Protective layer, battery assembly and electrical equipment

Abstract

The present invention provides a protective layer, a battery assembly and an electrical device, wherein the protective layer comprises a temperature control layer; the temperature control layer comprises a heat storage material; the compaction density of the temperature control layer is 0.5-3.0 g / cm 3 The particle size of the heat storage material is not less than 100 meshes; by limiting the compaction density of the temperature control layer and the particle size of the heat storage material in the temperature control layer, the volume utilization rate of the protective layer can be greatly increased, so that it can achieve a better effect of inhibiting heat spread even under limited thickness.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a protective layer, a battery assembly and an electrical device. Background Art

[0002] The safety of battery systems has always been one of the important issues in the development of the new energy and automotive industries, so it is of great significance to eliminate the potential safety hazards of battery systems. Generally, a single cell in a battery system may induce thermal runaway due to thermal abuse, electrical abuse, mechanical abuse, etc. This process usually heats up rapidly to above 600°C in a short period of time. Due to the large temperature gradient, the huge heat generated by thermal runaway will be transferred laterally to adjacent batteries, thereby inducing heat spread in the battery system, and ultimately causing safety issues such as fire and explosion.

[0003] At present, the technology to suppress heat spread mainly uses thermal insulation materials with excellent thermal insulation properties such as aerogel and mica sheets to suppress heat spread, and mainly relies on the low thermal conductivity of thermal insulation materials to block the lateral transfer of heat. However, the effect of suppressing heat spread in this way is still relatively limited. It is difficult to effectively suppress heat spread with limited thickness. Usually a large amount of thermal insulation material is required to effectively reduce the battery temperature.

[0004] Therefore, the thickness of the protective layer for suppressing heat spread in the existing technology is still relatively thick, and it is necessary to develop a new design to suppress heat spread. Summary of the invention

[0005] The present invention provides a protective layer for solving the problem that the thickness of the heat insulation layer for suppressing heat spread in the prior art is still relatively thick.

[0006] The present invention provides a battery assembly, which can suppress the spread of heat while reducing the thickness of the protective layer and improving the energy density of the battery assembly.

[0007] The present invention provides an electrical device, comprising the battery assembly, which reduces the potential safety hazard of the electrical device.

[0008] In a first aspect, the present invention provides a protective layer, comprising a temperature control layer; the temperature control layer comprises a heat storage material;

[0009] The compaction density of the temperature control layer is 0.5-3.0 g / cm 3 , the particle size of the heat storage material is not less than 100 mesh.

[0010] Furthermore, the compaction density of the temperature control layer is 0.8-2.0 g / cm 3 .

[0011] Furthermore, the protective layer also includes a heat insulation layer, and the heat insulation layer includes a first heat insulation layer and a second heat insulation layer respectively stacked on both sides of the temperature control layer.

[0012] Further, the thickness ratio of the first heat insulation layer to the temperature control layer is 0.5-10; and / or,

[0013] The thickness ratio of the second heat insulation layer to the temperature control layer is 0.5-10.

[0014] Further, the thickness of the first heat insulation layer is 0.2-10 mm; and / or,

[0015] The thickness of the temperature control layer is 0.1-10 mm; and / or,

[0016] The thickness of the second heat insulation layer is 0.2-10 mm.

[0017] Furthermore, the heat storage material is an inorganic material.

[0018] Further, the heat storage material includes at least one of a phase change material and a chemical heat storage material;

[0019] The phase change material includes at least one of a hydrated salt phase change material, a molten salt phase change material, a metal phase change material, and an alloy phase change material;

[0020] The chemical heat storage material includes Ni(OH)2, Mg(OH)2, MgH2, Co3O4, PbCO3, NH4HSO4, Ca(OH)2, Sr(OH)2, CaCO3, NaHCO3, NH4HCO 3、 At least one of BaO2, Ba(OH)2.

