Battery case, battery and method for producing battery case
By using cathode electrophoretic immersion paint of flame retardant coating on the metal plate of the battery case for coating and firing, the problem of easy ignition of traditional battery case at high temperature is solved, and a high flame retardant and long-life battery case is achieved This significantly improves user security.
Patent Information
- Application Number
- CN202380036776.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-14
- Filing Date
- 2023-08-25
- Publication Date
- 2024-12-13
AI Technical Summary
The traditional battery case is easily ignited at high temperatures due to the organic-based cathode electrophoretic dip paint used, which leads to battery fire, showing high ignitionability and combustibility, and poses safety risks.
The metal plate is coated with cathode electrophoretic paint containing flame retardant coating and fixed by baking to form a battery case with high flame retardant properties, ensuring high flame retardant effect at high temperatures and to all metals if necessary The surface of the plate is coated to prevent fire from spreading.
It realizes the high flame retardancy and long service life of the battery case, significantly reduces the combustibility, improves user safety, and especially shows good corrosion and flame-proof effects in high temperature environments.
Smart Images
Figure CN119137792A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a battery housing which is difficult to ignite and a battery with reduced flammability. In addition, the present invention also relates to a method for producing a battery housing which is difficult to ignite. Background Art
[0002] Traditionally, battery housings are coated with cathodic electrophoretic dip lacquer (CTL) for corrosion protection reasons. This coating has organic groups and is baked onto the surface to be protected at approximately 180°C. Currently used batteries, especially for electric vehicles, can cause self-accelerating fires inside the battery. In such a fire, the temperature of the battery rises greatly. Due to the organic groups in the CTL, the heat generated here can cause the battery housing to ignite. Therefore, batteries and battery housings currently on the market have a high ignitability and a high combustibility. Summary of the invention
[0003] The object of the present invention is to provide a battery housing and a battery with reduced flammability. In addition, the object of the present invention is to provide a method for producing a battery housing, by which a battery housing which is flame-retardant and therefore safe to use can be produced.
[0004] These objects are achieved by the features of the independent claims. The dependent claims have advantageous developments as their subject matter.
[0005] The object is therefore achieved by a battery housing, which comprises at least one metal plate. A battery housing in the sense of the invention is a housing which is designed to accommodate a plurality of battery cells. The battery cells are not restricted in detail, but in particular include rechargeable battery cells, such as are used in particular in electric vehicles.
[0006] The battery housing is not limited in shape and size, but includes at least one metal plate. Advantageously, the battery housing can be constructed in the form of a container into which a plurality of battery cells can be introduced, and for this purpose can also include two or more metal plates. The battery housing is provided for accommodating a plurality of battery cells and protecting the battery cells from mechanical effects. The battery housing is also protected from corrosion, namely by the surface of the at least one metal plate being coated with a cathodic electrophoretic dip lacquer.
[0007] As the metal plate, for example, a steel plate can be used.
[0008] According to the invention, a cathodic electrophoretic dip lacquer is understood to be a lacquer which is applied to a metal surface as conventionally by cathodic dipping and subsequently fired, so that all volatile components evaporate and the lacquer is fired into the surface of the metal sheet. Any chemical reaction of the components of the cathodic electrophoretic dip lacquer used for dipping is completed by the firing process, and the cathodic electrophoretic dip lacquer obtained from the cathodic electrophoretic dip lacquer after firing is characterized by very good corrosion-inhibiting or corrosion-reducing properties, which protect the metal sheets of the battery housing and lead to a long service life of the battery housing. In these properties and composition, the cathodic electrophoretic dip lacquer applied according to the invention hardly differs from conventional cathodic electrophoretic dip lacquer.
[0009] According to the invention, the cathodic electrophoretic coating comprises at least one flame retardant coating. Flame retardant coatings are known in the prior art and include halogenated coatings and halogen-free coatings. Halogen-free coatings are particularly preferred for environmental reasons. Here, one or more flame retardant coatings can be used in combination according to the invention. The flame retardant coatings used according to the invention are characterized by good temperature stability at the processing temperature of the coating, but exhibit a high flame retardant effect at temperatures above about 700° C. and in particular at 800° C. to 1000° C.
