Battery cell heat insulation pad capable of releasing heat and battery pack
By using a heat insulation pad with built-in phase change composite filler between lithium battery cells, heat is actively released, solving the problem that traditional heat insulation pads cannot prevent heat transfer, thus improving safety and cost-effectiveness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2026-04-10
AI Technical Summary
When existing lithium battery cells experience thermal runaway, traditional heat insulation pads cannot effectively prevent heat transfer, increasing the risk of thermal runaway in adjacent cells. In addition, they are costly and take up a lot of space.
It adopts a heat-releasing cell insulation pad with built-in phase change composite filler. The phase change liquid absorbs heat and expands, breaking through the sealing foil to release heat outward. Combined with the insulation layer and sealing foil design, it realizes active heat release.
It effectively reduces the risk of thermal runaway in adjacent cells, lowers thermal conductivity, reduces space occupation, lowers costs, and ensures the safety and efficiency of the battery pack.
Smart Images
Figure CN224110324U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of electric core thermal runaway, specifically relates to a kind of electric core heat insulation pad and battery pack that can release heat. BACKGROUND
[0002] With the rapid development of photovoltaic, wind power and other renewable energy, lithium battery energy storage industry also ushered in explosive growth. Lithium battery inevitably exists thermal runaway risk due to its charge and discharge principle, and how to prevent thermal runaway from further spreading becomes a problem in the industry.
[0003] Battery pack is usually designed as a closed box, in order to improve energy density, the electric cores are stacked very closely, when the electric core occurs thermal runaway, a large amount of heat is discharged with the pressure relief at the top of the electric core, and the heat not discharged needs to be slowly dissipated through the surface of the electric core, part of the heat is transferred to the adjacent electric core. If the temperature of the adjacent electric core is still much higher than the thermal runaway temperature before reaching the thermal runaway temperature, and still continuously transfers heat to the adjacent electric core, the adjacent electric core will have a high probability of triggering thermal runaway.
[0004] At present, the industry generally uses traditional heat insulation pad, that is, adding heat insulation pad between two electric cores to solve the problem, the heat insulation pad is made of single low thermal conductivity material, and the thermal resistance is high, which can greatly prevent the heat conduction of the thermal runaway electric core to the adjacent electric core, and cause the thermal runaway of the adjacent electric core, so as to prevent the spread of the accident.
[0005] Traditional heat insulation pad is passive heat insulation, such as silica gel foam and aerogel, which requires very low thermal conductivity of the material, and the thickness of the heat insulation pad needs to be increased. The cost of ultra-low thermal conductivity material is high, and increasing the thickness of the heat insulation pad will also greatly increase the cost, and will occupy the space of the electric core, which is not conducive to cost control and capacity design of battery pack. UTILITY MODEL CONTENTS
[0006] The utility model aims to provide a kind of electric core heat insulation pad and battery pack that can release heat, for blocking the heat transfer between electric cores, and can actively release heat, effectively reduce the risk of thermal runaway of adjacent electric core.
[0007] The utility model solves the technical problems by adopting the technical scheme of a kind of electric core heat insulation pad that can release heat, including the heat insulation pad between two electric cores, the heat insulation pad is embedded with phase change composite filler, the phase change composite filler absorbs the heat of the electric core and expands, the phase change composite filler expands to break through the heat insulation pad, so as to discharge heat outward.
[0008] Further, the phase change composite filler comprises a filler body and a phase change liquid, the filler body is used for carrying / housing / binding the phase change liquid, the phase change liquid is combined with the filler body to form the phase change composite filler.
[0009] Further, the phase change liquid absorbs heat to change from liquid state to gas state, so that the phase change composite filler is expanded; the phase change liquid in gas state or the phase change liquid in mixed state of gas and liquid breaks through the heat insulation pad and sprays out of the heat insulation pad, so that heat is discharged outward.
[0010] Further, the heat insulation pad comprises two superposed insulation layers, the phase change composite filler is arranged between the two insulation layers, and the two insulation layers encapsulate the phase change composite filler inside to form the heat insulation pad.
[0011] Further, the inner side of the insulation layer is provided with an encapsulation foil, and the two encapsulation foils on the two insulation layers encapsulate the phase change composite filler.
