JP2004039485A - Module battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module battery in which potting materials are used, and which is provided with a further higher cooling performance and vibration absorbing performance. <P>SOLUTION: While a pair of bosses 10, 11 (12, 13) of a prescribed height from the bottom wall 3a of a module case 3 are protrusively installed at the position corresponding to electrode tabs 6, 7 of the battery 2, a through hole 8 is installed in the electrode tabs 6, 7 of the battery 2. Then, after the battery 2 is coupled to a pair of bosses 10, 11 (12, 13) of the module case 3, undiluted solution of the potting material P is poured into the module case 3, and the battery 2 is embedded into the potting material P. As a result, the wall thickness of the potting material P can be controlled in the desired thickness, and the optimum vibration absorbing performance can be demonstrated. Furthermore, since the generation of heat of the battery 2 can be released efficiently to the module case main body 3 through the tabs 6, 7 and the bosses 10, 11, 12, 13, the cooling performance is improved. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a module battery including a plurality of batteries in which a power generation element (laminated electrode) is covered with an exterior film and sealed.
[0002]
[Prior art]
A battery in which a power generation element (laminated electrode) is sealed with an exterior film is small and light because the case is made of a film material. By combining a plurality of batteries into a module battery, for example, an electric vehicle or the like that requires high output is required. It is expected to be applied to the drive source of hybrid vehicles.
[0003]
Since this type of battery has low rigidity, a technique for holding and fixing the battery to a module case as disclosed in Japanese Patent Application Laid-Open No. 2001-256939 is known.
[0004]
[Problems to be solved by the invention]
However, the conventional module battery has a structure in which the battery is clamped and fixed to the module case, so that it is difficult to exhibit optimum vibration absorbing performance.
[0005]
The present invention relates to such an improvement of the prior art, and an object of the present invention is to provide a module battery having optimal vibration absorbing performance.
[0006]
[Means for Solving the Problems]
INDUSTRIAL APPLICABILITY The present invention is applied to a module battery in which a plurality of batteries in which a power generation element is sealed in an exterior film and a pair of electrode tabs are exposed from the exterior film are housed in a module case. Then, the battery is fastened and fixed to a boss projecting at a predetermined height from the bottom wall of the module case at a position corresponding to the electrode tab through a through hole provided in the electrode tab of the battery, and a potting material is attached to the module case. To fix the battery with a potting material.
[0007]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the thickness of a potting material can be managed to a desired thickness, and thereby the optimal vibration absorption can be exhibited.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 8 show an embodiment of the present invention. FIG. 1 is an overall view including a partially broken portion of a module battery according to this embodiment, and FIG. 2 is a cross section taken along line II-II in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1, FIG. 4 is an enlarged view of a portion A in FIG. 2, FIG. 5 is a battery used in the module battery of this embodiment, and FIG. FIG. 6 is a side view, FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5, FIG. 7 is a bus bar of the module battery of this embodiment, FIG. FIG. 8 is a side view, and FIG. 8 is an explanatory view showing a potting material injection step of the module battery.
[0009]
As shown in FIGS. 1 to 3, the module battery 1 of this embodiment is housed in a battery 2, a metal module case 3 for housing and modularizing the plurality of batteries 2, and housed in the module case 3. And a potting material P in which the battery 2 is embedded.
[0010]
"battery"
As shown in FIGS. 5 and 6, the battery 2 has a flat laminated electrode 21 as a power generating element disposed at the center of a pair of laminated films 22 and 23 as an exterior film. The laminated electrode 21 is covered by sandwiching both sides thereof, and the peripheral portions of the laminated films 22 and 23 are joined by heat welding (joining portion 2B), thereby sealing the electrolytic solution together with the laminated electrode 21 between the laminated films 22 and 23. It is. Thus, the external shape of the battery 2 is such that the portion where the power generation element is accommodated in the central portion of the battery is the thick portion 2A, and the joining portion 2B in the peripheral portion of the battery is the thin portion 2B.