[0021] Furthermore, the thermal storage material includes Mg(OH)2 and NaHCO3, and the mass ratio of Mg(OH)2 and NaHCO3 is (1~99): (1~99).

[0022] Furthermore, the temperature control layer also includes sticky particles with a mass percentage of 0-20%.

[0023] Furthermore, the temperature control layer also includes heat-conductive particles with a mass percentage of 0-20%.

[0024] Furthermore, the sticky particles include at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylate, and styrene-butadiene rubber.

[0025] Furthermore, the thermal insulation layer includes at least one of aerogel thermal insulation wool, mica sheet, vacuum insulation board, asbestos, glass wool, expanded pearl wool, slag wool, and foamed ceramics.

[0026] In a second aspect, the present invention provides a battery assembly comprising N protective layers as described in the first aspect and M battery cells, where N≥1 and M≥1.

[0027] In a third aspect, the present invention provides an electrical device comprising the battery assembly described in the second aspect.

[0028] The present invention provides a protective layer, comprising a temperature control layer; the temperature control layer comprises a heat storage material; by limiting the compaction density of the temperature control layer and the particle size of the heat storage material in the temperature control layer, the volume utilization rate of the protective layer can be greatly increased, so that it can achieve a better heat spread inhibition effect even under limited thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of a protective layer in one embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the structure of a battery assembly in one embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 1: Battery cell;

[0033] 2: The first insulation layer;

[0034] 3: Temperature control layer;

[0035] 4: Second insulation layer. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In a first aspect, the present invention provides a protective layer, comprising a temperature control layer; the temperature control layer comprises a heat storage material;

[0038] The compacted density of the temperature control layer is 0.5-3.0 g / cm 3 , the particle size of the heat storage material shall not be less than 100 mesh.

[0039] Since a single cell in the battery system may induce thermal runaway due to thermal abuse, electrical abuse, mechanical abuse and other different ways, the cell experiencing thermal runaway can quickly heat up to over 600°C in a short period of time. Due to the large temperature gradient, the huge heat generated by thermal runaway will be transferred horizontally to adjacent batteries, thereby inducing thermal spread in the battery system, and ultimately causing safety problems such as fire and explosion; therefore, it is necessary to set up a structure to inhibit heat spread between the cells to delay the transfer of heat from the thermal runaway cells to other batteries, so as to improve the safety performance of the battery and reduce losses at the same time.

[0040] The protective layer provided by the present invention includes a temperature control layer, and the temperature control layer includes a heat storage material; the temperature control layer is used to absorb and process a large amount of heat that has been transferred, and convert the thermal energy into other forms of energy; wherein, the temperature control layer includes a heat storage material, and a large amount of heat that has been transferred is absorbed and processed by the heat storage material, and the thermal energy is converted into other forms of energy, thereby reducing the surface temperature of the adjacent battery core to a safe range, thereby suppressing the occurrence of heat spread; and by limiting the compaction density of the temperature control layer, it can be ensured that the heat storage material in the temperature control layer is not easy to break, the integrity of the heat storage material is maintained, and the steam generated by the heat storage material after absorbing heat can be dissipated in time, and combined with the particle size of the heat storage material in the temperature control layer, it can ensure the heat absorption effect while greatly increasing the volume utilization rate of the protective layer, so that it can also achieve a better heat spread suppression effect under limited thickness.

[0041] The present invention provides a protective layer, comprising a temperature control layer; the temperature control layer comprises a heat storage material; by limiting the compaction density of the temperature control layer and the particle size of the heat storage material in the temperature control layer, the volume utilization rate of the protective layer can be greatly increased, so that it can achieve a better heat spread inhibition effect even under limited thickness.

[0042] Furthermore, the compaction density of the temperature control layer is 0.8-2.0 g / cm 3 .

[0043] The inventors found that when the compaction density of the temperature control layer is 0.8-2.0 g / cm 3 At the same time, it can further ensure the integrity of the heat storage material in the temperature control layer, and allow the steam generated by its heat absorption to dissipate in time, further improving the temperature control effect of the temperature control layer, while further improving the volume utilization rate of the protective layer and further reducing the thickness of the protective layer.

