Battery pack pressure determination method and device, medium and product

Abstract

The invention relates to a battery pack pressure determination method and device, a medium and a product, and relates to the technical field of battery simulation. The method comprises the following steps: under the condition that the operating temperature of the battery pack is greater than a threshold value, acquiring the air pressure in the battery pack at the current moment and the gas production rate of a battery cell in the battery pack at the current moment; determining the exhaust rate of the explosion-proof balance valve at the current moment according to the corresponding relationship among the air pressure at the current moment, the exhaust rate of the explosion-proof balance valve and the air pressure in the battery pack; and determining the air pressure at the target moment in the battery pack according to the air pressure at the current moment, the gas production rate at the current moment and the exhaust rate at the current moment. Therefore, the technical problems that the simulation period of a general technology is long, and the pressure value of the battery pack cannot be rapidly determined after the battery cells in the battery pack are in thermal runaway can be solved.

Description

Technical Field

[0001] The present invention relates to the field of battery simulation technology, and in particular to a method, device, medium and product for determining battery pack pressure. Background Art

[0002] When the battery cells in the battery pack experience thermal runaway (the operating temperature of the battery pack is greater than a threshold, for example, the temperature inside the battery pack is greater than 80°C), a large amount of gas will be rapidly ejected, causing the gas pressure inside the battery pack to rise rapidly, and even causing the gas inside the battery pack to explode. Therefore, battery packs are usually equipped with explosion-proof valves to discharge the gas inside the battery pack, reduce the gas pressure in the battery pack, and protect the battery pack.

[0003] In order to equip the battery pack with a suitable explosion-proof balancing valve, it is necessary to determine the pressure in the battery pack after the battery cell has thermal runaway. However, determining the pressure in the battery pack through the battery pack thermal runaway test consumes too many resources, and a simulation model is usually used to determine the pressure in the battery pack. Document CN114397100A discloses determining the gas production rate when in thermal runaway and the air permeability rate of a single explosion-proof valve after opening. However, this method is aimed at determining the number of explosion-proof balancing valves installed on the battery pack based on the gas production rate of the battery pack and the exhaust rate of the explosion-proof balancing valve, and cannot solve the problem of determining the pressure value of the battery pack after the battery cell in the battery pack has thermal runaway. Document CN117933004A discloses coupling the thermal runaway heat generation sub-model, the thermal runaway gas generation sub-model and the battery shell finite mechanics sub-model, and a thermal runaway heat generation-gas generation-valve opening coupling model can be obtained, and the stress state of the battery shell before exhaust and the safety valve opening pressure can be obtained. However, the simulation cycle of this method is long, and it cannot solve the problem of quickly determining the pressure value of the battery pack after the battery cell in the battery pack has thermal runaway. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, medium and product for determining battery pack pressure, so as to solve the technical problem that the prior art cannot quickly determine the pressure of the battery pack after thermal runaway of the battery cells in the battery pack.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is as follows:

[0006] In a first aspect, a method for determining a battery pack pressure is provided, comprising: when the operating temperature of the battery pack is greater than a threshold value, obtaining the current air pressure in the battery pack and the gas production rate of the battery cells in the battery pack at the current moment; determining the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the current air pressure, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack; determining the air pressure in the battery pack at a target moment according to the current air pressure, the gas production rate at the current moment and the exhaust rate at the current moment.

[0007] Optionally, the air pressure in the battery pack at a target moment is determined based on the current air pressure, the current gas production rate and the current exhaust rate, including: determining the net gas production rate of the battery pack based on the current gas production rate and the current exhaust rate; determining the change in air pressure in the battery pack from the current moment to the target moment based on the correspondence between the net gas production rate, the net gas production rate of the battery pack and the change in air pressure; determining the air pressure in the battery pack at the target moment based on the current air pressure and the change in air pressure.

[0008] Optionally, the method for determining the battery pack pressure also includes: during the gas production process of the battery cell, constructing a gas pressure curve of the battery pack according to the gas pressure at multiple moments in the battery pack; the multiple moments include a current moment and a target moment.

[0009] Optionally, when there are multiple explosion-proof balancing valves, the air pressure curve includes multiple air pressure curves corresponding one-to-one to the multiple explosion-proof balancing valves, and the battery pack pressure determination method also includes: determining the target explosion-proof balancing valve from the multiple explosion-proof balancing valves based on the maximum air pressure of the multiple air pressure curves and the maximum tolerable air pressure of the battery pack.

[0010] Optionally, the correspondence between the net gas production rate of the battery pack and the change in air pressure is constructed in the following manner: obtaining the initial air volume and environmental parameters in the battery pack; determining the relationship coefficient between the net gas production rate of the battery pack and the change in air pressure based on the initial air volume and environmental parameters; and constructing the correspondence between the net gas production rate of the battery pack and the change in air pressure based on the relationship coefficient.

[0011] Optionally, obtaining the gas production rate of the battery cells in the battery pack at the current moment includes: obtaining the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple moments and the multiple moments; determining the gas production rate at the current moment from the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple moments and the multiple moments.

[0012] Optionally, the net gas production rate of the battery pack is determined based on the gas production rate at the current moment and the exhaust rate at the current moment, including: determining the difference between the gas production rate at the current moment and the exhaust rate at the current moment as the net gas production rate of the battery pack.

[0013] Optionally, the air pressure in the battery pack at a target time is determined based on the air pressure at a current time and the change in air pressure, including: determining the sum of the air pressure at a current time and the change in air pressure as the air pressure in the battery pack at the target time.

[0014] In a second aspect, a battery pack pressure determination device is provided, comprising: a communication unit and a processing unit; the communication unit is used to obtain the current air pressure in the battery pack and the gas production rate of the battery cells in the battery pack at the current moment when the operating temperature of the battery pack is greater than a threshold value; the processing unit is used to determine the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the current air pressure, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack; the processing unit is also used to determine the air pressure in the battery pack at a target moment according to the current air pressure, the gas production rate at the current moment and the exhaust rate at the current moment.

[0015] Optionally, the processing unit is specifically used to: determine the net gas production rate of the battery pack based on the gas production rate at the current moment and the exhaust rate at the current moment; determine the change in air pressure in the battery pack from the current moment to the target moment based on the correspondence between the net gas production rate, the net gas production rate of the battery pack and the change in air pressure; determine the air pressure in the battery pack at the target moment based on the current air pressure and the change in air pressure.

[0016] Optionally, the processing unit is also used to construct a gas pressure curve of the battery pack according to the gas pressure at multiple moments in the battery pack during the gas production process of the battery cell; the multiple moments include the current moment and the target moment.

[0017] Optionally, when there are multiple explosion-proof balancing valves, the air pressure curve includes multiple air pressure curves corresponding one-to-one to the multiple explosion-proof balancing valves, and the processing unit is further used to determine the target explosion-proof balancing valve from the multiple explosion-proof balancing valves based on the maximum air pressure of the multiple air pressure curves and the maximum tolerable air pressure of the battery pack.

