JP3408676B2 - Organic electrolyte battery storage case - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery case containing at least one organic electrolyte battery. 2. Description of the Related Art As a typical example of an organic electrolyte battery, there is a lithium-ion battery that is currently receiving attention. Lithium-ion batteries use a specific carbon such as coke, graphite, and polyacene for the negative electrode, light metal oxides such as lithium cobaltate, lithium nickelate, and lithium manganate for the positive electrode, and an electrolyte composed of an organic solvent and a solute. It is a secondary battery. Lithium ion batteries have a high energy density not found in other batteries, and are characterized by low self-discharge. Recently, in order to satisfy the conflicting demands of miniaturization and weight reduction and extension of operation time of equipment, at least one lithium ion battery is housed in a case, and a battery pack connected in series is used for a radio, a telephone, a video camera and the like. It is widely applied to backup power supplies for portable devices, personal computers, word processors, etc. Recently, with the advancement of battery technology,
In some cases, the battery is designed so that the maximum temperature at which the battery is used is set to about 100 ° C., and the battery housing case itself is required to have high-temperature heat resistance. [0004] Conventionally, as a material for a battery storage case of a battery pack, for example, a rubber-modified styrene-acrylonitrile copolymer (hereinafter abbreviated as ABS), polycarbonate (hereinafter abbreviated as PC), PC / ABS and the like have been used.
ABS is the heat distortion temperature (HDT: ASTM-D648)
Is about 90 ° C., and there is an anxiety in heat resistance against the maximum temperature at the time of use of the battery set in the battery design. In the case of PC and PC / ABS, although the heat distortion temperature is 100 ° C. or higher, there is a problem in the resistance to organic electrolyte, so that when the organic electrolyte leaks from the battery into the battery pack, it comes into contact with the electrolyte. The parts cause swelling, dissolution, cracks, etc., and adversely affect peripheral devices. It should be noted that the same can be said for the ABS as for the organic electrolyte solution characteristics as for PC and PC / ABS. A battery pack provided with a battery storage case made of styrene-modified polyphenylene oxide is disclosed in Japanese Patent Publication No. 6-82547. Styrene-modified polyphenylene oxide has no problem with respect to heat resistance, and also with respect to the properties of organic electrolyte solution, it is difficult to use other ABS, P
C, which is described in the above-mentioned gazette as being more stable than PC / ABS, but a reaction ratio in a polymerization step of copolymerizing (grafting) styrene with polyphenylene oxide (hereinafter, referred to as polyphenylene ether in the present invention). It is very difficult to completely remove residual monomers or oligomers of styrene due to the problems described above and a complicated drying step, which has a problem that the organic electrolyte solution resistance is adversely affected. The method for producing polyphenylene ether obtained by copolymerizing (grafting) styrene is described in JP-B-46-41383, JP-B-47-1210, JP-B-47-1782, and JP-B-47-178. 411
No. 05, Japanese Patent Publication No. 52-38596, and US Pat. No. 3,522,326. More recently, the demand for flame-retardant case materials has been increasing in accordance with the progress of OA equipment flame retardancy. There are many. In the above-mentioned Japanese Patent Publication No. Hei 6-82547,
No mention is made of imparting flame retardancy to the material of the battery storage case. In order to impart flame retardancy to polyphenylene ether, most commonly used phosphate ester compounds such as triphenyl phosphate and 1,3-
If an attempt is made to use bis (diphenylphosphono) benzene or the like as a material for a battery housing case, the organic electrolyte solution resistance is reduced. Therefore, further improvement is required to use the most frequently used flame-retardant polyphenylene ether-based resin composition as a battery housing case requiring organic electrolyte solution resistance. [0010] The present invention is stable with respect to an organic electrolytic solution, and even when the electrolytic solution leaks from the inside of the battery at the time of an abnormality, poor appearance such as dissolution, swelling, and cracks may occur. An object of the present invention is to provide a safe battery storage case made of a flame-retardant polyphenylene ether-based resin composition. Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, have found that a styrene resin is copolymerized (grafted) with polyphenylene ether.
By simply blending without causing the heat resistance, the heat resistance can be maintained and the organic electrolyte solution resistance can be further improved. Furthermore, the following general formula (I)
The inventors have found that by containing the phosphate compound represented by (II) and / or (II), it is possible to have flame retardancy while maintaining the resistance to organic electrolyte solution, and reached the present invention. That is, according to the present invention, in a battery case accommodating at least one organic electrolyte battery, the battery case is made of polyphenylene ether and styrene resin.
