CN114142124A

CN114142124A - Lithium battery with multilayer film heat dissipation structure

Info

Publication number: CN114142124A
Application number: CN202111432701.9A
Authority: CN
Inventors: 刘国辉
Original assignee: Shenzhen Thanksun Technology Co ltd
Current assignee: Shenzhen Thanksun Technology Co ltd
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2022-03-04
Anticipated expiration: 2041-11-29
Also published as: CN114142124B

Abstract

The invention discloses a lithium battery with a multilayer film heat dissipation structure, which relates to the technical field of lithium batteries and comprises an insulating shell and an upper end cover positioned at the upper end of the insulating shell, wherein a plurality of layers of cathodes, a plurality of layers of anodes and a plurality of layers of diaphragms are arranged in an inner cavity of the insulating shell, and the cathodes, the anodes and the diaphragms are sequentially attached to a central shaft of the insulating shell from the inner side wall of the insulating shell; the diaphragm is formed by sequentially attaching a PP outer film, a PE film, a PP inner film, a heat-conducting coating and a heat-conducting film, wherein the heat-conducting coating is formed by coating heat-conducting silicone grease on the surface of the PP inner film, and the heat-conducting film is heat-conducting insulating glass fiber cloth. According to the invention, the heat-conducting coating is coated on the outer side of the PP inner membrane, and the heat-conducting film is attached to the outer side of the heat-conducting coating, so that the whole diaphragm has good heat-conducting property, the sealed cavity is formed in the heat exchange layer, the inner cavity of the sealed cavity is filled with water, and the service life of the diaphragm is prevented from being influenced by overhigh temperature by utilizing the characteristic of large specific heat capacity of water.

Description

Lithium battery with multilayer film heat dissipation structure

Technical Field

The invention relates to the technical field of lithium batteries, in particular to a lithium battery with a multilayer film heat dissipation structure.

Background

In recent years, the development of electric automobile technology and new energy power station energy storage technology is rapid, and the requirements of the technologies on the used batteries are higher and higher. Compared with other batteries, the lithium battery has better application prospect due to the advantages of high conversion efficiency, large energy density, environmental friendliness and the like. However, the characteristics of the lithium battery, such as the service life and the safety, are greatly affected by the temperature.

At present, the existing lithium battery can generate a large amount of heat in the using process, the heat is accumulated for a long time, the internal temperature of the lithium battery can be increased, the capacity attenuation of the battery is accelerated, the service life of the battery is shortened, and if the temperature continues to be increased to a certain degree, even safety accidents such as explosion and the like are caused. Therefore, it is necessary to invent a lithium battery having a multi-layered film heat dissipation structure to solve the above problems.

Disclosure of Invention

The present invention is directed to a lithium battery with a multi-layer heat dissipation structure, so as to solve the problems mentioned in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the lithium battery with the multilayer film heat dissipation structure comprises an insulating shell and an upper end cover positioned at the upper end of the insulating shell, wherein a plurality of layers of cathodes, a plurality of layers of anodes and a plurality of layers of diaphragms are arranged in an inner cavity of the insulating shell, and the cathodes, the anodes and the diaphragms are sequentially attached to a central shaft of the insulating shell from the inner side wall of the insulating shell;

the diaphragm is formed by sequentially attaching a PP outer film, a PE film, a PP inner film, a heat-conducting coating and a heat-conducting film, wherein the heat-conducting coating is formed by coating heat-conducting silicone grease on the surface of the PP inner film, and the heat-conducting film is heat-conducting insulating glass fiber cloth;

the upper end of the insulating shell is covered with an insulating heat conducting plate, the upper surface and the lower surface of the insulating heat conducting plate are respectively fixedly connected with the upper end cover and the insulating shell, the inner cavity of the upper end cover is provided with a heat exchange layer matched with the inner cavity, and the heat exchange layer is made of graphene materials;

the inner cavity of the heat exchange layer is annularly provided with a plurality of sealing cavities which are concentric, the inner cavities of the sealing cavities are filled with water, a communicating groove arranged in the heat exchange layer is arranged between every two adjacent sealing cavities, and the communicating groove is communicated with the inner cavities of every two adjacent sealing cavities.

Preferably, the outer side wall of the heat exchange layer is annularly provided with a groove, and the outer side wall of the upper end cover is provided with a matching groove matched with the groove.