[0044] Furthermore, if Figure 1 As shown, the protective layer also includes a heat insulation layer, and the heat insulation layer includes a first heat insulation layer 2 and a second heat insulation layer 4 respectively stacked on both sides of the temperature control layer 3.

[0045] Among them, the thermal insulation layer that is in direct contact with the battery cell with thermal runaway is used to block the heat transfer from the battery cell with thermal runaway, further delaying the occurrence of heat spread; the thermal insulation layer on the other side of the temperature control layer is used to prevent the heat from further spreading to the adjacent battery cells; it can further increase the volume utilization rate of the protective layer while ensuring the heat absorption effect, so that it can further achieve better heat spread inhibition effect under limited thickness.

[0046] In a specific embodiment, the thickness ratio of the first heat insulation layer to the temperature control layer is 0.5-10;

[0047] The thickness ratio of the second heat insulation layer to the temperature control layer is 0.5~10.

[0048] By further limiting the thickness ratio of the first thermal insulation layer to the temperature control layer, as well as the thickness ratio of the second thermal insulation layer to the temperature control layer, on the one hand, the volume utilization rate of the protective layer can be further improved, the thickness of the protective layer can be reduced, and the energy density of the battery assembly can be improved at the same time; on the other hand, the synergistic effect between the thermal insulation layer and the temperature control layer can be further exerted, so that the heat accumulated in the temperature control layer can be converted and reduced, further improving the effect of the protective layer in suppressing heat spread.

[0049] The thickness ratio of the first heat insulation layer to the temperature control layer can be further refined to 0.5~5; the thickness ratio of the second heat insulation layer to the temperature control layer can be further refined to 0.5~5.

[0050] Specifically, the thickness of the first thermal insulation layer is 0.2-10 mm;

[0051] The thickness of the temperature control layer is 0.1~10mm;

[0052] The thickness of the second thermal insulation layer is 0.2~10mm.

[0053] The inventors have found that when the thickness of the thermal insulation layer and the temperature control layer are within the above-mentioned specified range, the volume utilization rate of the protective layer can be further improved, the thickness of the protective layer can be reduced, and the energy density of the battery assembly can be improved at the same time; at the same time, the synergistic effect between the thermal insulation layer and the temperature control layer can be further exerted, so that the heat accumulated in the temperature control layer can be converted and reduced, further improving the effect of the protective layer in suppressing heat spread.

[0054] Among them, the thickness of the first thermal insulation layer can be further refined to 0.2~3mm;

[0055] The thickness of the temperature control layer can be further refined to 0.1~3mm;

[0056] The thickness of the second insulation layer can be further refined to 0.2~3mm.

[0057] Furthermore, the heat storage material is an inorganic material.

[0058] When inorganic heat storage materials are selected as the main component of the temperature control layer, it can not only convert heat to reduce the overall heat, but also further reduce the flammability risk of the temperature control layer itself, and further improve the safety of the protective layer.

[0059] Wherein, the heat storage material includes at least one of a phase change material and a chemical heat storage material;

[0060] The phase change material includes at least one of a hydrated salt phase change material, a molten salt phase change material, a metal phase change material, and an alloy phase change material;

[0061] Chemical thermal storage materials include Ni(OH)2, Mg(OH)2, MgH2, Co3O4, PbCO3, NH4HSO4, Ca(OH)2, Sr(OH)2, CaCO3, NaHCO3, NH4HCO 3、 At least one of BaO2, Ba(OH)2.

[0062] By specifically limiting the type of heat storage material, heat can be further converted to reduce the overall heat, and the flammability risk of the temperature control layer itself can be further reduced, thereby further improving the safety of the protective layer.

[0063] In a specific embodiment, the thermal storage material includes Mg(OH)2 and NaHCO3, and the mass ratio of Mg(OH)2 and NaHCO3 is (1~99): (1~99).

