Detection method, detection device and computer readable storage medium

Abstract

The invention provides a detection method, a detection device and a computer readable storage medium, in the method, a first model is determined according to a chemical reaction-based self-discharge effect of a battery monomer, and a second model is determined according to the chemical reaction-based self-discharge effect of the battery monomer and a physical factor-based self-discharge effect. The first model outputs a first open-circuit voltage value corresponding to the first standing time of the first battery monomer, the second model outputs a second open-circuit voltage value corresponding to the first standing time, and the safety degree of the first battery monomer is determined according to the difference value between the first open-circuit voltage value and the second open-circuit voltage value. For example, if the absolute value of the difference value is 0, it shows that the physical internal short circuit phenomenon does not exist in the first battery single body, and it shows that the safety degree of the first battery single body is high; if the absolute value of the difference value is greater than 0, the physical internal short circuit phenomenon exists in the first battery monomer, and the safety degree of the first battery monomer is relatively low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a detection method, a detection device, and a computer readable storage medium. BACKGROUND

[0002] With the development of new energy technology, the application field of batteries is becoming more and more extensive, such as being used as a power source to provide power for vehicles in order to reduce the use of non-renewable resources.

[0003] After the battery is taken off the production line, the battery needs to be idle for a long time before it reaches the customer. Due to various reasons, the customer will not use the battery immediately after receiving it, but continue to idle the battery, which includes a plurality of battery monomers. During the long-term idling of the battery monomer, the safety level of the battery monomer will also change, which will affect the use of the battery by the customer. Therefore, how to determine the safety level of the battery monomer after long-term idling is a technical problem to be solved at present. SUMMARY

[0004] The present application provides a detection method, a detection device, and a computer readable storage medium, which can support determining the safety level of the battery monomer after long-term idling.

[0005] In a first aspect, a detection method is provided, which includes: inputting a first idling time of a first battery monomer to a first model to obtain and output a first open circuit voltage (OCV) value corresponding to the first idling time, the first model being determined according to a self-discharge effect of the first battery monomer based on chemical reaction; inputting the first idling time to a second model to obtain and output a second OCV value corresponding to the first idling time, the second model being determined according to a self-discharge effect of the first battery monomer based on chemical reaction and a self-discharge effect based on physical factors; and determining a safety level of the first battery monomer according to an absolute value of a difference between the first OCV value and the second OCV value.

[0006] The first open circuit voltage value corresponding to the first standing time of the first battery cell is outputted by the first model determined according to the self-discharge effect of the first battery cell based on chemical reaction, and the second open circuit voltage value corresponding to the first standing time of the first battery cell is outputted by the second model determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors. The safety degree of the first battery cell can be determined by the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value. For example, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is 0, it indicates that there is no physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles inside the first battery cell is small, which indicates that the safety degree of the first battery cell is high. If the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is greater than 0, it indicates that there is a physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles inside the first battery cell is large, which indicates that the safety degree of the first battery cell is low.

[0007] Specifically, since the first model is a model determined according to the self-discharge effect of the first battery cell based on chemical reaction, the open circuit voltage value outputted by the first model can reflect the self-discharge effect of the first battery cell based on chemical reaction, and the second model is a model determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors, the open circuit voltage value outputted by the second model can reflect the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors. If the open circuit voltage value outputted by the first model is the same as the open circuit voltage value outputted by the second model, it indicates that the self-discharge effect existing in the first battery cell is the self-discharge effect based on chemical reaction, not the self-discharge effect based on physical factors. If the open circuit voltage value outputted by the first model is different from the open circuit voltage value outputted by the second model, it indicates that the first battery cell exists both the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors. Thus, the safety degree of the first battery cell after long-term standing can be determined by comparing the absolute value of the difference between the open circuit voltage value outputted by the first model and the open circuit voltage value outputted by the second model.

[0008] In addition, since the first model and the second model are both related to the first battery cell, the absolute value of the difference between the open circuit voltage value output by the first model and the open circuit voltage value output by the second model can be used to determine the safety degree of the first battery cell. Wherein, the above method can be applied to determine the safety degree of other battery cells, for example, a model 1 is determined according to the self-discharge effect of the second battery cell based on chemical reaction and a model 2 is determined according to the self-discharge effect of the second battery cell based on chemical reaction and the self-discharge effect based on physical factors, and the safety degree of the second battery cell is determined according to the absolute value of the difference between the open circuit voltage value output by the model 1 and the open circuit voltage value output by the model 2. Or, different battery cells correspond to different first models and second models respectively, in the case that the rest time of the different battery cells is the same, the first model and the second model corresponding to the different battery cells respectively will be different, and the absolute value of the difference between the open circuit voltage values corresponding to the different battery cells respectively will also be different, thereby realizing the determination of the safety degree of the different battery cells.

[0009] In a possible implementation, the determination of the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value comprises: determining the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value and a preset threshold value.

[0010] By setting the preset threshold value, the safety degree of the first battery cell can be more accurately determined. For example, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is less than the preset threshold value, the safety degree of the first battery cell is the first level, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is greater than or equal to the preset threshold value, the safety degree of the first battery cell is the second level, and the first level is higher than the second level, which means that the safety degree of the first battery cell in the first level is higher than the safety degree of the first battery cell in the second level.

[0011] In a possible implementation, the first model is obtained by model training according to the plurality of rest times of the first battery cell, the plurality of open circuit voltage values of the first battery cell and the self-discharge effect of the first battery cell based on chemical reaction, and the second model is obtained by model training according to the plurality of rest times of the first battery cell, the plurality of open circuit voltage values of the first battery cell and the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors, and the plurality of open circuit voltage values of the first battery cell and the plurality of rest times of the first battery cell correspond one by one.

[0012] By the above scheme, the reliability of the open-circuit voltage value output by the model can be improved. Specifically, since the first model and the second model are both models determined according to the model training of the plurality of standing times and the plurality of open-circuit voltage values of the first battery cell, the first model and the second model can both be used to predict the open-circuit voltage value of the first battery cell after long-term standing. In addition, the reliability of judging the safety degree of the first battery cell can also be improved. Specifically, the first model can be used to predict the open-circuit voltage value of the first battery cell under the self-discharge effect based on chemical reaction, the second model can be used to predict the open-circuit voltage value of the first battery cell under the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors, and for the same standing time, when the open-circuit voltage values output by the first model and the second model are the same, it indicates that the first battery cell has the self-discharge effect based on chemical reaction, and if the open-circuit voltage values output by the first model and the second model are different, it indicates that the first battery cell has both the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors.

[0013] In a possible implementation, the model parameters of the first model include a first coefficient, a second coefficient, and a third coefficient, and the first coefficient, the second coefficient, and the third coefficient are all related to the self-discharge effect of the battery cell based on chemical reaction. By the above model, the open-circuit voltage prediction of the battery cell forming the self-discharge effect due to chemical reaction can be realized.

[0014] In a possible implementation, the first model satisfies: , V is the open-circuit voltage value, where a1 is the first coefficient, b1 is the second coefficient, c1 is the third coefficient, t represents the standing time, and e represents the natural constant (the value is about 2.71828). By the above model, it can be supported that the open-circuit voltage prediction value output by the first model is close to the real open-circuit voltage value of the first battery cell, that is, the reliability of the open-circuit voltage prediction value output by the first model is high.

[0015] In a possible implementation, the model parameters of the second model include a fourth coefficient, a fifth coefficient, a sixth coefficient, a seventh coefficient, and an eighth coefficient, the fourth coefficient, the fifth coefficient, and the sixth coefficient are all related to the self-discharge effect of the battery cell based on chemical reaction, and the seventh coefficient and the eighth coefficient are all related to the self-discharge effect of the battery cell based on physical factors. By the above model, the open-circuit voltage prediction of the battery cell forming the self-discharge effect due to chemical reaction and physical factors can be realized.

[0016] In a possible implementation, the second model satisfies: V is an open-circuit voltage value, a2 represents a fourth coefficient, b2 represents a fifth coefficient, c2 represents a sixth coefficient, d represents a seventh coefficient, f represents an eighth coefficient, t is a standing time of the battery monomer, and e represents a natural constant.

[0017] Through the above model, since the seventh coefficient and the eighth coefficient are both related to the self-discharge effect of the battery monomer based on physical factors, the second model can be applied to a scenario of predicting the open-circuit voltage of the battery monomer with a physical internal short circuit.

