Model selection method for explosion-proof valve of battery pack, electronic equipment and storage medium

Abstract

The invention provides an explosion-proof valve type selection method for a battery pack, electronic equipment and a storage medium, and the method comprises the steps: obtaining the ventilation volume needed when a box body where the battery pack is located generates the maximum temperature difference before an explosion-proof valve is opened; the gas production rate of the battery pack after the anti-explosion valve is opened is obtained; according to the ventilation volume and the gas production rate, the explosion-proof valve of the battery pack is selected, so that the selected explosion-proof valve not only can balance the pressure difference inside and outside the box body, but also can quickly relieve pressure to prevent explosion, the explosion-proof effect of the explosion-proof valve is improved, and the safety of the battery pack is further improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method for selecting an explosion-proof valve of a battery pack, an electronic device and a storage medium. Background Art

[0002] A battery pack is usually composed of multiple groups of battery cells, and each battery cell is designed with an explosion-proof valve. When the pressure inside the battery cell is too high, the explosion-proof valve will automatically open to release the pressure to prevent an explosion.

[0003] In the related art, when selecting and designing the explosion-proof valve in the battery pack, the explosion-proof valve is selected by roughly estimating the air permeability after the explosion. On the one hand, it is difficult to ensure the rationality of the selection of the explosion-proof valve selected by this selection scheme, which will affect the rapid pressure relief effect; on the other hand, when the battery pack is in normal use, the explosion-proof valve selected by this selection scheme still has the problem of difficulty in balancing the internal and external air pressure difference of the box where the battery pack is located, which reduces the explosion-proof effect of the explosion-proof valve and affects the safety of the battery pack. Summary of the invention

[0004] The embodiments of the present invention provide a method for selecting an explosion-proof valve of a battery pack, an electronic device, and a storage medium, which improve the technical problem in the related art that the selection of explosion-proof valves is unreasonable, resulting in poor explosion-proof effect of the explosion-proof valves and reduced safety of the battery pack.

[0005] In a first aspect, an embodiment of the present invention provides a method for selecting an explosion-proof valve of a battery pack, the method comprising:

[0006] Obtaining the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened;

[0007] Obtaining the gas production rate of the battery pack after the explosion-proof valve is opened;

[0008] The explosion-proof valve of the battery pack is selected according to the air permeability and the gas production rate.

[0009] In one embodiment, obtaining the air permeability required when a temperature difference occurs in the box where the battery pack is located before the explosion-proof valve is opened includes:

[0010] Obtaining the maximum temperature difference generated by the box before the explosion-proof valve is opened and the time when the maximum temperature difference is generated;

[0011] The air permeability is determined according to the net volume of the box, the maximum temperature difference and the air production time.

[0012] In one embodiment, determining the air permeability according to the net volume of the box, the maximum temperature difference and the air production time includes:

[0013] Determine the gas expansion volume of the box under the maximum temperature difference according to the net volume;

[0014] The air permeability is determined according to the gas expansion volume and the gas production time.

[0015] In one embodiment, determining the air permeability according to the gas expansion volume and the gas production time includes:

[0016] Obtaining an initial air permeability according to a ratio of the gas expansion volume to the gas production time;

[0017] The air permeability is obtained according to a preset safety factor and the initial air permeability.

[0018] In one embodiment, obtaining the gas generation rate of the battery pack after the explosion-proof valve is opened includes:

[0019] Performing a thermal runaway test on each battery cell in the battery pack, and recording the gas production and test duration of the battery pack;

[0020] The gas production rate is obtained according to the gas production amount and the test duration.

[0021] In one embodiment, it further includes:

[0022] Obtaining the ultimate deformation pressure of the box before the explosion-proof valve is opened and the ultimate bursting pressure after the explosion-proof valve is opened;

[0023] The selecting the explosion-proof valve of the battery pack according to the air permeability and the gas production rate includes: selecting the explosion-proof valve of the battery pack according to the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate.

[0024] In one embodiment, obtaining the limit deformation pressure of the box before the explosion-proof valve is opened includes:

[0025] Obtaining the deformation pressure of the box body before the explosion-proof valve is opened when the box cover is under pressure and does not deform;

[0026] The limit deformation pressure is obtained according to the deformation pressure and a first preset pressure coefficient, wherein the first preset pressure coefficient is less than 1; and / or,

[0027] Obtaining the ultimate bursting pressure of the box after the explosion-proof valve is opened, including:

[0028] Obtaining the bursting pressure of the box body when the explosion-proof valve is opened and the box cover is under pressure without cracking;

[0029] The limit bursting pressure is obtained according to the bursting pressure and a second preset pressure coefficient, and the second preset pressure coefficient is less than 1.

