Batteries with thermal and structural adhesives on the sides

Abstract

A battery is provided having a thermal adhesive and a structural adhesive on the side. [Solution] A battery 10 is formed by stacking multiple battery cells 20, and each battery cell is composed of two current collecting layers 24, 25 sandwiching an electrochemical system 20. The current collecting layers are sealed with a structural adhesive 26 that surrounds the periphery of the electrochemical system, and an insulating coating 30 contacts the side of the current collecting layer to insulate it. In addition, a heat dissipation adhesive 40 is additionally provided in contact with the insulating coating and the structural adhesive to enhance the heat dissipation and insulation effect of the battery cell.

Description

[Technical field]

[0001] The present invention relates to a battery, and more particularly to a battery constructed using complete, independently sealed battery cells, with additional insulating coating and heat dissipating adhesive on the sides. [Background technology]

[0002] In recent years, with the rapid development of various portable electronic devices, electric vehicles, energy storage stations, and other fields, there is a high demand for energy storage devices that have a relatively high energy storage density and are environmentally friendly. In response to this demand, ion secondary batteries have become the first choice, and have further developed into various secondary batteries such as lithium ion secondary batteries, magnesium ion secondary batteries, and sodium ion secondary batteries. In actual practice, the most common method is to stack sheet-shaped battery cells in a single axial direction and then form a battery using an appropriate electrical connection method, which achieves sufficient capacity and can be used in various devices.

[0003] The conventional series connection method mainly involves connecting the battery cells through external tabs, and then sealing and insulating them with a heat-shrinkable film. However, since the heat shrinkable film only has an insulating effect and does not have a heat dissipation ability, the heat dissipation effect of the entire battery cell is greatly reduced. In addition, this type of structure also reduces the energy density of the battery cell since certain space is occupied by external features such as tabs. Additionally, the presence of features such as tabs increases the internal resistance of the battery cell. Although it is possible to use heat dissipation adhesives to dissipate heat from battery cells, the heat dissipation effect is quite limited because the heat dissipation adhesives come into contact with the outer surface of the battery and cannot directly dissipate heat from the internal battery cells, i.e., the location where the actual heat source is generated.

[0004] In view of this, the present invention presents a battery with a novel side heat dissipation adhesive and structural adhesive to address the above shortcomings. Summary of the Invention [Problem to be solved by the invention]

[0005] The main objective of the present invention is to provide a battery with thermal adhesive and structural adhesive on the side. This method additionally provides insulating adhesive and heat dissipation adhesive on the side of the current collecting layer of the stacked battery cells, greatly reducing the contact thermal resistance between the battery and the outside, and further improving the heat dissipation efficiency of the battery cells. [Means for solving the problem]

[0006] The present invention discloses a battery having a heat dissipation adhesive and a structural adhesive on the sides, which includes multiple battery cells stacked in contact with current collecting layers of different polarities, an insulating coating coating the sides of the current collecting layers, and a heat dissipation adhesive applied around the sides of the battery. Each battery cell is a complete, independent module, and each battery cell includes two current collecting layers and an electrochemical system, including an electrolyte system, disposed between the two current collecting layers. A structural adhesive is provided between the two current collecting layers to surround the electrochemical system, and an insulating coating is provided between adjacent structural adhesives to cover the sides of the two current collecting layers, thereby insulating the sides of the current collecting layers. An additional layer of thermal adhesive is then applied around the sides of the battery, covering the structural adhesive and the insulating coating. In addition, the heat dissipation adhesive contains particles with thermal conductivity, which can dissipate heat directly to the battery cell, greatly reducing the contact thermal resistance between the battery cell and the housing, and further achieving the purpose of improving the heat dissipation efficiency of the battery cell. The particles of the heat dissipation adhesive have at least two different particle sizes, which can achieve the effect of dense lamination and improve the resistance to external impact.