[0018] In a second aspect, a detection device is provided, which includes: a processing unit configured to input a first standing time of a first battery monomer into a first model to obtain and output a first open-circuit voltage value corresponding to the first standing time, the first model being determined according to a self-discharge effect of the first battery monomer based on chemical reactions; input the first standing time into a second model to obtain and output a second open-circuit voltage value corresponding to the first standing time, the second model being determined according to the self-discharge effect of the first battery monomer based on chemical reactions and a self-discharge effect based on physical factors; and determine a safety degree of the first battery monomer according to an absolute value of a difference between the first open-circuit voltage value and the second open-circuit voltage value.

[0019] The beneficial effects of the second aspect can be referred to the description of the beneficial effects of the first aspect.

[0020] In a possible implementation, the processing unit is configured to determine the safety degree of the first battery monomer according to the absolute value of the difference between the first open-circuit voltage value and the second open-circuit voltage value, including: determining the safety degree of the first battery monomer according to the absolute value of the difference between the first open-circuit voltage value and the second open-circuit voltage value and a preset threshold value.

[0021] In a possible implementation, the first model is obtained by model training according to a plurality of standing times of the first battery monomer, a plurality of open-circuit voltage values of the first battery monomer, and the self-discharge effect of the first battery monomer based on chemical reactions, and the second model is obtained by model training according to the plurality of standing times of the first battery monomer, the plurality of open-circuit voltage values of the first battery monomer, and the self-discharge effect of the first battery monomer based on chemical reactions and the self-discharge effect based on physical factors, the plurality of open-circuit voltage values of the first battery monomer and the plurality of standing times of the first battery monomer corresponding to each other.

[0022] In a possible implementation, model parameters of the first model include a first coefficient, a second coefficient, and a third coefficient, and the first coefficient, the second coefficient, and the third coefficient are all related to the self-discharge effect of the battery monomer based on chemical reactions.

[0023] In a possible implementation, the first model satisfies: , V is an open-circuit voltage value, wherein a1 is a first coefficient, b1 is a second coefficient, c1 is a third coefficient, t represents a standing time, and e represents a natural constant.

[0024] In a possible implementation, the model parameters of the second model include a fourth coefficient, a fifth coefficient, a sixth coefficient, a seventh coefficient, and an eighth coefficient, the fourth coefficient, the fifth coefficient, and the sixth coefficient are all related to the self-discharge effect of the battery cell based on chemical reactions, and the seventh coefficient and the eighth coefficient are both related to the self-discharge effect of the battery cell based on physical factors.

[0025] In a possible implementation, the second model satisfies: , V is an open-circuit voltage value, a2 represents a fourth coefficient, b2 represents a fifth coefficient, c2 represents a sixth coefficient, d represents a seventh coefficient, f represents an eighth coefficient, t is a standing time of the battery cell, and e represents a natural constant.

[0026] In a third aspect, a detection apparatus is provided, which includes a processor and a memory, the memory is configured to store a computer program, and the processor is configured to invoke the computer program to execute the method in the first aspect or any of the implementations thereof.

[0027] In a fourth aspect, a computer readable storage medium is provided, configured to store a computer program, the computer program causes a computer to execute the method in the first aspect or any of the implementations thereof. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 FIG. 1 shows a schematic diagram of an application scenario of the detection method according to an embodiment of the present application.

[0029] Figure 2 FIG. 2 shows a schematic flowchart of the detection method 200 according to an embodiment of the present application.

[0030] Figure 3 FIG. 3 shows a schematic diagram of model training of the first model.

[0031] Figure 4 FIG. 4 shows a schematic diagram of a relationship between the open-circuit voltage prediction value output by the first model and the real open-circuit voltage value of the second battery cell.

[0032] Figure 5 FIG. 5 shows a schematic diagram of a relationship between the open-circuit voltage prediction value output by the second model and the real open-circuit voltage value of the battery cell with a physical internal short circuit.

[0033] Figure 6 FIG. 6 shows a schematic diagram of a relationship between the open-circuit voltage prediction value output by different models and the real open-circuit voltage value of the battery cell with a physical internal short circuit.

[0034] Figure 7 A diagram showing one relationship between the first model and the second model.

[0035] Figure 8 A diagram showing another relationship between the first model and the second model.

[0036] Figure 9 A diagram showing another relationship between the first model and the second model.

[0037] Figure 10 A diagram showing another relationship between the first model and the second model.

[0038] Figure 11 A diagram showing another relationship between the first model and the second model.

[0039] Figure 12 A diagram showing another relationship between the first model and the second model.

[0040] Figure 13 A diagram showing one schematic block diagram of the detection apparatus 1300 according to an embodiment of the present application.

[0041] Figure 14 A diagram showing a hardware structure of the detection apparatus 1400 according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] Embodiments of the present application will be described below with reference to the accompanying drawings and examples. The following description and drawings are illustrative of the principles of the present application and are not intended to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0043] In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified. In addition, the terms "first", "second", and the like are used only for the purpose of description and are not to be construed as indicating or implying relative importance.

[0044] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terminology used in the specification of the present application is only for the purpose of describing specific embodiments of the present application and is not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0045] Reference to an "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments.

[0046] As described in the background section, after a battery is taken off the production line, the battery is in a static state until it is used, and the static state can last for a long time, for example, 3 months, 6 months, 12 months, 18 months, or even longer. During the long-term static state of the battery cell, the safety level of the battery cell also changes, which affects the use of the battery by the customer. For example, during the production of the battery, there are some small metal particles inside the battery cell, which do not significantly harm the safety of the battery cell and cannot be detected by the HIT-pot process. However, during the long-term static state of the battery cell, deposition occurs between the metal particles, which increases the size of the metal particles. When the size of the metal particles is greater than a size threshold, a physical internal short circuit occurs, which exacerbates the self-discharge effect of the battery cell and even causes thermal runaway of the battery cell when the battery cell is charged. Therefore, the battery provider needs to determine the safety level of the battery cell after long-term static state and provide the battery cell with a safety level that meets the requirements to the customer.

[0047] Currently, there is no suitable means for detecting the safety level of the battery cell after long-term static state, which leads to the fact that the safety level of the battery cell after long-term static state is unknown, thereby bringing potential risk hazards.

[0048] Therefore, the application provides a detection method. The first static time of the first battery cell is respectively input into a first model and a second model. The first model is a model determined according to a self-discharge effect of the first battery cell based on a chemical reaction. The second model is a model determined according to a self-discharge effect of the first battery cell based on a chemical reaction and a self-discharge effect based on a physical factor. The first model outputs a first open circuit voltage value corresponding to the first static time. The second model outputs a second open circuit voltage value corresponding to the first static time. The safety degree of the first battery cell can be determined by an absolute value of a difference between the first open circuit voltage value and the second open circuit voltage value. For example, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is 0, it indicates that there is no physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles in the first battery cell is small, which indicates that the safety degree of the first battery cell is high. If the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is greater than 0, it indicates that there is a physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles in the first battery cell is large, which indicates that the safety degree of the first battery cell is low.

[0049] Specifically, since the first model is a model determined according to a self-discharge effect of the first battery cell based on a chemical reaction, the open circuit voltage value output by the first model can reflect the self-discharge effect of the first battery cell based on a chemical reaction. The second model is a model determined according to a self-discharge effect of the first battery cell based on a chemical reaction and a self-discharge effect based on a physical factor. The open circuit voltage value output by the second model can reflect the self-discharge effect of the first battery cell based on a chemical reaction and the self-discharge effect based on a physical factor. If the open circuit voltage value output by the first model is the same as the open circuit voltage value output by the second model, it indicates that the self-discharge effect existing in the first battery cell is the self-discharge effect based on a chemical reaction, rather than the self-discharge effect based on a physical factor. If the open circuit voltage value output by the first model is different from the open circuit voltage value output by the second model, it indicates that the first battery cell exists both the self-discharge effect based on a chemical reaction and the self-discharge effect based on a physical factor. In this way, the safety degree of the first battery cell after long-term static can be determined by comparing the absolute value of the difference between the open circuit voltage value output by the first model and the open circuit voltage value output by the second model.