[0030] In one embodiment, the selection of the explosion-proof valve of the battery pack according to the limit deformation pressure, the limit bursting pressure, the air permeability and the gas production rate includes:

[0031] If the first air permeability rate of the explosion-proof valve to be determined under the ultimate deformation pressure is greater than the air permeability, and the second air permeability rate under the ultimate bursting pressure is greater than the gas production rate, the explosion-proof valve to be determined is determined to be the target explosion-proof valve of the battery pack.

[0032] In a second aspect, an embodiment of the present invention provides a device for selecting an explosion-proof valve of a battery pack, the device for selecting an explosion-proof valve of a battery pack comprising:

[0033] A first acquisition module is used to obtain the air permeability required when the box where the battery pack is located produces a maximum temperature difference before the explosion-proof valve is opened;

[0034] A second acquisition module is used to obtain the gas production rate of the battery pack after the explosion-proof valve is opened;

[0035] The selection module is used for selecting the explosion-proof valve of the battery pack according to the air permeability and the gas production rate.

[0036] In a third aspect, an embodiment of the present invention provides an electronic device, the electronic device comprising:

[0037] one or more processors;

[0038] Memory; and

[0039] One or more applications, wherein the one or more applications are stored in the memory and are configured to be executed by the processor to implement the steps in the method for selecting an explosion-proof valve for a battery pack as described in any one of the first aspects.

[0040] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program is loaded by a processor to execute the steps in the method for selecting an explosion-proof valve for a battery pack as described in any one of the first aspects.

[0041] In a fifth aspect, the present application also provides a computer program product, including a computer program / instruction, which, when executed by a processor, is used to execute the steps in the method for selecting an explosion-proof valve for a battery pack as described in any one of the first aspects above.

[0042] Beneficial effects of the embodiments of the present invention:

[0043] In an embodiment of the present invention, the air permeability required for the maximum temperature difference in the box where the battery pack is located before the explosion-proof valve is opened is obtained; the gas production rate of the battery pack after the explosion-proof valve is opened is obtained; and the explosion-proof valve of the battery pack is selected according to the air permeability and the gas production rate, so that the selected explosion-proof valve can not only balance the pressure difference between the inside and outside of the box, but also can quickly release pressure to prevent explosion, thereby improving the explosion-proof effect of the explosion-proof valve and thereby improving the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0045] Figure 1 It is a schematic flow chart of an embodiment of a method for selecting an explosion-proof valve of a battery pack provided by an embodiment of the present invention;

[0046] Figure 2 It is a schematic flow chart of another embodiment of the method for selecting an explosion-proof valve of a battery pack provided in an embodiment of the present application;

[0047] Figure 3 It is a flow chart of another embodiment of the method for selecting an explosion-proof valve of a battery pack provided in the embodiments of the present application;

[0048] Figure 4 It is a schematic structural diagram of an embodiment of an explosion-proof valve selection device for a battery pack provided in an embodiment of the present application;

[0049] Figure 5 It is a schematic diagram of the structure of an embodiment of an electronic device provided in the embodiments of the present application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device.

[0051] In the case of thermal runaway of the battery cells in an energy storage battery pack, the battery cells will generate a large amount of flammable gas. Usually, one or more explosion-proof valves are installed on the battery pack. If the opening value and air permeability of the explosion-proof valve are not selected correctly, it will affect the pressure relief effect and cause great safety hazards. At present, the selection of explosion-proof valves is usually made by roughly estimating the air permeability after the explosion. On the one hand, it is difficult to ensure the rationality of the explosion-proof valve selected by this selection scheme, which will affect the rapid pressure relief effect; on the other hand, when the explosion-proof valve selected by this selection scheme is in normal use of the battery pack, it is still difficult to balance the internal and external air pressure difference of the box where the battery pack is located, which reduces the explosion-proof effect of the explosion-proof valve and affects the safety of the battery pack.

[0052] In view of this, the present application proposes a method for selecting an explosion-proof valve for a battery pack, an electronic device and a computer storable medium to improve the rationality of the selection of the explosion-proof valve, enhance the explosion-proof effect of the explosion-proof valve, and thereby improve the safety of the battery pack.

[0053] like Figure 1 As shown, it is a flow chart of an embodiment of the method for selecting an explosion-proof valve of a battery pack in an embodiment of the present application. The execution subject of the embodiment of the present application is an electrical device or a control module in the electrical device. The control module can be a battery management system (Battery Management System, BMS), a vehicle control unit (VCU), etc. The embodiment of the present application is described in detail by taking the execution subject as BMS as an example. The method for selecting an explosion-proof valve of a battery pack includes:

[0054] 101. Obtain the air permeability required when the box where the battery pack is located produces a maximum temperature difference before the explosion-proof valve is opened.