[0018] Optionally, the correspondence between the net gas production rate of the battery pack and the change in air pressure is constructed in the following manner: obtaining the initial air volume and environmental parameters in the battery pack; determining the relationship coefficient between the net gas production rate of the battery pack and the change in air pressure based on the initial air volume and environmental parameters; and constructing the correspondence between the net gas production rate of the battery pack and the change in air pressure based on the relationship coefficient.

[0019] Optionally, the communication unit is specifically used to: obtain the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and the multiple times; determine the gas production rate at the current moment from the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and the multiple times.

[0020] Optionally, the processing unit is specifically used to: determine the difference between the gas production rate at a current moment and the exhaust rate at a current moment as the net gas production rate of the battery pack.

[0021] Optionally, the processing unit is specifically used to determine the sum of the air pressure at the current moment and the air pressure change as the air pressure in the battery pack at the target moment.

[0022] In a third aspect, a battery pack pressure determination device is provided, comprising a memory and a processor; the memory is used to store computer execution instructions, and the processor is connected to the memory through a bus; when the battery pack pressure determination device is running, the processor executes the computer execution instructions stored in the memory, so that the battery pack pressure determination device executes the battery pack pressure determination method of the first aspect.

[0023] The battery pack pressure determination device may be an electronic device, or a part of an electronic device, such as a chip system in an electronic device. The chip system is used to support the electronic device to implement the functions involved in the first aspect and any possible implementation thereof, for example, to obtain and determine the data and / or information involved in the above-mentioned battery pack pressure determination method. The chip system includes a chip, and may also include other discrete devices or circuit structures.

[0024] In a fourth aspect, a computer-readable storage medium is provided, the computer-readable storage medium comprising computer execution instructions, and when the computer execution instructions are run on a computer, the computer executes the battery pack pressure determination method described in the first aspect.

[0025] In a fifth aspect, a computer program product is also provided, which includes a computer program or instructions. When the computer instructions are run on a battery pack pressure determination device, the battery pack pressure determination device executes the battery pack pressure determination method as described in the first aspect above.

[0026] The above technical features of this application have the following beneficial effects:

[0027] (1) The present application can obtain the voltage at the current moment in the battery pack and the gas production rate of the battery cells in the battery pack at the current moment when the operating temperature of the battery pack is greater than a threshold value (also referred to as thermal runaway of the battery pack), and then determine the exhaust rate of the explosion-proof balancing valve at the current moment based on the corresponding relationship between the air pressure at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack. Then, determine the air pressure at the target moment in the battery pack based on the air pressure at the current moment, the gas production rate at the current moment and the exhaust rate at the current moment. Under normal circumstances, after determining that the battery pack has thermal runaway, the air pressure at the target moment in the battery pack needs to be determined by simulating the change in air pressure in the battery pack. Therefore, based on the corresponding relationship between the air pressure at the current moment in the battery pack, the gas production rate of the battery cells at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, the air pressure at the target moment in the battery pack can be quickly determined, thereby solving the technical problem that the air pressure at the target moment in the battery pack cannot be quickly determined under normal circumstances.

[0028] (2) The present application can determine the net gas production rate of the battery pack based on the gas production rate at the current moment and the exhaust rate at the current moment, and then determine the change in air pressure in the battery pack from the current moment to the target moment based on the net gas production rate of the battery pack, the corresponding relationship between the net gas production rate of the battery pack and the change in air pressure, and then determine the air pressure at the target moment based on the air pressure at the current moment and the change in air pressure. In this way, the air pressure in the battery pack at the target moment can be quickly determined through simple calculations and corresponding relationships.

[0029] (3) The present application can construct a pressure curve of the battery pack based on the pressure inside the battery pack at multiple times. The battery pack can also be analyzed based on the pressure curve of the battery pack. For example, the ability of the battery pack shell to withstand the thermal runaway pressure can be determined based on the pressure curve of the battery pack, and the pressure alarm threshold of the battery pack can be set based on the pressure curve of the battery pack.

[0030] (4) The present application can determine the target balancing valve from multiple explosion-proof balancing valves based on the maximum air pressure of the air pressure curve in the battery pack equipped with different explosion-proof balancing valves and the maximum air pressure that the battery pack can withstand, and use it to equip the battery pack. The explosion-proof balancing valve determined in this way is more suitable for this type of battery pack, which can ensure the safety of the battery pack and select a more economical explosion-proof balancing valve. The air tightness of the battery pack can be evaluated based on the air pressure curve of the battery pack.

[0031] (5) The present application can obtain the initial air volume and environmental parameters in the battery pack, and determine the relationship coefficient between the net gas production rate of the battery pack and the change in air pressure based on the initial air volume and environmental parameters, and then construct the corresponding relationship between the net gas production rate of the battery pack and the change in air pressure based on the relationship coefficient. In this way, the relationship between the net gas production rate of the battery pack and the change in air pressure can be determined through simple calculations, so that the air pressure in the battery pack at the target time can be determined later using the relationship between the net gas production rate of the battery pack and the change in air pressure.

[0032] (6) The present application can directly obtain the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and multiple times, and determine the gas production rate at the current time from the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and multiple times. In this way, through the corresponding relationship, the gas production rate of the battery cells in the battery pack at the current time can be quickly determined, so that the gas pressure in the battery pack at the target time can be determined later according to the gas production rate at the current time.

[0033] (7) The present application can determine the difference between the gas production rate at the current moment and the exhaust rate at the current moment as the net gas production rate of the battery pack. In this way, the net gas production rate of the battery pack can be determined through simple calculations, so that the net gas production rate of the battery pack can be used to subsequently determine the gas pressure in the battery pack at the target moment.

[0034] (8) The present application can determine the sum of the current air pressure and the air pressure change as the air pressure in the battery pack at the target time. In this way, the air pressure in the battery pack at the target time can be quickly determined through simple calculations and corresponding relationships.

[0035] It should be noted that the beneficial effects of the first, second, third, fourth and fifth aspects of the present application can all be referred to the analysis of the above beneficial effects and will not be repeated here.

[0036] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A schematic diagram of the structure of a battery pack pressure determination system provided in an embodiment of the present application;

[0039] Figure 2 A schematic diagram of a hardware structure of a communication device provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of a flow chart of a method for determining battery pack pressure provided in an embodiment of the present application;

[0041] Figure 4 A flowchart of another method for determining battery pack pressure provided in an embodiment of the present application;

[0042] Figure 5 A flowchart of another method for determining battery pack pressure provided in an embodiment of the present application;

[0043] Figure 6 A flowchart of another method for determining battery pack pressure provided in an embodiment of the present application;

[0044] Figure 7 A flowchart of another method for determining battery pack pressure provided in an embodiment of the present application;

[0045] Figure 8 A schematic diagram of an APP interface provided in an embodiment of the present application;

[0046] Fig. 9 A schematic diagram of another APP interface provided in an embodiment of the present application;

[0047] Fig.10 A schematic diagram of a result provided in an embodiment of the present application;

[0048] Fig.11 Another result schematic diagram provided for the embodiment of the present application;

[0049] Fig.12 Another result schematic diagram provided for the embodiment of the present application;

[0050] Fig.13 Another result schematic diagram provided for the embodiment of the present application;

[0051] Fig.14 A schematic diagram of the structure of a battery pack pressure determination device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0054] In order to facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and order of execution.