[0050] Figure 1 An application scenario of the detection method of the embodiment of the application is shown in a schematic diagram. As shown in the diagram, Figure 1 After the battery device is taken off the production line, it is transported by a long-distance transportation tool, Figure 1The battery device is transported to a warehouse of a customer and stored therein. The long-distance transportation can include domestic transportation and / or overseas transportation, and the long-distance transportation can take a long time, for example, 3 months, 6 months or even longer. The battery device is stored in the warehouse of the customer for a long time, for example, 6 months, 18 months or the like, due to various reasons.

[0051] The battery device can include at least one battery cell assembly for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, in parallel, or in a mixed connection through a busbar. The battery cell can be a secondary battery, which means that the battery cell can be used again by activating the active material through charging after discharging.

[0052] The battery cell can be a lithium ion battery, a lithium iron phosphate battery, a nickel cobalt manganese ternary battery, a nickel cobalt aluminum ternary battery, a sodium ion lithium battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, a negative electrode-free battery, etc. The type of battery cell can also be a laminated battery cell, a soft package battery cell, a square can battery cell, or a cylindrical battery cell, etc.

[0053] The battery cell assembly is usually formed by arranging a plurality of battery cells. As an example, the battery cell assembly is a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0054] The battery device can also be a battery pack, which includes a box and one or more battery cell assemblies, and the battery cell assemblies are contained in the box.

[0055] Figure 2 A schematic flowchart of the detection method 200 of the embodiments of the present application is shown. Optionally, the execution subject of the method 200 can be a detection device. The method 200 includes: S210, inputting the first standing time of the first battery cell to the first model to obtain and output the first open circuit voltage value corresponding to the first standing time, and the first model is determined according to the self-discharge effect of the first battery cell based on chemical reaction.

[0056] S220, inputting the first standing time into the second model to obtain and output a second open circuit voltage value corresponding to the first standing time, the second model being determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors.

[0057] S230, determining the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value.

[0058] By inputting the first standing time of the first battery cell into the first model and the second model respectively, the first model being a model determined according to the self-discharge effect of the first battery cell based on chemical reaction, the second model being a model determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors, the first model outputting a first open circuit voltage value corresponding to the first standing time, and the second model outputting a second open circuit voltage value corresponding to the first standing time, the safety degree of the first battery cell can be determined by the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value. For example, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is 0, it indicates that there is no physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles inside the first battery cell is small, which indicates that the safety degree of the first battery cell is high; if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is greater than 0, it indicates that there is a physical internal short circuit phenomenon in the first battery cell, or the size of the metal particles inside the first battery cell is large, which indicates that the safety degree of the first battery cell is low.

[0059] Specifically, since the first model is a model determined according to the self-discharge effect of the first battery cell based on chemical reaction, the open circuit voltage value output by the first model can reflect the self-discharge effect of the first battery cell based on chemical reaction, and the second model is a model determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors, the open circuit voltage value output by the second model can reflect the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors, if the open circuit voltage value output by the first model is the same as the open circuit voltage value output by the second model, it indicates that the self-discharge effect existing in the first battery cell is the self-discharge effect based on chemical reaction, but not the self-discharge effect based on physical factors, if the open circuit voltage value output by the first model is different from the open circuit voltage value output by the second model, it indicates that the first battery cell exists both the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors, thus, the safety degree of the first battery cell after long-term standing can be determined by comparing the absolute value of the difference between the open circuit voltage value output by the first model and the open circuit voltage value output by the second model.

[0060] In addition, since the first model and the second model are both related to the first battery cell, the absolute value of the difference between the open circuit voltage value output by the first model and the open circuit voltage value output by the second model can be used to determine the safety degree of the first battery cell. Wherein, the above method can be applied to determine the safety degree of other battery cells, for example, determining model 1 according to the self-discharge effect of the second battery cell based on chemical reaction and determining model 2 according to the self-discharge effect of the second battery cell based on chemical reaction and physical factors, and determining the safety degree of the second battery cell according to the absolute value of the difference between the open circuit voltage value output by model 1 and the open circuit voltage value output by model 2. Or, different battery cells correspond to different first models and second models respectively, in the case that the rest time of the different battery cells is the same, the first model and the second model corresponding to each of the different battery cells will be different, and the absolute value of the difference between the open circuit voltage values corresponding to each of the different battery cells will also be different, thereby realizing the determination of the safety degree of different battery cells.

[0061] Wherein, the time unit of the first rest time and the time unit supported by the aforementioned model are consistent, for example, if the aforementioned model supports days as the time unit, the time unit of the first rest time is days. For example, if the aforementioned model supports hours as the time unit, the time unit of the first rest time is hours. For example, if the aforementioned model supports minutes as the time unit, the time unit of the first rest time is minutes.

[0062] The first battery cell can be a battery cell in a transportation state, a battery cell stored in a customer's warehouse, or a battery cell that has been taken off the production line and not assembled into a transportation tool. Therefore, the rest time of the first battery cell is relative to the time when the first battery cell is taken off the production line. Wherein, the rest time of the first battery cell can be more than 10 days, or the rest time of the first battery cell can be less than 10 days.

[0063] After the detection device inputs the first rest time of the first battery cell into the first model and the second model respectively, the first model and the second model output the open circuit voltage value corresponding to the first rest time based on the internal inference process respectively. The detection device can directly display the safety degree of the first battery cell to the customer, or output the safety degree of the first battery cell to the display device, and output the safety degree of the first battery cell to the customer by the display device.

[0064] The first model is determined according to the self-discharge effect of the first battery cell based on chemical reaction, which can be understood as that the modeling of the first model is determined based on the self-discharge effect of the first battery cell based on chemical reaction, or the modeling of the first model refers to the self-discharge effect of the first battery cell based on chemical reaction. The self-discharge effect of the first battery cell based on chemical reaction can be understood as that when the first battery cell is left for a long time, the electrolyte will undergo oxidation-reduction reaction on the positive side and the negative side of the first battery cell, resulting in loss of active ions and decrease of the open circuit voltage value of the first battery cell.

[0065] The second model is determined according to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect of the first battery cell based on physical factors, which can be understood as that the modeling of the second model is determined based on the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect of the first battery cell based on physical factors, or the modeling of the second model refers to the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect of the first battery cell based on physical factors. The description of the self-discharge effect of the first battery cell based on chemical reaction can be referred to the description in the previous paragraph, and will not be repeated here. The self-discharge effect of the first battery cell based on physical factors can be understood as that when the first battery cell is left for a long time, there are small metal particles inside the pole piece of the first battery cell, which will not pierce the diaphragm between the positive electrode and the negative electrode, but will form a micro-short circuit, resulting in decrease of the open circuit voltage value of the first battery cell.

[0066] In one possible implementation, the method 200 further includes: determining the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value and a preset threshold value.

[0067] By setting the preset threshold value, the safety degree of the first battery cell can be more accurately determined. For example, if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is less than the preset threshold value, the safety degree of the first battery cell is the first level, and if the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value is greater than or equal to the preset threshold value, the safety degree of the first battery cell is the second level, and the first level is higher than the second level, which means that the safety degree of the first battery cell in the first level is higher than that of the first battery cell in the second level.

[0068] Specifically, the preset threshold value can be a threshold value configured according to the use experience of the battery cell, or a threshold value set according to the safe use state of the battery cell, and no limitation is made thereto.

[0069] For example, the preset threshold value is equal to the product of 0.005 mv / day and the standing time of the battery cell.

[0070] Exemplarily, the preset threshold value is equal to a product between 0.01 mv / day and the standing time of the battery cell.

[0071] Exemplarily, the preset threshold value is equal to a product between 0.02 mv / day and the standing time of the battery cell.

[0072] In one possible implementation, the first model is obtained by model training according to the plurality of standing times of the first battery cell, the plurality of open-circuit voltage values of the first battery cell, and the self-discharge effect of the first battery cell based on chemical reaction, and the second model is obtained by model training according to the plurality of standing times of the first battery cell, the plurality of open-circuit voltage values of the first battery cell, and the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect of the first battery cell based on physical factors, and the plurality of open-circuit voltage values of the first battery cell and the plurality of standing times of the first battery cell are in one-to-one correspondence.