[0055] The battery pack in this embodiment may be a power storage battery pack. In order to ensure the safety of the battery pack, the battery pack is installed in a sealed housing, i.e., a box. When the battery pack is in normal operation, i.e., when thermal runaway does not occur, the explosion-proof valve does not need to be opened. That is, before the explosion-proof valve is opened, it means that the battery pack is in normal operation, i.e., when the box does not explode.

[0056] The inventors found that the operating temperature of the power storage battery pack is between -40℃ and 60℃. In order to ensure normal operation within the operating temperature range, there is no need to open the explosion-proof valve for pressure relief. Before the explosion-proof valve is opened, the explosion-proof valve has a certain air permeability rate, so that the air permeability of the explosion-proof valve can be used to balance the internal and external air pressure difference of the box where the battery pack is located. When the temperature inside the battery pack box rises, the internal gas pressure increases, forming a pressure difference with the outside of the box. It is necessary to use an explosion-proof valve that matches the air permeability with the battery pack to balance the internal and external air pressure difference of the box where the battery pack is located. Therefore, in this embodiment, the air permeability required when the box produces the maximum temperature difference is obtained, so that the explosion-proof valve can be reasonably selected according to the air permeability in the future, so that the explosion-proof valve can balance the air pressure difference inside and outside the box when the battery pack is working normally, thereby improving the safety of the battery pack.

[0057] Specifically, the maximum temperature difference and the time when the maximum temperature difference occurs can be determined based on the normal operating temperature range of the battery pack, and the air permeability can be determined in combination with the volume of the battery pack. It can be understood that in this embodiment, by obtaining the air permeability required when the box produces the maximum temperature difference, the air permeability required for the temperature difference within the full range of the box can be analyzed to ensure that the obtained air permeability can match the full range of temperature differences, so that before the explosion-proof valve is opened, that is, the battery is working normally, the air permeability of the selected explosion-proof valve can balance the pressure difference inside and outside the box caused by the full range of temperature differences, thereby improving the rationality and effectiveness of the selection of the explosion-proof valve.

[0058] In one embodiment, Figure 2 As shown, step 101 includes:

[0059] 101A, obtaining the maximum temperature difference generated by the box before the explosion-proof valve is opened and the time when the maximum temperature difference is generated;

[0060] 101B, determining the air permeability according to the net volume of the box, the maximum temperature difference and the air production time.

[0061] The maximum temperature difference generated by the box before the explosion-proof valve is opened is the difference between the highest temperature Tmax and the lowest temperature Tmin in the temperature range of normal operation of the battery, such as 60-(-40) = 100°C. The generation time refers to the time it takes for the box where the battery pack is located to rise from the lowest temperature to the highest temperature before the explosion-proof valve is opened, such as 30 minutes.

[0062] The net volume is the volume under standard atmospheric pressure, which refers to the volume of the space inside the box minus the volume of the battery pack and the parts inside the box. It can be calculated based on the volume of the space inside the box, the volume of the battery pack, and the volume of the parts inside the box. The net volume of the air inside the box can also be used as the net volume.

[0063] Specifically, the computer device can calculate the air permeability based on the net volume, the maximum temperature difference and the gas production time.

[0064] In one embodiment, Figure 3 As shown, step 101B includes:

[0065] 101B1, determining the gas expansion volume of the box under the maximum temperature difference according to the net volume;

[0066] 101B2, determining the air permeability according to the gas expansion volume and the gas production time.

[0067] The gas expansion volume is the net volume of the box under atmospheric pressure corresponding to the maximum temperature difference.

[0068] Since the net volume is the volume under 1 standard atmospheric pressure, the gas expansion volume can be determined based on the atmospheric pressure and net volume under the maximum temperature difference.

[0069] P1=P×(Tmax-Tmin) / 273 (1)

[0070] In the above formula (1), (Tmax-Tmin) is the maximum temperature difference, P is 1 standard atmospheric pressure, i.e. 101.3 kPa, and P1 is the atmospheric pressure difference at the maximum temperature Tmax.

[0071] Based on the above formula (1), the gas expansion volume can be determined using formula (2).

[0072] V1=V×(Tmax-Tmin) / 273 (2)

[0073] In the above formula (2), (Tmax-Tmin) is the maximum temperature difference, V is the net volume, and V1 is the net volume at the highest temperature Tmax, that is, the gas expansion volume.

