JP4114415B2 - Electrode laminated battery cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, both surfaces of an electrode laminate in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween are sandwiched between a pair of laminate films each having a metal layer and a resin layer, and the peripheral edges of the pair of laminate films are The present invention relates to a cooling apparatus for an electrode stack type battery in which the inside is sealed and sealed inside.
[0002]
[Prior art]
In recent years, air pollution caused by exhaust gas from automobiles has become a problem. Electric vehicles powered by electricity and so-called hybrid cars that run in combination with an engine and motor are attracting attention. The development of batteries with high energy density and high output density occupies an important industrial position.
[0003]
Examples of such a high-power battery include a lithium ion battery. In this case, a cylindrical battery wound with a separator interposed between a positive electrode plate and a negative electrode plate, a flat positive electrode plate and a negative electrode plate, There is a laminated battery in which the separator is laminated with a separator interposed.
In the latter stacked type battery, both sides of a flat power generation element are sandwiched between a pair of laminate films, and the periphery is joined by thermal welding to seal the electrolyte together with the power generation element (Japanese Patent Laid-Open No. 11-224652). See the official gazette).
[0004]
Here, as a thing provided with the cooling structure which suppresses the temperature rise of a battery, there exists what was disclosed by Unexamined-Japanese-Patent No. 2001-143769 as an example in the above cylindrical battery. In this publication, a heat dissipation member is connected to the terminals of the positive and negative electrodes of the battery to cool the battery.
[0005]
On the other hand, since the laminated battery uses a laminate film as the outer case, the outer case is less rigid than the cylindrical battery, and the outer case swells due to gas generation due to decomposition of the electrolyte enclosed inside. There is. For this reason, when the cooling structure in the cylindrical battery described above is adopted in the stacked battery, the heat dissipation member is provided on the electrode terminal, and the battery is subjected to the low rigidity and swelling of the outer case. It is necessary to hold down from both sides with a separate member.
[0006]
[Problems to be solved by the invention]
As described above, in the stacked battery, when adopting the cooling structure of the cylindrical battery described above, a heat dissipating member provided on the electrode terminal and a pressing member for pressing the battery from both sides are required, and the number of parts increases. This increases the number of assembly steps.
[0007]
In view of the above, an object of the present invention is to suppress the increase in the number of parts and to hold down the battery from both sides and to improve the cooling performance.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention sandwiches both surfaces of an electrode laminate that laminates a positive electrode plate and a negative electrode plate with a separator in between, with a pair of laminate films each having a metal layer and a resin layer, the electrode stacked batteries for sealing the interior periphery of the pair of laminated films each other closely fixed to, pressed by the pair of pressing members from both sides, projecting the pressing member, outside the periphery of the electrode stacked type battery And cooling the electrode laminated battery with a plurality of the electrode laminated batteries along the thickness direction thereof. The holding member is interposed between the combined electrode stacked batteries, and the plurality of electrode stacked batteries are provided in correspondence with the electrode stacked batteries, respectively, and the cooling fins have the same cooling medium flow. Parallel arrangement so as to be positioned in the radiation area of the radiation fins of the cooling medium outlet side, it is constituted that greater than the heat radiation area of the radiation fins of the inlet side.
[0009]
【The invention's effect】
According to the present invention, the press even members Ru pressing both sides of the electrode stacked type battery, is projected from an edge of the electrode stacked type battery to the outside, the cooling radiator fins provided between the protruding portions cross the pressing member is the same Since the electrode stack type batteries are arranged in parallel so as to be located in the medium flow path, and the heat radiation area of the heat radiation fin on the cooling medium outlet side is larger than the heat radiation area of the heat radiation fin on the same inlet side, As a result, the battery can be pressed from both sides and the cooling performance can be improved while suppressing an increase in the number of parts.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 is a side view showing a cooling apparatus for an electrode laminated battery according to a first reference example of the present invention. The electrode laminated battery here is, for example, a lithium ion secondary battery mounted on a hybrid car that travels in combination with an engine and a motor.