[0012] Further, the area of the encapsulation foil is the same as that of the insulation layer, and the area of the phase change composite filler is smaller than that of the encapsulation foil.
[0013] The size of the encapsulation foil is the same as that of the insulation layer at most, and the exposed amount is reduced as much as possible.
[0014] Further, the phase change composite filler is arranged at the center of the two encapsulation foils, and the edges of the two encapsulation foils encapsulate the phase change composite filler into the heat insulation pad.
[0015] Further, the phase change composite filler is expanded to break through the encapsulation foil.
[0016] Further, the encapsulation of the encapsulation foil to the phase change composite filler at least comprises an encapsulation knot facilitating breaking, and the encapsulation knot is located at the edge position of the heat insulation pad.
[0017] The application further provides a battery pack, which is composed of a plurality of battery cells and a plurality of heat insulation pads.
[0018] The application has the following beneficial effects:
[0019] The heat insulation pad and the battery pack can release heat, the phase change composite filler is arranged in the heat insulation pad, the phase change composite filler absorbs heat through liquid-gas phase change and actively releases a large amount of heat by spraying.
[0020] The phase change liquid in the phase change composite has high specific heat capacity in liquid state, can absorb a large amount of heat when being converted from liquid state to gaseous state, can expand the heat insulation pad and break the heat insulation pad to spray outward to take away heat; and the filling body expands due to heat absorption, and the heat conductivity of the heat insulation pad is also significantly reduced to further block the remaining heat transfer. BRIEF DESCRIPTION OF DRAWINGS
[0021] The accompanying drawings incorporated in and forming a part of the specification illustrate embodiments of the present application and, together with the description, serve to explain the principles of the application. In the drawings, like reference numerals are used to indicate like elements throughout. The accompanying drawings are of some embodiments of the application and are not all the embodiments. Other drawings can be derived from these drawings by a person of ordinary skill in the art without paying creative labor.
[0022] Figure 1 An application schematic diagram of the heat-releasable battery cell heat insulation pad of the embodiment of the present application;
[0023] Figure 2 A structural diagram of the heat-releasable battery cell heat insulation pad of the embodiment of the present application;
[0024] Figure 3 A schematic diagram of the heat insulation pad absorbing heat and releasing heat outward when in the battery pack.
[0025] In the drawings: 1, battery cell; 2, heat insulation pad; 3, phase change composite filler; 21, insulation layer; 22, sealing foil; 23, upper sealing knot; 24, lower sealing knot; 31, filling body; 32, phase change liquid; 1a, right battery cell; 1b, left battery cell. DETAILED DESCRIPTION
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application and the prior art, specific implementation manners of the present application will be described below with reference to the drawings. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by a person of ordinary skill in the art without paying creative labor, and other embodiments can also be obtained. In addition, the design direction is only to represent the relative position relationship between the components, not the absolute position relationship.
[0027] The embodiment of the present application provides a heat-releasable battery cell heat insulation pad, please refer to Figure 1 、 Figure 2 、 Figure 3 , mainly including a heat insulation pad 2 placed between two battery cells 1, a phase change composite filler 3 built-in the heat insulation pad 2, the phase change composite filler 3 absorbs the heat of the battery cell 1 and expands, the phase change composite filler 3 expands to break the heat insulation pad 2, so as to discharge heat outward.
[0028] In the present application, the phase change composite filler 3 can be a filler with liquid-gas conversion. When converted from liquid to gas, it absorbs a large amount of heat, and the gas causes the thermal insulation pad 2 to expand, eventually breaking through the thermal insulation pad 2. At this time, the gas sprays out of the thermal insulation pad 2, which can simultaneously take away a large amount of heat.
[0029] In a specific embodiment, the phase change composite filler 3 can include a filler body 31 and a phase change liquid 32. The phase change liquid 32 can be carried / contained / restrained by the filler body 31, and the phase change liquid 32 and the filler body 31 are combined together to form a phase change composite filler 3 with relatively stable shape and molding, so as to be stored in the inside of the thermal insulation pad 2.
[0030] Specifically, the filler body 31 can be a flocculent material such as aerogel on the gel side. It can also be other high-temperature-resistant materials processed into flocculent for filling, such as aluminum silicate fiber cotton. A plurality of high-temperature-resistant materials can also be combined to form the filler body 31 to make up for the poor compatibility of some materials with the phase change liquid 32. The phase change liquid 32 can be a high-boiling-point insulating liquid such as fluorinated liquid and insulating oil.