[0074] Specifically, the gas expansion volume can be divided by the gas production time to calculate the air permeability.

[0075] In one embodiment, step 101B2 includes: obtaining an initial air permeability based on a ratio of the gas expansion volume to the gas production time; and obtaining the air permeability based on a preset safety factor and the initial air permeability.

[0076] The preset safety factor refers to a preset factor used to adjust the air permeability, ensure that the final air permeability can ensure the rationality of the selection, and improve the safety factor of the explosion-proof valve in the battery pack. For example, the preset safety factor can be 1.5.

[0077] The calculation formula of air permeability is as follows:

[0078]

[0079] In the above formula (3), α is the preset safety factor, t is the gas production time, V1 is the gas expansion volume, is the initial air permeability, and V2 is the air permeability.

[0080] Specifically, the ratio of the gas expansion volume to the gas production time can be calculated to obtain the initial air permeability, and then the initial air permeability is multiplied by a preset safety factor to obtain the air permeability. It can be understood that in this embodiment, by multiplying the initial air permeability by the preset safety factor, the safety factor of the explosion-proof valve selected based on the calculated air permeability is higher, thereby ensuring the safety performance of the selected explosion-proof valve in the battery pack.

[0081] 102. Obtain the gas production rate of the battery pack after the explosion-proof valve is opened.

[0082] Among them, after the explosion-proof valve is opened, it indicates that the explosion-proof valve is opened, that is, the battery pack has thermal runaway and it is necessary to release the pressure by opening the explosion-proof valve, that is, the box body explodes.

[0083] The gas production rate refers to the gas production rate after the battery pack explodes in the box, that is, after thermal runaway occurs.

[0084] Specifically, the gas production rate of the battery pack after the explosion-proof valve is opened can be obtained by performing a thermal runaway test on multiple battery cells in the battery pack. The gas production rate can also be estimated based on empirical values. For example, the gas production rate can be estimated based on the empirical value of 0.2L / S generated by a battery cell capacity of 1Ah. The estimated gas production rate of a 306Ah battery cell is 0.2L×306Ah=61.2L / S.

[0085] It can be understood that in this embodiment, by obtaining the gas production rate of the battery pack after the explosion-proof valve is opened, the air permeability rate in the case of box explosion can be considered when selecting the explosion-proof valve, so that the selected explosion-proof valve can efficiently release pressure, improve the explosion-proof effect of the explosion-proof valve, and thus improve the safety of the battery pack.

[0086] In one embodiment, obtaining the gas generation rate of the battery pack after the explosion-proof valve is opened includes:

[0087] A thermal runaway test is performed on each battery cell in the battery pack, and the gas production and test duration of the battery pack are recorded; the gas production rate is obtained based on the gas production and the test duration.

[0088] Specifically, each battery cell in the battery pack can be subjected to a thermal runaway test, and the gas production during the thermal runaway process can be collected. At the same time, the test time required for the gas production can be recorded, and the gas production rate can be obtained by dividing the gas production by the test time. It can be understood that in this example, by conducting a thermal runaway test on the battery cells in the battery pack and calculating the gas production rate based on the test data, the accuracy of the gas production rate is greatly improved compared to the rough estimation method, which is conducive to improving the rationality and reliability of the subsequent explosion-proof valve selection.

[0089] 103. Select an explosion-proof valve for the battery pack according to the air permeability and the gas production rate.

[0090] Specifically, whether the explosion-proof valve can balance the pressure difference between the inside and outside of the box can be judged according to the first air permeability rate and air permeability before the explosion-proof valve is opened, and whether the explosion-proof valve can quickly release pressure to prevent explosion can be judged according to the second air permeability rate and gas production rate after the explosion-proof valve is opened. Therefore, the explosion-proof valve of the battery pack is selected based on the air permeability and gas production rate, so that the selected explosion-proof valve can not only balance the pressure difference between the inside and outside of the box, but also quickly release pressure to prevent explosion, thereby improving the explosion-proof effect of the explosion-proof valve and thus improving the safety of the battery pack.

[0091] Whether the explosion-proof valve can balance the pressure difference between the inside and outside of the box can be judged according to the first air permeability rate and air permeability of the explosion-proof valve under the ultimate deformation pressure, and whether the explosion-proof valve can quickly release pressure to prevent explosion can be judged according to the second air permeability rate and gas production rate of the explosion-proof valve under the ultimate bursting pressure. Therefore, the explosion-proof valve of the battery pack is selected based on the ultimate deformation pressure, ultimate bursting pressure, air permeability and gas production rate, so that the selected explosion-proof valve can not only balance the pressure difference between the inside and outside of the box, but also quickly release pressure to prevent explosion, thereby improving the explosion-proof effect of the explosion-proof valve and thus improving the safety of the battery pack.