[0055] Before introducing in detail the battery pack pressure determination method provided in the present application, a brief introduction to the application scenarios and implementation environment involved in the present application is first given.

[0056] First, a brief introduction to the application scenarios involved in this application is given.

[0057] As described in the background technology, with the development of the new energy vehicle industry, electric vehicles occupy an important position. In order to improve the endurance of electric vehicles, power batteries usually use lithium-ion electric batteries with higher energy density to provide sufficient energy storage for electric vehicles. As an important energy storage component in electric vehicles, battery safety needs to be taken seriously. However, thermal runaway of battery packs is the biggest safety hazard.

[0058] When the battery cells in the battery pack experience thermal runaway (the operating temperature of the battery pack is greater than a threshold, for example, the temperature inside the battery pack is greater than 80°C), a large amount of gas will be rapidly ejected, causing the gas pressure inside the battery pack to rise rapidly until the battery pack cannot withstand the gas pressure inside the battery pack, which will cause the gas inside the battery pack to explode and cause a safety accident. Therefore, battery packs are usually equipped with explosion-proof balancing valves to discharge the gas inside the battery pack, reduce the gas pressure inside the battery pack, and protect the battery.

[0059] The exhaust rate (also called ventilation flow rate) of the explosion-proof balancing valve is proportional to the air pressure in the battery pack. Therefore, the air pressure in the battery pack needs to be considered when equipping the battery pack with an explosion-proof balancing valve. Within the pressure limit of the battery pack, choosing a suitable explosion-proof balancing valve takes into account both the safety of the battery pack and the economy of the explosion-proof balancing valve.

[0060] To determine the gas pressure after thermal runaway of the battery cells in the battery pack, it is usually necessary to monitor repeatedly. Using the entire battery pack for thermal runaway testing will consume a lot of resources. Therefore, a simulation model is usually used to simulate the gas changes in the battery pack to determine the pressure in the battery pack.

[0061] The general simulation method usually requires modeling the internal cavity of the battery pack, and then uses simulation software (such as Starccm+, Fluent) to simulate the pressure changes in the battery pack. However, the general simulation method has a large amount of calculation and a long simulation cycle. Especially when the volume of air in the battery pack is large, it is impossible to quickly determine the pressure inside the battery pack (also called air pressure).

[0062] In response to the above problems, an embodiment of the present application provides a method for determining the pressure of a battery pack. When the operating temperature of the battery pack is greater than a threshold value, first, the current air pressure in the battery pack and the gas production rate of the battery cells in the battery pack are obtained. Then, based on the corresponding relationship between the current air pressure, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, the exhaust rate of the explosion-proof balancing valve at the current moment is determined. Next, based on the current air pressure, the gas production rate at the current moment and the exhaust rate at the current moment, the air pressure in the battery pack at the target moment is determined.

[0063] From the above, it can be seen that when the operating temperature of the battery pack is greater than a threshold value, the present application can determine the exhaust rate of the explosion-proof balancing valve at the current moment based on the correspondence between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack and the air pressure in the battery pack obtained at the current moment, and then quickly determine the air pressure in the battery pack at the target moment based on the calculated exhaust rate at the current moment, the obtained air pressure at the current moment, and the gas production rate at the current moment.

[0064] The implementation environment of the above-mentioned battery pack pressure determination method may be the battery pack pressure determination system provided in the embodiment of the present application.

[0065] Figure 1 FIG. 1 is a schematic diagram showing the structure of a battery pack pressure determination system provided in an embodiment of the present application. Figure 1 As shown, the battery pack pressure determination system includes: a battery pack pressure determination device 101 , a data storage device 102 , and a data acquisition device 103 .

[0066] The battery pack pressure determination device 101 and the data storage device 102 are communicatively connected to each other, and the data acquisition device 103 is communicatively connected to the battery pack pressure determination device 101 and the data storage device 102 respectively.

[0067] In practical applications, the battery pack pressure determination device 101 can be connected to any number of data storage devices 102 and data acquisition devices 103. For ease of understanding, Figure 1 An example is given for description in which a battery pack pressure determination device 101 is connected to a data storage device 102 and a data acquisition device 103 .

[0068] In an embodiment of the present application, the data storage device 102 is used to provide the battery pack pressure determination device 101 with data for determining the battery pack pressure (for example, environmental parameters, the gas production rate of the battery cell at the current moment, etc.), and the data acquisition device 103 is used to provide the battery pack pressure determination device 101 with data for determining the battery pack pressure (for example, the air pressure in the battery pack at the current moment) so that the battery pack pressure determination device 101 determines the battery pack pressure according to the data sent by the data storage device 102.

[0069] Optionally, the physical devices of the battery pack pressure determination device 101, the data storage device 102 and the data acquisition device 103 may be terminals or other types of electronic devices, which is not limited in the embodiments of the present application.

[0070] Optionally, the terminal may be a device that provides voice and / or data connectivity to a user, a handheld device with wireless connection function, or other processing device connected to a wireless modem. The wireless terminal may communicate with one or more core networks via a radio access network (RAN). The wireless terminal may be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, or a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device that exchanges language and / or data with a radio access network, such as a mobile phone, tablet computer, laptop computer, netbook, personal digital assistant (PDA).

[0071] Optionally, the battery pack pressure determination device 101 and the data storage device 102 may be two devices independently provided, or may be integrated into the same device. When the battery pack pressure determination device 101 and the data storage device 102 are integrated into the same device, the data storage device 102 may be a storage module (such as a database, etc.) of the battery pack pressure determination device 101.

[0072] It is easy to understand that when the battery pack pressure determination device 101 and the data storage device 102 are integrated into the same device, the communication method between the battery pack pressure determination device 101 and the data storage device 102 is the communication between the internal modules of the device. In this case, the communication process between the two is the same as the communication process between the battery pack pressure determination device 101 and the data storage device 102 when they are independent of each other.

[0073] Optionally, the battery pack pressure determination device 101 and the data acquisition device 103 may be two devices independently provided, or may be integrated into the same device. When the battery pack pressure determination device 101 and the data acquisition device 103 are integrated into the same device, the data acquisition device 103 may be an acquisition module (such as a sensor, etc.) of the battery pack pressure determination device 101.