It consists command resin composition, the resin composition is, organic electrolyte battery storage case is characterized by containing the phosphoric acid ester compound represented by the following general formula (I) and / or (II). [0013] (Wherein Q1, Q2, Q3, and Q4 represent an alkyl group having 1 to 6 carbon atoms or hydrogen;
2, R3 and R4 represent a methyl group or hydrogen. n is 1
N1 and n2 represent integers from 0 to 2;
1, m2, m3, and m4 each represent an integer of 1 to 3. [0015] (Wherein Q1, Q2, Q3, and Q4 represent an alkyl group having 1 to 6 carbon atoms, and Q1 ', Q2', Q1
3 ′ and Q4 ′ represent hydrogen or an alkyl group having 1 to 6 carbon atoms. n shows the integer of 1 or more. Hereinafter, the present invention will be described in detail. The phosphate compound used in the present invention is represented by the above general formulas (I) and (II). In the general formula (I), Q1, Q2, Q3,
Particularly preferred among Q4 is hydrogen or a methyl group. R1, R2, R3, and R4 represent a methyl group or hydrogen. N1 and n2 each represent an integer of 0 to 2. n is 1
The heat resistance and workability differ depending on the number. The preferred range of n is 1-5. Further, the phosphoric ester may be a mixture of n-mers. The phosphate compound used in the present invention is:
It has a bonding structure with a specific bifunctional phenol and a terminal structure with a specific monofunctional phenol. Specific bifunctional phenols include 2,2-bis (4-hydroxyphenyl) propane [commonly known as bisphenol A], 2,2-bis (4-hydroxy-3-methylphenyl) propane, and bis (4-hydroxyphenyl) Methane, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-
Bisphenols such as bis (4-hydroxyphenyl) ethane are exemplified, and bisphenol A is particularly preferred. The phosphoric ester compound used in the present invention is a compound in which two or more phosphoric esters are bound with a specific bifunctional phenol. Specific monofunctional phenols include unsubstituted phenols, monoalkylphenols, dialkylphenols, and trialkylphenols,
Alternatively, a mixture of two or more kinds is mentioned, and phenol, cresol, dimethylphenol (mixed xylenol), 2,6-dimethylphenol, and trimethylphenol are particularly preferable. Further, by using a monoalkylphenol, a dialkylphenol, or a trialkylphenol as the monofunctional phenol, a resin composition having further improved organic electrolyte solution resistance can be obtained. As described above, the phosphate compound used in the present invention has a bonding structure of bisphenols and an ester structure of monofunctional phenol at the same time, and when added to a resin, can provide a resin composition having excellent practicality. Phosphate ester compound and polyphenylene ether which are excellent not only in organic electrolyte solution resistance but also in thermal stability
Resin composition obtained by blending a styrene resin (hereinafter PP
A resin composition in which E-type resin is abbreviated) can provide a battery storage case having flame retardancy and excellent organic electrolyte solution resistance. In the present invention, the mixing ratio of the PPE resin and the phosphate compound is preferably 0.01 to 200 parts by weight, more preferably 0.1 to 90 parts by weight, based on 100 parts by weight of the PPE resin. Parts by weight. If the amount of the phosphoric acid ester compound is less than 0.01 part by weight, the flame-retardant effect is not sufficiently exhibited, and if the amount of the phosphoric acid ester compound is more than 200 parts by weight, the organic electrolyte solution resistance is adversely affected. The organic electrolyte battery storage case of the present invention may be used in combination with the above-mentioned phosphate compound within a range not to impair the effects of the present invention, by using triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, A known phosphate such as silenyl phosphate can be used. In addition, other flame-retardant additives, such as decabromodiphenyl ether,
Known organic halogen compounds such as tetrabromobisphenol A, hexabromobenzene, hexabromocyclododecane, and perchlorocyclodecane; halogen-containing inorganic compounds such as antimonium bromide; and organic compounds such as red phosphorus, polyphosphoric acid, and ammonium phosphate. Or nitrogen-containing compounds such as inorganic phosphorus compounds, halogen-containing phosphorus compounds such as tris (halopropyl) phosphate and tris (haloethyl) phosphate, melamine, uric acid, methylolmelamine, dicyanamide, melamine formaldehyde resin, uric acid formaldehyde resin and triazine compound. , Magnesium hydroxide, aluminum hydroxide, inorganic hydrates such as dawsonite, antimony oxide,
Inorganic compounds such as barium antimonate, barium metaborate, zirconium oxide, zirconium hydroxide, barium metaborate, and tin oxide can also be used in combination. Also, an anti-dripping agent such as polytetrafluoroethylene and a siloxane compound can be used in combination. The PPE used in the present invention has the following general formula (I)
II), having a reduced viscosity (0.5
g / dl, chloroform solution, measured at 30 ° C.)