[0092] In one embodiment, the method also includes: obtaining the ultimate deformation pressure of the box body before the explosion-proof valve is opened and the ultimate bursting pressure after the explosion-proof valve is opened; selecting the explosion-proof valve of the battery pack according to the air permeability and the gas production rate, including: selecting the explosion-proof valve of the battery pack according to the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate.

[0093] Specifically, whether the explosion-proof valve can balance the pressure difference between the inside and outside of the box can be judged according to the first air permeability rate and air permeability of the explosion-proof valve under the ultimate deformation pressure, and whether the explosion-proof valve can quickly release pressure to prevent explosion can be judged according to the second air permeability rate and gas production rate of the explosion-proof valve under the ultimate bursting pressure. Therefore, the explosion-proof valve of the battery pack is selected based on the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate. Since the air permeability speed of the explosion-proof valve under the ultimate deformation pressure and the ultimate bursting pressure are taken into consideration, the selected explosion-proof valve can more efficiently balance the pressure difference between the inside and outside of the box, and can more quickly release pressure to prevent explosion, thereby further improving the rationality of the selection of the explosion-proof valve, further enhancing the explosion-proof effect of the explosion-proof valve, and thereby improving the safety of the battery pack.

[0094] In one embodiment, obtaining the ultimate deformation pressure of the box body before the explosion-proof valve is opened includes: obtaining the deformation pressure of the box body before the explosion-proof valve is opened, when the box cover is under pressure without deformation; obtaining the ultimate deformation pressure according to the deformation pressure and a first preset pressure coefficient, and the first preset pressure coefficient is less than 1; and / or obtaining the ultimate bursting pressure of the box body after the explosion-proof valve is opened, includes: obtaining the bursting pressure of the box body after the explosion-proof valve is opened, when the box cover is under pressure without cracking; obtaining the ultimate bursting pressure according to the bursting pressure and a second preset pressure coefficient, and the second preset pressure coefficient is less than 1.

[0095] Among them, the deformation pressure is the limit pressure of the box body before the explosion-proof valve is opened, when the box cover is under pressure without bulging and deforming. The bursting pressure is the limit pressure of the box body after the explosion-proof valve is opened, when the box cover is under pressure without cracking. Specifically, the limit pressure value of the box cover without bulging and deforming can be calculated according to the material and thickness of the box cover of the box. In practical applications, the smaller the pressure before the explosion-proof valve is opened, the better the effect of explosion-proof balancing the pressure difference inside and outside the box. Therefore, the pressure before the explosion-proof valve is opened can be reduced on the basis of the deformation pressure. The deformation pressure can be reduced by multiplying the deformation pressure by a first preset pressure coefficient less than 1 to obtain the limit deformation pressure. The explosion-proof valve selected according to the limit deformation pressure can more efficiently balance the pressure difference inside and outside the box.

[0096] Specifically, the maximum pressure value that the box cover can withstand without cracking and leaking can be calculated based on the material and thickness of the box cover of the box body. In practical applications, the smaller the opening pressure of the explosion-proof valve is, the earlier the valve is opened and the longer the valve is opened, the more gas can be discharged. Therefore, the opening pressure of the explosion-proof valve can be reduced on the basis of the bursting pressure. The bursting pressure can be reduced by multiplying the bursting pressure by a second preset pressure coefficient less than 1 to obtain the limit bursting pressure. The explosion-proof valve selected according to the limit bursting pressure opens when the pressure of the gas in the box is relatively low, and has a long enough time to release pressure, thereby improving the pressure relief and explosion-proof effect of the explosion-proof valve.

[0097] In one example, the box cover is made of SPCC or SGCC with a thickness of 1mm. The box pressure resistance value is less than 2kPa without bulging and deformation, and less than 20kPa without cracking and leakage, that is, the deformation pressure is 2kPa, the bursting pressure is 20kPa, the first preset pressure coefficient and the second preset pressure coefficient are both 0.8, at this time the ultimate deformation pressure is 1.6kPa, and the ultimate bursting pressure is 16kPa.