[0012]
A hybrid car (HEV) is a vehicle system equipped with a power generation unit together with a motor / controller and an energy storage system. While ordinary electric vehicles (EVs) can only travel a limited distance due to battery energy density limitations, HEV supplies energy through power generation, so output can be supplied with fewer batteries. It becomes.
[0013]
The electrode stacked battery 1 shown in FIG. 1 is an assembled battery configured by stacking a plurality of layers vertically. Each electrode-laminated battery 1 has a positive electrode plate and a negative electrode plate (not shown) sandwiched between a pair of laminated films each having a metal layer and a resin layer. In this structure, the periphery of the pair of laminate films is closely fixed to each other and the inside is sealed.
[0014]
That is, the electrode laminated battery 1 has a very low rigidity as it is because the laminate film is used as an exterior case.
[0015]
For this reason, in the electrode laminated battery 1 described above, the pressing plate 3 as a pressing member is disposed between the upper and lower surfaces and between them, and the pressing plate 3 is fixed to a plurality of fixing tools 5 such as fixing bolts. It is fastened and fixed by means of, and pressed from both upper and lower sides to cope with low rigidity.
[0016]
The pressing plate 3 protrudes outward from the periphery of the electrode laminated battery 1 (on the right side in FIG. 1), and the protruding portion 3a of the pressing plate 3 dissipates heat generated from the electrode stacked battery 1. The heat dissipation part is used.
[0017]
According to the electrode laminated battery cooling device configured as described above, both sides of the electrode laminated battery 1 are pressed by the pressing plate 3 to cope with the low rigidity and swelling of the outer case, and the electrode. The heat generated from the stacked battery 1 is transmitted to the pressing plate 3 and radiated from the protrusion 3a. This heat dissipation suppresses the temperature rise of the electrode laminated battery 1 and improves the battery performance.
[0018]
In this case, since the protruding portion 3a serving as the heat radiating portion is integrated with the pressing plate 3, the number of parts and the number of assembling steps can be reduced as compared with the case where the pressing member and the heat radiating portion are separate members.
[0019]
The positive electrode plate in the electrode laminated battery 1 described above has a positive electrode active material provided on the surface of the base material, which is a lithium nickel composite oxide, specifically, a general formula LiNi _1-x MxO ₂ (where 0.01 ≦ x ≦ 0.5 and M is a compound represented by the following formula: Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr.
[0020]
The positive electrode active material 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 (where 0.9 ≦ y ≦ 1.2, 0.01 ≦ z ≦ 0.5, and M ′ is Fe, Co, Ni, And at least one of Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, and Sr.).
[0021]
In addition, the general formula LiCo _1-x MxO ₂ (where 0.01 ≦ x ≦ 0.5, M is Fe, Ni, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca , And at least one of Sr.) may be included.
[0022]
The above-described lithium nickel composite oxide, lithium manganese composite oxide, lithium cobalt composite oxide, and the like are mixed with carbonates such as lithium, nickel, manganese, cobalt, and the like according to the composition. It can be obtained by firing in the temperature range of 1000 ° C. The starting material is not limited to carbonates, and can be synthesized in the same manner from hydroxides, oxides, nitrates, organic acid salts, and the like.
[0023]
The average particle size of the positive electrode active material such as lithium nickel composite oxide or lithium manganese composite oxide is preferably 30 μm or less.
[0024]
On the other hand, as the negative electrode active material in the negative electrode plate, the specific surface area is to use a 0.05 m ² / g or more, a range of 2m ² / g. Thereby, formation of a film called SEI (Solid Electrolyte Interface) on the negative electrode surface can be sufficiently suppressed.
[0025]
When the specific surface area of the negative electrode active material is less than 0.05 m ² / g, since the place where lithium can go in and out is too small, lithium doped in the negative electrode active material during charging is out of the negative electrode active material during discharge. Not fully dedope, charge / discharge efficiency decreases. On the other hand, when the specific surface area of the negative electrode active material exceeds 2 m ² / g, SEI formation on the negative electrode surface cannot be controlled.
