Phase change thermal insulation structure for lithium battery

Abstract

The utility model discloses a kind of phase change heat insulation structures for lithium battery, comprising: phase change core material, including laminated phase change material layer one and phase change material layer two;Encapsulation layer, the encapsulation layer is coated in the outside of the phase change core material, the encapsulation layer includes first encapsulation layer and second encapsulation layer, the circumferential side of the first encapsulation layer and second encapsulation layer is overlapped and is bonded to form adhesive part, the width of the adhesive part from the side close to phase change core material to the side away from phase change core material, for the 2 times of the phase change core material thickness.In work, when battery cell thermal runaway, phase change core material in encapsulation layer can be changed from solid to liquid to absorb heat, and from liquid to gaseous to absorb heat, effectively block the heat generated by cell spread, and in certain limit can maintain the structure shape of phase change core material.

Description

Technical Field

[0001] This utility model relates to the field of heat insulation technology, and in particular to a phase change heat insulation structure for lithium batteries. Background Technology

[0002] With the development of the lithium battery industry and the widespread application of lithium batteries, the safety of lithium batteries has become a major concern. Because lithium batteries are energy-intensive, they release a large amount of heat and gas and are accompanied by flames when they run out of control. Moreover, the electrochemical reaction is difficult to extinguish. Without protection, it can quickly spread from a single cell to the entire battery pack, causing very serious consequences and even casualties. Therefore, thermal runaway protection for lithium batteries is essential.

[0003] Existing technologies typically employ thermal insulation materials, such as silicone foam, aerogel, and nanoporous materials, placed between battery cells to prevent the heat from a runaway cell from spreading to adjacent cells. However, this method does not completely eliminate thermal runaway; it only slows down its spread. While the heat generated by thermal runaway is blocked and delayed, it does not disappear, leaving a risk of delayed thermal runaway. This does not meet the safety requirement of preventing the entire battery pack from catching fire or exploding. The risk of delayed thermal runaway can lead to secondary accidents during or after rescue operations, posing further safety threats.

[0004] Therefore, a phase change thermal insulation structure for lithium batteries is still needed to solve the above problems. Utility Model Content

[0005] This utility model provides a phase change thermal insulation structure for lithium batteries that solves the above-mentioned problems.

[0006] The objective of this utility model is achieved through the following technical solution: A phase change thermal insulation structure for lithium batteries, comprising: The phase change core material includes a stacked phase change material layer one and a phase change material layer two; An encapsulation layer covers the outer side of the phase change core material. The encapsulation layer includes a first encapsulation layer and a second encapsulation layer. The peripheral sides of the first and second encapsulation layers overlap to form an adhesive portion. The width of the adhesive portion from the side closest to the phase change core material to the side furthest from the phase change core material is twice the thickness of the phase change core material. Preferably, it further includes a release element attached to the encapsulation layer, the outer surface of the release element being covered with a tearable portion for exposing the adhesive layer of the release element after tearing.

[0007] Preferably, the release liner is made of silicone release paper or PET silicone release film, and the thickness of the release liner is 0.1-0.15mm.

[0008] Preferably, the encapsulation layer comprises a stacked protective layer, a penetration barrier layer, and a heat-sealing layer, wherein the thickness of the protective layer is greater than or equal to 20 μm, the thickness of the penetration barrier layer is greater than or equal to 30 μm, the thickness of the heat-sealing layer is greater than or equal to 40 μm, and the total thickness of the encapsulation layer is greater than or equal to 120 μm.

[0009] Preferably, the adhesive layer comprises an adhesive and a substrate, the adhesive is coated on the substrate, the thickness of the adhesive layer is 20-200 μm, the adhesive is acrylic or acrylic self-adhesive, and the substrate is PET or cotton paper.

[0010] Preferably, the first encapsulation layer comprises ceramic fibers impregnated in water and salt.

