Early warning method for thermal runaway of battery

Abstract

The invention relates to the field of power systems, and provides a battery thermal runaway early warning method. The battery thermal runaway early warning method comprises the following steps: S1, adding a first substance in a material layer on a battery shell, wherein the first substance can release a first gas when the temperature of the battery shell reaches a preset value; and S2, detecting the first gas through the monitoring device, and when the monitoring device detects the first gas, sending a battery thermal runaway signal by the alarm device. The first gas can be detected and a thermal runaway signal can be generated without starting or damaging an explosion-proof method on a battery shell after thermal runaway spreads. The occurrence of thermal runaway is warned in advance according to the thermal runaway signal, the thermal runaway of the battery can be found in the early stage of thermal runaway before the battery shell is damaged, timely intervention is performed, and accidents such as fire and explosion caused by serious thermal runaway are avoided through early warning.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a battery thermal runaway early warning method. Background Art

[0002] When the battery is in thermal runaway, the thermal runaway reaction inside generates a large amount of heat, flammable gas and smoke. The battery shell opens or deforms and ruptures due to the increase in internal pressure, causing the generated flammable gas and smoke to leak. Under the ignition of high temperature or electric sparks, flammable gas and smoke are very easy to catch fire and explode.

[0003] Early warning of battery thermal runaway and early intervention in battery thermal runaway are the key to reducing losses from battery thermal runaway. The current battery thermal runaway warning method mainly detects signals such as gas, smoke, sparks, etc. generated after the battery explosion-proof valve is opened or deformed and ruptured, as well as fire signals such as temperature exceeding the standard caused by battery temperature rise, to achieve early warning of battery thermal runaway. These methods require the opening of the valve or damage to the battery shell to detect related gases, large amounts of smoke and open flames. At this time, the battery has already suffered a serious failure, making it difficult to achieve a long-term early warning, which delays the handling of battery thermal runaway accidents. Summary of the invention

[0004] In order to solve the above technical problem or at least partially solve the above technical problem, the present application provides a battery thermal runaway early warning method.

[0005] The present application embodiment provides a battery thermal runaway early warning method, comprising:

[0006] S1, adding a first substance to a material layer on a battery housing, wherein the first substance can release a first gas when the temperature of the battery housing reaches a preset value;

[0007] S2, detecting a first gas through a monitoring device, and when the monitoring device detects the first gas, an alarm device sends a battery thermal runaway signal.

[0008] According to an embodiment of the first aspect of the present application, the material layer includes at least one of an insulating material layer and a back adhesive layer, and the insulating material layer is bonded to the battery housing through the back adhesive layer.

[0009] According to an embodiment of the first aspect of the present application, the insulating material layer includes at least one of a PET insulating film, an epoxy resin and an acrylic insulating coating.

[0010] According to an embodiment of the first aspect of the present application, the back adhesive layer includes at least one of acrylic acid, ethylene-vinyl acetate resin glue, thermoplastic polyurethane rubber, acrylate, polyurethane, silicone and styrene-butadiene rubber.

[0011] According to an embodiment of the first aspect of the present application, the first substance includes at least one of non-methane total hydrocarbons, isopropanol, acetone, dichloromethane, ethyl acetate, methyl acetate, methyl formate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, formaldehyde, acetaldehyde, ammonia, benzene, toluene, xylene, tetrahydrofuran, cyclohexane, styrene, trichloroethylene, dichlorobenzene, trichloroethane, 1,3-butadiene and diisocyanate.

[0012] According to an embodiment of the first aspect of the present application, the first substance is dispersed in the material layer.

[0013] According to an embodiment of the first aspect of the present application, the mass ratio of the first substance to the material layer is 2% to 30%.

[0014] According to an embodiment of the first aspect of the present application, the first substance is incorporated into the material layer in the form of adsorption particles, and the adsorption particles include an adsorbent and the first substance.

[0015] According to an embodiment of the first aspect of the present application, the mass proportion of the adsorption particles in the material layer is 2% to 40%;

[0016] And / or, the mass ratio of the first substance in the adsorption particles is 10% to 90%.

[0017] According to an embodiment of the first aspect of the present application, the adsorbent includes at least one of molecular sieves, diatomaceous earth, montmorillonite, sepiolite, a metal organic framework compound, activated carbon, silica gel, alumina and mesoporous silica.

[0018] According to an embodiment of the first aspect of the present application, the preset value is 70°C-120°C.