[0031] In the present application, the thermal insulation pad 2 can include two insulating layers 21. The large side of the two insulating layers 21 is placed and adhered together, and the phase change composite filler 3 is placed between the two insulating layers 21. The phase change composite filler 3 is stored inside by the two insulating layers 21 to form the thermal insulation pad 2.
[0032] In a feasible embodiment, a sealing foil 22 can be provided on the inner side of the insulating layer 21. The phase change composite filler 3 is stored by the two sealing foils 22 on the two insulating layers 21.
[0033] For example, the sealing foil 22 can be an inner structure of the insulating layer 21, that is, the sealing foil 22 is fixed on the inner side of the insulating layer 21. When the inner sides of the two insulating layers 21 are adhered, the two sealing foils 22 are opposite to each other, and the phase change composite filler 3 is placed between the two sealing foils 22. At this time, the edges of the two sealing foils 22 are sealed and connected, so as to form a closed space inside, and the phase change composite filler 3 with a size slightly smaller than the two sealing foils 22 can be stored.
[0034] Specifically, the area of the sealing foil 22 can be the same as that of the insulating layer 21, and the area of the phase change composite filler 3 is smaller than that of the sealing foil 22. The two sealing foils 22 on the two insulating layers 21 can store the phase change composite filler 3.
[0035] In a feasible embodiment, the phase change composite filler 3 can be placed in the center of the two sealing foils 22 for storage, and the edges of the two sealing foils 22 can store the phase change composite filler 3 in the thermal insulation pad 2.
[0036] The two insulation layers 21 can be symmetrically attached to the same side of a sealing foil 22, and the two insulation layers 21 can be stacked together to form two sealing foils 22 that are attached to each other. It can be understood that the two insulation layers 21 are connected together by the sealing foil 22, and the folding line of the sealing foil 22 can be located at the boundary of the two insulation layers 21, or can coincide with the boundary, or can be located inside the boundary. When the sealing is performed, the sealing size at the folding line can be the same as the sealing size at other positions.
[0037] The sealing can be performed by hot-pressing packaging, and the two sealing foils 22 that are attached to each other can be bonded together, or can be bonded by using glue. The sealing size is the width of the two sealing foils 22 that are bonded together. It can be understood that when the two sealing foils 22 are connected together, the above sealing method can be performed based on the outer insulation layer 21, for example, the two insulation layers 21 can be pressed at the outer part to achieve the sealed connection of the two sealing foils 22 at the inner part.
[0038] In this application, the phase change composite filler 3 in a stable form is sealed between the two sealing foils 22 at room temperature, and the phase change composite filler 3 is arranged between the two insulation layers 21 to form the thermal insulation pad 2. When heat is generated from the battery cell 1 attached to the thermal insulation pad 2, the phase change composite filler 3 in the thermal insulation pad 2 absorbs the heat, and the phase change liquid 32 can be converted into a gaseous state after absorbing a large amount of heat, so that the thermal insulation pad 2 expands and finally breaks the sealing structure (hereinafter referred to as sealing) of the sealing foil 22. At this time, the expanded gas can be sprayed out of the broken part (the broken part can be generated at the sealing or other relatively weak position of the sealing foil 22), and a large amount of heat can be discharged to the outside. The insulation layer 21 and the filler 31 that remain between the battery cells 1 still have the thermal insulation effect, and have the thermal insulation effect of a conventional thermal insulation pad.
[0039] As a preferred option, the material with heat absorption and expansion can be selected to construct the filler 31. In the case of high temperature of thermal runaway, the filler 31 expands, and the thermal conductivity of the thermal insulation pad 2 is significantly reduced, so that the remaining heat can be further blocked from being transmitted to the surrounding battery cells. Of course, the material with a relatively low expansion coefficient can also be selected to construct the filler 31.
[0040] In this application, the sealing of the sealing foil 22 to the phase change composite filler 3 includes at least one sealing that is easy to break, and the sealing is preferably located at the edge of the thermal insulation pad 2.