[0073] By the above scheme, the reliability of the open-circuit voltage value output by the model can be improved. Specifically, since the first model and the second model are both determined by model training according to the plurality of standing times of the first battery cell and the plurality of open-circuit voltage values, the first model and the second model can both be used to predict the open-circuit voltage value of the first battery cell after long-term standing. In addition, the reliability of judging the safety degree of the first battery cell can also be improved. Specifically, the first model can be used to predict the open-circuit voltage value of the first battery cell under the self-discharge effect based on chemical reaction, and the second model can be used to predict the open-circuit voltage value of the first battery cell under the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors. For the same standing time, when the open-circuit voltage values output by the first model and the second model are the same, it indicates that the first battery cell has the self-discharge effect based on chemical reaction, and if the open-circuit voltage values output by the first model and the second model are different, it indicates that the first battery cell has both the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors.

[0074] The plurality of open-circuit voltage values of the first battery cell and the plurality of resting time of the first battery cell can be one-to-one correspondence, which can include the following understanding: one open-circuit voltage value of the first battery cell corresponds to one resting time of the first battery cell. Wherein, the plurality of open-circuit voltage values of the first battery cell can also correspond to the resting time of the same first battery cell. For example, when the time unit of the resting time of the first battery cell is day, the open-circuit voltage of the first battery cell can be measured multiple times within a certain test date, and a plurality of open-circuit voltage values are obtained, which correspond to the test date. For example, when the time unit of the resting time of the first battery cell is hour, the open-circuit voltage of the first battery cell can be measured multiple times within a certain test hour, and a plurality of open-circuit voltage values are obtained, which correspond to the test hour.

[0075] A possible example, the time unit of the resting time of the first battery cell is day, and the resting time of the first battery cell corresponds to the open-circuit voltage value of the first battery cell.

[0076] A possible example, the lower limit and the upper limit of the time range corresponding to the plurality of resting time of the first battery cell are 0 days and 30 days respectively.

[0077] Optionally, the first model is obtained by model training according to the plurality of resting time of the second battery cell, the plurality of open-circuit voltage values of the second battery cell and the self-discharge effect of the battery cell based on chemical reaction, and the second model is obtained by model training according to the plurality of resting time of the second battery cell, the plurality of open-circuit voltage values of the second battery cell and the self-discharge effect of the battery cell based on chemical reaction and the self-discharge effect based on physical factors. The plurality of open-circuit voltage values of the second battery cell and the plurality of resting time of the second battery cell are one-to-one correspondence.

[0078] Wherein, the first battery cell and the second battery cell can have the same characteristics. For example, the first battery cell and the first battery cell are battery cells produced in the same batch, or the type of the first battery cell and the type of the second battery cell are the same, such as the first battery cell and the second battery cell are both soft package battery cells. Or, the constituent materials of the first battery cell and the constituent materials of the second battery cell are the same. Wherein, the constituent materials of the battery cell include but are not limited to: negative electrode material, positive electrode material, electrolyte and diaphragm material, etc. When the first battery cell and the second battery cell have the same characteristics, the model obtained according to the resting time and the open-circuit voltage value of the second battery cell can be applied to predict the open-circuit voltage value of the first battery cell.

[0079] The first battery cell and the second battery cell can have different characteristics. For example, the first battery cell and the first battery cell are battery cells produced in different batches, or the type of the first battery cell is different from the type of the second battery cell, such as the type of the first battery cell is a soft-pack battery cell, and the type of the second battery cell is a laminated battery cell. Alternatively, the first battery cell and the second battery cell have different constituent materials. When the first battery cell and the second battery cell have different characteristics, the embodiments of the present application can support adjusting or fine-tuning (arbitrary adjustment) of the foregoing model, so that the foregoing model can be applied to predict the open circuit voltage value of the first battery cell.

[0080] In one possible implementation, the lower limit and the upper limit of the time range corresponding to the plurality of rest times of the second battery cell are 10 days and 90 days, respectively.

[0081] By selecting the above time range, both the reliability of the open circuit voltage value of the battery cell and the test period can be reduced, thereby reducing the cost. Specifically, because the reliability of the open circuit voltage value of the second battery cell before being rested for 10 days is low due to the influence of battery polarization, by excluding the open circuit voltage value of the second battery cell before being rested for 10 days, the reliability of the training data can be ensured, thereby improving the accuracy of the foregoing model.

[0082] When the time range corresponding to the plurality of rest times of the second battery cell is 10 days to 90 days, the plurality of open circuit voltage values of the second battery cell can include the open circuit voltage values corresponding to part of the rest times in the time range, for example, the plurality of open circuit voltage values of the second battery cell include the open circuit voltage values corresponding to the time range of 20 days to 60 days.

[0083] In one example, the embodiments of the present application support testing the open circuit voltage of the second battery cell once a day, and then 90 open circuit voltage values of the second battery cell can be obtained. The plurality of open circuit voltage values of the second battery cell can include part or all of the open circuit voltage values except the open circuit voltage values before the second battery cell is rested for 10 days.

[0084] In one example, the embodiments of the present application support testing the open circuit voltage of the second battery cell once every 5 days, and then 32 open circuit voltage values of the second battery cell can be obtained. The plurality of open circuit voltage values of the second battery cell can include part or all of the open circuit voltage values except the open circuit voltage values before the second battery cell is rested for 10 days.

[0085] In one example, the embodiment of the present application supports testing the open circuit voltage of the second battery cell once every 7 days, and then 15 open circuit voltage values of the second battery cell can be obtained. The plurality of open circuit voltage values of the second battery cell can include part or all of the 15 open circuit voltage values except the open circuit voltage value before the second battery cell is rested for 10 days.

[0086] In one example, the embodiment of the present application supports testing the open circuit voltage of the second battery cell once every 10 days, and then 10 open circuit voltage values of the second battery cell can be obtained. The plurality of open circuit voltage values of the second battery cell can include part or all of the 10 open circuit voltage values except the open circuit voltage value before the second battery cell is rested for 10 days.

[0087] In one possible implementation, the model parameters of the first model include a first coefficient, a second coefficient, and a third coefficient. The values of the first coefficient, the second coefficient, and the third coefficient are all related to the self-discharge effect of the battery cell based on chemical reactions.

[0088] Through the above model, the open circuit voltage of the battery cell with the self-discharge effect due to chemical reactions can be predicted.

[0089] In one possible implementation, the first model satisfies: V is the open circuit voltage value, a1 is the first coefficient, b1 is the second coefficient, c1 is the third coefficient, t represents the resting time, and e represents the natural constant (the value is about 2.71828).

[0090] Through the above model, the open circuit voltage prediction value output by the first model can be close to the real open circuit voltage value of the first battery cell, that is, the reliability of the open circuit voltage prediction value output by the first model is high.

[0091] The above model is only an example for understanding. The embodiment of the present application can support obtaining a new model based on the above model, for example, , or .

[0092] In one possible implementation, b1 is related to one or more of the number of charge transfers, the Faraday constant, the gas constant, and the initial open circuit voltage value of the battery cell. c1 is related to one or more of the number of charge transfers z, the Faraday constant R, the gas constant F1, the exchange current density I 01 , the self-discharge equivalent capacitance C, and the resting time of the battery cell. a1 is related to the discharge cutoff voltage of the battery cell.

[0093] Through the above model, the reliability of the open circuit voltage prediction value output by the first model can be higher.

[0094] When a1 is related to the discharge cut-off voltage of the battery cell, the value of a can be equal to the discharge cut-off voltage of the battery cell, or the value of a1 can be equal to the difference between the discharge cut-off voltage of the battery cell and a fixed value. The value of a1 can also be obtained according to the open circuit voltage value of the second battery cell after a long period of standing, for example, when the standing time of the second battery cell is 90 days, the value of a1 can be determined according to the open circuit voltage value of the second battery cell after standing for 90 days. Wherein, the aforementioned open circuit voltage value after a long period of standing can be understood as the open circuit voltage value of the second battery cell after an infinite period of standing. In addition, the discharge cut-off voltage can be replaced by a known lower voltage limit, etc.

[0095] When b1 is related to one or more of z, F, R and the initial open circuit voltage value of the battery cell, and c1 is related to one or more of z, F, R, I 01 , self-discharge equivalent capacitance and standing time of the battery cell, the combination between the parameters related to b1 and the parameters related to c1 has multiple ways, and the specific combination between the parameters related to b1 and the parameters related to c1 is not limited by the embodiments of the present application.