[0019] Compared with the prior art, the technical solution provided by the embodiments of the present application has the following advantages:

[0020] The battery thermal runaway warning method provided in the embodiment of the present application includes: S1, adding a first substance to a material layer on a battery shell, wherein the first substance can release a first gas when the temperature of the battery shell reaches a preset value; S2, detecting the first gas through a monitoring device, and when the monitoring device detects the first gas, an alarm device sends a battery thermal runaway signal.

[0021] Without waiting for the explosion-proof device on the battery shell to be opened or damaged after the thermal runaway spreads, the first gas can be detected and a thermal runaway signal can be generated. According to the thermal runaway signal, the occurrence of thermal runaway can be warned in advance. Before the battery shell is damaged, the battery can be found to have thermal runaway in the early stage of thermal runaway, and timely intervention can be made to prevent accidents such as fire and explosion caused by severe thermal runaway. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0024] The current battery thermal runaway warning methods mainly detect signals such as gas, smoke, and sparks generated after the battery valve is opened or deformed and ruptured, as well as fire signals such as temperature exceeding the standard caused by the battery temperature rise, to achieve early warning of battery thermal runaway. These methods require the battery shell explosion-proof valve to be opened or damaged in order to detect related gases, large amounts of smoke, and open flames. At this time, the battery has already suffered a serious failure, making it difficult to achieve a long-term early warning, which delays the handling of battery thermal runaway accidents.

[0025] In view of this, an embodiment of the present application provides a battery thermal runaway warning method, including: S1, adding a first substance to the material layer on the battery shell, the first substance releases a volatile substance after being heated, that is, the first substance can release a first gas when the temperature of the battery shell reaches a preset value.

[0026] The preset value range is 70°C-120°C, and the preset value can be 80°C, 90°C, 100°C or 110°C. When thermal runaway of the battery occurs, the surface temperature of the battery shell will continue to rise. When the temperature of the battery shell reaches the preset value, the first substance in the material layer on the battery shell will release the first gas when heated. The first gas is a characteristic gas that can be detected by the monitoring device.

[0027] S2, detecting a first gas through a monitoring device, and when the monitoring device detects the first gas, the alarm device sends a battery thermal runaway signal. The monitoring device may be a VOC gas detector.

[0028] Without waiting for the explosion-proof device on the battery shell to be opened or damaged after the thermal runaway spreads, the first gas can be detected and a thermal runaway signal can be generated. According to the thermal runaway signal, the occurrence of thermal runaway can be warned in advance. Before the battery shell is damaged, the battery can be found to have thermal runaway in the early stage of thermal runaway, and timely intervention can be made to prevent accidents such as fire and explosion caused by severe thermal runaway.

[0029] In some embodiments, the material layer includes at least one of an insulating material layer and a back adhesive layer, and the insulating material layer is bonded to the battery housing through the back adhesive layer. The insulating material layer can be a blue film on the battery housing. The battery housing is provided with an insulating material layer to prevent battery short circuit, and a first substance can be added to the insulating material layer. The first substance can also be added to the back adhesive layer, or the first substance can be added to both the insulating material layer and the back adhesive layer. For a battery housing with only an insulating material layer but no back adhesive layer, the first substance is added to the insulating material layer.

[0030] In some embodiments, the insulating material layer includes at least one of a PET insulating film, an epoxy resin, and an acrylic insulating coating. The insulating material layer can be a PET insulating film or an epoxy resin, and the insulating material of the epoxy resin is directly fixed on the battery housing after curing without the need for adhesive bonding.

[0031] In some embodiments, the adhesive layer includes at least one of acrylic acid, ethylene-vinyl acetate resin glue, thermoplastic polyurethane rubber, acrylate, polyurethane, silicone and styrene-butadiene rubber. The adhesive layer can be made of styrene-butadiene rubber, and the adhesive layer is adhered to the outer surface of the battery shell. The adhesive layer can also be made of acrylate.

[0032] In some embodiments, the first substance includes at least one of non-methane total hydrocarbons, isopropyl alcohol, acetone, methylene chloride, ethyl acetate, methyl acetate, methyl formate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, formaldehyde, acetaldehyde, ammonia, benzene, toluene, xylene, tetrahydrofuran, cyclohexane, styrene, trichloroethylene, dichlorobenzene, trichloroethane, 1,3-butadiene and diisocyanate.

[0033] In some embodiments, the first substance is dispersed in the material layer.

[0034] In some embodiments, the mass ratio of the first substance to the material layer is 2% to 30%.

[0035] In some embodiments, the first substance is incorporated into the material layer in the form of adsorption particles, and the adsorption particles include an adsorbent and the first substance.