[0074] It is easy to understand that when the battery pack pressure determination device 101 and the data acquisition device 103 are integrated into the same device, the communication mode between the battery pack pressure determination device 101 and the data acquisition device 103 is the communication between the internal modules of the device. In this case, the communication process between the two is the same as the communication process between the battery pack pressure determination device 101 and the data acquisition device 103 when they are independent of each other.

[0075] For ease of understanding, the present application is described by taking the example that the battery pack pressure determination device 101 , the data storage device 102 , and the data acquisition device 103 are independent of each other.

[0076] The battery pack pressure determination device in the battery pack pressure determination system includes: Figure 2 The following are the components included. Figure 2 Taking the communication device shown as an example, the hardware structure of the battery pack pressure determination device is introduced.

[0077] Figure 2 , which is a schematic diagram of a hardware structure of a communication device provided in an embodiment of the present application. The communication device includes a processor 21, a memory 22, a communication interface 23, and a bus 24. The processor 21, the memory 22, and the communication interface 23 can be connected via a bus 24.

[0078] The processor 21 is the control center of the communication device, which can be a processor or a general term for multiple processing elements. For example, the processor 21 can be a general-purpose central processing unit (CPU) or other general-purpose processors. Among them, the general-purpose processor can be a microprocessor or any conventional processor.

[0079] As an embodiment, the processor 21 may include one or more CPUs, such as Figure 2 CPU0 and CPU1 are shown in the figure.

[0080] The memory 22 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0081] In a possible implementation, the memory 22 may exist independently of the processor 21, and the memory 22 may be connected to the processor 21 via a bus 24 to store instructions or program codes. When the processor 21 calls and executes the instructions or program codes stored in the memory 22, the battery pack pressure determination method provided in the following embodiments of the present application can be implemented.

[0082] In the embodiment of the present application, for the communication device, the software programs stored in the memory 22 are different, so the functions implemented by the communication device are different. The functions performed by each device will be described in conjunction with the following flowchart.

[0083] In another possible implementation, the memory 22 may also be integrated with the processor 21 .

[0084] The communication interface 23 is used for the communication device to connect with other devices through a communication network, and the communication network may be Ethernet, wireless access network, wireless local area network (WLAN), etc. The communication interface 23 may include a receiving unit for receiving data and a sending unit for sending data.

[0085] The bus 24 may be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 2 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0086] It should be pointed out that Figure 2 The structure shown in the figure does not constitute a limitation on the communication device, except Figure 2 In addition to the components shown, the communication device may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0087] The battery pack pressure determination method provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0088] The battery pack pressure determination method provided in the embodiment of the present application is applied to Figure 1 The battery pack pressure determination device 101 in the battery pack pressure determination system shown in FIG. Figure 3 The method for determining the battery pack pressure provided in the embodiment of the present application includes:

[0089] S301. When the operating temperature of the battery pack is greater than a threshold, the battery pack pressure determination device obtains the current air pressure in the battery pack and the gas generation rate of the battery cells in the battery pack at the current moment.

[0090] When the operating temperature inside the battery pack is greater than the threshold, it will be judged as thermal runaway. Different types of batteries have different temperature thresholds for entering thermal runaway.

[0091] Exemplarily, when the battery is a ternary lithium battery, the threshold value is 180°C.

[0092] As another example, when the battery is a lithium iron phosphate battery, the threshold value is 200°C.

[0093] As another example, when the battery is a lithium cobalt oxide battery, the threshold value is 150°C.

[0094] Optional, combined Figure 1 The battery pack pressure determination device can obtain the current air pressure in the battery pack from the data acquisition device.

[0095] Optional, combined Figure 1 The battery pack pressure determination device can obtain the gas generation rate of the battery cells in the battery pack at the current moment from the data storage device.

[0096] S302. The battery pack pressure determination device determines the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the current air pressure, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack.

[0097] The exhaust rate of the explosion-proof balancing valve is positively correlated with the air pressure in the battery pack. The greater the air pressure in the battery pack, the greater the exhaust rate of the explosion-proof balancing valve.

[0098] The corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack includes the corresponding relationship between multiple exhaust rates of the explosion-proof valve and multiple air pressures in the battery pack.

[0099] The battery pack pressure determination device can find the exhaust rate corresponding to the air pressure at the current moment in the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, and determine the exhaust rate corresponding to the air pressure at the previous moment as the exhaust rate of the explosion-proof balancing valve at the current moment.

[0100] Among them, the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack is constructed in the following way:

[0101] Firstly, the battery pack pressure determination device can obtain the exhaust rate of the explosion-proof balancing valve corresponding to multiple air pressures under multiple air pressures in actual applications.

[0102] Then, the battery pack pressure determination device may preset the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the gas pressure in the battery pack, and the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the gas pressure in the battery pack satisfies the following formula:

[0103] v out =aP 2 +bP+c;

[0104] Among them, v outIt is used to indicate the exhaust rate of the explosion-proof balancing valve, P is used to indicate the air pressure in the battery pack, a is used to indicate the quadratic term coefficient in the above corresponding relationship, b is used to indicate the linear term coefficient in the above corresponding relationship, and c is used to indicate the constant term coefficient in the above relationship.

[0105] Next, the battery pack pressure determination device can substitute the exhaust rate of the explosion-proof balancing valve corresponding to multiple air pressures in actual applications under multiple air pressures into the above formula to determine the coefficient a, coefficient b and coefficient c in the above relationship.

[0106] Optionally, the battery pack pressure determination device can determine the relationship parameters (also referred to as the pressure-flow parameters of the explosion-proof balancing valve) of the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack based on the performance parameters of the explosion-proof balancing valve.

[0107] Optional, combined Figure 1 The battery pack pressure determination device can directly obtain the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack from the data storage device.

[0108] S303 . The battery pack pressure determination device determines the air pressure in the battery pack at a target time according to the current air pressure, the current gas production rate, and the current gas exhaust rate.

[0109] Optionally, the time difference between the target time and the current time may be 2s, 1s, 0.5s or 0.1s.

[0110] Optionally, the battery pack pressure determination device may determine the initial time when the battery cell in the battery pack experiences thermal runaway as the current time, and then determine the air pressure at the target time. Then, the air pressure at the target time is set as the air pressure at the current time, and the air pressure at the next target time is determined.

[0111] Exemplarily, when the time difference between the target moment and the current moment is 2s, the battery pack pressure determination device sets the initial moment when the battery cells in the battery pack undergo thermal runaway to 0s. The battery pack pressure determination device determines the air pressure in the battery pack at the 2nd second based on the air pressure at 0s, the gas production rate at 0s, and the exhaust rate at 0s. Then, the battery pack pressure determination device determines the air pressure in the battery pack at the 4th second based on the air pressure at the 2nd second, the gas production rate at the 2nd second, and the exhaust rate at the 2nd second. Next, the battery pack pressure determination device determines the air pressure in the battery pack at the 6th second based on the air pressure at the 4th second, the gas production rate at the 4th second, and the exhaust rate at the 4th second. By analogy, the battery pack pressure determination device can determine the air pressure at multiple target moments after thermal runaway of the battery cells in the battery pack occurs.