[0011]
The laminated electrode 21 is obtained by sequentially laminating a plurality of positive plates 21A and negative plates 21B with a separator 21C interposed therebetween. Each positive electrode plate 21A is connected to a positive electrode tab 6 via a positive electrode lead 21D, and each negative electrode plate 21B is connected to a negative electrode tab 7 via a negative electrode lead 21E. The positive electrode tab 6 and the negative electrode tab 7 are laminated. The films 22 and 23 are pulled out from the thin portions 2B of the films 22 and 23.
[0012]
The positive electrode tab 6 and the negative electrode tab 7 are formed of a metal foil such as Al, Cu, Ni, and Fe. In this embodiment, the positive electrode tab 6 is formed of Al and the negative electrode tab 7 is formed of Ni. In addition, the laminate films 22 and 23 are formed such that a nylon layer α as a resin layer, an adhesive layer β, an aluminum foil layer γ as a metal layer, PE (polyethylene) or PP ( (Polypropylene) layer δ.
[0013]
"Battery material"
The battery 2 of this embodiment uses a high-energy-density, high-output lithium-ion secondary battery, and is an optimal module battery as a vehicle drive source. More specifically, the lithium ion secondary battery has the following configuration.
[0014]
As the positive electrode active material of the positive electrode forming the positive electrode plate 21A, a lithium nickel composite oxide, specifically, a general formula LiNi _1-x MxO ₂ (where 0.01 ≦ x ≦ 0.5, M Contains at least one of Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, and Sr).
[0015]
The positive electrode can also contain a positive electrode active material other than the lithium nickel composite oxide. As the positive electrode active material other than the lithium nickel composite oxide, for example, a general formula LiyMn _2-z M′zO ₄ (provided that 0.9 ≦ y ≦ 1.2, 0.01 ≦ z ≦ 0.5, and M 'Is at least one of Fe, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, and Sr.) Things. Also, a general formula LiCo _1-x MxO ₂ (where 0.01 ≦ x ≦ 0.5, and M is Fe, Ni, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti , Mg, Ca, and Sr) may be contained.
[0016]
Lithium nickel composite oxide, lithium manganese composite oxide and lithium cobalt composite oxide, for example, a carbonate such as lithium, nickel, manganese, and cobalt are mixed according to the composition, and the mixture is heated to 600 ° C. to 1000 ° C. in an oxygen-containing atmosphere. It is obtained by firing in a temperature range. The starting materials are not limited to carbonates, and can be synthesized from hydroxides, oxides, nitrates, organic acid salts, and the like.
[0017]
The average particle size of the positive electrode active material such as a lithium nickel composite oxide and a lithium manganese composite oxide is preferably 30 μm or less.
[0018]
As the negative electrode active material forming the negative electrode plate 21B, a specific surface area to use a 0.05 m ² / g or more, a range of ^2m 2 / g. By setting the content in this range, formation of SEI (Solid Electrolyte Interface) on the surface of the negative electrode can be sufficiently suppressed.
[0019]
When the specific surface area of the negative electrode active material is less than 0.05 m ² / g, the place where lithium can enter and exit is too small, so that the lithium doped in the negative electrode active material during charging is discharged from the negative electrode active material during discharging. It is not sufficiently undoped, and the charge / discharge efficiency decreases. On the other hand, when the specific surface area of the negative electrode active material exceeds 2 m ² / g, formation of SEI on the negative electrode surface cannot be controlled.
[0020]
As the negative electrode active material, any material can be used as long as it is capable of doping and undoping lithium with a potential with respect to lithium of 2.0 V or less, and specifically, a non-graphitizable carbon material, Organic polymer made by firing artificial graphite, natural graphite, pyrolytic graphite, coke such as pitch coke, needle coke, petroleum coke, graphite, glassy carbon, phenolic resin and furan resin at appropriate temperature It is possible to use a carbonaceous material such as a compound fired body, carbon fiber, activated carbon, and carbon black.