[0096] For example, b1 is related to z, and c1 is related to F, such as b1 is z or b1 is a constant determined based on z, and c1 is F or c1 is a constant determined based on F. For another example, b1 is related to z and F, and c1 is related to R and z, such as b1 is the combination of z and F or b1 is a constant determined based on z and F, and c1 is the combination of R and z or c1 is a constant determined based on R and z.

[0097] In one possible implementation, the model parameters of the second model include a fourth coefficient, a fifth coefficient, a sixth coefficient, a seventh coefficient and an eighth coefficient, the fourth coefficient, the fifth coefficient and the sixth coefficient are all related to the self-discharge effect of the battery cell based on chemical reaction, and the seventh coefficient and the eighth coefficient are all related to the self-discharge effect of the battery cell based on physical factors.

[0098] Through the above model, the open circuit voltage of the battery cell which forms the self-discharge effect due to chemical reaction and physical factors can be predicted.

[0099] In one possible implementation, the second model satisfies: , V is the open circuit voltage value, a2 represents the fourth coefficient, b2 represents the fifth coefficient, c2 represents the sixth coefficient, d represents the seventh coefficient, f represents the eighth coefficient, t represents the standing time, and e represents the natural constant.

[0100] By the above model, since the seventh coefficient and the eighth coefficient are both related to the self-discharge effect of the first battery monomer based on physical factors, this can support the application of the second model to the scenario of predicting the open circuit voltage of the first battery monomer with a physical internal short circuit.

[0101] The above model is only understood as an example, and the embodiments of the present application can support obtaining a new model based on the above model, for example, , or + .

[0102] In one possible implementation, b2 is related to one or more of the number of charge transfers, the Faraday constant, the gas constant, and the initial open circuit voltage value of the battery monomer, c2 is related to one or more of the number of charge transfers z, the Faraday constant R, the gas constant F2, the exchange current density I 02 , the self-discharge equivalent capacitance C, and the standing time of the battery monomer, and a2 is related to the discharge cutoff voltage of the battery monomer.

[0103] By the above model, this can make the reliability of the open circuit voltage prediction value output by the second model higher.

[0104] When a2 is related to the discharge cutoff voltage of the battery monomer, the value of a2 can be equal to the discharge cutoff voltage of the battery monomer, or the value of a2 can be equal to the difference between the discharge cutoff voltage of the battery monomer and a fixed value. The value of a2 can also be obtained according to the open circuit voltage value of the second battery monomer after a long period of standing, for example, when the standing time of the second battery monomer is 90 days, the value of a2 can be determined according to the open circuit voltage value of the second battery monomer after standing for 90 days. Wherein, the aforementioned open circuit voltage value after a long period of standing can be understood as the open circuit voltage value of the second battery monomer after an infinite period of standing. In addition, the discharge cutoff voltage can be replaced by a lower limit voltage and the like.

[0105] When b2 is related to one or more of z, F, R, and the initial open circuit voltage value of the battery monomer, and c2 is related to one or more of z, F, R, I 02 , the self-discharge equivalent capacitance, and the standing time of the battery monomer, there are many ways to combine the parameters related to b2 and the parameters related to c2, and the embodiments of the present application do not limit the specific combination between the parameters related to b2 and the parameters related to c2.

[0106] For example, b2 is related to z and c2 is related to F, such as b2 is z or b2 is a constant determined based on z, and c2 is F or c2 is a constant determined based on F. For another example, b2 is related to z and F, and c2 is related to R and z, such as b2 is a combination of z and F or b2 is a constant determined based on z and F, and c2 is a combination of R and z or c2 is a constant determined based on R and z.

[0107] The above model is described below in combination with a specific example.

[0108] In one possible implementation, the first model satisfies:

[0109] The above model is determined based on a self-discharge effect of a battery cell based on a chemical reaction. Specifically, the above formula can represent a leakage current model of the battery cell based on side reactions on the positive electrode side and the negative electrode side.

[0110] wherein a1= , b1= , c1= .

[0111] In one possible implementation, the second model satisfies: +

[0112] The above model is determined based on a self-discharge effect of a battery cell based on a chemical reaction and a self-discharge effect based on a physical factor.

[0113] wherein V t is an open-circuit voltage value of the battery cell after being left for t, V0 is an initial open-circuit voltage value of the battery cell, V ∞ is an open-circuit voltage value of the battery cell after being left for an infinite time, V ∞ may also be understood as a discharge cutoff voltage or equilibrium potential of the battery cell, z is a charge transfer number, F is a Faraday constant, R is a gas constant, I0 is an exchange current density, t is a standing time of the battery cell, and T represents a temperature of an environment in which the battery cell is located.

[0114] wherein a2= , b2= , c2= , d= , f= When the model is trained, The value of the open-circuit voltage of the first battery monomer can be determined according to a plurality of open-circuit voltage values of the first battery monomer, for example, when the last three of the plurality of standing times of the first battery monomer are 25 days, 27 days and 30 days respectively, the present embodiment can support taking the average value of the sum of the open-circuit voltage value corresponding to the standing time of 25 days of the first battery monomer, the open-circuit voltage value corresponding to the standing time of 27 days of the first battery monomer and the open-circuit voltage value corresponding to the standing time of 30 days of the first battery monomer, and the average value is The value of the open-circuit voltage of the first battery monomer can be determined according to a plurality of open-circuit voltage values of the first battery monomer, for example, when the last three of the plurality of standing times of the first battery monomer are 25 days, 27 days and 30 days respectively, the present embodiment can support taking the average value of the sum of the open-circuit voltage value corresponding to the standing time of 25 days of the first battery monomer, the open-circuit voltage value corresponding to the standing time of 27 days of the first battery monomer and the open-circuit voltage value corresponding to the standing time of 30 days of the first battery monomer, and the average value is The final value of the open-circuit voltage of the first battery monomer can be determined based on the average value in the model iteration process.

[0115] When the model is trained, The value of the open-circuit voltage of the first battery monomer is related to the environmental temperature and SOC of the first battery monomer, so the initial value of can be constructed, for example, The initial value of the open-circuit voltage of the first battery monomer is 0.001, and the initial value of the open-circuit voltage of the first battery monomer can be updated in the subsequent model training process. The initial value of the open-circuit voltage of the first battery monomer can be constructed, for example, The initial value of the open-circuit voltage of the first battery monomer is 0.001, and the initial value of the open-circuit voltage of the first battery monomer can be updated in the subsequent model training process.

[0116] When the model is trained, The value of the open-circuit voltage of the first battery monomer is related to the electrochemical parameters of the constituent material of the first battery monomer, so the initial value of can be constructed, for example, The initial value of the open-circuit voltage of the first battery monomer is 0.001, and the initial value of the open-circuit voltage of the first battery monomer can be updated in the subsequent model training process.

[0117] When the model is trained, the present embodiment can support setting a corresponding value range for , and , for example, The value range of the open-circuit voltage of the first battery monomer is 2.0-4.3, The value range of the open-circuit voltage of the first battery monomer is -1-1, The value range of the open-circuit voltage of the first battery monomer is -2-2.

[0118] When the model is trained, the present embodiment can support setting a corresponding value range for d and f, for example, the value range of d is -1-0, and the value range of f is 0-1.

[0119] After determining the above parameters, the present embodiment can support using a plurality of standing times of the first battery monomer and a plurality of open-circuit voltage values corresponding to the plurality of standing times of the first battery monomer to train the model, so as to obtain the above-mentioned model.

[0120] The above-mentioned model is only an example, and the present embodiment can support determining a new model based on the above-mentioned model, for example, , for example, wait.

[0121] For ease of description, the following description will take the example of model training based on multiple resting times and multiple open-circuit voltage values ​​of the second battery cell.

[0122] To further improve the reliability of the open-circuit voltage values ​​output by the aforementioned model, embodiments of this application can support adjusting the initial charge of the second battery cell according to actual shipping requirements, and determining the open-circuit voltage value of the second battery cell after long-term resting based on the initial charge of the second battery cell. That is, multiple resting times of the second battery cell and multiple open-circuit voltage values ​​corresponding to the multiple resting times are determined based on the initial charge of the second battery cell.

[0123] For example, if a customer requires the initial charge level of a single battery cell to be 40% SOC, this embodiment of the application can support adjusting the initial charge level of the second battery cell to 40% SOC. Specifically, this embodiment of the application can support adjusting the initial charge level of the second battery cell to the customer's required charge level through either of the following two methods.