[0064] The inventors have found that when the heat storage material is in the combination ratio specified above, the effective utilization rate of the temperature control layer absorption can be further improved, the safety problem of thermal runaway batteries can be further reduced, and the effect of the protective layer in suppressing heat spread can be improved.

[0065] In a specific embodiment, the temperature control layer further includes 0-20% by mass of sticky particles.

[0066] It can be understood that by adding sticky particles, the loose materials in the temperature control layer can be bonded into shape to improve space utilization; the mechanical strength and stability of the temperature control layer can be further increased, and the interface bonding force between the temperature control layer and the thermal insulation layer can be further enhanced to ensure close bonding between the layers of material, which can further improve the overall heat dissipation effect and enhance the effect of suppressing heat spread.

[0067] In another specific embodiment, the temperature control layer further includes heat conductive particles with a mass percentage of 0-20%.

[0068] By adding thermally conductive particles to the temperature control layer, heat can be further evenly transferred to the temperature control layer, thereby improving the conversion rate of the temperature control layer, further exerting the heat absorption capacity of the temperature control layer, reducing the lateral transfer of heat, and further improving the effect of suppressing heat spread.

[0069] Optionally, the thermally conductive particles include at least one of metal particles and graphite.

[0070] Optionally, the adhesive particles include at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylate, and styrene-butadiene rubber.

[0071] By further limiting the types of sticky particles, the mechanical strength and stability of the temperature control layer can be further increased, and the interface bonding force between the temperature control layer and the thermal insulation layer can be further enhanced to ensure close bonding between the layers of material, thereby further improving the effect of suppressing heat spread.

[0072] The heat-insulating layer includes at least one of aerogel heat-insulating wool, mica sheet, vacuum insulation board, asbestos, glass wool, expanded pearl wool, slag wool and foamed ceramics.

[0073] When the heat insulating layer is selected from the materials defined above, heat transfer can be further delayed.

[0074] The present invention does not limit the preparation method of the protective layer. In one embodiment, the first thermal insulation layer, the temperature control layer and the second thermal insulation layer are assembled by hot pressing.

[0075] In a second aspect, the present invention provides a battery assembly comprising N protective layers of the first aspect and M battery cells, where N≥1 and M≥1.

[0076] The present invention provides a battery assembly, comprising N protective layers and M battery cells, wherein the M battery cells are connected in series and / or in parallel.

[0077] Furthermore, M≥2, a protective layer is arranged between two adjacent battery cells; by arranging a protective layer between every two adjacent battery cells, the heat spread can be effectively delayed when thermal runaway occurs in the single battery cell, and due to the structure of the protective layer and the limited compaction density of the temperature control layer and the particle size of the heat storage material in the temperature control layer, the volume utilization rate of the protective layer can be greatly increased, so that it can achieve a better effect of suppressing heat spread even at a limited thickness, thereby improving the capacity density of the battery assembly.

[0078] In a third aspect, the present invention provides an electrical device comprising the battery assembly of the second aspect.

[0079] The present invention provides an electrical device, comprising the battery assembly, which reduces the potential safety hazard of the electrical device.

[0080] The present invention does not limit the specific types of electrical equipment, and may include electric vehicles, mobile phones, smart homes, robots, drones, electronic cigarettes, speakers, and any other equipment that requires battery components to power it.

