A method, system and storage medium for explosion-proof valve opening design of battery cell housing

Abstract

The present invention discloses an explosion-proof valve opening design method, system, and storage medium for a battery cell housing, including S1: Collect the explosion-proof cover valve opening times of the battery cell housing from historical data and arrange them in descending order to obtain a valve opening time set T = {t1, t2, …, tn-1, tn}, where tn represents the nth valve opening time, and tn < tn-1; S2: Apply pressure to the inside of the battery cell housing at different rates according to the valve opening time set T, and the pressure application time is the valve opening time, to obtain a corresponding pressure set Q = {q1, q2, …, qm-1, qm}, where qm > qm-1, and qm represents the maximum explosion-proof cover valve opening pressure corresponding to the pressure application time tn; S3: Design a valve opening value according to the pressure set Q, the minimum valve opening value is q1 - w, and the maximum valve opening value is qm + w, where w represents the design error and w is a positive number.

Description

Technical Field

[0001] The present invention relates to the field of battery cell safety technology, and in particular to an explosion-proof valve opening design method, system, and storage medium for a battery cell housing. Background Art

[0002] With the development of technology, the development of lithium-ion batteries has made significant progress and can be applied to most electric vehicles, realizing clean energy travel. Therefore, the safety of batteries needs to be guaranteed.

[0003] Lithium-ion batteries mainly use notching and welding explosion-proof membranes as explosion-proof devices. When the battery heats up, the gas inside the battery expands and the pressure increases to a certain extent, the notch or explosion-proof membrane will be unsoldered or ruptured, and the gas will be released and the pressure will be relieved, thereby preventing the battery from exploding. The sources of gas production inside the battery are generally overcharging, over-discharging, overheating, long-term storage, high-current charging and discharging, water molecules entering the battery, etc. The most serious consequence is thermal runaway. Analysis of the above gas production causes can be basically divided into slow processes and instantaneous processes.

[0004] After the battery explosion-proof cover is packaged, each manufacturer will use a positive pressure gas pressurization method, generally pressurizing it to 0.6Mpa~1Mpa for testing, with a tolerance controlled at ±0.2Mpa; if the valve opens normally, it meets the design requirements.

[0005] For example, when the battery produces gas slowly and opens the valve, such as in long-term storage, the valve opening time is t1, the eruption volume is j1, and the pressure at the valve port is q1; when the battery produces gas instantaneously and opens the valve, such as in thermal runaway, the valve opening time is t2, the eruption volume is j2, and the pressure at the valve port is q2. Studies have shown that the parameter values ​​corresponding to different gas production scenarios (slow gas production and instantaneous gas production) are different, and the corresponding performance of the severity of thermal runaway in the battery pack is also inconsistent. For example, if an internal short circuit occurs, gas is produced violently and the battery explosion-proof cover is opened instantaneously, the gas production pressure is much greater than the design value of more than 1Mpa, and in more serious cases, the battery shell bursts. The positive pressure gas pressurization method cannot completely cover all scenarios when the battery produces gas and the valve opens. For the same battery cell, different gas production rates represent inconsistent damage to the battery cell. Such a design verification method has defects. Summary of the invention

[0006] In view of the problem of low test reliability of lithium-ion battery explosion-proof devices in the prior art, the present invention proposes an explosion-proof valve opening design method, system, and storage medium for a battery cell shell. By simulating the battery cell valve opening conditions in all scenarios and using the pressurization rate to test the valve opening under different conditions, timely pressure relief is achieved to prevent battery explosion and improve safety and reliability.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A method for designing an explosion-proof opening valve for a battery cell housing comprises the following steps:

[0009] S1: Collect the valve opening time of the explosion-proof cover of the battery shell from the historical data and arrange them in order from large to small to obtain the valve opening time set T = {t1, t2, ..., tn-1, tn}, tn represents the nth valve opening time, and tn <tn-1;

[0010] S2: According to the valve opening time set T, the inside of the battery cell housing is pressurized at different rates, the pressurization time is the valve opening time, and the corresponding pressure set Q = {q1, q2, ..., qm-1, qm} is obtained, qm>qm-1, qm represents the maximum pressure of the explosion-proof cover valve corresponding to the pressurization time tn;

[0011] S3: Design the valve opening value according to the pressure set Q. The minimum valve opening value is q1-w, and the maximum valve opening value is qm+w. w represents the design error and is a positive number.