[0021]
In addition, a metal capable of forming an alloy with lithium and an alloy thereof can also be used. Specifically, lithium is doped with lithium at a relatively low potential such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, and tin oxide. In addition to oxides and nitrides thereof to be dedoped, nitrides thereof, group 3B typical elements, elements such as Si and Sn, or MxSi, MxSn (where M represents one or more metal elements excluding Si or Sn). ) Can be used. Among these, it is particularly preferable to use Si or a Si alloy.
[0022]
Further, as the electrolytic solution, in addition to a liquid prepared by dissolving an electrolyte salt in a non-aqueous solvent, a polymer gel electrolyte in which a solution in which the electrolyte salt is dissolved in a non-aqueous solvent is held in a polymer matrix, Is also good.
[0023]
When a polymer gel electrolyte is used as the non-aqueous electrolyte, a polymer material to be used includes polyvinylidene fluoride, polyacrylonitrile, and the like.
[0024]
As the non-aqueous solvent, any non-aqueous solvent used so far in this type of non-aqueous electrolyte secondary battery can be used, such as propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, and diethyl carbonate. Dimethyl carbonate, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolan, 4-methyl-1,3-dioxolan, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile and the like. One of these non-aqueous solvents may be used alone, or two or more of them may be used in combination.
[0025]
In particular, the non-aqueous solvent preferably contains an unsaturated carbonate, and specifically, preferably contains vinylene carbonate, ethyleneethylidene carbonate, ethylene isopropylidene carbonate, propylidene carbonate, and the like. Among them, it is most preferable to contain vinylene carbonate. By containing unsaturated carbonate as the non-aqueous solvent, it is considered that an effect due to the properties of SEI generated in the negative electrode active material (function of the protective film) is obtained, and the overdischarge resistance is further improved.
[0026]
Further, the unsaturated carbonate is preferably contained in the electrolyte at a ratio of 0.05% by weight or more and 5% by weight or less, particularly preferably at a ratio of 0.5% by weight or more and 3% by weight or less. Is most preferred. By setting the content of the unsaturated carbonate in the above range, a non-aqueous secondary battery having a high initial discharge capacity and a high energy density can be obtained.
[0027]
The electrolyte salt is not particularly limited as long as it is a lithium salt exhibiting ion conductivity. For example, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiCl, LiBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, and the like can be used. One of these electrolyte salts may be used alone, or two or more thereof may be used in combination.
[0028]
"Module case"
As shown in FIGS. 1 to 3, the module case 3 has a container shape having an upper opening, and is sealed by a lid 4. A pair of bosses 10 and 11 and a pair of bosses 12 and 13 project from the inner surface of the bottom wall 3 a of the module case 3 at positions corresponding to the electrode tabs (the positive electrode tab 6 and the negative electrode tab 7) of each battery 2. .
[0029]
In this embodiment, two batteries 2, 2 stacked back to back are used as a set, and the electrode tabs 6, 7 of the set of batteries 2 are placed on a pair of bosses 10, 11 and bolts B are used. The electrode tabs 6, 7 of a set of batteries 2 are placed on a pair of bosses 12, 13 and fastened and fixed with bolts B. The battery 2 is provided with through holes 8 in the electrode tabs 6 and 7 in advance, and is fastened and fixed to the boss 10 (11, 12, 13) through the through holes 8.
[0030]
The pair of bosses 10, 11 and the pair of bosses 12, 13 are set at a predetermined height from the inner surface of the bottom wall 3 a of the module case 3, so that between the inner surface of the bottom wall 3 a of the module case 3 and the battery 2. Uniform voids are formed. Therefore, when the undiluted solution of the potting material P is injected into the module case 3 (see FIG. 8), the potting material P surely flows between the bottom wall 3a of the module case 3 and the battery 2 and a predetermined time has elapsed. The thickness of the potting material P that is solidified is uniform.
[0031]
Here, between the batteries 2 and between the batteries 2 and the input / output terminals 17 and 18 are electrically connected by a flat bus bar 14 and L-shaped bus bars 15 and 16 to form a high-power circuit. However, in this embodiment, each bus bar 14, 15, 16 is fastened together with the electrode tabs 6, 7 of the battery 2 to the bosses 10, 11, 12, 13 together.