[0081] Hereinafter, a protective layer provided by the present invention is described in detail through specific embodiments. Example 1

[0082] Figure 2 FIG. 1 is a schematic diagram of the structure of a battery assembly in one embodiment of the present invention. Figure 2 As shown, in the stacking direction of the battery assembly in this embodiment, a composite layer is provided between any two adjacent battery cells 1; the composite layer comprises a first heat insulation layer 2, a temperature control layer 3, and a second heat insulation layer 4;

[0083] The thicknesses of the first insulation layer 2, the temperature control layer 3, and the second insulation layer 4 are 1.1 mm, 1.6 mm, and 1.1 mm, respectively. The first insulation layer 2 is made of aerogel insulation cotton. The temperature control layer 3 includes 90% of 100-mesh chemical heat storage material Mg(OH)2, 5% of sticky particles (polyvinylidene fluoride), and 5% of thermal conductive particles (graphite), with a compaction density of 0.5 g / cm 3 ; The second insulation layer 4 uses aerogel insulation cotton. Example 2

[0084] In the stacking direction of the battery assembly in this embodiment, a composite layer is provided between any two adjacent battery cells; the composite layer comprises a first heat insulation layer, a temperature control layer, and a second heat insulation layer;

[0085] The thicknesses of the first insulation layer, temperature control layer, and second insulation layer are 1.8 mm, 0.2 mm, and 1.8 mm, respectively. The first insulation layer uses aerogel insulation cotton. The temperature control layer includes 83% of 200-mesh chemical heat storage material Al(OH)3, 8% of sticky particles (polyacrylic acid), and 9% of thermal conductive particles (graphite), with a compaction density of 1.5 g / cm 3 ; The second insulation layer uses aerogel insulation cotton. Example 3

[0086] In the stacking direction of the battery assembly in this embodiment, a composite layer is provided between any two adjacent battery cells; the composite layer comprises a first heat insulation layer, a temperature control layer, and a second heat insulation layer;

[0087] The thicknesses of the first insulation layer, temperature control layer, and second insulation layer are 1.1 mm, 1.6 mm, and 1.1 mm, respectively. The first insulation layer uses aerogel insulation cotton. The temperature control layer includes 96% of 300-mesh chemical heat storage material NaHCO3, 2% of sticky particles (polyacrylate), and 2% of thermal conductive particles (aluminum metal particles), with a compaction density of 1.0 g / cm 3 ; The second insulation layer uses aerogel insulation cotton. Example 4

[0088] The difference between this embodiment and embodiment 1 is that the compaction density of the temperature control layer is 2.8 g / cm3 . Example 5

[0089] The difference between this embodiment and embodiment 1 is that the thickness of the first heat insulation layer is 0.5 mm. Example 6

[0090] The difference between this embodiment and embodiment 1 is that the thickness of the second heat insulation layer is 0.5 mm. Example 7

[0091] The difference between this embodiment and embodiment 1 is that the temperature control layer is made of epoxy resin material. Example 8

[0092] The difference between this embodiment and embodiment 3 is that the temperature control layer includes 95% of 300-mesh chemical heat storage material NaHCO3 and 5% of heat-conductive particles. Example 9

[0093] The difference between this embodiment and embodiment 3 is that the temperature control layer includes 96% of 300-mesh chemical heat storage material NaHCO3 and 4% of sticky particles. Example 10

[0094] The difference between this embodiment and embodiment 1 is that both the first thermal insulation layer and the second thermal insulation layer are made of mica sheets. Embodiment 11

[0095] The difference between this embodiment and embodiment 1 is that both the first heat insulation layer and the second heat insulation layer are made of foamed ceramics. Example 12

[0096] The difference between this embodiment and embodiment 1 is that both the first thermal insulation layer and the second thermal insulation layer are made of vacuum thermal insulation panels. Example 13

[0097] The difference between this embodiment and embodiment 1 is that both the first heat insulation layer and the second heat insulation layer are made of asbestos. Embodiment 14

[0098] The difference between this embodiment and embodiment 1 is that both the first heat insulation layer and the second heat insulation layer are made of glass wool. Embodiment 15

[0099] The difference between this embodiment and embodiment 1 is that the heat storage material is barium hydroxide octahydrate phase change material. Example 16

[0100] The difference between this embodiment and embodiment 1 is that the heat storage material is NaNO3 molten salt phase change material. Embodiment 17

[0101] The difference between this embodiment and embodiment 1 is that the heat storage material is a 60Sn-40Bi metal alloy phase change material. Embodiment 18

[0102] The difference between this embodiment and embodiment 1 is that the protective layer only includes the temperature control layer. Embodiment 19

[0103] The difference between this embodiment and embodiment 1 is that the heat storage material is Mg(OH)2 and NaHCO3 in a mass ratio of 3:2.