It is preferably in the range of 5 to 0.70, and more preferably in the range of 0.20 to 0.60.
Or it is a copolymer. Embedded image (R1, R2, R3 and R4 are each
Hydrogen, halogen, a primary or secondary lower alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbonoxy group or at least two carbon atoms having a halogen atom and an oxygen atom They are selected from the group consisting of separated halohydrocarbon oxy groups, and may be the same or different from each other. As a specific example of this PPE, for example, poly (2,6)
-Dimethyl 1,4-phenylene ether), poly (2-
Methyl-6-ethyl-1,4-phenylene ether),
Poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether), and the like. Further, 2,6-dimethylphenol and other phenols (For example, 2,3,6,-
Polyphenylene ether copolymers such as polymers with trimethylphenol and 2-methyl-6-butylphenol) are also included. Among them, poly (2,6-dimethyl-
(1,4-phenylene ether), a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol is preferred, and poly (2,6-dimethyl-1,4-phenylene ether) is more preferred. . The method for producing PPE used in the present invention is not particularly limited as long as it can be obtained by a known method. For example, US Pat. No. 3,306,874, US Pat. U.S. Pat. No. 3,257,357, U.S. Pat. No. 3,257,358, Japanese Patent Publication No. 52-17880,
Examples of the method include the methods described in JP-A-51197 and JP-A-63-152628. In addition, the PPE used in the present invention is
Modification obtained by reacting PE with an α, β-unsaturated carboxylic acid or a derivative thereof in the presence, absence, or absence of a radical generator in a molten state, a dissolved state, or a slurry state at a temperature of 80 to 350 ° C. It may be PPE (0.01 to 10% by weight is grafted or added), or may be a mixture of the above-mentioned PPE and modified PPE at an arbitrary ratio. The polystyrene resin (hereinafter abbreviated as PS resin) used in the present invention generally means a vinyl aromatic polymer or a rubber-modified aromatic polymer. Examples of the vinyl aromatic polymer include styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4
-Dimethylstyrene, ethylstyrene, p-tert-
Polymers such as nuclear alkyl-substituted styrenes such as butylstyrene; α-methyl-substituted styrenes such as α-methylstyrene and α-methyl-p-methylstyrene; and copolymers of one or more of these with at least one other vinyl compound. Examples of the polymer include a polymer and a copolymer of two or more of these. Examples of the compound copolymerizable with the vinyl aromatic compound include methacrylates such as methyl methacrylate and ethyl methacrylate, acrylonitrile,
Examples thereof include unsaturated nitrile compounds such as methacrylonitrile, and acid anhydrides such as maleic anhydride. Particularly preferred polymers among these polymers are polystyrene, A
BS. The rubber used for the rubber-modified vinyl aromatic polymer is preferably polybutadiene, styrene-butadiene copolymer, polyisoprene, butadiene-isoprene copolymer, natural rubber, and ethylene-propylene copolymer. As the modified vinyl aromatic polymer, rubber-modified polystyrene (hereinafter abbreviated as HIPS) and ABS are preferable. These PPE and PS are 20:80 to 1
It is preferable to blend in the range of 00: 0. The resin blended in these ranges is preferably blended in an amount of 30 to 90% by weight of the whole molded body of the case. Storage cases outside these ranges are particularly resistant to organic electrolyte properties, heat resistance, moldability, rigidity,
It is unsuitable as an organic electrolyte battery storage case because physical properties such as strength are reduced. The resin composition used in the present invention may contain a thermoplastic elastomer, if desired. Examples of the thermoplastic elastomer include a styrene-butadiene block copolymer, a styrene-butadiene block copolymer in which part or all of a butadiene portion is hydrogenated, an ethylene-propylene elastomer, a styrene-grafted ethylene-propylene elastomer, and a thermoplastic polyester elastomer. , An ethylene ionomer resin, a core-shell polymer composed of a rubber-like core and a shell of a non-rubber-like polymer, and the like, in particular, a styrene-butadiene block copolymer, and a part or all of a butadiene portion are hydrogenated, Styrene-butadiene block copolymers are preferred. Further, in the resin composition used in the present invention,
In order to further improve the mechanical properties, heat resistance and the like, a filler can be blended. This filler is not particularly limited as long as it satisfies the required characteristics of the organic electrolyte battery storage case, and those conventionally used in thermoplastic resins, for example, inorganic salts, glass, carbon, metals, Sera