[0124] Method 1: Discharge first, then charge.

[0125] Method 1 includes the following steps: Step 1: Let it stand for 10 minutes to allow polarization to dissipate; Step 2: The second battery cell discharges at a constant DC current of 0.05 times until the voltage of the second battery cell drops to the preset minimum cutoff voltage and the discharge stops, that is, the second battery cell is fully discharged. Step 3: Let it stand for 10 minutes to allow polarization to dissipate; Step 4: The second battery cell is charged with a constant current of 0.05 times until the charge in the second battery cell reaches 40% of the nominal capacity of the second battery cell, at which point charging stops. Step 5: Let it stand for 10 minutes to allow polarization to dissipate.

[0126] The parameters mentioned in the above steps are for illustrative purposes only and are not final constraints.

[0127] By using steps 1 to 5 in Method 1, the initial charge of the second battery cell can meet the customer's needs.

[0128] Method 2: Charge first, then discharge.

[0129] Method 2 includes the following steps: Step 1: Let it stand for 10 minutes to allow polarization to dissipate; Step 2, the second battery cell is charged at a constant current of 0.05 times until the second battery cell is charged to the nominal capacity of the second battery cell, that is, the second battery cell is fully charged; Step 3, stand for 10 minutes to eliminate polarization; Step 4, the second battery cell is discharged at a constant direct current of 0.05 times until the SOC of the second battery cell is 40% of the nominal capacity of the second battery cell; Step 5, stand for 10 minutes to eliminate polarization.

[0130] The parameters appearing in the above steps are only examples and are not final.

[0131] Through steps 1 to 5 in mode 2, the initial capacity of the second battery cell can meet the customer's demand.

[0132] When the initial capacity of the second battery cell meets the customer's demand, the embodiment of the application can support self-discharge testing of the second battery cell, that is, the second battery cell is stored in a predetermined environment, such as a normal temperature environment or a high temperature environment, and the open circuit voltage value of the second battery cell is measured every certain period of time by a voltmeter or other equipment (such as an impedance meter), for example, every 5 days or 10 days, and the test time of the second battery cell and the corresponding open circuit voltage value are recorded.

[0133] The following describes the process of model training using a plurality of standing times of the second battery cell and a plurality of open circuit voltage values corresponding to the plurality of standing times, respectively. Hereinafter, the model training of the first model is described as an example, but the content is also applicable to the scenario of model training of the second model. It is uniformly stated that the horizontal axis in the following figure represents the standing time of the battery cell, in days, and the vertical axis represents the open circuit voltage value of the battery cell, in v, which will not be described again.

[0134] Figure 3 An illustrative diagram of model training of the first model is shown. As Figure 3 shown, the circle points represent the real open circuit voltage values of the second battery cell, and the standing time of the second battery cell corresponding to the real open circuit voltage values of the second battery cell belongs to this time range: the standing time of the second battery cell is 0 days and the standing time of the second battery cell is 90 days. The fitting curve represents the change trend of the open circuit voltage prediction value output by the first model based on 10 open circuit voltage values and corresponding 10 standing times in the 20 open circuit voltage values, that is, excluding the open circuit voltage values before the second battery cell stands for 10 days, and selecting the open circuit voltage values after the second battery cell stands for 10 days.

[0135] Figure 3 In the first model, a = 3.57642, b = 0.056277, and c = -0.001375. The first model is: V = 3.57642 + 0.056277 .

[0136] Figure 4 A diagram showing the relationship between the open-circuit voltage prediction value output by the first model and the actual open-circuit voltage value of the second battery cell is shown. In the diagram, Figure 4 the content corresponds to the absence of a physical internal short circuit in the battery cell. As Figure 4 shown, the first model is: V = 3.57642 + 0.056277 , the circle represents the open-circuit voltage value of the second battery cell before it was left to stand for 90 days, the triangle represents the open-circuit voltage value of the second battery cell after it was left to stand for 90 days, and the fitted curve represents the change trend of the open-circuit voltage prediction value output by the first model. When the standing time of the second battery cell is less than 175 days, the actual open-circuit voltage value of the second battery cell is basically consistent with the open-circuit voltage prediction value output by the first model. When the standing time of the second battery cell is greater than 175 days and less than 360 days, there is an error between the actual open-circuit voltage value of the second battery cell and the open-circuit voltage prediction value output by the first model, and the maximum value of the error between the actual open-circuit voltage value of the second battery cell and the open-circuit voltage prediction value output by the first model is less than 0.001 V. It can be known from Figure 4 that the first model has high accuracy in predicting the open-circuit voltage value of the battery cell after long-term standing.

[0137] In the following, the relationship between the open-circuit voltage prediction value output by the second model and the actual open-circuit voltage value of the battery cell with a physical internal short circuit is described. Figure 5

[0138] Figure 5 A diagram showing a relationship between the open-circuit voltage prediction value output by the second model and the actual open-circuit voltage value of the battery cell with a physical internal short circuit is shown. As Figure 5 shown, the second model is: V = 3.904996 + 0.002214 -0.000021 ​The dots represent the actual open-circuit voltage values ​​of the second battery cell. The fitted curve shows the trend of the predicted open-circuit voltage value output by the second model. When the resting time of the second battery cell is less than 200 days, the predicted open-circuit voltage value output by the second model is basically consistent with the actual open-circuit voltage value of the second battery cell. When the resting time of the second battery cell is greater than 200 days but less than 360 days, there is a certain error between the predicted open-circuit voltage value output by the second model and the actual open-circuit voltage value of the second battery cell. The maximum error between the predicted open-circuit voltage value output by the second model and the actual open-circuit voltage value of the second battery cell is less than 0.00005.

[0139] The following text combines Figure 6 The relationship between the predicted open-circuit voltage values ​​output by different models and the actual open-circuit voltage values ​​of battery cells with physical internal short circuits is described.

[0140] Figure 6 This diagram illustrates the relationship between the predicted open-circuit voltage values ​​from different models and the actual open-circuit voltage values ​​of battery cells with physical internal short circuits. The dots represent the actual open-circuit voltage values ​​of the second battery cell, and the fitted curves represent the changing trends of the predicted open-circuit voltage values ​​output by the open-circuit voltage models. Figure 6 The model shown was obtained by training the model based on the open-circuit voltage values ​​of the second battery cell during the resting period of 10 to 90 days.

[0141] like Figure 6 As shown in (a), the first model is: V = 3.902480 + 0.004228 When the resting time of the second battery cell is less than 100 days, the actual open-circuit voltage value of the second battery cell is basically consistent with the predicted open-circuit voltage value output by the first model. When the resting time of the second battery cell is greater than 100 days but less than 360 days, there is an error between the actual open-circuit voltage value of the second battery cell and the predicted open-circuit voltage value output by the first model, and this error increases with the increase of the resting time of the second battery cell.

[0142] like Figure 6 As shown in (b), the second model is: V = 3.904996 + 0.002214 -0.000021 When the resting time of the second battery cell is less than 250 days, the actual open-circuit voltage value of the second battery cell is basically consistent with the predicted open-circuit voltage value output by the second model. When the resting time of the second battery cell is greater than 250 days but less than 360 days, there is a small error between the actual open-circuit voltage value of the second battery cell and the predicted open-circuit voltage value output by the second model.

[0143] contrastFigure 6 As shown in (a) and (b), the second model can predict the self-discharge degradation of individual battery cells after a long period of rest with relatively high accuracy. In addition, the second model can also accurately capture the degradation sources of interfacial chemical reactions and physical internal short circuits in the training data, thus enabling it to output a more accurate predicted value of open-circuit voltage.

[0144] Figure 6 The description is based on the example of using the open-circuit voltage values ​​corresponding to the resting time of the second battery cell in the range of 10 to 90 days for model training. Since the model training effect of the open-circuit voltage values ​​corresponding to the resting time of the second battery cell in the range of 20 to 60 days is basically the same as that of the open-circuit voltage values ​​corresponding to the resting time of the second battery cell in the range of 10 to 90 days, it will not be elaborated further.

[0145] The following text combines Figures 7 to 12 The relationship between the first model and the second model is further described. Specifically, Figure 7 The content described refers to battery cell 1. Figure 8 The content shown refers to battery cell 2. Figure 9 The content shown refers to battery cell 3. Figure 10 The content shown refers to battery cell 4. Figure 11 The content shown refers to battery cell 5. Figure 12 The content shown refers to battery cell 1, battery cell 2, battery cell 3, battery cell 4, and battery cell 5.

