Resin Composition

Abstract

The present application relates to an adhesive composition capable of fixing a battery cell in a battery module and a battery pack. According to one example of the present application, there is provided a two-component urethane-based adhesive composition which has excellent storage stability and processability and is capable of providing physical properties required in related uses in a short time.

Claims

1. A urethane-based composition comprising a main composition part comprising an ester-based polyol resin; a curing agent composition part comprising a polyisocyanate; a filler; and an anionic dispersant comprising a phosphoric acid ester, wherein the anionic dispersant is contained in an amount of less than 20 parts by weight relative to 100 parts by weight of the sum of the ester-based polyol resin and the polyisocyanate.

2. The urethane-based composition according to claim 1, wherein the filler and the anionic dispersant are included in the main composition part or the curing agent composition part.

3. The urethane-based composition according to claim 2, wherein the filler is contained in an amount of 50 to 2,000 parts by weight relative to 100 parts by weight of the sum of the ester-based polyol resin and polyisocyanate contents.

4. The urethane-based composition according to claim 2, wherein the curing agent composition part comprises less than 20 parts by weight of the anionic dispersant relative to 100 parts by weight of the polyisocyanate.

5. The urethane-based composition according to claim 2, wherein the main composition part comprises less than 20 parts by weight of the anionic dispersant relative to 100 parts by weight of the ester-based polyol resin.

6. The urethane-based composition according to claim 4, wherein the anionic dispersant is contained in an amount of 0.01 to 5 parts by weight relative to 100 parts by weight of the filler.

7. The urethane-based composition according to claim 2, wherein the main composition part or the curing agent composition part has an initial viscosity (V.sub.1) of 1,000,000 cP or less as measured at room temperature within 24 hours after mixing components of main composition part or the curing agent composition part, wherein when the V.sub.1 is measured in a shear rate range of 0.01 to 10.0/s using a rheological property measuring device (ARES), it is a viscosity value measured at a point of 2.5/s.

8. The urethane-based composition according to claim 7, wherein the main composition part or the curing agent composition part satisfies the following relational expression 1 after at least 2 months:
V.sub.2/V.sub.12[Relational Expression 1] wherein, V.sub.1 is the initial viscosity of the main composition part or the curing agent composition part and V.sub.2 is a viscosity measured after mixing the components and after a predetermined time exceeding 24 hours, wherein when the V.sub.2 is measured in a shear rate range of 0.01 to 10.0/s using a rheological property measuring device (ARES), it is a viscosity value measured at a point of 2.5/s.

9. The urethane-based resin composition according to claim 1, wherein the filler has a moisture content of 1,000 ppm or less.

10. The urethane-based composition according to claim 1, wherein the ester-based polyol resin is an amorphous polyol, in which a crystallization temperature (Tc) and a melting temperature (Tm) are not observed in a DSC (differential scanning calorimetry) analysis, or has a melting temperature (Tm) of less than 15 C.

11. The urethane-based composition according to claim 1, wherein each of the ester-based polyol resin and the polyisocyanate has a viscosity of less than 10,000 cP.

12. The urethane-based composition according to claim 1, wherein a mixture of the ester-based polyol resin and polyisocyanate has a glass transition temperature (Tg) of less than 0 C. after curing.

13. The urethane-based composition according to claim 1, wherein the ester-based polyol resin is represented by the following formula 2 or 3: ##STR00003## wherein, X is a carboxylic acid-derived unit, Y is a polyol-derived unit, n is a number within a range of 2 to 10, and m is a number within a range of 1 to 10.

14. The urethane-based composition according to claim 13, wherein the carboxylic acid-derived unit X is one or more units selected from the group consisting of a phthalic acid unit, an isophthalic acid unit, a terephthalic acid unit, a trimellitic acid unit, a tetrahydrophthalic acid unit, a hexahydrophthalic acid unit, a tetrachlorophthalic acid unit, an oxalic acid unit, an adipic acid unit, an azelaic acid unit, a sebacic acid unit, a succinic acid unit, a malic acid unit, a glutaric acid unit, a malonic acid unit, a pimelic acid unit, a suberic acid unit, a 2,2-dimethylsuccinic acid unit, a 3,3-dimethylglutaric acid unit, a 2,2-dimethylglutaric acid unit, a maleic acid unit, a fumaric acid unit, an itaconic acid unit and a fatty acid unit.