[0104] Comparative Example 1

[0105] The difference between this comparative example and Example 1 is that the temperature control layer uses 50-mesh Na2SO4·10H2O phase change material.

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is that the compaction density of the temperature control layer is 4 g / cm 3 .

[0108] Comparative Example 3

[0109] The difference between this comparative example and Example 1 is that the temperature control layer adopts hydrogel.

[0110] Test Example 1

[0111] The battery assemblies in the above embodiments and comparative examples were subjected to the thermal propagation test of the module in GB / T 36276-2023 “Lithium-ion Batteries for Power Energy Storage”; the test results are shown in Table 1.

[0112] Table 1

[0113]

[0114] It can be seen from Table 1 that the protective layer provided by the present invention can effectively control the heat transfer of the thermal runaway battery cell, delay the occurrence of heat spread, reduce the possibility of thermal runaway of adjacent battery cells, and reduce the recycling cost; through the structure of the protective layer and the limited compaction density of the temperature control layer and the particle size of the heat storage material in the temperature control layer, the volume utilization rate of the protective layer can be greatly increased, so that it can achieve a better effect of suppressing heat spread even with a limited thickness.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protective layer, characterized in that: It includes a temperature control layer; the temperature control layer includes a heat storage material; The compaction density of the temperature control layer is 0.5-3.0 g / cm 3 , the particle size of the thermal storage material is not less than 100 mesh; The protective layer further includes a heat insulation layer, the heat insulation layer includes a first heat insulation layer and a second heat insulation layer respectively stacked on both sides of the temperature control layer, the thickness ratio of the first heat insulation layer to the temperature control layer is 0.5-10, and the thickness ratio of the second heat insulation layer to the temperature control layer is 0.5-10; The heat storage material includes at least one of a phase change material and a chemical heat storage material; The phase change material includes at least one of a hydrated salt phase change material, a molten salt phase change material, a metal phase change material, and an alloy phase change material; The chemical heat storage material includes Ni(OH)2, Mg(OH)2, MgH2, Co3O4, PbCO3, NH4HSO4, Ca(OH)2, Sr(OH)2, CaCO3, NaHCO3, NH4HCO 3、 At least one of BaO2 and Ba(OH)2; The temperature control layer also includes sticky particles whose mass percentage is greater than 0 and less than or equal to 20% and thermal conductive particles whose mass percentage is greater than 0 and less than or equal to 20%.

2. The protective layer according to claim 1, characterized in that: The compaction density of the temperature control layer is 0.8-2.0 g / cm 3 .

3. The protective layer according to claim 1, characterized in that: The thickness of the first heat insulation layer is 0.2-10 mm; and / or, The thickness of the temperature control layer is 0.1-10 mm; and / or, The thickness of the second heat insulation layer is 0.2-10 mm.

4. The protective layer according to claim 1, characterized in that: The thermal storage material includes Mg(OH)2 and NaHCO3, and the mass ratio of Mg(OH)2 to NaHCO3 is (1-99): (1-99).

5. The protective layer according to any one of claims 1 to 4, characterized in that: The sticky particles include at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylate, and styrene-butadiene rubber.

6. The protective layer according to any one of claims 1 to 4, characterized in that: The heat insulation layer includes at least one of aerogel heat insulation wool, mica sheet, vacuum insulation board, asbestos, glass wool, expanded pearl wool, slag wool and foamed ceramics.

7. A battery assembly, characterized in that: The invention comprises N protective layers as described in any one of claims 1 to 6 and M battery cells, wherein N≥1 and M≥1.

8. An electrical device, characterized in that: A battery assembly comprising the battery assembly of claim 7.

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