[0146] Figure 7 A schematic diagram illustrating a relationship between the first model and the second model is shown. Figure 7 In the first model, V = 3.538994 + 0.04373 × The second model is V = 3.536491 + 0.046224 × -0.000009×t 1.00001 For example: like Figure 7As shown in (a), curve 1 represents the trend of the predicted open-circuit voltage output by the first model, and curve 2 represents the trend of the predicted open-circuit voltage output by the second model. When the resting time of battery cell 1 is less than or equal to 150 days, the predicted open-circuit voltage of battery cell 1 output by the first model is the same as that output by the second model. When the resting time of battery cell 1 is greater than 150 days, the predicted open-circuit voltage of battery cell 1 output by the first model is different from that output by the second model. The description of the difference between the predicted open-circuit voltage of battery cell 1 output by the first model and the predicted open-circuit voltage of battery cell 1 output by the second model can be found in [reference needed]. Figure 7 (b)

[0147] like Figure 7 As shown in (b), the curve represents the trend of the difference between the predicted open-circuit voltage of battery cell 1 output by the first model and the predicted open-circuit voltage of battery cell 1 output by the second model. When the resting time of battery cell 1 is less than or equal to 150 days, the difference between the predicted open-circuit voltage of battery cell 1 output by the first model and the predicted open-circuit voltage of battery cell 1 output by the second model is basically 0. When the resting time of battery cell 1 is greater than 150 days, the difference between the predicted open-circuit voltage of battery cell 1 output by the first model and the predicted open-circuit voltage of battery cell 1 output by the second model increases with the increase of resting time, but the overall trend of change is relatively slow, that is, the slope of the curve is small.

[0148] Figure 8 A schematic diagram illustrating yet another relationship between the first and second models is shown. Figure 8 In the first model, V = 3.90248 + 0.004228 × The second model is: V = 3.904996 + 0.002214 × -0.000021×t 0.999724 For example: like Figure 8 As shown in (a), curve 1 represents the trend of the predicted open-circuit voltage output by the first model, and curve 2 represents the trend of the predicted open-circuit voltage output by the second model. When the resting time of battery cell 1 is less than or equal to 100 days, the predicted open-circuit voltage of battery cell 2 output by the first model is the same as that output by the second model. When the resting time of battery cell 2 is greater than 100 days, the predicted open-circuit voltage of battery cell 2 output by the first model is different from that output by the second model. The description of the difference between the predicted open-circuit voltage of battery cell 2 output by the first model and the predicted open-circuit voltage of battery cell 2 output by the second model can be found in [reference needed].Figure 8 (b)

[0149] like Figure 8 As shown in (b), the curve represents the trend of the difference between the predicted open-circuit voltage of battery cell 2 output by the first model and the predicted open-circuit voltage of battery cell 2 output by the second model. When the resting time of battery cell 2 is less than or equal to 100 days, the difference between the predicted open-circuit voltage of battery cell 1 output by the first model and the predicted open-circuit voltage of battery cell 2 output by the second model is basically 0. When the resting time of battery cell 2 is greater than 150 days, the difference between the predicted open-circuit voltage of battery cell 2 output by the first model and the predicted open-circuit voltage of battery cell 2 output by the second model increases with the increase of resting time, but the overall trend is relatively slow, that is, the slope of the curve is small. In addition, the physical internal shortness of battery cell 2 is relatively large. Under long-term operating conditions, the voltage decay caused by the physical internal shortness increases linearly.

[0150] Figure 9 A schematic diagram illustrating yet another relationship between the first model and the second model is shown. Figure 9 In the first model, V = 3.611068 + 0.021902 × The second model is: V = 3.632643 + 0.005593 × -0.000057×t 1.00012 For example: like Figure 9 As shown in (a), curve 1 represents the trend of the predicted open-circuit voltage output by the first model, and curve 2 represents the trend of the predicted open-circuit voltage output by the second model. When the resting time of battery cell 3 is less than or equal to 100 days, the predicted open-circuit voltage of battery cell 3 output by the first model is the same as that output by the second model. When the resting time of battery cell 3 is greater than 100 days, the predicted open-circuit voltage of battery cell 3 output by the first model is different from that output by the second model. The description of the difference between the predicted open-circuit voltage of battery cell 3 output by the first model and the predicted open-circuit voltage of battery cell 3 output by the second model can be found in [reference needed]. Figure 9 (b)

[0151] like Figure 9As shown in (b), the curve represents the trend of the difference between the predicted open-circuit voltage of battery cell 3 output by the first model and the predicted open-circuit voltage of battery cell 3 output by the second model. When the resting time of battery cell 3 is less than or equal to 100 days, the difference between the predicted open-circuit voltage of battery cell 3 output by the first model and the predicted open-circuit voltage of battery cell 3 output by the second model is basically 0. When the resting time of battery cell 3 is greater than 100 days, the difference between the predicted open-circuit voltage of battery cell 3 output by the first model and the predicted open-circuit voltage of battery cell 3 output by the second model increases with the increase of resting time, but the overall trend is relatively slow, that is, the slope of the curve is small.

[0152] Figure 10 A schematic diagram illustrating yet another relationship between the first and second models is shown. Figure 10 In the first model, V = 3.266597 + 0.01641 × The second model is: V = 3.279814 + 0.004069 × -0.00007×t 0.999899 For example: like Figure 10 As shown in (a), curve 1 represents the trend of the predicted open-circuit voltage output by the first model, and curve 2 represents the trend of the predicted open-circuit voltage output by the second model. When the resting time of battery cell 4 is less than or equal to 100 days, the predicted open-circuit voltage of battery cell 4 output by the first model is the same as that output by the second model. When the resting time of battery cell 4 is greater than 100 days, the predicted open-circuit voltage of battery cell 4 output by the first model is different from that output by the second model. The description of the difference between the predicted open-circuit voltage of battery cell 4 output by the first model and the predicted open-circuit voltage of battery cell 4 output by the second model can be found in [reference needed]. Figure 10 (b)

[0153] like Figure 10 As shown in (b), the curve represents the trend of the difference between the predicted open-circuit voltage of battery cell 4 output by the first model and the predicted open-circuit voltage of battery cell 4 output by the second model. When the resting time of battery cell 4 is less than or equal to 100 days, the difference between the predicted open-circuit voltage of battery cell 4 output by the first model and the predicted open-circuit voltage of battery cell 4 output by the second model is basically 0. When the resting time of battery cell 4 is greater than 100 days, the difference between the predicted open-circuit voltage of battery cell 4 output by the first model and the predicted open-circuit voltage of battery cell 4 output by the second model increases with the increase of the resting time, but the overall trend is relatively rapid, that is, the slope of the curve is large.

[0154] Figure 11 A schematic diagram illustrating yet another relationship between the first and second models is shown. Figure 11 In the first model, V = 4.12817 + 0.046733 × The second model is V = 4.128959 + 0.045972 × -0.000005×t 1.000009 For example: like Figure 11 As shown in (a), since the changing trends of the open-circuit voltage prediction values ​​output by the first model and the second model are basically the same, the curves in the figure can simultaneously represent the changing trends of both the open-circuit voltage prediction values ​​output by the first and second models. As can be seen from the figure, the open-circuit voltage prediction values ​​of battery cell 5 output by the first model and the second model are basically the same. The description of the difference between the open-circuit voltage prediction values ​​of battery cell 5 output by the first model and the second model can be found in [reference needed]. Figure 11 (b)

[0155] like Figure 11 As shown in (b), the curve represents the trend of the difference between the predicted open-circuit voltage of battery cell 5 output by the first model and the predicted open-circuit voltage of battery cell 5 output by the second model. When the resting time of battery cell 5 is less than or equal to 100 days, the difference between the predicted open-circuit voltage of battery cell 5 output by the first model and the predicted open-circuit voltage of battery cell 5 output by the second model is basically 0. When the resting time of battery cell 5 is greater than 100 days, the difference between the predicted open-circuit voltage of battery cell 5 output by the first model and the predicted open-circuit voltage of battery cell 5 output by the second model increases with the increase of resting time, but the overall trend is relatively slow, that is, the slope of the curve is small.

