the busbar on the corresponding battery module is about to over-temperature based on whether the difference between the first over-temperature threshold and the first temperature difference is greater than or equal to the first threshold value.

8. The battery pack busbar over-temperature detection system according to claim 7, characterized in that, It also includes a second over-temperature prediction module; The temperature acquisition module is also used to convert the temperature signal into the maximum value of the bus temperature value corresponding to the first battery module and the maximum value of the non-bus temperature value corresponding to the second battery module. The calculation and processing module is also used to calculate the second temperature difference value based on the maximum value of the busbar temperature value corresponding to the first battery module and the maximum value of the non-busbar temperature value corresponding to the second battery module. The second over-temperature prediction module is connected to the calculation and processing module and is used to predict whether the busbar corresponding to the busbar temperature value is about to over-temperature based on whether the difference between the second over-temperature threshold and the second temperature difference value is greater than or equal to the second threshold value.

9. The battery pack busbar over-temperature detection system according to claim 7, characterized in that, It also includes a third over-temperature prediction module; The third over-temperature prediction module is connected to the temperature acquisition module and is used to predict whether the busbar on the corresponding battery module is about to over-temperature based on whether the third temperature difference value is greater than or equal to the third threshold value.

10. The battery pack busbar over-temperature detection system according to claim 7, characterized in that, The calculation and processing module is also used to calculate the average value based on the temperature values ​​at multiple locations outside the busbars in a single battery module, and use the average value as the non-busbar temperature value of the battery module.

11. An application of the battery pack bus over-temperature detection method according to any one of claims 1-6, characterized in that, The application includes at least one of the following: Application of battery pack busbar over-temperature detection method in battery pack charging; the application in battery pack charging includes reducing the charging voltage of the battery pack according to a set voltage reduction ratio when it is predicted that the busbar is about to over-temperature. Application of the battery pack busbar over-temperature detection method on the battery pack data platform; the application on the battery pack data platform includes sending a prediction record to the data platform when it is predicted that the busbar is about to over-temperature; when the number of prediction records sent is greater than or equal to a set number, the data platform marks the battery pack as having a faulty state. The application of the battery pack busbar over-temperature detection method in battery pack testing and maintenance; the application in battery pack testing and maintenance includes indicating that when it is predicted that the busbar is about to over-temperature, it indicates that there is a fault in the busbar in the battery pack, and then the battery pack or busbar is returned for repair.

12. A storage medium storing a computer-executable program matching the battery pack bus over-temperature detection method according to any one of claims 1-6, characterized in that, When the computer-executable program is running, the battery pack bus over-temperature detection method is executed.

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