[0007] A detailed explanation will be given below using specific examples. The objectives, technical contents, features and effects achieved by the present invention can be more easily understood. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 2 is a schematic diagram of a battery having a thermal adhesive and a structural adhesive on the side of the present invention; [Figure 1B] 1 is a schematic diagram of another embodiment of a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Figure 2A] 1 is a schematic diagram of a battery cell in a battery having a thermal adhesive and a structural adhesive on the side of the present invention; [Figure 2B] 1 is an exploded schematic view of a battery cell in a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; [Figure 3A] FIG. 2 is a schematic diagram of a battery cell stack having a heat dissipation adhesive and a structural adhesive on the side of the battery according to the present invention; [Figure 3B] 1 is a schematic diagram of a battery cell stack having heat dissipation adhesive and structural adhesive on the side of the present invention, and an insulating coating is additionally provided. [Figure 4A] 1 is a schematic diagram of another embodiment of an insulating coating for a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Figure 4B] 1 is a schematic diagram of another embodiment of an insulating coating for a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Diagram 5] 1 is a schematic diagram of another embodiment of a battery cell in a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Figure 6A] FIG. 6 is a schematic diagram of a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention, which is constructed using the battery cell of FIG. 5 . [Figure 6B] FIG. 6 is a schematic diagram of a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention, which is constructed using the battery cell of FIG. 5 . [Figure 6C] FIG. 6 is a schematic diagram of a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention, which is constructed using the battery cell of FIG. 5 . [Figure 6D]FIG. 6 is a schematic diagram of a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention, which is constructed using the battery cell of FIG. 5 . [Figure 7A] 1 is a schematic diagram of another embodiment of an insulating coating for a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Figure 7B] 1 is a schematic diagram of another embodiment of an insulating coating for a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention; FIG. [Figure 8] FIG. 1 is a schematic diagram of an embodiment in which a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention is used in a rectangular battery. [Figure 9] 1 is a schematic diagram comparing temperatures in an experiment in which a battery having a heat dissipation adhesive and a structural adhesive on the side of the present invention was used in a rectangular battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In order to make the advantages, spirit and features of the present invention more easily and clearly understandable, the following detailed description and discussion will be given by way of example and with reference to the figures. It should be noted that these examples are merely representative examples of the present invention, and the embodiments and claims of the present invention are not limited to only the forms of these examples. The purpose of providing these examples is merely to make the disclosure of the present invention more thorough and easily understandable.

[0010] The terms used in the various embodiments disclosed in the present invention are used only for the purpose of describing particular embodiments and are not intended to be limiting of the various embodiments disclosed in the present invention. Unless expressly indicated otherwise, the use of the singular includes the plural. Unless otherwise limited, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments disclosed herein belong. The above terms (e.g., terms defined in a commonly used dictionary) are to be construed as having the same meaning as in the context in the same technical field, and are not to be construed as having an idealized or overly formal meaning, unless expressly limited in various embodiments disclosed in the present invention.

[0011] In the present specification, the term "embodiment," "specific embodiment," and the like means that the combination of specific features, structures, materials, or characteristics described in the embodiment is included in at least one embodiment of the present invention. In this specification, general descriptions of the above terms do not necessarily refer to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments.

[0012] Please refer to Figure 1A. The battery 10 having a heat dissipation adhesive and a structural adhesive on the side surface disclosed in the present invention is formed by stacking a plurality of battery cells 20 in a single axial direction. The sides of the battery cell 20 are coated with an insulating coating 30 and a heat dissipation adhesive 40, and the battery cell 20 is a complete and independent module. The battery 10 can be housed in a housing as an electric energy supply unit, and is, for example, a rectangular battery. The battery cell 20 will be described below.