[0011] Preferably, the second encapsulation layer comprises glass fibers impregnated in water and salt.

[0012] Preferably, the encapsulation layer comprises multiple layers that are alternately distributed as a first encapsulation layer and a second encapsulation layer.

[0013] Compared with the prior art, the beneficial effects of this utility model include at least the following: The product is primarily designed to address the large amount of heat generated during thermal runaway in lithium batteries. It utilizes phase change materials to absorb and dissipate this heat, reducing the temperature of the runaway cell and fundamentally solving the thermal runaway problem. The layered structure stacked inside the encapsulation layer is the main structure of the phase change core material. During operation, when the battery cell experiences thermal runaway, the phase change core material within the encapsulation layer transforms from a solid to a liquid state to absorb heat, and then from a liquid to a gaseous state to absorb heat again. This effectively prevents the spread of heat generated by the cell and maintains the structural shape of the phase change core material to a certain extent. Attached Figure Description

[0014] Figure 1 This is a top view of the phase change thermal insulation structure according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of one side of the phase change heat insulation structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the phase change core material structure according to an embodiment of the present invention.

[0015] Explanation of reference numerals in the attached figures: 1. Phase change core material; 2. Encapsulation layer; 21. First encapsulation layer; 22. Second encapsulation layer; 23. Adhesive part; 3. Release mold; 4. Tear-off part; 5. Adhesive layer. Detailed Implementation

[0016] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.

[0017] Reference Figure 1-3 The terms used to describe position and direction in this utility model are based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this utility model.

[0018] This utility model provides a phase change thermal insulation structure for lithium batteries, comprising: a phase change core material 1 and an encapsulation layer 2. It includes a first phase change material layer and a second phase change material layer stacked together; the encapsulation layer 2 covers the outer side of the phase change core material 1, and the encapsulation layer 2 includes a first encapsulation layer 21 and a second encapsulation layer 22. The peripheral sides of the first encapsulation layer 21 and the second encapsulation layer 22 overlap and adhere to form an adhesive portion 23. The width of the adhesive portion 23 from the side closest to the phase change core material 1 to the side furthest from the phase change core material 1 is twice the thickness of the phase change core material 1. The adhesive portion 23 refers to the overlapping part of the two composite first encapsulation layer 21 and second encapsulation layer 22. Along the thickness direction perpendicular to the phase change core material 1, the width of the adhesive portion 23 is twice the thickness of the phase change core material 1. Through testing, it has been verified that this combination of thickness and width can provide a stable external support structure for the phase change core material 1, preventing leakage of the phase change core material 1 before it absorbs heat during phase change, thereby reducing the effective heat absorption of the battery cell. The adhesive portion 23 is formed by bonding with adhesive or other means and serves as the edge of the encapsulation layer 2.

[0019] Preferably, the device further includes a release liner 3 adhered to the encapsulation layer 2. The outer surface of the release liner 3 is covered with a tear-away portion 4, which exposes the adhesive layer 5 of the release liner 3 after tearing. The release liner 3 can be provided on both sides of the encapsulation layer 2, or on either side. It can be easily removed by the tear-away portion 4, allowing the heat insulation structure to be directly adhered to the heating surface of the battery cell. This ensures complete adhesion, improves the thermal conductivity efficiency for transferring heat between the phase change material 1 when the battery cell generates heat, and enhances the immediacy of heat absorption when the phase change material generates a large amount of heat in the battery cell. This effectively prevents the spread of heat generated by the battery.

[0020] Preferably, the material of the tear-off part 4 is silicone release paper or PET silicone release film, and the thickness of the release element 3 is 0.1-0.15mm. The release element 3 made of this material can maintain good repellency, making it easy to tear, while also maintaining the adhesive effect of the adhesive layer 5 for a long time, thereby ensuring a long-term heat absorption effect on the battery cell.