[0112] Exemplarily, when the time difference between the target moment and the current moment is 2s, the battery pack pressure determination device sets the initial moment when the battery cells in the battery pack undergo thermal runaway to 0s. The battery pack pressure determination device determines the air pressure in the battery pack at the 1st second based on the air pressure at 0s, the gas production rate at 0s, and the exhaust rate at 0s. Then, the battery pack pressure determination device determines the air pressure in the battery pack at the 2nd second based on the air pressure at the 1st second, the gas production rate at the 1st second, and the exhaust rate at the 1st second. Next, the battery pack pressure determination device determines the air pressure in the battery pack at the 3rd second based on the air pressure at the 2nd second, the gas production rate at the 2nd second, and the exhaust rate at the 2nd second. By analogy, the battery pack pressure determination device can determine the air pressure at multiple target moments after thermal runaway occurs in the battery cells in the battery pack.

[0113] The present application can obtain the voltage at the current moment in the battery pack and the gas production rate of the battery cells in the battery pack at the current moment when the operating temperature of the battery pack is greater than a threshold value (also referred to as thermal runaway of the battery pack), and then determine the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the air pressure at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, and then determine the air pressure at the target moment in the battery pack according to the air pressure at the current moment, the gas production rate at the current moment and the exhaust rate at the current moment. Under normal circumstances, after determining that the battery pack has thermal runaway, the air pressure at the target moment in the battery pack needs to be determined by simulating the change in air pressure in the battery pack, so the air pressure at the target moment in the battery pack can be quickly determined according to the corresponding relationship between the air pressure at the current moment in the battery pack, the gas production rate of the battery cells at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, thereby solving the technical problem that the air pressure at the target moment in the battery pack cannot be quickly determined under normal circumstances.

[0114] In some embodiments, in combination Figure 3 ,like Figure 4 As shown, in S303, the battery pack pressure determination device determines the air pressure in the battery pack at the target time according to the air pressure at the current time, the gas production rate at the current time, and the exhaust rate at the current time, specifically including:

[0115] S401. The battery pack pressure determination device determines the net gas production rate of the battery pack according to the gas production rate at the current moment and the exhaust rate at the current moment.

[0116] In some embodiments, the battery pack pressure determination device determines the difference between the gas production rate at the current moment and the exhaust rate at the current moment as the net gas production rate of the battery pack.

[0117] The present application can determine the difference between the gas production rate at the current moment and the exhaust rate at the current moment as the net gas production rate of the battery pack. In this way, the net gas production rate of the battery pack can be determined through simple calculations, so that the net gas production rate of the battery pack can be used to subsequently determine the air pressure in the battery pack at the target moment.

[0118] Specifically, the battery pack pressure determination device can determine the difference between the current gas production rate and the current exhaust rate as the net gas production rate of the battery pack. The net gas production rate v of the battery pack satisfies the following formula:

[0119] v=v i nt -v out ;

[0120] Among them, v int Used to indicate the gas production rate at the current moment, v out Used to indicate the exhaust rate at the current moment.

[0121] S402 , the battery pack pressure determination device determines the air pressure change in the battery pack from the current time to the target time according to the net gas production rate and the correspondence between the net gas production rate of the battery pack and the air pressure change.

[0122] In some embodiments, the correspondence between the net gas production rate of the battery pack and the gas pressure change is constructed in the following manner:

[0123] The battery pack pressure determination device obtains the initial air volume and environmental parameters in the battery pack.

[0124] Environmental parameters include: normal temperature, normal pressure, ambient atmospheric pressure, ambient temperature and ideal gas constant.

[0125] Normal temperature T a =298 Kelvin (Kelvin, K).

[0126] Normal pressure P a =100 kilo Pascal (kPa).

[0127] The battery pack pressure determination device determines the relationship coefficient between the net gas production rate of the battery pack and the air pressure change according to the initial air volume and environmental parameters.

[0128] First, the battery pack pressure determination device can determine the corresponding relationship between the amount of substance of the gas ejected from the battery cell and the gas pressure of the gas ejected from the battery cell according to the initial air volume, the ambient atmospheric pressure, the ideal gas constant and the ambient temperature. The corresponding relationship between the amount of substance n of the gas ejected from the battery cell and the gas pressure P of the gas ejected from the battery cell satisfies the following formula:

[0129] n=(P+P b )V 0 / RT;

[0130] Among them, P b Used to indicate ambient atmospheric pressure, V 0 is used to represent the initial air volume, R is used to represent the ideal gas constant, and T is used to represent the ambient temperature.

[0131] Then, the battery pack pressure determination device can determine the volume of the gas ejected from the battery cell according to the amount of the substance of the gas ejected from the battery cell, the ideal gas constant, normal temperature and normal pressure. The volume of the gas ejected from the battery cell satisfies the following formula:

[0132] V=nRT a / P 0 ;

[0133] Among them, n is used to represent the amount of gas emitted by the battery cell, R is used to represent the ideal gas constant, and T a Used to indicate normal temperature, P a Used to indicate normal pressure.

[0134] Based on the above formula, the battery pack pressure determination device can determine the corresponding relationship between the volume of the gas ejected from the battery cell and the gas pressure of the gas ejected from the battery cell. The corresponding relationship between the volume V of the gas ejected from the battery cell and the gas pressure P of the gas ejected from the battery cell satisfies the following formula:

[0135] V=V 0 T a (P+P a ) / TP a ;

[0136] Among them, P b Used to indicate ambient atmospheric pressure, V 0 is used to represent the initial air volume, T is used to represent the ambient temperature, T a Used to indicate normal temperature, P a Used to indicate normal pressure.

[0137] Next, the battery pack pressure determination device can determine the corresponding relationship between the net gas production rate of the battery pack and the air pressure change according to the real-time change rate of the volume of the gas ejected from the battery cell over time, that is, the battery pack pressure determination device can derive the corresponding relationship between the volume V of the gas ejected from the battery cell and the air pressure P of the gas ejected from the battery cell to obtain the relationship coefficient between the net gas production rate of the battery pack and the air pressure change.

[0138] The battery pack pressure determination device constructs a corresponding relationship between the net gas production rate of the battery pack and the gas pressure change according to the relationship coefficient.

[0139] The battery pack pressure determination device determines the corresponding relationship between the net gas production rate of the battery pack and the gas pressure change according to the relationship coefficient.