[0041] In a specific implementation, the sealing can be arranged at the upper part of the thermal insulation pad 2, that is, the upper sealing 23, and the direction of the explosion-proof valve of the battery cell 1 is consistent. Of course, the sealing can also be arranged at the lower part of the thermal insulation pad 2, that is, the lower sealing 24, as shown in FIG. Figure 2
[0042] In the case of multiple seals, the burst pressure of each seal can be the same or different. Taking two seals as an example, the burst pressures of the two seals can be different, and the single seal is preferentially broken first, i.e., the burst pressure of the upper seal 23 is less than that of the lower seal 24. The burst pressures of the two seals can also be the same, i.e., the burst pressures of the upper seal 23 and the lower seal 24 are the same, which can be adjusted according to the installation mode of the battery cell, the actual situation, etc.
[0043] The application also proposes a battery pack composed of a plurality of battery cells 1 and a plurality of the above-mentioned thermal insulation pads 2, which are arranged between two battery cells 1, as shown in Figure 3
[0044] The thermal insulation pad 2 carried in the battery pack can be a disposable product. When thermal runaway occurs, the phase change liquid 32 in the adjacent thermal insulation pad 2 bursts the sealed space formed by the sealing foil 22. At this time, the thermal insulation pad 2 has failed, and a new thermal insulation pad 2 can be replaced synchronously when the battery cell is replaced.
[0045] It should be noted that when the battery cell generates thermal runaway, its temperature rises sharply, and the maximum temperature during thermal runaway is much higher than the temperature range during normal operation of the battery cell. Therefore:
[0046] The phase change liquid 32 always remains in a liquid phase within the temperature range during normal operation of the battery cell, and the thermal insulation pad 2 can absorb heat within the temperature range during normal operation, and can be repeatedly used without worrying about being burst due to heat absorption.
[0047] During thermal runaway, the temperature of the battery cell is much higher than the temperature range during normal operation. At this time, the phase change liquid 32 changes from a liquid phase to a gas phase after absorbing a large amount of heat, expands, and bursts the sealed space, thereby achieving the effect of absorbing heat and dissipating heat to the outside of the battery cell.
[0048] During the temperature rise of the battery cell 1, the phase change liquid 32 has a high specific heat capacity and can absorb a large amount of heat. After reaching a certain temperature, the phase change liquid 32 changes from a liquid to a gas, causing the space sealed by the sealing foil 22 to expand, and eventually burst out of the sealing of the sealing foil 22. Of course, it can also be other relatively weak positions of the sealing foil 22, not the sealing position; the burst sealing is preferred.
[0049] During the process of triggering thermal runaway of the battery cell, the temperature of the battery cell can be divided into three temperature ranges: working temperature, medium temperature range (before thermal runaway), and high temperature range (after thermal runaway). The following is based on Figure 3 to explain:
[0050] The thermal insulation pad 2 and the battery cell 1 are tightly attached under the action of pressure. The battery cell 1 in the middle is an abnormal battery cell, and the left battery cell 1a and the right battery cell 1b on both sides are normal battery cells.
[0051] When the temperature of the battery cell 1 exceeds the upper limit of the working temperature and enters the medium temperature section, the phase change liquid 32 continuously absorbs heat during this process, and as the temperature continues to rise, the filler 31 begins to slowly expand; at this time, the thermal insulation pad 2 remains relatively stable, as shown in 2-1 of FIG. 6; Figure 2
[0052] When the battery cell 1 triggers thermal runaway, the temperature rises sharply into the high temperature section, and then the valve is opened to spray gas and take away a large amount of heat, and then the temperature begins to decrease; at this time, the phase change liquid 32 in the thermal insulation pad 2 on both sides of the battery cell 1 absorbs a large amount of heat and changes from a liquid state to a gas state, and when the pressure reaches a certain value, the sealing or edge of the edge of the sealing foil 22 breaks, and the gas is sprayed out and takes away a large amount of heat, as shown in 2-2 of FIG. 7; Figure 2
[0053] During this process, the temperature of the thermal insulation pad 2 will jump down temporarily, the expansion of the filler 31 approaches the maximum value, and the overall thermal conductivity of the thermal insulation pad 2 approaches the minimum value, further blocking the heat transfer between the two sides of the battery cell, but the temperature will still slowly rise.