[0032]
FIG. 4 shows this joint structure, which is representative of the joint structure to the boss 13. Specifically, as shown in FIG. 4, the joint fastening structure includes an insulating washer 25, a bus bar 14, a positive electrode tab 6 of a stacked set of batteries 2, an insulating washer 26, on the top surface of the boss 13. The structure is such that washers 27 are sequentially stacked, and these are both fastened and fixed to the boss 13 with bolts B.
[0033]
Cooling fins 19 are provided on the outer surface of the bottom wall 3 a of the module case 3 at positions corresponding to the bosses 10, 11, 12, and 13. 7 → bolt B → bosses 10, 11, 12, 13 → (module case 3 main body) → cooling fin 19 → heat is radiated to the atmosphere, and heat can be radiated more efficiently.
[0034]
In this embodiment, the cooling fins 19 are provided on the back surfaces of the bosses 10, 11, 12, and 13 as described above, but the cooling fins 31 are provided on the entire outer surface of the bottom wall 3a of the module case 3 as shown in FIG. May be provided. In this case, the cooling performance of the module battery 30 is further improved. Moreover, the rigidity of the module case 3 is improved by the cooling fins 31 and the handling of the module battery 30 is also improved.
[0035]
"Assembly process"
Hereinafter, an assembly process of the module battery 1 of this embodiment will be described.
[0036]
(1) First, a pair of batteries 2, 2 stacked back-to-back with bus bars 14, 15 on a pair of bosses 10, 11 of module case 3 via insulating washer 25, insulating washer 26, and washer 27. By fastening the tabs 6 and 7 together, the batteries 2 and 2 are fixed (see FIG. 4). Similarly, the tabs 6, 7 of a pair of batteries 2, 2 stacked on the busbars 14, 16 and back to back via a pair of bosses 12, 13 via insulating washers 25, insulating washers 26, and washers 27. To secure the batteries 2 and 2 (see FIG. 4).
(2) Next, the bus bars 15 and 16 are connected to the input / output terminals 17 and 18 to form a high-power circuit. Here, a continuity test is performed to check whether the circuit is formed without any abnormality. If the circuit is broken, the bolt B is removed and parts are partially replaced. (3) The continuity test of the circuit is normal. If there is, the potting material injection nozzle N is inserted near the bottom wall 3a of the module case 3 as shown in FIG. 8, and the potting material P stock solution is injected from the bottom wall 3a of the module case 3 (4). Then, after the potting material P is solidified, the module case 3 is covered with the lid 4 and joined to obtain a module battery 1.
[0037]
"Effects"
Here, in order to exhibit vibration absorption, it is also conceivable that the battery 102 is placed in the module case 101 and a potting material P such as urethane resin is poured and fixed as shown in FIGS.
[0038]
However, in this case, it is difficult to inject the potting material into an appropriate state. That is, as shown in FIG. 10, when the potting material P stock solution is injected with the batteries 102, 102,... Arranged on the bottom wall 101a of the module case 101, the module case 101 and the batteries 102, 102,. -It is difficult to make the potting material P sufficiently wrap around the gap with the gap, and the vibration absorption of the potting material P cannot be sufficiently exhibited. Also, as shown in FIG. 11, a structure in which a spacer 107 is arranged between the bottom wall 101a of the module case 101 and the batteries 102, 102,. It is difficult to reduce the thickness, and it is difficult to exhibit sufficient vibration absorption. Moreover, in this case, since the potting material P becomes discontinuous at the spacer 107, vibration absorption at the spacer 107 cannot be expected, and stress concentrates around the spacer 107. The potting material P may be decomposed or peeled off.
[0039]
On the other hand, according to the module battery 1 of this embodiment, the pair of bosses 10, 11 (12, 12) are located at positions corresponding to the pair of electrode tabs 6, 7 of the battery 2 from the inner surface of the bottom wall 3a of the module case 3. 13), the electrode tabs 6, 7 of the battery 2 are provided with through holes 8, and the battery 2 is fastened and fixed to the bosses 10, 11 (12, 13) of the module case 3. Since the battery 2 is fixed to the potting material P by pouring the undiluted solution of the potting material P into the potting material P, the thickness of the potting material P can be controlled to a desired thickness, and optimal vibration absorption performance can be exhibited.