Any one of mix, mica, wood flour, talc, asbestos and the like can be appropriately selected and used according to required characteristics. The form is not particularly limited, but is preferably in the form of powder, granule, fiber, flake, whisker, etc., and if necessary, surface treatment with a silane coupling agent. Alternatively, a filler subjected to a convergence treatment with a sizing agent can also be used. With respect to the amount of addition, the necessary amount may be added according to the required properties of the organic electrolyte battery storage case, for example, heat resistance, organic electrolyte resistance, rigidity, strength, and appearance. However, if the addition amount exceeds 50% by weight, poor filling will occur due to insufficient amount of resin, and the moldability will be extremely deteriorated. In addition, various additives such as flow improvers, plasticizers, release agents, ultraviolet absorbers, ultraviolet inhibitors, antioxidants, light In addition to stabilizers, antistatic agents, dyes and pigments, silicone oils such as dimethyl silicon, methyl phenyl silicon, fluorine-modified silicon and the like, and additives for improving sliding properties such as difluidized molybdenum may be added in desired amounts. it can. The resin composition used in the present invention is not particularly limited, and can be kneaded and manufactured using a kneading machine such as an extruder, a heating roll, a kneader, and a Banbury mixer. Further, the method for molding the organic electrolyte battery storage case of the present invention is not particularly limited, and a commonly used injection molding method, blow method, compression molding method, or the like is used. Hereinafter, the present invention will be described in detail with reference to examples. The physical properties were evaluated by forming a dumbbell piece (3 mmt) from each material and adding it to an organic electrolyte solution.
After immersion for 0 hours, the following procedure was performed. In this case, as the organic electrolyte, 1.0 M: propylene carbonate containing LiPF _6: methyl ethyl carbonate = 1: 1 mixed solution, and 1.0 M: ethylene carbonate containing LiPF _6: diethyl carbonate = 1: 1 mixture The solution was used. (1) A test piece left for 240 hours in an atmosphere of 25 ° C. and 50% RH was used as a blank, and the weight change rate was 25 ° C. and an atmosphere of 50% RH.
The change in weight of the test piece after immersion in an atmosphere of 60 ° C. and 50% RH for 240 hours was expressed in percentage. (2) Tensile strength retention rate A blank left for 240 hours in an atmosphere of 25 ° C. and 50% RH is used as a blank, and is used for 240 hours in an atmosphere of 25 ° C. and 50% RH and an atmosphere of 60 ° C. and 50% RH. Tensile strength retention after immersion was expressed as a percentage. Measurement is 25
The test was performed in an atmosphere of 50 ° C. and 50% RH in accordance with ASTM-D638. (3) Appearance evaluation 25 ° C, 50% RH atmosphere, 60 ° C, 50% R
The appearance after immersion for 240 hours in an atmosphere of H was visually observed and evaluated. (4) Flammability In the case where the flame retardant was blended in the examples, after immersing in a 1/16 inch test piece for 240 hours, the burning time was measured in accordance with the vertical burning test method specified in UL-94. did. Reference Example 1 A resin composition containing a PPE-based resin is P
The poly 2,6-dimethyl-1, whose intrinsic viscosity [η] measured in chloroform at 30 ° C. as 0.5 was 0.52.
Asahi Kasei Kogyo Co., Ltd., a product of Asahi Kasei Kogyo Co., Ltd., a product of Asahi Kasei Kogyo Co., Ltd., which uses 60% by weight of 4-phenylene ether, 20% by weight of Asahi Kasei Polystyrene 685 (hereinafter abbreviated as GPPS) as a polystyrene resin, and HIPS. After using polystyrene H940520% by weight and octadecyl-3- (3-5-di-tert-butyl-4-hydroxyphenyl) propionate 0.2% by weight as a stabilizer, they were uniformly blended with a Henschel mixer. The mixture was melt-kneaded with a PCM-30 twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd.) set at a cylinder temperature of 300 ° C. to form pellets. Using these pellets, 2
A test piece was prepared by injection molding at 80 ° C. and evaluated. REFERENCE EXAMPLE 2 Except that PPE was changed to 40% by weight and GPPS was changed to 40% by weight, melt kneading and pelletizing were performed in the same manner as in Example 1, and injection molding was performed at 270 ° C. to prepare a test piece. , Was evaluated. Examples 1 to 3 After the resin composition of Reference Example 1 was uniformly blended with a Henschel mixer, three kinds of flame retardants were blended as follows. Table 1 shows the base composition excluding the flame retardant.