[0010] Advantageously, the flame retardant coating material is already incorporated into the cathodic electrophoretic dip varnish for coating the metal sheets by dip varnishing and thus becomes a permanent component of the resulting dip varnish after application and firing, so that the metal sheets coated with the dip varnish are characterized by high flame retardant properties, whereby the battery housing is very flame resistant. If a plurality of metal sheets are present on the battery housing, the flame retardant effect can be improved by coating all metal sheets, in particular not only the inner surface but also the outer surface, with the cathodic electrophoretic dip varnish having the flame retardant coating material.
[0011] According to an advantageous embodiment, the outer surface of the metal sheet is coated with a cathodic electrophoretic dip lacquer. This effectively prevents the spread of a possible fire and thus improves the user safety of the battery housing.
[0012] It is further advantageous if the cathodic electrophoretic dip varnish contains an additional coating material having a maximum content of 1% by mass and in particular 0.1% by mass, relative to the total mass of the cathodic electrophoretic dip varnish. This means that, apart from the flame-retardant coating material, preferably no additional coating material is added to the cathodic electrophoretic dip varnish for coating the metal sheet and forming the cathodic electrophoretic dip varnish after application and firing.
[0013] Particularly preferably, the flame retardant coating material is the only coating material in the cathodic electrophoretic dip coating. Therefore, the amount of coating materials other than the flame retardant coating material or materials in the cathodic electrophoretic dip coating material is substantially 0% by mass.
[0014] In order to prolong and better control the flame retardant effect, the flame retardant coating is preferably present in an encapsulated form. Encapsulation can also improve the anti-corrosion effect of the cathodic electrophoretic dip coating.
[0015] The flame retardant coating that can be used exemplarily is selected from phosphinate, ammonium polyphosphate, zinc borate, triaryl phosphate, melamine phosphate, antimony trioxide, aluminum hydroxide, magnesium hydroxide and trialkyl phosphate. A particularly good flame retardant coating with very good environmental friendliness is aluminum diethylphosphinate. Therefore, as the flame retardant coating in the battery housing described herein, it is preferred to use the coating comprising aluminum diethylphosphinate.
[0016] The cathodic electrophoretic dip lacquer for the battery housing can be constructed in the same way as conventional cathodic dip lacquers and preferably comprises at least one crosslinking resin in order to produce a permanent corrosion protection and also a permanent flame retardant effect. The resin is not particularly restricted and can be based on acrylates, polyurethanes, epoxides, etc. Further additives can also be contained, such as fillers or additives, such as, in particular, carbon black, aluminum silicate and / or magnesium silicate, aluminum and / or pH regulators, catalysts, wetting agents, etc.
[0017] Furthermore, the invention also describes a battery comprising a battery housing constructed as described above. Furthermore, the battery also contains one or more battery cells, which are in particular rechargeable. The battery is designed in particular for use in electric vehicles (E-Auto). By using the battery housing according to the invention for the battery according to the invention, a battery with high flame retardancy and therefore very good user safety is also provided.
[0018] Furthermore, a method for producing a battery housing is described according to the invention. The battery housing comprises at least one metal sheet. Here, the method comprises the step of coating at least one surface of the metal sheet by means of a cathodic electrophoretic dip lacquer, wherein the cathodic electrophoretic dip lacquer comprises at least one flame retardant coating. Further additives, such as, for example, fillers, such as carbon black, aluminum silicate and / or magnesium silicate, pH regulators, resins or resin precursors, crosslinking agents, catalysts; wetting agents, dispersing additives, solvents, etc. may also be contained in the cathodic electrophoretic dip lacquer. Furthermore, the method comprises the step of baking the cathodic electrophoretic dip lacquer to stabilize the dip lacquer on the metal surface. Preferably, all metal sheets of the battery housing are coated with the cathodic electrophoretic dip lacquer. This can be done on the inside of the metal sheet (towards the inside of the battery housing) and / or on the outside of the metal sheet (towards the surroundings of the battery housing). Baking is carried out at a temperature suitable for stabilizing the paint on the metal surface. In the case of a chemical crosslinking reaction, the temperature for baking can be in particular 150° C. to 400° C. and in particular 170° C. to 250° C.
[0019] The flame retardant coating used according to the invention is characterized by good temperature stability at the processing temperature of the dip coating, that is, also at the baking temperature of up to 400° C. However, the flame retardant coating exhibits a high flame retardant effect at temperatures above about 700° C. and in particular in the temperature range of 800° C. to 1000° C., in which combustion usually leads to battery fires.
[0020] The advantages, advantageous effects and embodiments described for the battery housing according to the invention also apply to the method according to the invention for producing a battery housing. Furthermore, the method according to the invention can be used to produce a battery housing according to the invention.