[0098] In another example, an inflation test can be performed on a sealed box to test the ultimate pressure value of the box cover, or CAE simulation can be used to determine the deformation pressure and bursting pressure. For example, the box pressure resistance value is less than 2kPa without bulging and deformation, and less than 20kPa without cracking and leakage, that is, the deformation pressure is 2kPa, and the bursting pressure is 20kPa. The ultimate deformation pressure is set to 1.6kPa within the tolerance range of the explosion-proof valve balance pressure, and the ultimate bursting pressure is set to 16kPa within the tolerance range of the explosion-proof valve bursting pressure.

[0099] In one embodiment, an explosion-proof valve of a battery pack is selected according to the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate, including: if a first air permeability rate of the explosion-proof valve to be determined under the ultimate deformation pressure is greater than the air permeability, and a second air permeability rate under the ultimate bursting pressure is greater than the gas production rate, determining that the explosion-proof valve to be determined is the target explosion-proof valve of the battery pack.

[0100] Specifically, when the air permeability rate before the explosion-proof valve is opened is greater than the air permeability required to produce the maximum temperature difference of the box, and the air permeability rate after the explosion-proof valve is opened is greater than the gas production rate, and both conditions are met, it is determined that the explosion-proof valve meets the selection requirements and the explosion-proof valve is used as the target explosion-proof valve.

[0101] In a specific embodiment, as shown in Table 1, it is a parameter table of the box and the battery pack:

[0102] Table 1: Parameters of the box and battery pack

[0103]

[0104] According to the above table:

[0105] The maximum temperature difference is Tmax-Tmin=60-(-40)=100°C;

[0106] The gas expansion volume when the box produces the maximum temperature difference is V2 = 20.95L × (100÷273) ≈ 7.67L;

[0107] The air volume V1 required for the maximum temperature difference of the box: 7.67L÷30min×1.5≈0.38L / min (1.5 is the safety factor);

[0108] Air permeability requirement before the explosion-proof valve is opened: 1.6kPa air permeability before the explosion-proof valve is opened > the air permeability required for the temperature difference of the box (0.38L / min);

[0109] The ventilation rate requirement after the explosion-proof valve is opened: the ventilation rate of 16kPa after the explosion-proof valve is opened is greater than the gas production rate of the battery cell (3672L / min);

[0110] If a certain type of explosion-proof valve is found to have an air permeability rate of 0.4L / min at 1.6kPa and an air permeability rate of 4000L / min at 16kPa by looking up the table, then this type of explosion-proof valve meets the selection requirements.

[0111] The method for selecting an explosion-proof valve for the above-mentioned battery pack obtains the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened; obtains the gas production rate of the battery pack after the explosion-proof valve is opened; and selects the explosion-proof valve of the battery pack according to the air permeability and the gas production rate, so that the selected explosion-proof valve can not only balance the pressure difference between the inside and outside of the box, but also can quickly release pressure to prevent explosion, thereby improving the explosion-proof effect of the explosion-proof valve and thus improving the safety of the battery pack.

[0112] like Figure 4 As shown, the embodiment of the present application further provides a battery pack explosion-proof valve selection device 200, and the battery pack explosion-proof valve selection device 200 includes:

[0113] The first acquisition module 201 is used to obtain the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened;

[0114] A second acquisition module 202 is used to obtain the gas production rate of the battery pack after the explosion-proof valve is opened;

[0115] The selection module 203 is used to select the explosion-proof valve of the battery pack according to the air permeability and the gas production rate.

[0116] In one embodiment, the first acquisition module 201 is specifically used to: obtain the air permeability required for the box where the battery pack is located to produce the maximum temperature difference before the explosion-proof valve is opened; obtain the gas production rate of the battery pack after the explosion-proof valve is opened; and select the explosion-proof valve of the battery pack according to the ultimate deformation pressure of the box before the explosion-proof valve is opened and the ultimate bursting pressure after the explosion-proof valve is opened, the air permeability and the gas production rate.

[0117] In one embodiment, the first acquisition module 201 is further specifically used to: obtain the maximum temperature difference generated by the box and the time when the maximum temperature difference is generated before the explosion-proof valve is opened; determine the air permeability according to the net volume of the box, the maximum temperature difference and the gas production time.

[0118] In one embodiment, the first acquisition module 201 is further specifically used to: determine the gas expansion volume of the box under the maximum temperature difference according to the net volume; and determine the air permeability according to the gas expansion volume and the gas production time.

[0119] In one embodiment, the first acquisition module 201 is further specifically used to: obtain an initial air permeability according to a ratio of the gas expansion volume to the gas production time; and obtain the air permeability according to a preset safety factor and the initial air permeability.

[0120] In one embodiment, the second acquisition module 202 is specifically used for:

[0121] Performing a thermal runaway test on each battery cell in the battery pack, and recording the gas production and test duration of the battery pack;

[0122] The gas production rate is obtained according to the gas production amount and the test duration.