[0026]
As the negative electrode active material, any material can be used as long as it is a material capable of doping and dedoping lithium in a range where the lithium potential is 2.0 V or less, specifically, a non-graphitizable carbon material, Organic polymer obtained by firing and carbonizing artificial graphite, natural graphite, pyrolytic graphite, coke such as pitch coke, needle coke, petroleum coke, graphite, glassy carbon, phenolic resin, furan resin, etc. Carbonaceous materials such as compound fired bodies, carbon fibers, activated carbon, and carbon black can be used.
[0027]
Metals capable of forming alloys with lithium and alloys thereof can also be used. Specifically, lithium is doped at a relatively low potential, such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, and tin oxide. In addition to oxides to be dedoped, nitrides thereof, group 3B typical elements, elements such as Si and Sn, or, for example, MxSi, MxSn (wherein M represents one or more metal elements excluding Si or Sn. Si and Sn alloys represented by () can be used. Among these, it is particularly preferable to use Si or Si alloy.
[0028]
For each base material of the positive electrode plate and the negative electrode plate, it is preferable to use a high-purity material in order to prevent deterioration of the battery performance due to corrosion during the electrochemical reaction of the battery. For example, when pure aluminum, pure copper, or pure nickel is used, the purity is preferably 99% or more. However, this requirement for purity does not exclude other components (alloy components) added for alloying.
[0029]
The electrolyte may be a so-called liquid electrolyte prepared by dissolving an electrolyte salt in a nonaqueous solvent, or a solution in which the electrolyte salt is dissolved in a nonaqueous solvent is held in a polymer matrix. It may be a polymer gel electrolyte. When a polymer gel electrolyte is used as the non-aqueous electrolyte, examples of the polymer material to be used include polyvinylidene fluoride and polyacrylonitrile.
[0030]
As the non-aqueous solvent, any non-aqueous solvent used so far in this type of non-aqueous electrolyte secondary battery can be used, for example, propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, diethyl carbonate. Dimethyl carbonate, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propionitrile and the like. These nonaqueous solvents may be used alone or in combination of two or more.
[0031]
In particular, the non-aqueous solvent preferably contains an unsaturated carbonate, and specifically, preferably contains vinylene carbonate, ethylene ethylidene carbonate, ethylene isopropylidene carbonate, propylidene carbonate, and the like. Among these, it is most preferable to contain vinylene carbonate. By containing unsaturated carbonate as the non-aqueous solvent, it is considered that the effect due to the properties of SEI (function of the protective film) produced in the negative electrode active material is obtained, and the overdischarge resistance is further improved.
[0032]
The unsaturated carbonate is preferably contained in the electrolyte in a proportion of 0.05% by weight or more and 5% by weight or less, and particularly preferably 0.5% by weight or more and 3% by weight or less. By setting the unsaturated carbonate content in the above range, a non-aqueous secondary battery having a high initial discharge capacity and a high energy density is obtained.
[0033]
The electrolyte salt is not particularly limited as long as it is a lithium salt exhibiting ionic 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, etc. can be used. These electrolyte salts may be used alone or in combination of two or more.
[0034]
FIG. 2 is a side view showing a cooling apparatus for an electrode laminated battery according to a second reference example of the present invention. In this reference example , the entire assembled battery constituted by laminating a plurality of the electrode laminated batteries 1 of FIG. 1 is housed in the battery box 7 including the pressing plate 3.
[0035]
And the protrusion part 3a used as the thermal radiation part of the pressing plate 3 is made to protrude outside from the battery box 7. FIG.
[0036]
In the second reference example , the temperature rise in the battery box 7 housing the electrode laminated battery 1 due to the heat generated by the electrode laminated battery 1 can be suppressed by the heat radiation from the protruding portion 3a.
[0037]
In the first and second reference examples described above, the projecting portion 3a is set to a position for receiving the traveling wind of the vehicle, or cooling air is blown toward the projecting portion 3a by a separate blower fan, The heat dissipation effect is further increased.
[0038]
Note that a heat pipe may be used as the pressing member instead of the pressing plate 3.