[0140] The present application can obtain the initial air volume and environmental parameters in the battery pack, and determine the relationship coefficient between the net gas production rate of the battery pack and the change in air pressure based on the initial air volume and environmental parameters, and then construct the corresponding relationship between the net gas production rate of the battery pack and the change in air pressure based on the relationship coefficient. In this way, the relationship between the net gas production rate of the battery pack and the change in air pressure can be determined through simple calculations, so that the air pressure in the battery pack at the target time can be determined later using the relationship between the net gas production rate of the battery pack and the change in air pressure.

[0141] S403: The battery pack pressure determination device determines the air pressure in the battery pack at a target time according to the current air pressure and the air pressure change.

[0142] In some embodiments, the battery pack pressure determination device determines the sum of the air pressure at the current moment and the air pressure change as the air pressure in the battery pack at the target moment.

[0143] The battery pack pressure determination device can determine the sum of the current air pressure and the air pressure change as the air pressure in the battery pack at the target time.

[0144] The present application can determine the sum of the current air pressure and the air pressure change as the air pressure in the battery pack at the target time. In this way, the air pressure in the battery pack at the target time can be quickly determined through simple calculations and corresponding relationships.

[0145] The present application can determine the net gas production rate of the battery pack based on the gas production rate at the current moment and the exhaust rate at the current moment, and then determine the change in air pressure in the battery pack from the current moment to the target moment based on the net gas production rate of the battery pack, the corresponding relationship between the net gas production rate of the battery pack and the change in air pressure, and then determine the air pressure at the target moment based on the current air pressure and the change in air pressure. In this way, the air pressure in the battery pack at the target moment can be quickly determined through simple calculations and corresponding relationships.

[0146] In some embodiments, in combination Figure 4 ,like Figure 5 As shown, the method for determining the battery pack pressure also includes:

[0147] S501. During the gas production process of the battery cell, the battery pack pressure determination device constructs a gas pressure curve of the battery pack according to the gas pressure in the battery pack at multiple times.

[0148] The multiple moments include a current moment and a target moment.

[0149] Optionally, when the multiple moments are consecutive moments, the air pressure curve of the battery pack is a continuous curve.

[0150] Optionally, the battery pack pressure determination device can obtain the air pressure in the battery pack at multiple times through calculation, and construct an air pressure curve of the battery pack.

[0151] Specifically, the relationship between the air pressure in the battery pack at the target time, time, and air pressure change satisfies the following formula:

[0152] F(t, P, ΔP) = v int (t)-v out (P)-v(ΔP)=0;

[0153] Among them, v int (t) is used to represent the corresponding relationship between the gas production rate of the battery cell at multiple times and multiple times, v out (P) is used to indicate the corresponding relationship between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack, and v(ΔP) is used to indicate the corresponding relationship between the net gas production rate of the battery pack and the change in air pressure.

[0154] At the initial moment, battery thermal runaway has not yet begun, the gas production rate of the battery cell at t=0 is 0, and P is 0 (because at t=0, the air pressure in the battery pack is consistent with the ambient atmospheric pressure, so P is 0).

[0155] In the calculation process, t n-1 is the current moment, t n is the target time, P n-1 is the current air pressure, P n is the air pressure at the target time, the time change Δt n =t n -t n-1 , pressure change ΔP n =P n -P n-1 , set t = t 0 =0,P=P 0 =0,Δt 1 =t 1 , pressure change ΔP 1 =P 1 Substituting into the above formula, we can determine P 1 Then, P 1 Substituting the known quantity into the formula, we can determine P 2 , and so on, the battery pack pressure determination device can determine the pressure at multiple moments, and then, the battery pack pressure determination device determines the air pressure curve of the battery pack based on the air pressure at multiple moments.

[0156] This application can construct a pressure curve of the battery pack based on the pressure inside the battery pack at multiple times. And analyze the battery pack based on the pressure curve of the battery pack. For example, the ability of the battery pack shell to withstand the thermal runaway pressure can be determined based on the pressure curve of the battery pack, the pressure alarm threshold of the battery pack can be set based on the pressure curve of the battery pack, and the air tightness of the battery pack can be evaluated based on the pressure curve of the battery pack.

[0157] In some embodiments, in combination Figure 5 ,like Figure 6 As shown, in the case where there are multiple explosion-proof balancing valves, the air pressure curve includes multiple air pressure curves corresponding to the multiple explosion-proof balancing valves one by one, and the battery pack pressure determination method also includes:

[0158] S601. The battery pack pressure determination device determines a target explosion-proof balancing valve from multiple explosion-proof balancing valves according to the maximum air pressure of multiple air pressure curves and the maximum air pressure that the battery pack can withstand.

[0159] Exemplarily, when the maximum air pressure that the battery pack can withstand is 12000Pa, the battery pack pressure determination device determines the air pressure curves in the battery pack after thermal runaway of the battery cells in the battery pack occurs when the battery pack is equipped with type A explosion-proof balancing valve, type B explosion-proof balancing valve, and type C explosion-proof balancing valve, respectively. Among them, the maximum air pressure of the air pressure curve in the battery pack equipped with type A explosion-proof balancing valve is 9000Pa, the maximum air pressure of the air pressure curve in the battery pack equipped with type B explosion-proof balancing valve is 11000Pa, and the air pressure curve in the battery pack equipped with type C explosion-proof balancing valve is interrupted. From the above, it can be seen that the battery pack equipped with type C explosion-proof balancing valve explodes, and the battery packs equipped with type A explosion-proof balancing valve and type B explosion-proof balancing valve can effectively protect the battery pack, but the maximum air pressure in the battery pack equipped with type B explosion-proof balancing valve is closer to the maximum air pressure that the battery pack can withstand, so the battery pack determines type B explosion-proof balancing valve as the target explosion-proof balancing valve.

[0160] This application can determine the target balancing valve from multiple explosion-proof balancing valves based on the maximum air pressure of the air pressure curve in the battery pack equipped with different explosion-proof balancing valves and the maximum pressure that the battery pack can withstand, and use it to equip the battery pack. The explosion-proof balancing valve determined in this way is more suitable for this type of battery pack, which can ensure the safety of the battery pack and choose a more economical and affordable explosion-proof balancing valve.

[0161] In some embodiments, in combination Figure 6 ,like Figure 7 As shown, in S301, optionally, the battery pack pressure determination device obtains the gas generation rate of the battery cells in the battery pack at the current moment, specifically including:

[0162] S701. A battery pack pressure determination device obtains a correspondence between gas production rates of battery cells in the battery pack at multiple times and multiple times.

[0163] Optional, combined Figure 1 The battery pack pressure determination device can obtain the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and multiple times (also known as the gas production flow curve after thermal runaway of the battery cell) from the data storage device.

[0164] Optionally, the corresponding relationship between the gas production rate of the battery cell at multiple times and the multiple times can be measured through experiments and stored in a data storage device.

[0165] S702 . The battery pack pressure determination device determines the gas production rate at the current moment from the correspondence between the gas production rates of the battery cells in the battery pack at multiple moments and the multiple moments.