[0036] In some embodiments, the mass percentage of adsorbed particles in the material layer is 2% to 40%;

[0037] And / or, the mass ratio of the first substance in the adsorption particles is 10% to 90%.

[0038] In some embodiments, the adsorbent includes at least one of molecular sieves, diatomaceous earth, montmorillonite, sepiolite, metal organic framework compounds, activated carbon, silica gel, alumina, and mesoporous silica.

[0039] In some embodiments, the preset value is 70°C-120°C, preferably 80°C-100°C.

[0040] The following are several specific implementation methods:

[0041] In the first embodiment, the insulating material layer of the battery shell is made of PET insulating film, and the adhesive layer is made of styrene-butadiene rubber. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde. The first substance is directly dispersed in the insulating material layer, the dispersion ratio is 3wt.%, and the preset value is 80°C. A VOC gas detector is used to detect characteristic volatile gases.

[0042] In the second embodiment, the insulating material layer of the battery shell is made of epoxy resin, and the epoxy resin insulating material layer is directly fixed on the battery shell by curing, and no adhesive layer is required. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde, which are directly dispersed in the insulating material layer. The mass addition ratio of the first substance is 3wt.%, and the preset value is 80°C. A VOC gas detector is used to detect characteristic volatile gases.

[0043] In the third embodiment, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts styrene-butadiene rubber. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde, which are directly dispersed in the adhesive layer, and the mass addition ratio of the first substance is 3wt.%. The preset value is 80°C. A VOC gas detector is used to detect characteristic volatile gases.

[0044] In the fourth embodiment, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts styrene-butadiene rubber. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde, and is incorporated into the insulating material layer by the method of adsorption particles. The mass addition ratio of the first substance is 3wt.%, the mass proportion of the first substance in the adsorption particles is 10wt.%, the mass proportion of the adsorbent is 90wt.%, the adsorbent is diatomaceous earth, and the diameter of the adsorption particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0045] In Example 5, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts styrene-butadiene rubber. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde, and is incorporated into the adhesive layer by the method of adsorption particles. The mass addition ratio of the first substance is 3wt.%, the mass proportion of the first substance in the adsorption particles is 10wt.%, the mass proportion of the adsorbent is 90wt.%, the adsorbent is diatomaceous earth, and the diameter of the adsorption particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0046] In Example 6, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts styrene-butadiene rubber. The first substance is composed of 50wt.% ethyl acetate and 50wt.% formaldehyde, and is incorporated into the adhesive layer by the method of adsorbing particles. The mass addition ratio of the first substance is 3wt.%, the mass proportion of the first substance in the adsorbed particles is 30wt.%, and the mass proportion of the adsorbent is 70wt.%. The adsorbent adopts a metal organic framework compound, and the diameter of the adsorbed particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0047] In embodiment 7, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts styrene-butadiene rubber. The first substance is composed of 50wt.% dimethyl carbonate and 50wt.% acetone, which can be incorporated into the adhesive layer by the method of adsorbing particles. The mass addition ratio of the first substance is 3wt.%, the mass proportion of the first substance in the adsorbed particles is 30wt.%, and the mass proportion of the adsorbent is 70wt.%. The adsorbent adopts a metal organic framework compound, and the diameter of the adsorbed particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0048] Embodiment 8: The insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts acrylic acid. The first substance is composed of 50wt.% dimethyl carbonate and 50wt.% acetone, which can be incorporated into the adhesive layer by the method of adsorbing particles. The mass addition ratio of the first substance is 3wt.%, the mass proportion of the first substance in the adsorbed particles is 30wt.%, and the mass proportion of the adsorbent is 70wt.%. The adsorbent adopts a metal organic framework compound, and the diameter of the adsorbed particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0049] In the ninth embodiment, the insulating material layer of the battery shell adopts PET insulating film, and the adhesive layer adopts acrylic acid. The first substance is composed of 50wt.% dimethyl carbonate and 50wt.% acetone, and can be incorporated into the adhesive layer by the method of adsorbing particles. The mass addition ratio of the first substance is 6wt.%, the mass proportion of the first substance in the adsorbed particles is 30wt.%, and the mass proportion of the adsorbent is 70wt.%. The adsorbent adopts a metal organic framework compound, and the diameter of the adsorbed particles is 2μm. The preset value is 80℃. A VOC gas detector is used to detect characteristic volatile gases.

[0050] Comparative experiment: 280Ah energy storage lithium iron phosphate battery thermal runaway warning verification experiment

[0051] In the comparative example, the first substance is not added into the material layer of the battery housing.