[0012] Preferably, in S2, the pressurization rate is Kn=V / tn, Kn represents the pressurization rate corresponding to the nth valve opening time, V represents the internal volume of the battery cell housing, and tn represents the nth valve opening time.

[0013] Preferably, in S3, w is 0.1 MPa.

[0014] Preferably, the method further includes: conducting a field test on the designed opening valve value, and correcting the designed opening valve value according to the test result to ensure that the designed opening valve value covers the pressure set Q.

[0015] Preferably, the drop test includes internal short circuit, heating, needle puncture, external short circuit and overcharge.

[0016] The present invention also provides an explosion-proof valve opening design system for a battery cell housing, comprising:

[0017] In the data repository, the valve opening time set T = {t1, t2, ..., tn-1, tn}, tn is used to store the explosion-proof cover <tn-1;

[0018] A pressurizing module, used to pressurize the inside of the battery cell housing at different rates according to the explosion-proof cover valve opening time set T in the data repository, where the pressurizing time is the valve opening time;

[0019] A pressure detection module is used to detect the pressure inside the battery cell shell;

[0020] The human-computer interaction module is used to display the detected pressure and interact with the operator.

[0021] The present invention also provides a storage medium on which a computer program is stored, and the steps of the design method are implemented when the computer program is executed.

[0022] In summary, due to the adoption of the above technical solution, compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The present invention pressurizes the battery cell shell at different pressurization rates, thereby actually simulating the battery cell valve opening conditions in all scenarios, testing the valve opening under different conditions, and designing a suitable valve opening value to achieve timely pressure relief under any condition, prevent battery explosion, and improve safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a method for designing an explosion-proof valve opening for a battery cell casing according to an exemplary embodiment of the present invention.

[0025] Figure 2 Schematic diagram of an explosion-proof valve opening design system for a battery cell casing according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0027] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] like Figure 1 As shown, the present invention provides an explosion-proof valve opening design method for a battery cell housing, which specifically includes the following steps:

[0029] S1: Get the explosion-proof cover valve opening time set T = {t1, t2, ..., tn-1, tn}, tn from historical data <tn-1。

[0030] In this embodiment, an explosion-proof cover is installed on the battery cell housing. When the internal pressure of the battery cell reaches a designed value, the explosion-proof cover opens a valve to release the pressure.

[0031] The sources of gas generation inside the battery generally include overcharging, over-discharging, overheating, long-term storage, high-current charging and discharging, and the entry of water molecules into the battery. Therefore, the rate of pressure change inside is different, resulting in differences in the valve-opening time of the explosion-proof cover plate.

[0032] In this embodiment, there is a certain error in the design value of the explosion-proof cover plate. The prior art uses the method of pressurizing with positive-pressure gas and pressurizes to the design value of 1 Mpa for detection. If the explosion-proof cover plate opens the valve, it is considered that the design value meets the requirements. However, the error range of the design value is ±0.2 Mpa. The explosion-proof cover plate opens the valve when the internal pressure of the battery cell housing is 0.8 Mpa, and the explosion-proof cover plate opens the valve only when the internal pressure of the battery cell housing is 1.2 Mpa; this makes the test results unreliable.

[0033] In this embodiment, the set of valve-opening times of the explosion-proof cover plate is T = {t1, t2,..., tn-1, tn}, and tn < tn-1, that is, tn represents the minimum valve-opening time of the explosion-proof cover plate.

[0034] S2: Pressurize the inside of the battery cell at different rates according to the set of valve-opening times of the explosion-proof cover plate, and the pressurization time is the valve-opening time. Then the set of corresponding pressures Q = {q1, q2,..., qm-1, qm} when the pressure detection module detects the valve-opening time, and qm > qm-1, where qm represents the maximum pressure of the explosion-proof cover plate corresponding to the pressurization time tn.

[0035] In this embodiment, under actual working conditions, in different gas generation scenarios, the rate of pressure change inside the battery cell is different, and even greater than the design value under harsh working conditions. Therefore, the present invention uses different pressurization rates to simulate and cover all gas generation working conditions to obtain the corresponding valve-opening pressure values of the battery cell.

[0036] The pressurization rate is K = V / tn, where V represents the internal volume of the battery cell housing.