[0039]
FIG. 3 is a structural diagram of a heat radiating portion showing a cooling device for an electrode laminated battery according to a third reference example of the present invention. In this reference example , corrugated radiating fins 9 are provided between the protruding portions 3a of the pressing plate 3 in FIG. 1 or FIG. By providing the heat radiation fins 9, the heat radiation effect can be further improved.
[0040]
FIG. 4 is a side view showing a cooling apparatus for an electrode laminated battery according to a fourth reference example of the present invention. In this reference example , a battery pair 11 in which two electrode-stacked batteries 1 are overlapped with each other is pressed from both sides with a pressing plate 13 as a pressing member. Here, the above-described battery pair 11 has two stages, but this may be further increased to three stages or four stages.
[0041]
Then, the battery pair 11 in which the two electrode-stacked batteries 1 are stacked, as shown in FIG. 5 which is a cross-sectional view taken along the line AA of FIG. Are arranged in parallel. The pressing plate 13 presses the plurality of battery pairs 11 arranged in parallel simultaneously from both sides.
[0042]
Each electrode-stacked battery 1 includes a positive electrode tab 15 and a negative electrode tab 17 drawn out from an internal positive electrode plate and negative electrode plate on both the left and right sides in FIG. The left and right arrangements of the positive electrode tab 15 and the negative electrode tab 17 are opposite to each other between adjacent battery pairs 11 as shown in FIG. The positive electrode tab 15 and the negative electrode tab 17 of each adjacent battery pair 11 are connected by a bus bar 19 so that the plurality of battery pairs 11 arranged in parallel are electrically connected in series with each other.
[0043]
Moreover, the above-mentioned holding | maintenance board 13 is provided with the protrusion part 13a used as the thermal radiation part which protrudes outside from the peripheral part vicinity of both the left and right sides in FIG. A heat radiating fin component 21 is provided between the heat radiating portions 13a.
[0044]
The radiating fin component 21 includes an outer side plate 23 positioned between the tip portions of the protruding portion 13a, an inner side plate 25 positioned between the protruding portions 13a in the vicinity of the bus bars 17 and 19, and upper and lower end plates 27 and 29. And a plurality of radiating fins 31 are vertically stacked on the inner side surrounded by the plates 23, 25, 27, and 29. The plurality of radiating fins 31 described above form a waveform in the left-right direction in FIG. 4, and a partition plate 33 is provided between them.
[0045]
According to the above-described fourth reference example , both sides of the battery pair 11 including the two electrode stacked batteries 1 are pressed by the pressing plate 13 to cope with the low rigidity of the electrode stacked battery 1, and The heat generated from the electrode laminated battery 1 is transmitted to the holding plate 13 and is radiated from the left and right protrusions 13a and the radiation fin component 21.
[0046]
In this case, since heat is radiated also from the heat radiating fins 31 provided in the heat radiating fin component 21, the heat radiating effect is further improved, and the performance of the electrode laminated battery 1 is further improved.
[0047]
In the fourth reference example , as shown in FIG. 5, the vehicle traveling wind serving as cooling air is changed from one side (lower side in FIG. 5) to the other side (FIG. 5). By disposing in the vehicle so that it flows to the upper side), the heat dissipation effect is further improved. Or you may make it flow cooling air toward the radiation fin 31 with the ventilation fan separately provided from the one side of the arrangement direction of the battery pair 11. FIG.
[0048]
Then, in the fourth reference example, the heat radiating fin configuration unit 21, since it is possible integrated into one of the pressing plate 13 of the upper and lower sides in FIG. 4, the protruding portion 13a and the radiating the heat radiating portion The fin components 21 can be integrated with the pressing plate 3, and the number of parts and the number of assembling steps can be reduced as compared with the case where the pressing member and the heat radiating portion are separate members.
[0049]
6 to 8 show a first embodiment of the present invention. FIG. 6 is a plan view showing a state in which a plurality of battery pairs 11 are arranged in parallel as in the fourth reference example shown in FIGS. 4 and 5. In this embodiment, the cooling fin constituent members 21a, 21b, 21c, 21d, 21e, and 21f are shown along the flow direction of the cooling air constituting the same cooling medium flow path (from the bottom to the top in FIG. 6). 7, the heat dissipating areas of the heat dissipating fins 31a, 31b, 31c, 31d, 31e, and 31f are changed.