[0166] The battery pack pressure determination device can find the gas production rate corresponding to the current moment from the correspondence between the gas production rates of the battery cells in the battery pack at multiple moments and the multiple moments, so as to determine the gas production rate at the current moment.

[0167] The present application can directly obtain the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and multiple times, and determine the gas production rate at the current time from the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and multiple times. In this way, through the corresponding relationship, the gas production rate of the battery cells in the battery pack at the current time can be quickly determined, so that the gas pressure in the battery pack at the target time can be determined later according to the gas production rate at the current time.

[0168] Optionally, the battery pack pressure determination device may also provide an application (Application, APP) interface, the APP interface is as follows Figure 8 As shown in the figure, the APP interface includes the import of gas production curve (i.e. the corresponding relationship between the gas production rate of the battery cell at multiple times and multiple times), input parameters and results. Among them, the gas production curve import can import the corresponding relationship between the gas production rate of the battery cell at multiple times and multiple times, and the input parameter can input the air domain volume V 0 , Normal temperature T a , ambient temperature T, ambient atmospheric pressure P b , explosion-proof valve (also called explosion-proof balancing valve) parameter a, explosion-proof valve parameter b, explosion-proof valve parameter c, and the results show the pressure change curve (also called battery pack air pressure curve).

[0169] For example, the operation process of the APP interface is as follows: Fig. 9 shown.

[0170] First, the battery pack pressure determination device imports the cell gas production curve and edits the input parameters. Then, click Calculate to generate the pressure change curve.

[0171] From the above, we can see that the APP interface can support the import of gas production curves, modification of environmental parameters, modification of explosion-proof balancing valve parameters, and rapid calculation of battery pack parameters.

[0172] First, the battery pack pressure determination device can import the gas production curve in the APP interface and input parameters, where the parameters include the initial air volume (also called the battery pack volume), ambient temperature, ambient atmospheric pressure, and the relationship parameters between the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack (i.e., parameter a, parameter b, parameter c).

[0173] The battery pack pressure determination can then determine the gas pressure of the battery pack and generate a gas pressure curve of the battery pack.

[0174] For example, the corresponding relationship between the gas production rate of the battery cell at multiple times and multiple times (also referred to as time) is as follows: Fig.10 As shown in (a), the corresponding relationship between the exhaust rate of the explosion-proof balance valve and the air pressure in the battery pack is as follows Fig.10 In the case shown in (b), the ambient temperature is 40°C, the ambient atmospheric pressure is 97.2Kpa, the initial air volume of the battery pack is 58.8L, and the battery pack pressure determination device can determine the air pressure curve in the battery pack as follows Fig.10 The solid line portion shown in (c) in FIG.

[0175] The 3D simulation software determines the pressure curve inside the battery pack under the same conditions. Fig.10 The dotted line portion shown in (c) in FIG.

[0176] In another exemplary embodiment, the corresponding relationship between the gas production rate of the battery cell at multiple times and the multiple times is as follows: Fig.11 As shown in (a), the corresponding relationship between the exhaust rate of the explosion-proof balance valve and the air pressure in the battery pack is as follows Fig.11 In the case shown in (b), the ambient temperature is 40°C, the ambient atmospheric pressure is 97.2Kpa, the initial air volume of the battery pack is 81.5L, and the battery pack pressure determination device can determine the air pressure curve in the battery pack as follows Fig.11 The solid line portion shown in (c) in FIG.

[0177] The 3D simulation software determines the pressure curve inside the battery pack under the same conditions. Fig.11 The dotted line portion shown in (c) in FIG.

[0178] In another exemplary embodiment, the corresponding relationship between the gas production rate of the battery cell at multiple times and the multiple times is as follows: Fig.12 As shown in (a), the corresponding relationship between the exhaust rate of the explosion-proof balance valve and the air pressure in the battery pack is as follows Fig.12 In the case shown in (b), the ambient temperature is 40°C, the ambient atmospheric pressure is 97.2Kpa, the initial air volume of the battery pack is 72.7L, and the battery pack pressure determination device can determine the air pressure curve in the battery pack as follows Fig.12 The solid line portion shown in (c) in FIG.

[0179] The 3D simulation software determines the pressure curve inside the battery pack under the same conditions. Fig.12 The dotted line portion shown in (c) in FIG.

[0180] Depend on Fig.12 As can be seen from (c), the solid line portion coincides with the dotted line portion, that is, the air pressure curve determined by the battery pack pressure determination device is the same as the air pressure curve inside the battery pack determined by the three-dimensional simulation software under the same conditions.

[0181] In another exemplary embodiment, the corresponding relationship between the gas production rate of the battery cell at multiple times and the multiple times is as follows: Fig.13 As shown in (a), the corresponding relationship between the exhaust rate of the explosion-proof balance valve and the air pressure in the battery pack is as follows Fig.13 In the case shown in (b), the ambient temperature is 40°C, the ambient atmospheric pressure is 97.2Kpa, the initial air volume of the battery pack is 111.2L, and the battery pack pressure determination device can determine the air pressure curve in the battery pack as follows Fig.13 The solid line portion shown in (c) in FIG.

[0182] The 3D simulation software determines the pressure curve inside the battery pack under the same conditions. Fig.13 The dotted line portion shown in (c) in FIG.

[0183] As can be seen from the above, the pressure curve inside the battery pack determined by the battery pack pressure determination device is consistent with the three-dimensional simulation software, and the maximum pressure value error reaches 95%. In addition, compared with the three-dimensional simulation software, the battery pack pressure determination device can quickly modify the input parameters, and it usually only takes a few minutes or even tens of seconds to determine the air pressure inside the battery pack. Therefore, compared with the three-dimensional simulation software, this application greatly reduces the processing time and can quickly and accurately determine the air pressure inside the battery pack at the target time.

[0184] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the method. In order to realize the above functions, it includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0185] The embodiment of the present application can divide the functional modules of the battery pack pressure determination device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. Optionally, the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0186] Fig.14 FIG. 1 is a schematic diagram showing the structure of a battery pack pressure determination device provided in an embodiment of the present application. Fig.14 As shown, the battery pack pressure determination device includes: a communication unit 1401 and a processing unit 1402;

[0187] The communication unit 1401 is used to obtain the current air pressure in the battery pack and the gas production rate of the battery cells in the battery pack at the current moment when the operating temperature of the battery pack is greater than a threshold value; the processing unit 1402 is used to determine the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the current air pressure, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack; the processing unit 1402 is also used to determine the air pressure in the battery pack at a target moment according to the current air pressure, the gas production rate at the current moment and the exhaust rate at the current moment.

[0188] Optionally, the processing unit 1402 is specifically used to: determine the net gas production rate of the battery pack based on the gas production rate at the current moment and the exhaust rate at the current moment; determine the change in air pressure in the battery pack from the current moment to the target moment based on the correspondence between the net gas production rate, the net gas production rate of the battery pack and the change in air pressure; determine the air pressure in the battery pack at the target moment based on the current air pressure and the change in air pressure.