Preferably, the middle part of the upper surface of the upper end cover is provided with a positive terminal, the middle part of the upper surface of the insulating heat-conducting plate is fixedly connected with a conductive column, and the upper end of the conductive column is fixed with the positive terminal and keeps electric connection.

Preferably, the upper surface of the insulating heat-conducting plate is fixedly connected with a plurality of conducting strips distributed in an annular array, and one end of each conducting strip is fixedly connected with the outer side wall of each conducting column.

Preferably, the upper end of the positive electrode is fixedly connected with a plurality of positive electrode conductive films distributed in an annular array, and the upper end of each positive electrode conductive film penetrates through the lower surface of the insulating heat-conducting plate and is fixedly connected with the corresponding conductive sheet.

Preferably, the lower end surface of the insulating shell is provided with a negative end, the lower end of the negative electrode is fixedly connected with a plurality of negative conductive films distributed in an annular array, and the negative conductive films are electrically connected with the negative end at the lower end of the insulating shell.

Preferably, a gap is formed between the upper end surface of the diaphragm and the lower surface of the insulating heat conduction plate, a heat conduction ring is arranged in the gap, and the heat conduction ring is made by filling heat conduction silicone grease in the gap.

Preferably, the inside wall fixedly connected with reinforcing frame of insulating casing, be provided with graphite alkene heat conduction membrane in the clearance of reinforcing frame, graphite alkene heat conduction membrane bonds at insulating casing's inside wall, and the medial surface of graphite alkene heat conduction membrane keeps flushing with the medial surface of reinforcing frame.

Preferably, a cavity is formed in the middle shaft of the inner cavity of the insulating shell, electrolyte is filled in the cavity, and the electrolyte comprises a solvent, a solute and an additive, wherein the solvent, the solute and the additive are respectively 30%, 50% and 10% in volume.

Preferably, the solvent is made of any one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl potassium carbonate and polycarbonate, the solute is a conventional lithium salt, namely lithium hexafluorophosphate, and the additives include a film forming additive, a high temperature additive, a low temperature additive rate type additive, an overcharge additive and a flame retardant additive.

The invention has the technical effects and advantages that:

1. according to the invention, the multilayer diaphragm is arranged, the heat-conducting coating is coated on the outer side of the PP inner film in the diaphragm, and the heat-conducting film is attached to the outer side of the heat-conducting coating, so that the whole diaphragm has good heat-conducting property;

2. according to the invention, the reinforcing frame is fixedly connected to the inner side wall of the insulating shell and consists of a plurality of strip-shaped plates which are mutually crossed, so that the structural strength of the insulating shell can be enhanced, and the device is prevented from being damaged under pressure;

3. according to the invention, the plurality of conducting strips distributed in an annular array are fixedly connected to the upper surface of the insulating heat conducting plate, the conducting strips are fixed and electrically connected with the conducting posts, the anode conducting film penetrates through the insulating heat conducting plate and is fixed and electrically connected with the conducting strips, the heat exchange layer is positioned in the inner cavity of the upper end cover and is matched with the inner cavity of the upper end cover, and the heat exchange layer has good conductivity, so that the heat exchange layer can perform heat transfer and simultaneously perform good electrical connection on the plurality of conducting strips, thereby enhancing the stability of electrical connection between the anode and the anode.

Drawings

Fig. 1 is a perspective view of the overall structure of the present invention.

Fig. 2 is a perspective view of the separator structure of the present invention.

FIG. 3 is an enlarged view of the structure at A in FIG. 1 according to the present invention.

Fig. 4 is an exploded view of the interior of the upper end cap structure of the present invention.

Fig. 5 is a perspective view of the insulating housing structure of the present invention.

In the figure: 1. an insulating housing; 2. an upper end cover; 3. a negative electrode; 4. a positive electrode; 5. a diaphragm; 51. a PP outer film; 52. a PE film; 53. PP inner film; 54. a thermally conductive coating; 55. a heat conductive film; 6. an insulating heat-conducting plate; 7. a heat exchange layer; 8. sealing the cavity; 9. a communicating groove; 10. a groove; 11. a mating groove; 12. a positive terminal; 13. a conductive post; 14. a conductive sheet; 15. a positive electrode conductive film; 16. a negative electrode conductive film; 17. a heat conducting ring; 18. a reinforcing frame.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a lithium battery with a multilayer film heat dissipation structure as shown in figures 1-5, which comprises an insulating shell 1 and an upper end cover 2 positioned at the upper end of the insulating shell 1, wherein a plurality of layers of cathodes 3, a plurality of layers of anodes 4 and a plurality of layers of diaphragms 5 are arranged in an inner cavity of the insulating shell 1, the cathodes 3, the anodes 4 and the diaphragms 5 are sequentially attached to a central shaft of the insulating shell 1 from the inner side wall of the insulating shell 1, the cathode 3 is made of graphite material and has high specific capacity and good charge-discharge reversibility, so that good size and mechanical stability are kept in a lithium intercalation process, the anode 4 is made of lithium iron phosphate LFP, lithium cobalt oxide LCO or lithium manganese oxide LMO, the lithium iron phosphate LFP, the lithium cobalt oxide LCO or the lithium manganese oxide LMO has stable electrochemical performance and a structure which is not easy to decompose, and has a higher oxidation-reduction potential and a higher specific capacity, so that the functions of energy storage and release are realized;