15. The urethane-based composition according to claim 13, wherein the polyol-derived unit Y is any one or two or more units selected from the group consisting of an ethylene glycol unit, a propylene glycol unit, a 1,2-butylene glycol unit, a 2,3-butylene glycol unit, a 1,3-propanediol unit, a 1,3-butanediol unit, a 1,4-butanediol unit, a 1,6-hexanediol unit, a neopentyl glycol unit, a 1,2-ethylhexyldiol unit, a 1,5-pentanediol unit, a 1,9-nonanediol unit, a 1,10-decanediol unit, a 1,3-cyclohexanedimethanol unit, a 1,4-cyclohexanedimethanol unit, a glycerin unit and a trimethylolpropane unit.

16. The urethane-based composition according to claim 1, wherein the polyisocyanate is a non-aromatic polyisocyanate.

17. The urethane-based composition according to claim 1, wherein the filler comprises alumina, AlN (aluminum nitride), BN (boron nitride), silicon nitride, SiC, or BeO.

18. A battery module comprising a module case having a top plate, a bottom plate and sidewalls, wherein an inner space is formed by the top plate, the bottom plate, and the sidewalls; a plurality of battery cells existing in the inner space of the module case; and a resin layer formed by curing the urethane-based composition according to claim 1 and in contact with the plurality of battery cells.

19. A battery pack comprising one or more battery modules according to claim 18.

20. An automobile comprising the battery module according to claim 18.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0122] FIG. 1 shows an example of determining an amorphous characteristic or a sufficiently low crystallizability of an ester-based polyol according to one example of the present application.

[0123] FIG. 2 shows an exemplary module case, which can be applied in the present application.

[0124] FIG. 3 schematically shows a form in which battery cells are housed in a module case.

[0125] FIG. 4 schematically shows an exemplary bottom plate where injection holes and observation holes are formed.

[0126] FIGS. 5 and 6 schematically show an exemplary battery pouch which can be used as a battery cell.

[0127] FIGS. 7 and 8 schematically show the structure of an exemplary battery module.

[0128] The reference numerals and symbols related to the drawings are as follows. [0129] 10: module case [0130] 10a: bottom plate [0131] 10b: sidewall [0132] 10c: top plate [0133] 10d: guiding portion [0134] 20: battery cell [0135] 30: resin layer [0136] 50a: injection hole [0137] 50b: observation hole [0138] 40: insulating layer [0139] 100: pouch type cell [0140] 110: electrode assembly [0141] 120: exterior material [0142] 121: upper pouch [0143] 122: lower pouch [0144] S: sealing portion

BEST MODE

[0145] Hereinafter, the battery module of the present application will be described with reference to examples and comparative examples, but the scope of the present application is not limited by the following range.

[0146] Evaluation Methods

[0147] 1. Dispersibility

[0148] The initial viscosity (V.sub.1) of each isocyanate-containing curing agent composition part prepared in Examples and Comparative Examples was measured. Specifically, it was confirmed that the temperature dropped to room temperature (about 25 C.) within 24 hours after mixing the isocyanate, the filler and the dispersant, and the viscosity based on a shear rate of 2.5/s at room temperature was measured using a rheometer (parallel type rheometer). The evaluation criteria are as follows. The higher the viscosity, it means that the dispersing effect depending on the addition of the dispersant is not sufficient.

[0149] O: viscosity of 500,000 cP or less

[0150] : more than 500,000 to 1,000,000 cP or less

[0151] X: more than 1,000,000 cP

[0152] 2. Storage Stability

[0153] It was measured for each isocyanate-containing curing agent composition part prepared in Examples and Comparative Examples. Specifically, the time taken until the viscosity (V.sub.2) had more than doubled from the initial viscosity (V.sub.1) measured within 24 hours after mixing the isocyanate with the filler and the dispersant was confirmed. The evaluation criteria are as follows. The shorter the time taken to reach the viscosity (V.sub.2) having more than doubled, it means that the storage stability is poorer with respect to the reaction of the isocyanate with the dispersant.