[0013] Please refer to Figures 2A and 2B. The battery cell 20 includes two current collecting layers 24, 25, an electrochemical system 201, and a structural adhesive 26, and the electrochemical system 201 includes a separator 21, active material layers 22, 23 provided separately on either side of the separator 21, and an electrolyte system that transfers the reactive ions of the active material layers 22, 23. The material of separator 21 can be selected from insulating materials that do not have ion conductivity or materials that have ion conductivity. When the material of separator 21 is selected from insulating materials that do not have ion conductivity, it has micropores and ions pass through with the aid of an electrolyte. For example, it may be a porous layer formed from a polymeric or glass fiber material, or a structure having microvoids formed by lamination or sintering of ceramic particulate materials, or a mixture of the above. When the material of separator 21 is an ion-conductive material, for example a ceramic powder or sintered body of an oxide solid electrolyte, separator 21 can transmit ions without having (micro)cavities, and contact transmission occurs through the solid-solid interface of the oxide solid electrolyte itself. The microcavities may be in the form of through holes or ant nests (non-linear through holes).

[0014] Regarding the ceramic powder constituting separator 21, regardless of whether it is an insulating material having no ion conductivity in separator 21 or an oxide solid electrolyte having ion conductivity in separator 21, the initial particle size range of the ceramic powder may be micrometer size or nanometer size, or a mixture of the two with a relatively large difference, for example a mixture of micrometer size and nanometer size. When the ceramic powder is selected from insulating materials that do not have ionic conductivity, titanium dioxide (TiO 2 ), aluminum trioxide (Al 2 O 3 ), silicon dioxide (SiO 2 ) or alkylated ceramic particles. When the ceramic powder is selected from oxide solid electrolytes having ionic conductivity, a specific material is lithium lanthanum zirconium oxide (Li 7 La 3 Zr 2 O 12 , LLZO) or lithium aluminum titanium phosphate (LATP). In addition, the ceramic powder used in the separator 21 may be formed by mixing the insulating ceramic material and an oxide solid electrolyte. When the separator is formed by stacking ceramic powders, a polymer adhesive such as polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), polytetrafluoroethene (PTFE), acrylic acid glue, epoxy resin (Epoxy), polyethylene oxide (PEO), polyacrylonitrile (PAN) or polyimide (PI) may be further included.

[0015] The electrolyte system may be a liquid, colloidal, solid electrolyte, or a mixed electrolyte of any combination thereof. The active material layers 22 , 23 are separated by an intermediate separator 21 , and the active material layers 22 , 23 , the electrolyte system and the separator 21 further comprise an electrochemical system 201 . By desorption or insertion / alloying of the active material components of the active material layers 22, 23, it is possible to convert chemical energy into electrical energy for use (power supply) or to convert electrical energy into chemical energy for storage in the system (charging), and the generated electrons can be directly released to the outside through the current collecting layers 24, 25. The material of the current collecting layers 24, 25 is an electronic conductor material, typically copper and aluminum, but of course other metals or metal alloys such as nickel, tin, silver, gold, etc. may also be used. The material of the current collecting layers 24, 25 may be a conductive polymer material.

[0016] The current collecting layers 24, 25 of the battery cell 20 are sandwiched between the current collecting layers 24 and 25, and in combination with a structural adhesive 26 provided around the periphery of the current collecting layers 24, 25, form a sealing structure for the battery cell 20, isolating the electrochemical system 201 from the external environment. The structural adhesive 26 is a polymer material that can adhere to the surfaces of the current collecting layers 24, 25 and is durable against the electrolyte system. There are no particular limitations to the material, and a thermosetting resin is preferred. By way of example, the structural adhesive 26 may be made of an epoxy resin, polyethylene, polypropylene, polyurethane, thermoplastic polyimide, silicone resin, acrylic resin, silica gel, or a UV curable adhesive. The structural adhesive 26 is sandwiched between the peripheral portions of the two current collecting layers 24, 25, surrounding and sealing the electrochemical system 201 (the active material layers 22, 23 and the intermediate separator 21), while at least a portion of both end faces of the structural adhesive 26 are bonded to the current collecting layers 24, 25. The structural adhesive 26 and the two current collecting layers 24 , 25 seal the electrolyte system between the two current collecting layers 24 , 25 so that it does not leak or inter-flow with the electrolyte systems of the other battery cells 20 . Thus, the battery cell 20 is a complete, independent power supply module formed by direct sealing of the current collecting layers 24, 25 and the structural adhesive 26.