[0052] Experimental conditions: The battery is heated using a heating plate with a size of 180mm×150mm and a power of 950W. The thermal runaway test method is the relevant method of GB36276. Analyze whether the alarm device sends a thermal runaway signal before the explosion-proof valve of the battery shell opens when the battery is in thermal runaway, and compare the effect of the battery thermal runaway warning (advance warning time). The final battery thermal runaway suppression effect is shown in Table 1.

[0053] Table 1 Results of thermal runaway warning verification test for lithium iron phosphate battery

[0054] Example Whether to warn before the battery opens the valve Early warning time Embodiment 1 yes 391s Embodiment 2 yes 403s Embodiment 3 yes 571s Embodiment 4 yes 384s Embodiment 5 yes 568s Embodiment 6 yes 612s Embodiment 7 yes 609s Embodiment 8 yes 607s Embodiment 9 yes 623s Comparative Example 1 no /

[0055] It can be seen from Example 1 to Example 9 in Table 1 that adding the first substance in the battery shell insulating material layer and in the back glue layer can detect the first gas of the battery thermal runaway warning before the battery explosion-proof valve is opened, and realize the early warning of the battery thermal runaway. In the comparative example, no gas was detected before the battery explosion-proof valve was opened, and no thermal runaway signal was issued. By comparing Examples 1, 2, 4 and Examples 3, 5, 6, 7, 8, and 9, it can be seen that the warning time of adding the first substance in the back glue layer of the shell insulating material will be slightly longer than the warning time of adding the first substance in the battery shell insulating material layer. This is because when the first substance is added to the back glue layer, when the battery generates heat in the early stage of thermal runaway, the first gas is more likely to volatilize, so it is detected earlier. From the comparison of Examples 6, 7, 8 and Example 5, it can be seen that the use of strong adsorption substances such as metal organic framework compounds can adsorb more first substances than substances with small surface area and adsorption properties such as diatomaceous earth, so the time in advance can be longer when warning. From the comparison of Example 8 and Example 9, it can be seen that the more first substances are added, the better the early warning capability is.

[0056] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0057] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery thermal runaway early warning method, characterized in that: include: S1, adding a first substance to a material layer on a battery housing, wherein the first substance can release a first gas when the temperature of the battery housing reaches a preset value; S2, detecting a first gas through a monitoring device, and when the monitoring device detects the first gas, an alarm device sends a battery thermal runaway signal.

2. The battery thermal runaway early warning method according to claim 1, characterized in that: The material layer includes at least one of an insulating material layer and a back adhesive layer, and the insulating material layer is adhered to the battery housing through the back adhesive layer.

3. The battery thermal runaway early warning method according to claim 2, characterized in that: The insulating material layer includes at least one of a PET insulating film, an epoxy resin, and an acrylic insulating coating.

4. The battery thermal runaway early warning method according to claim 2, characterized in that: The back adhesive layer includes at least one of acrylic acid, ethylene-vinyl acetate resin adhesive, thermoplastic polyurethane rubber, acrylate, polyurethane, silicone and styrene-butadiene rubber.

5. The battery thermal runaway early warning method according to claim 1, characterized in that: The first substance includes at least one of non-methane total hydrocarbons, isopropanol, acetone, dichloromethane, ethyl acetate, methyl acetate, methyl formate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, formaldehyde, acetaldehyde, ammonia, benzene, toluene, xylene, tetrahydrofuran, cyclohexane, styrene, trichloroethylene, dichlorobenzene, trichloroethane, 1,3-butadiene and diisocyanate.

6. The battery thermal runaway early warning method according to claim 2, characterized in that: The first substance is dispersed in the material layer.

7. The battery thermal runaway early warning method according to claim 6, characterized in that: The mass ratio of the first substance to the material layer is 2% to 30%.

8. The battery thermal runaway early warning method according to claim 2, characterized in that: The first substance is mixed into the material layer in the form of adsorption particles, and the adsorption particles include an adsorbent and the first substance.

9. The battery thermal runaway early warning method according to claim 8, characterized in that: The mass proportion of the adsorbed particles in the material layer is 2% to 40%; And / or, the mass ratio of the first substance in the adsorption particles is 10% to 90%.

10. The battery thermal runaway early warning method according to claim 8, characterized in that: The adsorbent includes at least one of molecular sieves, diatomaceous earth, montmorillonite, sepiolite, metal organic framework compounds, activated carbon, silica gel, alumina and mesoporous silica.

11. The battery thermal runaway early warning method according to claim 1, characterized in that: The preset value is 70°C-120°C.