specifically, the separator 5 is formed by sequentially laminating a PP outer film 51, a PE film 52, a PP inner film 53, a heat conductive coating 54, and a heat conductive film 55, the PP outer film 51, i.e., a polypropylene film, a thermoplastic resin obtained by polymerizing propylene, the high frequency insulation function is excellent, because it hardly absorbs water, the insulation function is not affected by temperature, the dielectric coefficient is high, the voltage resistance and the arc resistance are good, the PE film 52, namely the PE protective film, is made of special polyethylene PE plastic as the base material, it has the advantages of good tolerance, large impact strength and good insulating property, the heat-conducting coating 54 is made by coating heat-conducting silicone grease on the surface of the PP inner film 53, the heat-conducting film 55 is heat-conducting insulating glass fiber cloth, the type number is XK-F60, the heat conductivity coefficient is 5.8W, and the material is formed by compounding ultra-high filling ceramic powder and 30um ultrathin glass fiber (http:// www.glpoly.com.cn/goods _ daorejueyuyanijiaokzhi 58. html);

secondly, an insulating heat conducting plate 6 covers the upper end of the insulating shell 1, the upper surface and the lower surface of the insulating heat conducting plate 6 are fixedly connected with the upper end cover 2 and the insulating shell 1 respectively, the insulating heat conducting plate 6 plays a role in sealing the inner cavity of the insulating shell 1, meanwhile, the insulating heat conducting plate 6 has insulating property, the upper end of the negative electrode 3 can be prevented from being electrically connected with the upper end of the positive electrode 4, a heat exchange layer 7 matched with the inner cavity of the upper end cover 2 is arranged in the inner cavity of the upper end cover 2, and the heat exchange layer 7 is made of graphene materials, so that the insulating heat conducting plate has extremely high electric conduction and heat conduction performance, and is light in weight and high in toughness;

furthermore, a plurality of sealing cavities 8 are annularly arranged in the inner cavity of the heat exchange layer 7, the sealing cavities 8 are concentric, the inner cavity of the sealing cavity 8 is filled with water, heat generated by the cathode 3 and the anode 4 is transferred to the inside of the heat exchange layer 7 through the insulating heat conduction plate 6, the heat exchange layer 7 transfers a part of heat to the upper end cover 2 and exchanges heat with the outside, the other part of heat is absorbed by water in the inner cavity of the sealed cavity 8, and water is a liquid having the largest specific heat capacity under normal regulation, even if water absorbs heat inside the heat exchange layer 7, its self also can not rapid heating up to can effectively avoid this device bulk temperature too high, be provided with the intercommunication groove 9 of seting up in heat exchange layer 7 inside between two adjacent sealed chambeies 8, the inner chamber of two adjacent sealed chambeies of intercommunication groove 9 intercommunication, the setting of intercommunication groove 9 is used for communicateing the inner chamber of a plurality of sealed chambeies 8.

And, the lateral wall ring at heat transfer layer 7 has seted up recess 10, and the lateral wall of upper end cover 2 is provided with the cooperation groove 11 with recess 10 looks adaptation, and the setting of recess 10 and cooperation groove 11 is used for increasing the area of contact between heat transfer layer 7 and the upper end cover 2 to improve heat exchange efficiency.