[0040]
In addition, heat generated by the battery 2 can be efficiently released to the module case main body through the electrode tabs 6, 7 and the bosses 10, 11, 12, 13 so that the cooling performance is improved. Further, since the module case 3 is made of metal, the heat generated by the battery 2 can be more efficiently radiated.
[0041]
In addition, according to the module battery 1 of this embodiment, the electrode tabs 6 and 7 of the battery 2 are fastened together with the bus bars 14, 15 and 16, thereby facilitating the assembling work. That is, when a plurality of batteries are modularized, usually, the plurality of batteries and the bus bar are welded (for example, by ultrasonic welding), sub-assembled, and then housed in a module case. The subassembly with the hard bus bar is difficult to handle, and the assembly work of the module battery is complicated. However, in this embodiment, since the battery 2 and the bus bars 14, 15, 16 are sequentially assembled to the module case 3 and fastened together, the assembling work is facilitated. In addition, a continuity test is performed before the potting material P is injected, and if it is abnormal, it is easy to partially replace the potting material P, so that quality control is also easy.
[0042]
Further, according to the module battery 1 of this embodiment, since the cooling fins 19 are provided at positions corresponding to the bosses 10, 11, 12, and 13 on the outer surface of the bottom wall 3a of the module case 3, heat can be more efficiently radiated, and The cooling performance of the battery 1 is further improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a module battery according to this embodiment.
FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 3 is a sectional view taken along the line III-III in FIG. 1;
FIG. 4 is an enlarged view of a portion A in FIG. 2;
FIG. 5 is a battery used for the module battery according to the embodiment, in which FIG. 5A is a top view and FIG. 5B is a side view.
FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;
FIG. 7 is a bus bar of the module battery according to this embodiment, in which a diagram a is a top view and a diagram b is a side view.
FIG. 8 is an explanatory view showing a potting material injection step of the module battery.
FIG. 9 is a diagram showing a modification of the module battery of the present invention.
FIG. 10 is an explanatory view showing a conventional example of a module battery.
FIG. 11 is an explanatory view showing a conventional example of a module battery.
[Explanation of symbols]
1 Module Battery 2 Battery 3 Module Case 3a Module Case Bottom Wall 6 Positive Electrode Tab (Electrode Tab)
7 Negative electrode tab (electrode tab)
8 Through hole 10 Boss 11 Boss 12 Boss 13 Boss 14 Bus bar 15 Bus bar 16 Bus bar 19 Cooling fin 21 Stacked electrode (power generation element)
22 Laminating film (exterior film)
23 Laminate film (exterior film)
25 Insulating washer (insulating material)
26 Insulating washer (insulating material)
P Potting material 30 Module battery 31 Cooling fin

Claims (5)

A battery including a battery in which a pair of electrode tabs is exposed from the exterior film while sealing the power generation element in the exterior film, and a module case accommodating a plurality of the batteries,
At a position corresponding to the electrode tab of each battery, a boss having a predetermined height is projected from the bottom wall of the module case, and a through hole is provided in the electrode tab of the battery.
A module battery, wherein the battery is fastened and fixed to a boss of the module case through a through hole of an electrode tab of the battery, and a potting material is poured into the module case to fix the battery to the potting material. The module battery according to claim 1,
The module case is made of metal,
The battery module according to claim 1, wherein the electrode tabs of the battery are fastened and fixed by bolts with an insulating material interposed between bosses of the module case. The module battery according to claim 1 or 2, wherein:
A module battery, wherein the electrode tab of the battery is fastened together with a bus bar. The module battery according to any one of claims 1 to 3, wherein
A module battery, wherein cooling fins are provided on a bottom wall outer surface of the module case at positions corresponding to the bosses. The module battery according to any one of claims 1 to 3, wherein
A module battery, wherein cooling fins are provided on the entire outer surface of the bottom wall of the module case.

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