[0123] In one embodiment, the explosion-proof valve selection device of the battery pack further includes:

[0124] A third acquisition module is used to obtain the ultimate deformation pressure of the box before the explosion-proof valve is opened and the ultimate bursting pressure after the explosion-proof valve is opened;

[0125] The selection module 203 is specifically used to select the explosion-proof valve of the battery pack according to the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate.

[0126] In one embodiment, the third acquisition module is specifically used to: acquire the deformation pressure of the box body before the explosion-proof valve is opened when the box cover is under pressure and does not deform;

[0127] The limit deformation pressure is obtained according to the deformation pressure and a first preset pressure coefficient, wherein the first preset pressure coefficient is less than 1; and / or,

[0128] Obtaining the bursting pressure of the box body when the explosion-proof valve is opened and the box cover is under pressure without cracking;

[0129] The limit bursting pressure is obtained according to the bursting pressure and a second preset pressure coefficient, and the second preset pressure coefficient is less than 1.

[0130] In one embodiment, the selection module 203 is specifically used for:

[0131] If the first air permeability rate of the explosion-proof valve to be determined under the ultimate deformation pressure is greater than the air permeability, and the second air permeability rate under the ultimate bursting pressure is greater than the gas production rate, the explosion-proof valve to be determined is determined to be the target explosion-proof valve of the battery pack.

[0132] The embodiment of the present application further provides an electronic device, which integrates any explosion-proof valve selection device for a battery pack provided in the embodiment of the present application, and the electronic device includes:

[0133] one or more processors;

[0134] Memory; and

[0135] One or more applications, wherein the one or more applications are stored in the memory and are configured to be executed by the processor in the method for selecting an explosion-proof valve for a battery pack described in any of the above-mentioned embodiments of the method for selecting an explosion-proof valve for a battery pack.

[0136] The present application also provides an electronic device that integrates any explosion-proof valve selection device for a battery pack provided in the present application. Figure 5 As shown, it shows a schematic diagram of the structure of the electronic device involved in the embodiment of the present application, specifically:

[0137] The electronic device may include components such as a processor 301 with one or more processing cores, a memory 302 with one or more computer-readable storage media, a power supply 303, and an input unit 304. Those skilled in the art will appreciate that Figure 5 The electronic device structure shown in the figure does not constitute a limitation of the electronic device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0138] in:

[0139] The processor 301 is the control center of the electronic device. It uses various interfaces and lines to connect various parts of the entire electronic device. By running or executing software programs and / or modules stored in the memory 302, and calling data stored in the memory 302, it executes various functions of the electronic device and processes data, thereby monitoring the electronic device as a whole. Optionally, the processor 301 may include one or more processing cores; preferably, the processor 301 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface, and application programs, and the modem processor mainly processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 301.

[0140] The memory 302 can be used to store software programs and modules. The processor 301 executes various functional applications and data processing by running the software programs and modules stored in the memory 302. The memory 302 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 302 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices. Accordingly, the memory 302 may also include a memory controller to provide the processor 301 with access to the memory 302.

[0141] The electronic device also includes a power supply 303 for supplying power to each component. Preferably, the power supply 303 can be logically connected to the processor 301 through a power management system, so that the power management system can manage charging, discharging, power consumption and other functions. The power supply 303 can also include one or more DC or AC power supplies, recharging systems, power failure detection circuits, power converters or inverters, power status indicators and other arbitrary components.

[0142] The electronic device may further include an input unit 304, which may be used to receive input digital or character information and generate keyboard, mouse, joystick, optical or trackball signal input related to user settings and function control.

[0143] Although not shown, the electronic device may also include a display unit, etc., which will not be described in detail here. Specifically in this embodiment, the processor 301 in the electronic device will load the executable files corresponding to the processes of one or more applications into the memory 302 according to the following instructions, and the processor 301 will run the application stored in the memory 302 to achieve various functions, as follows: obtain the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened; obtain the gas production rate of the battery pack after the explosion-proof valve is opened; select the explosion-proof valve of the battery pack according to the air permeability and the gas production rate.

[0144] A person of ordinary skill in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be completed by instructions, or by controlling related hardware through instructions. The instructions may be stored in a computer-readable storage medium and loaded and executed by a processor.