[0017] Please refer now to Figure 3A. The battery cells 20 described above are stacked in a single axial direction and in the same direction, and are connected in series with each other. As shown in the figure, all current collecting layers 24 of the same polarity are placed facing upward, and all current collecting layers 25 of the other polarity are stacked facing downward. Please also refer to Figures 1A, 3A and 3B. The sides of the current collecting layers 24, 25 may be coated with an insulating coating 30 to insulate the sides of the current collecting layers 24, 25 from the outside environment, and then further coated with a heat dissipating adhesive 40. As shown in FIG. 3B, an open groove 301 is formed between the current collecting layers 24, 25 coated with the insulating coating 30 and the structural adhesive 26. Since the heat dissipation adhesive 40 is coated on the outside of the insulating coating 30 and the structural adhesive 26, it also fills the inside of the groove 301 and simultaneously coats the insulating coating 30 and the structural adhesive 26, thereby further enhancing the heat dissipation effect. Thus, in battery 10, the internal battery cells 20 have direct face-to-face contact with the current collecting layers 24, 25 to form an internal series connection, and by employing this large-area face-to-face connection, the internal resistance value is accordingly reduced, and the heat energy generated during operation is also reduced. Regarding the exterior, the current collecting layer 24 of the uppermost battery cell 20 and the current collecting layer 25 of the lowermost battery cell 20 are used as output terminals, and the remaining peripheral portions are covered with a heat dissipation adhesive 40 . Therefore, it is possible to significantly reduce the contact thermal resistance between the battery 10 and the outside, and further to increase the heat dissipation efficiency of the battery 10.

[0018] In another embodiment, as shown in FIG. 1B, the insulating coating 30 can extend to the sides of the entire battery cell 20, i.e., in addition to covering the sides of the current collecting layers 24, 25, it also covers the sides of the structural adhesive 26, and then the insulating coating 30 is covered with the heat dissipation adhesive 40.

[0019] Also see Figure 4A. During the process of coating with the insulating coating 30, if the battery cells 20 are slightly misaligned, the insulating coating 30 also penetrates into the gap between the two adjacently stacked current collecting layers 24, 25, thereby sealing the gap and side edges that appear between the two stacked current collecting layers 24, 25, and preventing the heat dissipation adhesive 40 that is coated later from coming into contact with the current collecting layers 24, 25 through the gap. In another embodiment, as shown in FIG. 4B , the insulating coating 30 can extend to the sides of the entire battery cell 20, i.e., in addition to covering the sides of the current collecting layers 24, 25, it also covers the sides of the structural adhesive 26, and then the insulating coating 30 is covered with the heat dissipation adhesive 40.

[0020] The heat dissipation adhesive 40 is filled into the groove 301 by the coating method described above, and then coated with the insulating coating 30 and the structural adhesive 26. In addition, after coating with the insulating coating 30, the heat dissipation adhesive 40 can be formed on the outside of the insulating coating 30 and the structural adhesive 26 by immersion.

[0021] The insulating coating 30 is made of inorganic insulating particles, and the material is, for example, silicon carbide (SiC), aluminum oxide (Al 2 O 3 ), boron carbide (B 4 C), silicon nitride (Si 3 N 4 ) or titanium nitride (TiN). The heat dissipation adhesive 40 is selected from shapeless caulking materials having the ability to deform under a certain force, such as heat conductive silica gel, heat conductive gel or heat conductive insulating paste. It has a favorable thermal conductivity capability compared to the insulating coating 30 and furthermore powders with high thermal conductivity capability can be added, such as powders of metals such as zinc, aluminum, etc. or metal oxides.