[0054] When the temperature of the battery cell 1 after thermal runaway and the temperature of the battery cell on both sides begin to decrease synchronously, the battery pack will slowly tend to be stable, and the battery cell on the other side will not trigger thermal runaway. During the entire process, the battery cell on the other side of the battery cell 1 that triggers thermal runaway has not reached the critical value of the thermal runaway temperature.
[0055] It can be understood that the phase change liquid 32 sprayed out of the thermal insulation pad 2 on both sides can be pure gas, or a mixture of gas and liquid. These sprayed phase change liquids 32 can be poured on the battery cell 1 that triggers thermal runaway to achieve the effect of cooling.
[0056] Heat transfer is from a medium with a high temperature to a medium with a low temperature. When a material with a high specific heat capacity absorbs a large amount of heat, the temperature rises relatively slowly. The phase change liquid 32 uses a material with a high liquid specific heat capacity, and the liquid-gas two-phase conversion can greatly absorb heat, which can avoid the thermal insulation pad from rising too fast and transferring heat to the battery cell on the other side too early and too fast.
[0057] In this application, the temperature of the liquid-gas phase change is lower than the thermal runaway temperature of the battery cell and higher than the working temperature of the battery cell, which can release heat before the battery cell on the other side triggers thermal runaway, and can also ensure the stability of the state during normal work. The expansion temperature of the filler 31 is higher than the working temperature of the battery cell, so as to ensure the stability of the system in the working state. The filler 31 uses a fluffy material that expands, and after expansion, the thermal insulation pad has a low thermal conductivity at high temperatures.
[0058] It is to be noted that the relational terms herein, such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
[0059] The above further describes the present application in detail in connection with specific preferred embodiments. It is to be noted that the specific embodiments of the present application are not limited to these descriptions. For those skilled in the art of the present application, some simple deductions or substitutions can be made without departing from the concept of the present application, and all of them shall be considered as falling within the protection scope of the present application.
Claims
1. A heat-releasable cell insulation pad, characterized by, The heat insulation pad (2) is arranged between two electric cores (1), and the phase change composite filler (3) is arranged in the heat insulation pad (2), the phase change composite filler (3) absorbs heat of the electric core (1) and expands, and the phase change composite filler (3) expands to break the heat insulation pad (2) to discharge heat outward. The heat insulation pad (2) comprises two overlapped insulation layers (21), and the phase change composite filler (3) is arranged between the two insulation layers (21), and the two insulation layers (21) seal the phase change composite filler (3) inside to form the heat insulation pad (2). The inner side of the insulation layer (21) is provided with a sealing foil (22), and the two sealing foils (22) on the two insulation layers (21) seal the phase change composite filler (3). The sealing foil (22) seals the phase change composite filler (3) at least by a sealing knot which is easily broken, and the sealing knot is located at the edge of the heat insulation pad (2).
2. The electrically heatable cell insulating mat according to claim 1, characterized in that The phase change composite filler (3) comprises a filler body (31) and a phase change liquid (32), the filler body (31) is used for carrying / housing / restraining the phase change liquid (32), and the phase change liquid (32) is combined with the filler body (31) to form the phase change composite filler (3).
3. A heat-releasable electrical core insulating pad according to claim 2, wherein, The phase change liquid (32) absorbs heat to change from liquid state to gaseous state, so that the phase change composite filler (3) expands, and the phase change liquid (32) in gaseous state or the phase change liquid (32) in mixed state of gaseous state and liquid state breaks the heat insulation pad (2) and sprays out of the heat insulation pad (2), so as to discharge heat outward.
4. The electrically heatable cell insulating mat according to claim 1, characterized in that The area of the sealing foil (22) is the same as the area of the insulation layer (21), and the area of the phase change composite filler (3) is smaller than the area of the sealing foil (22).
5. A heat-releasable electrical core insulating pad according to claim 4, wherein The phase change composite filler (3) is arranged at the center of the two sealing foils (22), and the edges of the two sealing foils (22) seal the phase change composite filler (3) in the heat insulation pad (2).
6. The electric battery separator pad of claim 1, wherein, The phase change composite filler (3) expands to break the sealing foil (22).
7. A battery pack, characterized by, The battery pack is composed of a plurality of electric cores (1) and a plurality of heat insulation pads (2) as claimed in claim 1, and the heat insulation pad (2) is arranged between two electric cores (1).