[0021] Preferably, the encapsulation layer 2 comprises a stacked protective layer, a penetration barrier layer, and a heat-sealing layer. The thickness of the protective layer is greater than or equal to 20 μm, the thickness of the penetration barrier layer is greater than or equal to 30 μm, the thickness of the heat-sealing layer is greater than or equal to 40 μm, and the total thickness of the encapsulation layer 2 is greater than or equal to 120 μm. The protective layer... Preferably, the adhesive layer 5 comprises an adhesive and a substrate. The adhesive is coated on the substrate, and the thickness of the adhesive layer 5 is 20-200 μm. The adhesive is an acrylic or acrylic self-adhesive, and the substrate is PET or cotton paper. The adhesive layer 5 includes a substrate, which can be PET or cotton paper with adsorption properties. The substrate effectively adsorbs the adhesive, allowing the phase change core material 1 to be stably adhered to the battery through the adhesive layer 5, maintaining the timely phase change heat absorption effect.

[0022] Preferably, the first encapsulation layer 21 comprises ceramic fibers impregnated in water and salt.

[0023] Preferably, the second encapsulation layer 22 comprises glass fibers impregnated in water and salt. A single-layer phase change core material 1 cannot simultaneously achieve a wide temperature range and a long service life. By combining the high-temperature liquid-locking effect of ceramic fibers with the low-temperature controlled release effect of glass fibers, the limitations of a single material are overcome. This improves the phase change heat insulation and absorption effect of the lithium battery.

[0024] Preferably, the encapsulation layer 2 comprises multiple layers with alternating first encapsulation layer 21 and second encapsulation layer 22. This alternating arrangement of multiple layers of first encapsulation layer 21 and second encapsulation layer 22 overcomes the limitations of single materials and improves the phase change heat insulation and absorption effect of lithium batteries. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A phase change thermal insulation structure for lithium batteries, characterized in that, include: The phase change core material includes a stacked phase change material layer one and a phase change material layer two; An encapsulation layer covers the outer side of the phase change core material. The encapsulation layer includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer and the second encapsulation layer overlap and adhere to form an adhesive portion. The width of the adhesive portion from the side near the phase change core material to the side away from the phase change core material is twice the thickness of the phase change core material.

2. The phase change thermal insulation structure for lithium batteries according to claim 1, characterized in that, It also includes a release element bonded to the encapsulation layer, the outer surface of which is covered with a tearable tear-off portion for exposing the adhesive layer of the release element after tearing.

3. The phase change thermal insulation structure for lithium batteries according to claim 2, characterized in that, The material of the tear-off part is silicone release paper or PET silicone release film, and the thickness of the release part is 0.1-0.15mm.

4. The phase change thermal insulation structure for lithium batteries according to claim 1, characterized in that, The encapsulation layer includes a stacked protective layer, a penetration barrier layer, and a heat-sealing layer. The thickness of the protective layer is greater than or equal to 20 μm, the thickness of the penetration barrier layer is greater than or equal to 30 μm, the thickness of the heat-sealing layer is greater than or equal to 40 μm, and the total thickness of the encapsulation layer is greater than or equal to 120 μm.

5. The phase change thermal insulation structure for lithium batteries according to claim 2, characterized in that, The adhesive layer includes an adhesive and a substrate. The adhesive is coated on the substrate. The thickness of the adhesive layer is 20-200 μm. The adhesive is an acrylic or acrylic self-adhesive, and the substrate is PET or cotton paper.

6. The phase change thermal insulation structure for lithium batteries according to claim 1, characterized in that, The first encapsulation layer comprises ceramic fibers impregnated in water and salt.

7. The phase change thermal insulation structure for lithium batteries according to claim 1, characterized in that, The second encapsulation layer comprises glass fibers impregnated in water and salt.

8. The phase change thermal insulation structure for lithium batteries according to claim 1, characterized in that, The encapsulation layer comprises multiple layers that are alternately distributed as a first encapsulation layer and a second encapsulation layer.

Images