[0022] In another embodiment, for example with respect to material particle size, the insulating coating 30 may be a coating composed of nanometer-sized inorganic insulating particles, and the thermal adhesive 40 is composed of particles having high thermal conductivity capabilities. The particle size of the particles with high thermal conductivity of the heat dissipation adhesive 40 is larger than the particle size of the inorganic insulating particles of the insulating coating 30, for example, the particle size of the particles with high thermal conductivity of the heat dissipation adhesive 40 is micrometer-sized, and contains at least two kinds of powders of different sizes, thereby achieving the effect of a relatively dense lamination. The micrometer-sized and relatively dense laminated heat dissipation adhesive 40 can provide suitable rigidity and enhance the resistance of the battery 10 to resist external forces. The inorganic insulating particles of the insulating coating 30 have a relatively small particle size, and can form a relatively dense and preferable insulating surface on the side surfaces of the current collecting layers 24, 25. Furthermore, it is possible to reduce the thickness required for the insulating coating 30, increasing the proportion of the heat dissipating adhesive 40, and further improving the heat dissipation performance of the battery 10.

[0023] For another embodiment, see FIG. The structural adhesive 26 can be designed to protrude from the sides of the current collecting layers 24, 25 to prevent short circuits caused by improper contact of burrs on the current collecting layers 24, 25 or improper contact of the current collecting layers due to bending or misalignment between the battery cells 20. Therefore, after the battery cells 20 are stacked, the insulating coating 30 similarly covers the side surfaces of the current collecting layers 24, 25 to provide insulation, as shown in FIGS. 6A and 6B. As shown in FIG. 6C, the structural adhesive 26 protrudes from the sides of the current collecting layers 24 and 25 and from the insulating coating 30, so that grooves 301 are formed between the structural adhesive 26. Next, the heat dissipation adhesive 40 is coated and filled into the groove 301, and at the same time, the heat dissipation adhesive 40 also covers the insulating coating 30 and the structural adhesive 26, further enhancing the heat dissipation effect. The heat dissipation adhesive 40 is filled into the groove 301 by the coating method described above, and in addition to being further coated with the insulating coating 30 and the structural adhesive 26, it is also possible to form the heat dissipation adhesive 40 by coating with the insulating coating 30 and then immersing it. In another embodiment, as shown in FIG. 6D , the insulating coating 30 can extend to the sides of the entire battery cell 20, i.e., in addition to covering the sides of the current collecting layers 24, 25, it also covers the sides of the structural adhesive 26, and then the insulating coating 30 is covered with the heat dissipation adhesive 40.

[0024] Also see FIG. 7A. During the process of coating with the insulating coating 30, if the battery cells 20 are slightly misaligned, the insulating coating 30 also penetrates into the gap between the two adjacent stacked current collecting layers 24, 25, thereby sealing the gap and side edges that appear between the two stacked current collecting layers 24, 25, and preventing the heat dissipation adhesive 40 that is coated later from coming into contact with the current collecting layers 24, 25 through the gap. In another embodiment, as shown in FIG. 7B, the insulating coating 30 can extend to the sides of the entire battery cell 20, i.e., in addition to covering the sides of the current collecting layers 24, 25, it also covers the sides of the structural adhesive 26, and then the insulating coating 30 is covered with the heat dissipation adhesive 40.

[0025] In order to further verify the heat dissipation performance of the present invention, a simulation measurement was carried out using a rectangular battery in which the battery 10 having the heat dissipation adhesive and structural adhesive on the side of the present invention was mounted in a housing 50. As shown in FIG. 8, the temperature difference between the side surface of the housing 50 and the side surface of the battery cell 20 is calculated and verified. Specifically, it can be calculated using the following formula: TIFF0003250421000002.tif11150

[0026] In the formula, ΔX is the distance between the two sampled points (m), q x / A is the heat flux (W / m 2 ), and K is the effective thermal conductivity (W / mk).

[0027] Please refer to FIG. 9 for the temperature difference curve diagram based on this computational simulation. It can be seen that with the passage of time of use, the temperature (difference) of the structure utilizing the present invention is obviously smaller than the temperature difference of the known structure. In other words, the temperature difference between the sides of the housing and battery cell of the present invention is smaller than the temperature difference between the sides of the housing and battery cell of known structures, and the thermal energy accumulated in the battery cell inside the housing can be conducted to the housing via the heat dissipation adhesive and dissipated, compared to known structures, so the heat dissipation efficiency of the battery cell can be improved.