[0156] Figure 12This diagram illustrates another relationship between the first and second models. Curve 1 represents the trend of the difference between the predicted open-circuit voltage values ​​of battery cell 1 output by different models; Curve 2 represents the trend of the difference between the predicted open-circuit voltage values ​​of battery cell 2 output by different models; Curve 3 represents the trend of the difference between the predicted open-circuit voltage values ​​of battery cell 3 output by different models; Curve 4 represents the trend of the difference between the predicted open-circuit voltage values ​​of battery cell 4 output by different models; and Curve 5 represents the trend of the difference between the predicted open-circuit voltage values ​​of battery cell 5 output by different models. Comparing curves 1 to 5, it can be seen that the physical internal shortness of battery cell 1 and battery cell 5 is relatively low, indicating that the safety levels of battery cell 1 and battery cell 5 are relatively high. Although the physical internal shortness of battery cell 2 and battery cell 3 is relatively large, it is still within an acceptable range. Therefore, the safety levels of battery cell 2 and battery cell 3 can be further assessed. The physical internal shortness of battery cell 4 is greater than that of the other battery cells, indicating that the safety level of battery cell 4 is relatively low.

[0157] The detection method 200 has been described above. The detection apparatus according to an embodiment of this application will now be described. The detection apparatus can execute the detection method 200. The detection apparatus can be a battery management system (BMS), or other types of devices; there is no limitation on this.

[0158] Figure 13 A schematic block diagram of a detection device 1300 according to an embodiment of this application is shown. Figure 14 As shown, the detection device 1300 may include: a processing unit 1320, configured to: input a first resting time of the first battery cell into a first model, obtain and output a first open-circuit voltage value corresponding to the first resting time, wherein the first model is determined based on the self-discharge effect of the first battery cell based on chemical reaction; input the first resting time into a second model, obtain and output a second open-circuit voltage value corresponding to the first resting time, wherein the second model is determined based on the self-discharge effect of the first battery cell based on chemical reaction and the self-discharge effect based on physical factors; and determine the safety level of the first battery cell based on the absolute value of the difference between the first open-circuit voltage value and the second open-circuit voltage value.

[0159] Optionally, the detection device 1300 may further include a communication unit 1310, which is used to acquire the first resting time of the first battery cell.

[0160] The detection device 1300 can perform the corresponding operations in the detection method 200, which will not be described in detail here for the sake of brevity.

[0161] Figure 14 A hardware structure diagram of the detection device 1400 of the embodiment of the present application is shown. The detection device 1400 comprises a memory 1401, a processor 1402, a communication interface 1403 and a bus 1404. The memory 1401, the processor 1402 and the communication interface 1403 are communicatively connected to each other through the bus 1404.

[0162] The memory 1401 can be a read-only memory (ROM), a static storage device and a random access memory (RAM). The memory 1401 can store a program, and when the program stored in the memory 1401 is executed by the processor 1402, the processor 1402 and the communication interface 1403 are used to execute each step of the detection method 200.

[0163] The processor 1402 can adopt a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), a graphics processing unit (GPU) or one or more integrated circuits, and is used to execute a related program to implement the functions required by the units in the device of the embodiment of the present application or execute the detection method 200.

[0164] The processor 1402 can also be an integrated circuit chip with a signal processing capability. In the implementation process, each step of the detection method 200 can be completed by the integrated logic circuit of hardware or the instruction in the form of software in the processor 1402.

[0165] The processor 1402 can also be a general-purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution or executed by a combination of hardware and software modules in the processor. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium in the art. The storage medium is located in the memory 1401, and the processor 1402 reads the information in the memory 1401, and combines the hardware to complete the function required by the unit included in the detection device 1400, or executes the detection method 200.

[0166] The communication interface 1403 uses a transceiver such as but not limited to a transceiver to realize the communication between the detection device 1400 and other devices or communication networks.

[0167] The bus 1404 can include a path for transmitting information between various components (e.g., memory 1401, processor 1402, communication interface 1403) of the detection device 1400.

[0168] The detection device 1400 only shows the memory, processor, communication interface, and in the specific implementation process, the detection device 1400 can also include other devices necessary for normal operation. At the same time, according to the specific needs, the detection device 1400 can also include hardware devices for realizing other additional functions. In addition, those skilled in the art should understand that the detection device 1400 can also include only the devices necessary for the present application, and does not have to include all the devices shown in the ​

[0169] The embodiments of the present application also provide a computer readable storage medium for storing a computer program, the computer program being used for executing the method of various embodiments of the present application. The computer readable storage medium can be a transitory computer readable storage medium or a non-transitory computer readable storage medium.

[0170] The present application also provides a computer program product, the computer program product comprising a computer program stored on a computer readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer, the computer executes the above-mentioned battery detection method. ​

[0171] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those ordinarily skilled in the art should understand: the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced equivalently, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of detection, characterized in that, The method comprises: inputting a first rest time of a first battery cell into a first model to obtain and output a first open circuit voltage value corresponding to the first rest time, the first model being determined according to a self-discharge effect based on chemical reaction of the first battery cell; inputting the first rest time into a second model to obtain and output a second open circuit voltage value corresponding to the first rest time, the second model being determined according to the self-discharge effect based on chemical reaction and a self-discharge effect based on physical factors of the first battery cell; determining a safety degree of the first battery cell according to an absolute value of a difference between the first open circuit voltage value and the second open circuit voltage value.

2. The method of claim 1, wherein, The determining of the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value comprises: determining the safety degree of the first battery cell according to the absolute value of the difference between the first open circuit voltage value and the second open circuit voltage value and a preset threshold value.

3. The method according to claim 1 or 2, characterized in that, The first model is obtained by model training according to a plurality of rest times of the first battery cell, a plurality of open circuit voltage values of the first battery cell and the self-discharge effect based on chemical reaction of the first battery cell, and the second model is obtained by model training according to the plurality of rest times of the first battery cell, the plurality of open circuit voltage values of the first battery cell and the self-discharge effect based on chemical reaction and the self-discharge effect based on physical factors of the first battery cell, the plurality of open circuit voltage values of the first battery cell and the plurality of rest times of the first battery cell corresponding to each other.

4. The method according to claim 1 or 2, characterized in that, Model parameters of the first model comprise a first coefficient, a second coefficient and a third coefficient, and the first coefficient, the second coefficient and the third coefficient are all related to the self-discharge effect based on chemical reaction of the first battery cell.

5. The method of claim 4, wherein, The first model satisfies: , V represents an open circuit voltage value, wherein a1 is the first coefficient, b1 is the second coefficient, c1 is the third coefficient, t represents a standing time, and e represents a natural constant.

6. The method of claim 1 or 2, wherein, Model parameters of the second model comprise a fourth coefficient, a fifth coefficient, a sixth coefficient, a seventh coefficient and an eighth coefficient, the fourth coefficient, the fifth coefficient and the sixth coefficient are all related to the self-discharge effect based on chemical reaction of the first battery cell, and the seventh coefficient and the eighth coefficient are all related to the self-discharge effect based on physical factors of the first battery cell.

7. The method of claim 6, wherein, The second model satisfies: wherein V represents an open circuit voltage value, a2 represents the fourth coefficient, b2 represents the fifth coefficient, c2 represents the sixth coefficient, d represents the seventh coefficient, f represents the eighth coefficient, t represents a standing time, and e represents a natural constant.

8. A detection device, characterized in that The method comprises: a processing unit, configured to: input a first rest time of a first battery cell into a first model to obtain and output a first open circuit voltage value corresponding to the first rest time, the first model being determined according to a self-discharge effect based on chemical reaction of the first battery cell; input the first rest time into a second model to obtain and output a second open circuit voltage value corresponding to the first rest time, the second model being determined according to the self-discharge effect based on chemical reaction and a self-discharge effect based on physical factors of the first battery cell; determine a safety degree of the first battery cell according to an absolute value of a difference between the first open circuit voltage value and the second open circuit voltage value.

9. A detection device, characterized in that The method comprises: a memory configured to store a program; A processor configured to execute a program stored in the memory, the processor being configured to perform the detection method according to any one of claims 1 to 7 when the program stored in the memory is executed.

10. A computer-readable storage medium, characterized in that, A computer program product for storing a computer program which causes a computer to perform the detection method according to any one of claims 1 to 7.

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