And, be provided with positive terminal 12 in the middle part of the upper surface of upper end cover 2, the upper surface middle part fixedly connected with of insulating heat-conducting plate 6 leads electrical pillar 13, and the upper end of leading electrical pillar 13 is fixed with positive terminal 12 and keeps electric connection, the upper surface fixedly connected with of insulating heat-conducting plate 6 is a plurality of conducting strips 14 that are annular array distribution, the one end of conducting strip 14 and the lateral wall fixed connection who leads electrical pillar 13, the upper end fixedly connected with of anodal 4 is a plurality of anodal conducting films 15 that are annular array distribution, the upper end of anodal conducting film 15 runs through the lower surface of insulating heat-conducting plate 6 and with conducting strip 14 fixed connection, therefore anodal 4 can keep electric connection with conducting strip 14 through anodal conducting film 15, and a plurality of conducting strips 14 all with leading electrical pillar 13 electric connection, therefore a plurality of anodal 4 of insulating housing 1 inner chamber all can keep electric connection with positive terminal 12.

Secondly, a negative end is arranged on the lower end face of the insulating shell 1, a plurality of negative conductive films 16 distributed in an annular array are fixedly connected to the lower end of the negative electrode 3, and the negative conductive films 16 are electrically connected with the negative end of the lower end of the insulating shell 1.

Further, a gap is formed between the upper end surface of the diaphragm 5 and the lower surface of the insulating heat-conducting plate 6, a heat-conducting ring 17 is arranged in the gap, the heat-conducting ring 17 is made of heat-conducting silicone grease filled in the gap, and the heat-conducting ring 17 is used for conducting heat and timely transferring heat inside the insulating shell 1 to the insulating heat-conducting plate 6.

And, inside wall fixedly connected with reinforcing frame 18 at insulating casing 1, reinforcing frame 18 comprises a plurality of intercrossing's bar shaped plate, a structural strength for strengthening insulating casing 1, be provided with graphite alkene heat conduction membrane in reinforcing frame 18's the clearance, graphite alkene heat conduction membrane bonds at insulating casing 1's inside wall, and graphite alkene heat conduction membrane's medial surface keeps flushing with reinforcing frame 18's medial surface, graphite alkene heat conduction membrane can be with insulating casing 1 inner chamber's partial heat transfer to insulating casing 1 on, thereby accelerate thermal giving off.

Meanwhile, a cavity is arranged at the center axis of the inner cavity of the insulating shell 1, electrolyte is filled in the cavity, the electrolyte comprises a solvent, a solute and an additive, the volume percentage of the solvent is respectively 30%, 50% and 10%, the solvent is made of any one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl potassium carbonate and polycarbonate, the solute is conventional lithium salt, namely lithium hexafluorophosphate, the additive comprises a film forming additive, a high-temperature additive, a low-temperature additive multiplying additive, an overcharge additive and a flame retardant additive, and the electrolyte is made of materials in the prior art.

The invention relates to a secondary battery, namely a rechargeable battery, which mainly works by the back-and-forth insertion and de-insertion of lithium ions between a positive electrode and a negative electrode, so as to realize the storage and release of energy; taking lithium cobaltate positive electrode and graphite negative electrode lithium ion battery as examples:

during charging, under the action of an external electric field, lithium elements in molecules of LiCoO2 serving as a positive electrode material are separated to form positively charged lithium ions Li⁺Moving from the positive electrode to the negative electrode, and carrying out chemical reaction with carbon atoms of the negative electrode to generate LiC6, so that the LiC6 is stably embedded into the laminated graphite negative electrode;

on discharge, contrary to charging, the internal electric field is reversed, Li⁺The lithium cobaltate is extracted from the negative electrode, returns to the positive electrode along the direction of the electric field and becomes lithium cobaltate molecules LiCoO2 again;

in the charge-discharge process, insulating casing 1 is inside can continuously produce the heat, multilayer heat conduction coating 54 and multilayer heat conduction film 55 set up be convenient for with the heat all stand everywhere inside insulating casing 1, with avoid in insulating casing 1 local area high temperature and lead to impairedly, and heat conduction ring 17 can transmit the heat on heat transfer layer 7 through insulating heat-conducting plate 6, the heat on heat transfer layer 7 surface carries out the heat exchange through upper end cover 2 and external world this moment, the inside heat of heat transfer layer 7 can be absorbed by the water of sealed chamber 8 inner chamber, thereby reach effective radiating effect, secondly, the graphite alkene heat conduction membrane of coating on insulating casing 1 inner wall can also carry out the heat exchange through insulating casing 1 with the external world with partial heat, in order to accelerate thermal giving off.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims

1. Lithium cell with multilayer film heat radiation structure, including insulating casing (1) and upper end cover (2) that are located insulating casing (1) upper end, its characterized in that: the inner cavity of the insulating shell (1) is provided with a plurality of layers of cathodes (3), a plurality of layers of anodes (4) and a plurality of layers of diaphragms (5), and the cathodes (3), the anodes (4) and the diaphragms (5) are sequentially attached to the central axis of the insulating shell (1) from the inner side wall of the insulating shell (1);

the diaphragm (5) is formed by sequentially attaching a PP outer membrane (51), a PE membrane (52), a PP inner membrane (53), a heat-conducting coating (54) and a heat-conducting film (55), wherein the heat-conducting coating (54) is formed by coating heat-conducting silicone grease on the surface of the PP inner membrane (53), and the heat-conducting film (55) is heat-conducting insulating glass fiber cloth;

an insulating heat conducting plate (6) covers the upper end of the insulating shell (1), the upper surface and the lower surface of the insulating heat conducting plate (6) are fixedly connected with the upper end cover (2) and the insulating shell (1) respectively, a heat exchange layer (7) matched with the inner cavity of the upper end cover (2) is arranged in the inner cavity of the upper end cover, and the heat exchange layer (7) is made of graphene materials;

a plurality of sealed cavities (8) are annularly formed in the inner cavity of the heat exchange layer (7), the sealed cavities (8) are concentric, water is filled in the inner cavity of each sealed cavity (8), a communicating groove (9) formed in the inner part of the heat exchange layer (7) is formed between every two adjacent sealed cavities (8), and the communicating groove (9) is communicated with the inner cavities of every two adjacent sealed cavities (8).

2. The lithium battery with a multilayer film heat dissipation structure of claim 1, wherein: the outer side wall of the heat exchange layer (7) is annularly provided with a groove (10), and the outer side wall of the upper end cover (2) is provided with a matching groove (11) matched with the groove (10).

3. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 2, wherein: the upper surface middle part of upper end cover (2) is provided with positive terminal (12), the upper surface middle part fixedly connected with of insulating heat-conducting plate (6) leads electrical pillar (13), and the upper end that leads electrical pillar (13) is fixed and keeps electric connection with positive terminal (12).

4. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 3, wherein: the upper surface of the insulating heat-conducting plate (6) is fixedly connected with a plurality of conducting plates (14) distributed in an annular array, and one end of each conducting plate (14) is fixedly connected with the outer side wall of each conducting column (13).

5. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 4, wherein: the upper end of the positive electrode (4) is fixedly connected with a plurality of positive electrode conductive films (15) distributed in an annular array, and the upper end of each positive electrode conductive film (15) penetrates through the lower surface of the insulating heat-conducting plate (6) and is fixedly connected with the conducting plate (14).

6. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 5, wherein: the lower terminal surface of insulating casing (1) is provided with the negative pole end, the lower extreme fixedly connected with of negative pole (3) is a plurality of negative pole conducting films (16) that are the annular array and distribute, and negative pole conducting film (16) and the negative pole end electric connection of insulating casing (1) lower extreme.

7. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 6, wherein: a gap is arranged between the upper end face of the diaphragm (5) and the lower surface of the insulating heat conducting plate (6), a heat conducting ring (17) is arranged in the gap, and the heat conducting ring (17) is made by filling heat conducting silicone grease in the gap.

8. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 7, wherein: the utility model discloses a graphene heat-conducting film, including insulating casing (1), be provided with graphite alkene heat-conducting film in the clearance of strengthening frame (18), the inside wall fixedly connected with strengthening frame (18) of insulating casing (1), graphite alkene heat-conducting film bonds at the inside wall of insulating casing (1), and the medial surface of graphite alkene heat-conducting film keeps flushing with the medial surface of strengthening frame (18).

9. The lithium battery with a multilayer film heat dissipation structure as claimed in claim 8, wherein: a cavity is formed in the middle shaft of the inner cavity of the insulating shell (1), electrolyte is filled in the cavity, and the electrolyte comprises a solvent, a solute and an additive, wherein the solvent, the solute and the additive are respectively 30%, 50% and 10% in volume.

10. The lithium battery with a multilayer film heat dissipation structure of claim 9, wherein: the solvent is made of any one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, potassium carbonate ethyl ester and polycarbonate, the solute is conventional lithium salt, namely lithium hexafluorophosphate, and the additives comprise a film forming additive, a high-temperature additive, a low-temperature additive multiplying factor type additive, an overcharge additive and a flame retardant additive.