[0154] O: 2 months or more

[0155] : 1 month or more to less than 2 months

[0156] X: less than 1 month

[0157] 3. Curing Rate

[0158] The main composition parts and the curing agent composition parts prepared in Examples and Comparative Examples, and the catalyst were mixed and it was evaluated according to the completion time of curing. The completion of curing may mean that when the curing reaction occurs at room temperature and 30 to 70% relative humidity for 24 hours, the conversion rate based on the NCO peak as confirmed by a TF-IR analysis is 80% or more. The shorter the time required for the curing completion, it means that the relevant composition is injected into the module and then fast cured, whereby the desired properties can be secured in a short time.

[0159] O: within 2 days

[0160] : within one week

[0161] X: after one week

EXAMPLES AND COMPARATIVE EXAMPLES

Example 1

[0162] Main Composition Part:

[0163] A composition comprising, as the caprolactone-based polyol represented by Formula 2 above, a polyol having a number of repeating units (m in Formula 2) of about 1 to 3 or so and containing 1,4-butanediol as the polyol-derived unit (Y in Formula 2) was used. In addition, an alumina filler and a phosphoric acid-based anionic dispersant were mixed in the amounts shown in Table 1 below. The used amount of polyol is 100 g.

[0164] Curing Agent Composition Part:

[0165] A composition comprising polyisocyanate (HDI, hexamethylene diisocyanate) was used. In addition, an alumina filler and a phosphoric acid-based anionic dispersant were mixed in the amounts shown in Table 1 below. The used amount of isocyanate is 100 g.

[0166] In addition, the constitution of the main composition part and the constitution of the curing agent composition part were mixed together with 0.1 wt % of DBTDL.

Example 2 and Comparative Examples 1 to 7

[0167] A two-component urethane-based composition was prepared in the same manner, except for the difference described in Table 1 below.

TABLE-US-00001 TABLE 1 Curing Main agent composition composition Dispersant part part *Func- Disper- Disper- tional Filler sant Filler sant Type group (g) (g) (g) (g) Example 1 Anionic P 500 5 500 5 2 Anionic P 1000 15 1000 15 Compar- 1 Anionic C 1000 15 1000 15 ative 2 Anionic S 1000 15 1000 15 Example 3 Cationic Amine 1000 15 1000 15 4 Neutralized 1000 15 1000 15 5 Non-ionic 1000 15 1000 15 6 Anionic P 1000 20 1000 20 7 Anionic P 1000 25 1000 15 *Functional group P: phosphoric acid-derived functional group C: carboxylic acid-derived functional group S: sulfonic acid-derived functional group Amine: amine-derived functional group Note: Dibutyltin dilaurate (DBTDL) was used in a predetermined amount as a catalyst

[0168] The physical properties of the prepared examples and comparative examples were measured as described below. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Curing agent composition part Curing rate Isocyanate of the entire Dispersability storage stability composition Example 1 2 Comparative 1 X Example 2 X 3 X 4 X 5 X 6 X X 7 X

[0169] As shown in Tables 1 and 2, in the case of Comparative Examples 1 to 5, which do not have the constitution of the present invention, it can be seen that dispersibility is poor. In the case of these comparative examples, since the viscosity was excessively high, sufficient processability at the time of being actually injected into the battery module could not be secured, so that the experiment on the storage stability or the curing rate did not proceed. In addition, in the case of Comparative Examples 6 and 7, due to the use of an excess of dispersant, it can be confirmed that the storage stability of the isocyanate or the curing rate of the entire composition has been lowered as compared to Examples. In particular, it is considered that the stability of the isocyanate is related to the content of the dispersant contained in the curing agent and the curing rate is related to the content of the entire dispersant contained in the main agent and the curing agent, where referring to Comparative Example 7, it can be confirmed that the storage stability of the isocyanate is not bad, but the curing rate is not good.