[0028] To summarise the above, the present invention provides a battery with thermal adhesive and structural adhesive on the sides. The internal current collecting layers are directly laminated to reduce resistance, and external mechanisms such as tabs are eliminated to increase the overall energy density. At the same time, the sides of the current collecting layer are first coated with an insulating coating to insulate the sides of the current collecting layer and reduce the risk of short-circuiting the internal series connections. Next, the thermally conductive adhesive is filled into the grooves between the insulating coating and the structural adhesive, and then the insulating coating and the structural adhesive are coated. In addition, the heat dissipation adhesive contains particles with thermal conductivity, which can dissipate heat directly to the battery cell, greatly reducing the contact thermal resistance between the battery cell and the housing, and further achieving the purpose of improving the heat dissipation efficiency of the battery cell. The particles of the heat dissipation adhesive have at least two different particle sizes, which can achieve the effect of dense lamination and further improve the resistance to external force impact.

[0029] However, the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, any equivalent changes or modifications made based on the features and spirit described in the scope of the application of the present invention should be included within the scope of the utility model registration claim of the present invention. [Explanation of symbols]

[0030] 10 Battery 20 Battery Cells 201 Electrochemistry 21 Separator 22 Active material layer 23 Active material layer 24 Current collecting layer 25 Current collecting layer 26 Structural Adhesives 30 Insulation coating 301 Groove 40 Heat dissipating adhesive 50 Case

Claims

1. Two current collecting layers arranged parallel to each other; an electrochemical system provided between the two current collecting layers; a structural adhesive disposed between the two current collecting layers and surrounding the electrochemical system; and a plurality of battery cells stacked together in a single axial direction. Two insulating coatings respectively covering the side surfaces of the two current collecting layers; A battery having a heat dissipation adhesive and a structural adhesive on its side, the heat dissipation adhesive being provided around the side of the battery cell, covering the structural adhesive and the insulating coating, and including particles having thermal conductivity, the particles having at least two different particle sizes.

2. The battery having a heat dissipation adhesive and a structural adhesive on the side as described in claim 1, characterized in that the structural adhesive and the two current collecting layers are a sealing structure for the battery cell, and only charges move between the battery cells, no electrochemical reaction takes place, and the electrolyte system of the electrochemical system does not flow between each other.

3. The battery having a heat dissipation adhesive and a structural adhesive on the side as claimed in claim 1 , wherein the structural adhesive protrudes from the two current collecting layers.

4. 4. The battery having a heat dissipation adhesive and a structural adhesive on the side surface as described in claim 1 or 3, characterized in that the insulating coating further extends to the side surface of the structural adhesive.

5. The battery having a heat dissipation adhesive and a structural adhesive on the side surface according to claim 3 , wherein the structural adhesive further protrudes from the insulating coating.

6. The battery having a heat dissipation adhesive and a structural adhesive on the side as described in claim 5, characterized in that the heat dissipation adhesive is filled into a groove formed by the structural adhesive of the battery cell protruding from the current collecting layer.

7. 4. The battery having a heat dissipation adhesive and a structural adhesive on the side as described in claim 1 or 3, characterized in that when the battery cells are shifted relative to each other, the insulating coating penetrates into the gap between the two adjacently stacked current collecting layers and seals the gap and side edges exposed between the two current collecting layers.

8. The battery having a heat dissipation adhesive and a structural adhesive on its side surface as described in claim 7, characterized in that the insulating coating further extends to the side surface of the structural adhesive.

9. The battery having a heat dissipation adhesive and a structural adhesive on the side as described in claim 1, characterized in that the insulating coating contains inorganic insulating particles, and the particle size of the inorganic insulating particles is smaller than the particle size of the particles having thermal conductivity in the heat dissipation adhesive.

10. The battery having a heat dissipation adhesive and a structural adhesive on the side surface as claimed in claim 1 , wherein the heat dissipation adhesive comprises a powder of metal or metal oxide.

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