[0021] According to another advantageous development, the total content of the flame retardant coating material is 10% to 20% (mass) and in particular 12% to 19% (mass) with respect to the total mass of the cathodic electrophoretic dip lacquer. It is further preferred that the flame retardant coating material is the only coating material in the cathodic electrophoretic dip lacquer. This means that, in addition to one or more flame retardant coating materials, no other coating materials are added to the cathodic electrophoretic dip lacquer. The cathodic electrophoretic dip lacquer can thus be constructed like a conventional cathodic electrophoretic dip lacquer, wherein, however, the coating material commonly used is replaced by one or more flame retardant coating materials.
[0022] In order to further reduce the flammability, all outer surfaces of all metal sheets of the cell housing are advantageously coated with a cathodic electrophoretic dip lacquer. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Further details, features and advantages of the invention are apparent from the following description and the accompanying drawings.
[0024] Figure 1 A schematic diagram of a battery housing according to an advantageous embodiment is shown. DETAILED DESCRIPTION
[0025] The invention is explained with reference to an exemplary embodiment. Figure 1 Only the components that are important to the present invention are shown in the figure. For the sake of clarity, all other components are omitted.
[0026] Specifically, Figure 1 A battery housing 1 is shown, which is designed in a rectangular shape and comprises six metal plates 2. In order to be able to insert a plurality of battery cells into the battery housing 1, the metal plates 2 can be at least partially detachably connected to one another. Furthermore, the battery housing 1 can comprise an electrical connection region 3 for electrically connecting the battery cells to an electrical load.
[0027] The outer surface of the metal plate 2 is coated with a cathodic electrophoretic dip varnish 4. The dip varnish is obtained by cathodic dipping of the cathodic electrophoretic dip varnish after firing the cathodic electrophoretic dip varnish and contains a flame retardant coating 5. The flame retardant coating 5 comprises, in particular, aluminum diethylphosphinate.
[0028] The battery housing 1 is characterized not only by high corrosion protection but also by a high flame retardant effect by the flame retardant coating 5. The battery housing 1 thus provides high flame resistance and is characterized by high user safety.
[0029] In addition to the above written description of the invention, reference is hereby made expressly to the disclosures supplementary thereto. Figure 1 A diagrammatic illustration of the present invention is provided in FIG.
[0030] Reference numerals list
[0031] 1Battery housing
[0032] 2 Metal Plates
[0033] 3Electrical connection area
[0034] 4. Cathodic electrophoretic immersion coating
[0035] 5. Flame retardant coating
Claims
1. A battery housing (1), comprising at least one metal plate (2), wherein: At least one surface of the metal plate (2) is coated with a cathodic electrophoretic dip varnish (4), wherein the cathodic electrophoretic dip varnish (4) comprises at least one flame retardant coating (5).
2. The battery housing (1) according to claim 1, wherein: The outer surface of the metal plate (2) is coated with the cathodic electrophoretic dip varnish (4).
3. The battery housing (1) according to claim 1 or 2, wherein: The cathodic electrophoretic dip varnish (4) contains a further coating material having a maximum content of 1% by mass, in particular 0.1% by mass, relative to the total mass of the cathodic electrophoretic dip varnish (4).
4. The battery housing (1) according to any one of the preceding claims, wherein: The flame retardant coating (5) exists in an encapsulated form.
5. The battery housing (1) according to any one of the preceding claims, wherein: The flame retardant coating (5) comprises aluminum diethylphosphinate.
6. The battery housing (1) according to any one of the preceding claims, wherein: The cathodic electrophoretic dip varnish (4) comprises at least one cross-linking resin.
7. A battery comprising a battery housing (1) according to any one of the preceding claims.
8. A method for producing a battery housing (1), the battery housing comprising at least one metal plate (2), wherein: At least one surface of the metal sheet (2) is coated by cathodic electrophoretic dip lacquer and then the at least one surface is fired, wherein the cathodic electrophoretic dip lacquer comprises at least one flame retardant coating material (5).
9. The method according to claim 8, wherein: The total content of the flame retardant coating (5) is 10% to 20% (mass), in particular 12% to 19% (mass), relative to the total mass of the cathodic electrophoretic dip coating, and the flame retardant coating (5) is the only coating in the cathodic electrophoretic dip coating.
10. The method according to claim 8 or 9, wherein: All outer surfaces of all metal plates (2) of the battery housing (1) are coated by cathodic electrophoretic dip coating.