[0037] In this embodiment, when V is constant, the smaller tn is, the greater the pressurization rate k is, and the greater the corresponding pressure qm inside the battery cell housing is. If the designed value of the valve-opening pressure of the explosion-proof cover plate needs to be designed larger accordingly; the larger tn is, the smaller the pressurization rate k is, and the smaller the corresponding pressure qm inside the battery cell housing is. If the designed value of the valve-opening pressure needs to be designed smaller accordingly.

[0038] For example, if the valve-opening time of the explosion-proof cover plate is t1, then the pressurization rate at the design stage is k1 = V / t1, and the corresponding pressure inside the battery cell housing is q1; if the valve-opening time of the explosion-proof cover plate is tn, then the pressurization rate at the design stage is kn = V / tn, and the corresponding pressure inside the battery cell housing is qn.

[0039] S3: Design the valve opening value according to the pressure set Q. The minimum valve opening value is q1-w, and the maximum valve opening value is qm+w, where w represents the error, for example 0.1Mpa. Then conduct a landing test to correct the designed valve opening value.

[0040] In this embodiment, the landing test includes triggering means such as internal short circuit, heating, acupuncture, external short circuit, and overcharging.

[0041] In this embodiment, the valve opening value can also be designed in advance and a landing test can be carried out, and then the designed valve opening value can be verified using the above-mentioned design method. It should be ensured that the final designed valve opening value contains the pressure set Q, so as to avoid the occurrence of severe working conditions as much as possible.

[0042] like Figure 2 As shown, the present invention also provides an explosion-proof valve opening design system for a battery cell housing, comprising a data storage library, a pressure detection module, a pressurization module and a human-computer interaction module.

[0043] The data repository stores the explosion-proof cover valve opening time set T = {t1, t2, ..., tn-1, tn}, tn <tn-1;

[0044] A pressurizing module, used to pressurize the inside of the battery cell housing at different rates according to the explosion-proof cover valve opening time set T in the data repository, where the pressurizing time is the valve opening time;

[0045] A pressure detection module is used to detect the pressure inside the battery cell shell;

[0046] The human-computer interaction module is used to display the detected pressure so that the operator can directly view it.

[0047] In this embodiment, a storage medium is also provided for storing a program for executing the explosion-proof valve opening design method for a battery cell housing.

[0048] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for designing an explosion-proof valve opening for a battery cell housing, characterized in that: The specific steps include: S1: Collect the valve opening time of the explosion-proof cover of the battery shell from the historical data and arrange them in order from large to small to obtain the valve opening time set T = {t1, t2, ..., tn-1, tn}, tn represents the nth valve opening time, and tn <tn-1; S2: According to the valve opening time set T, the inside of the battery cell housing is pressurized at different rates, the pressurization time is the valve opening time, and the corresponding pressure set Q = {q1, q2, ..., qm-1, qm} is obtained, qm>qm-1, qm represents the maximum pressure of the explosion-proof cover valve corresponding to the pressurization time tn; Wherein: the rate of pressurization is Kn=V / tn, Kn represents the pressurization rate corresponding to the nth valve opening time, V represents the internal volume of the battery shell, and tn represents the nth valve opening time; S3: Design the valve opening value according to the pressure set Q. The minimum valve opening value is q1-w, and the maximum valve opening value is qm+w. w represents the design error and is a positive number.

2. A method for designing an explosion-proof valve opening for a battery cell housing according to claim 1, characterized in that: In the S3, w is 0.1 MPa.

3. The explosion-proof valve design method for a battery cell housing according to claim 1, characterized in that: Also includes: Carry out a field test on the designed opening valve value, and calibrate the designed opening valve value according to the test result to ensure that the designed opening valve value covers the pressure set Q.

4. A method for designing an explosion-proof valve opening for a battery cell housing as claimed in claim 3, characterized in that: The drop test includes internal short circuit, heating, needle puncture, external short circuit and overcharge.

5. An explosion-proof valve opening design system for a battery cell housing based on the method described in any one of claims 1 to 4, characterized in that: include: In the data repository, the valve opening time set T = {t1, t2, ..., tn-1, tn}, tn is used to store the explosion-proof cover <tn-1; A pressurizing module, used to pressurize the inside of the battery cell housing at different rates according to the explosion-proof cover valve opening time set T in the data repository, where the pressurizing time is the valve opening time; A pressure detection module is used to detect the pressure inside the battery cell shell; The human-computer interaction module is used to display the detected pressure and interact with the operator.

6. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the design method according to any one of claims 1 to 4 are implemented.

Images