(A mixture of n = 1 to 3) (bisphenol A / polycresyl phosphate) or phosphate ester B (a mixture of n = 1 to 3) (bisphenol A / poly (2,6-xyenyl) ) Phosphate or phosphate ester C (mixture of n = 1 to 3) (bisphenol A / polyphenyl phosphate)
After blending uniformly in parts by weight Henschel mixer, ginseng
Pellets were obtained in the same manner as in Example 1 . Using the pellets, injection molding was performed at 280 ° C. to prepare test pieces, which were evaluated. Comparative Examples 1 and 2 The flame retardants used in Examples 1 to 3 were added to phosphoric ester D (1,3-bis (diphenylphosphono) benzene) and phosphoric ester E (triphenyl phosphate), respectively. Except having changed, it blended and pelletized like Example 1-3 , obtained the test piece, and evaluated. [Table 1] Comparative Example 3 The same PPE as in Reference Example 1 was added at 60% by weight and G
After copolymerizing (grafting) 20% by weight of PPS by the method disclosed in Japanese Patent Publication No. 52-38596, 20% by weight of HIPS and octadecyl-3- (3-5-diamine) as a stabilizer were used. -t- butyl-4-hydroxyphenyl) with propionate 0.2 wt%, example
Pellets were prepared in the same manner as in Example 1, and the test pieces were evaluated. Comparative Example 4 The same PPE as in Reference Example 1 was added at 10% by weight,
Pelletizing was performed in the same manner as in Reference Example 1 except that PPS was changed at 70% by weight, and injection molding was performed at 260 ° C. to obtain a test piece, which was evaluated. Comparative Example 5 A test piece was obtained by injection molding a PC (Iupilon S-3000R, manufactured by Mitsubishi Engineering-Plastic Corporation) at 275 ° C. and evaluated. Comparative Example 6 ABS (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.)
JSR-XT01] was injection molded at 260 ° C. to obtain a test piece, which was evaluated. [Table 2] As is clear from Table 2, Reference Examples 1 and 2
Further, Examples 1 to 3 are superior to Comparative Examples 1 to 6 in weight change rate, tensile strength retention rate, and appearance, and have excellent characteristics as an organic electrolyte battery storage case. (2
Excellent characteristics such as 5 ° C. and 50% RH) can be obtained only by using a blended resin composition without copolymerizing (grafting) a styrene-based resin to PPE. Therefore, it is considered that the residual monomer and oligomer of styrene are significantly reduced. Reference Examples 3-4 and Examples 4-6 Reference Examples 1-2 and
And the same test pieces as in Examples 1 to 3 were used in Examples 6 to 1 , respectively.
After setting to 0 and immersing in an atmosphere of 60 ° C. and 50% RH for 240 hours, each evaluation was performed at 25 ° C. and 50% RH. Comparative Examples 7 and 8 The same test pieces as Comparative Examples 1 and 2 were used as Comparative Examples 7 and 8, respectively, immersed in an atmosphere of 60 ° C. and 50% RH for 240 hours, and then immersed in 25 ° C. and 50% RH. Each evaluation was performed. [Table 3] As is clear from the table, in Examples 4 to 6 , the change in weight, the tensile strength retention, and the appearance were little changed even in the immersion test in an atmosphere of 60 ° C. and 50% RH at 25 ° C. It has excellent characteristics as an organic electrolyte battery storage case. The organic electrolyte battery storage case of the present invention has the following features.
It is extremely stable to organic electrolytes. Further, it has flame retardancy while maintaining the organic electrolyte solution resistance. Therefore, even when the electrolyte leaks from the inside of the battery at the time of abnormality, there is no significant appearance defect such as dissolution, swelling, and cracking. Also, even if the electrolyte ignites for some reason, there is no danger of the battery pack being ignited, and a safe battery pack can be provided.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 2/10 H01M 10/40

Claims (1)

(57) [Claim 1] In a battery case accommodating at least one organic electrolyte battery, the battery case is made of a resin composition obtained by blending styrene resin with polyphenylene ether, and the resin composition An organic electrolyte battery storage case, characterized in that the substance contains a phosphate compound represented by the following general formula (I) and / or (II). Embedded image (Wherein Q1, Q2, Q3, and Q4 represent an alkyl group having 1 to 6 carbon atoms or hydrogen, and R1, R2, R3, and R
4 represents a methyl group or hydrogen. n is an integer of 1 or more, n1 and n2 are integers of 0 to 2, and m1, m2,
m3 and m4 each represent an integer of 1 to 3. ) (Wherein Q1, Q2, Q3, and Q4 represent an alkyl group having 1 to 6 carbon atoms, and Q1 ′, Q2 ′, Q3 ′, and Q4 ′)
Represents hydrogen or an alkyl group having 1 to 6 carbon atoms. n
Represents an integer of 1 or more. )