[0189] Optionally, the processing unit 1402 is further used to construct a gas pressure curve of the battery pack according to the gas pressure at multiple moments in the battery pack during the gas production process of the battery cell; the multiple moments include a current moment and a target moment.

[0190] Optionally, when there are multiple explosion-proof balancing valves, the air pressure curve includes multiple air pressure curves corresponding one-to-one to the multiple explosion-proof balancing valves, and the processing unit 1402 is further used to determine the target explosion-proof balancing valve from the multiple explosion-proof balancing valves based on the maximum air pressure of the multiple air pressure curves and the maximum tolerable air pressure of the battery pack.

[0191] Optionally, the correspondence between the net gas production rate of the battery pack and the change in air pressure is constructed in the following manner: obtaining the initial air volume and environmental parameters in the battery pack; determining the relationship coefficient between the net gas production rate of the battery pack and the change in air pressure based on the initial air volume and environmental parameters; and constructing the correspondence between the net gas production rate of the battery pack and the change in air pressure based on the relationship coefficient.

[0192] Optionally, the communication unit 1401 is specifically used to: obtain the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and the multiple times; determine the gas production rate at the current moment from the corresponding relationship between the gas production rate of the battery cells in the battery pack at multiple times and the multiple times.

[0193] Optionally, the processing unit 1402 is specifically used to determine the difference between the gas production rate at the current moment and the exhaust rate at the current moment as the net gas production rate of the battery pack.

[0194] Optionally, the processing unit 1402 is specifically used to determine the sum of the air pressure at the current moment and the air pressure change as the air pressure in the battery pack at the target moment.

[0195] An embodiment of the present application also provides a computer-readable storage medium, which includes computer execution instructions. When the computer execution instructions are executed on a computer, the computer executes the battery pack pressure determination method provided in the above embodiment.

[0196] An embodiment of the present application also provides a computer program, which can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program can implement the battery pack pressure determination method provided in the above embodiment.

[0197] Those skilled in the art should be aware that in one or more of the above examples, the functions described in this application can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer-readable storage media and communication media, wherein communication media include any media that facilitates the transmission of computer programs from one place to another. Storage media can be any available media that can be accessed by general or special-purpose computers.

[0198] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0199] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the modules or units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the coupling or direct coupling or communication connection between each other shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms. The unit described as a separate component may or may not be physically separated, and the component displayed as a unit may be a physical unit or multiple physical units, that is, it may be located in one place, or it may be distributed in multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0200] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on such an understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the general technology or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a U disk, a mobile hard disk, a ROM, a RAM, a disk, or an optical disk.

[0201] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining battery pack pressure, characterized in that: The method comprises: When the operating temperature of the battery pack is greater than a threshold, obtaining the current air pressure in the battery pack and the gas generation rate of the battery cells in the battery pack at the current moment; Determining the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the air pressure at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack; The air pressure in the battery pack at a target time is determined according to the air pressure at the current time, the gas production rate at the current time, and the gas exhaust rate at the current time.

2. The method according to claim 1, characterized in that The step of determining the air pressure in the battery pack at a target time according to the air pressure at the current time, the gas production rate at the current time, and the gas exhaust rate at the current time includes: Determining a net gas production rate of the battery pack according to the gas production rate at the current moment and the gas exhaust rate at the current moment; Determining the change in air pressure in the battery pack from the current moment to the target moment according to the corresponding relationship between the net gas production rate, the net gas production rate of the battery pack, and the change in air pressure; The air pressure in the battery pack at a target time is determined according to the air pressure at the current time and the air pressure change.

3. The method according to claim 2, characterized in that The method further comprises: During the gas production process of the battery cell, a gas pressure curve of the battery pack is constructed according to the gas pressure in the battery pack at multiple moments; the multiple moments include the current moment and the target moment.

4. The method according to claim 3, characterized in that In the case where there are multiple explosion-proof balancing valves, the air pressure curve includes multiple air pressure curves corresponding to the multiple explosion-proof balancing valves one by one, and the method further includes: A target explosion-proof balancing valve is determined from the plurality of explosion-proof balancing valves according to the maximum air pressure of the plurality of air pressure curves and the maximum tolerable air pressure of the battery pack.

5. The method according to claim 2, characterized in that: The corresponding relationship between the net gas production rate of the battery pack and the gas pressure change is constructed in the following way: Obtaining initial air volume and environmental parameters in the battery pack; Determine a coefficient of relationship between a net gas production rate of the battery pack and a change in air pressure according to the initial air volume and the environmental parameters; The corresponding relationship between the net gas production rate of the battery pack and the gas pressure change is constructed according to the relationship coefficient.

6. The method according to claim 1, characterized in that The obtaining of the gas generation rate of the battery cell in the battery pack at the current moment includes: Obtaining the corresponding relationship between the gas generation rate of the battery cells in the battery pack at multiple times and multiple times; The gas production rate at the current moment is determined from the correspondence between the gas production rates of the cells in the battery pack at multiple moments and the multiple moments.

7. The method according to claim 2, characterized in that The determining the net gas production rate of the battery pack according to the gas production rate at the current moment and the exhaust rate at the current moment includes: The difference between the gas production rate at the current moment and the exhaust rate at the current moment is determined as the net gas production rate of the battery pack.

8. The method according to claim 2, characterized in that: The step of determining the air pressure in the battery pack at a target time according to the air pressure at the current time and the air pressure change includes: The sum of the air pressure at the current moment and the air pressure change is determined as the air pressure in the battery pack at the target moment.

9. A battery pack pressure determination device, characterized in that: The battery pack pressure determination device comprises: a communication unit and a processing unit; The communication unit is used to obtain the gas pressure in the battery pack at the current moment and the gas generation rate of the battery cells in the battery pack at the current moment when the operating temperature of the battery pack is greater than a threshold; The processing unit is used to determine the exhaust rate of the explosion-proof balancing valve at the current moment according to the corresponding relationship between the air pressure at the current moment, the exhaust rate of the explosion-proof balancing valve and the air pressure in the battery pack; The processing unit is further used to determine the air pressure in the battery pack at a target moment according to the air pressure at the current moment, the gas production rate at the current moment, and the gas exhaust rate at the current moment.

10. A battery pack pressure determination device, characterized in that: include: A processor and a memory; wherein the memory is used to store one or more programs, and the one or more programs include computer-executable instructions. When the device is running, the processor executes the computer-executable instructions stored in the memory to enable the device to perform the method described in any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: When the computer-executable instructions stored in the computer-readable storage medium are executed by a processor of a battery pack pressure determination device, the battery pack pressure determination device is capable of performing the method according to any one of claims 1 to 8.

12. A computer program product, characterized in that The computer program product comprises: a computer program or instructions, and when the computer program or instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 8.

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