[0145] To this end, an embodiment of the present application provides a computer-readable storage medium, which may include: a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc. A computer program is stored thereon, and the computer program is loaded by a processor to execute the steps in any method for selecting an explosion-proof valve for a battery pack provided in an embodiment of the present application. For example, the computer program loaded by the processor can execute the following steps: obtaining the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened; obtaining the gas production rate of the battery pack after the explosion-proof valve is opened; and selecting the explosion-proof valve of the battery pack according to the air permeability and the gas production rate.

[0146] The embodiments of the present application also provide a computer program product, including a computer program / instruction, which, when executed by a processor, is used to execute the steps in any method for selecting an explosion-proof valve for a battery pack provided in the embodiments of the application.

[0147] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0148] In specific implementation, the above units or structures can be implemented as independent entities, or can be arbitrarily combined to be implemented as the same or several entities. The specific implementation of the above units or structures can refer to the previous method embodiments, which will not be repeated here.

[0149] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for selecting an explosion-proof valve for a battery pack, characterized in that: The method comprises: Obtaining the air permeability required when the box where the battery pack is located produces the maximum temperature difference before the explosion-proof valve is opened; Obtaining the gas production rate of the battery pack after the explosion-proof valve is opened; The explosion-proof valve of the battery pack is selected according to the air permeability and the gas production rate.

2. The method for selecting an explosion-proof valve for a battery pack according to claim 1, characterized in that: The obtaining of the air permeability required when a temperature difference is generated in the box where the battery pack is located before the explosion-proof valve is opened includes: Obtaining the maximum temperature difference generated by the box before the explosion-proof valve is opened and the time when the maximum temperature difference is generated; The air permeability is determined according to the net volume of the box, the maximum temperature difference and the air production time.

3. The method for selecting an explosion-proof valve for a battery pack according to claim 2, characterized in that: The determining of the air permeability according to the net volume of the box, the maximum temperature difference and the air production time includes: Determine the gas expansion volume of the box under the maximum temperature difference according to the net volume; The air permeability is determined according to the gas expansion volume and the gas production time.

4. The method for selecting an explosion-proof valve for a battery pack according to claim 3, characterized in that: The determining of the air permeability according to the gas expansion volume and the gas production time comprises: Obtaining an initial air permeability according to a ratio of the gas expansion volume to the gas production time; The air permeability is obtained according to a preset safety factor and the initial air permeability.

5. The method for selecting an explosion-proof valve for a battery pack according to claim 1, characterized in that: The obtaining of the gas generation rate of the battery pack after the explosion-proof valve is opened includes: Performing a thermal runaway test on each battery cell in the battery pack, and recording the gas production and test duration of the battery pack; The gas production rate is obtained according to the gas production amount and the test duration.

6. The method for selecting an explosion-proof valve for a battery pack according to claim 1, characterized in that: Also includes: Obtaining the ultimate deformation pressure of the box before the explosion-proof valve is opened and the ultimate bursting pressure after the explosion-proof valve is opened; The selecting the explosion-proof valve of the battery pack according to the air permeability and the gas production rate includes: selecting the explosion-proof valve of the battery pack according to the ultimate deformation pressure, the ultimate bursting pressure, the air permeability and the gas production rate.

7. The method for selecting an explosion-proof valve for a battery pack according to claim 6, characterized in that: The obtaining of the limit deformation pressure of the box before the explosion-proof valve is opened includes: Obtaining the deformation pressure of the box body before the explosion-proof valve is opened when the box cover is under pressure and does not deform; The limit deformation pressure is obtained according to the deformation pressure and a first preset pressure coefficient, wherein the first preset pressure coefficient is less than 1; and / or, Obtaining the ultimate bursting pressure of the box after the explosion-proof valve is opened, including: Obtaining the bursting pressure of the box body when the explosion-proof valve is opened and the box cover is under pressure without cracking; The limit bursting pressure is obtained according to the bursting pressure and a second preset pressure coefficient, and the second preset pressure coefficient is less than 1.

8. The method for selecting an explosion-proof valve for a battery pack according to claim 6, characterized in that: The selecting of the explosion-proof valve of the battery pack according to the limit deformation pressure, the limit bursting pressure, the air permeability and the gas production rate includes: If the first air permeability rate of the explosion-proof valve to be determined under the ultimate deformation pressure is greater than the air permeability, and the second air permeability rate under the ultimate bursting pressure is greater than the gas production rate, the explosion-proof valve to be determined is determined to be the target explosion-proof valve of the battery pack.

9. An electronic device, characterized in that: It comprises a memory and a processor; the memory stores an application program, and the processor is used to run the application program in the memory to execute the steps in the method for selecting an explosion-proof valve for a battery pack according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps in the method for selecting an explosion-proof valve for a battery pack according to any one of claims 1 to 8.

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