[0050]
Specifically, as shown in FIG. 7, the waveform of the heat-radiating fin 31a on the most inlet side shown in FIG. 7A is enlarged to minimize the heat radiation area, and the most on the outlet side shown in FIG. The heat radiation area is maximized by reducing the waveform of the heat radiation fin 31f. In the middle (b), (c), (d), and (e) in the middle, the radiation fins 31b, 31c, 31d, and 31e sequentially reduce the waveform along the flow of the cooling air to reduce the radiation area. Increasingly larger.
[0051]
The reason why the surface area of the radiating fin is changed along the flow of the cooling air will be described with reference to FIG. FIG. 8 shows the battery rising temperature (vertical axis) during charging / discharging with respect to the flow direction (horizontal axis) of the cooling air due to the difference in the heat radiation area of the radiation fins. Here, the broken line P, the alternate long and short dash line Q, and the alternate long and two short dashes line R are all in the radiating fin constituting members 21a, 21b, 21c, 21d, 21e, and 21f, as in the fourth reference example shown in FIGS. The heat dissipating area of the heat dissipating fins is made uniform, and the heat dissipating area ratio of the heat dissipating fins is increased gradually with the broken line P being 1.0, the dash-dot line Q being 2.0, and the two-dot chain line R being 3.0. It is.
On the other hand, the solid line S is according to the first embodiment shown in FIGS. That is, the heat radiation area of the heat radiation fin is changed between 1.0 and 3.0 in the above area ratio so as to increase sequentially from the inlet side to the outlet side of the cooling air.
[0052]
According to this, under the conditions (P, Q, R) in which the area ratio is uniform, the temperature increase of the battery is suppressed as the heat dissipation area increases. That is, the two-dot chain line R having an area ratio of 3.0 suppresses the temperature rise most.
[0053]
However, in the case of the two-dot chain line R in which the area ratio is increased, the temperature difference between the inlet side temperature and the outlet side temperature is large, and the temperature is not uniform among a plurality of batteries arranged in parallel. Variation of the self-discharge having the property increases between the batteries, which causes deterioration of the battery.
[0054]
Further, when considering the solid line S in which the area ratio is changed and the alternate long and short dash line Q in which the area ratio is 2.0 in a state where the total sum of the entire heat radiation area is equal, the present embodiment in which the area ratio is changed. The thing of the solid line S can suppress the temperature rise of the battery of the exit side where temperature rises most. For this reason, the one with the one-dot chain line Q having a uniform area ratio cannot effectively suppress the temperature rise of the battery on the outlet side, so that the battery is likely to deteriorate. Battery deterioration can be prevented.
[0055]
As described above, according to the present embodiment corresponding to the solid line S in which the area ratio is changed, the battery is prevented from deteriorating and the temperature rise difference of each battery is small. It is possible to suppress variations in the amount of charge between the batteries, and to prevent a decrease in the output characteristics of the batteries.
[Brief description of the drawings]
FIG. 1 is a side view showing a cooling apparatus for an electrode laminated battery according to a first reference example of the present invention.
FIG. 2 is a side view showing a cooling device for an electrode laminated battery according to a second reference example of the present invention.
FIG. 3 is a structural diagram of a heat radiating portion showing a cooling device for an electrode laminated battery according to a third reference example of the present invention.
FIG. 4 is a side view showing a cooling apparatus for an electrode laminated battery according to a fourth reference example of the present invention.
5 is a cross-sectional view taken along the line AA in FIG.
FIG. 6 is a plan view showing a cooling device for an electrode-stacked battery according to the first embodiment of the present invention.
7 is an explanatory diagram showing a change in the shape of the radiating fin along the flow of cooling air in the cooling device of FIG. 6;
FIG. 8 is an explanatory diagram showing a temperature rise of the battery along the flow of cooling air due to a difference in heat radiation area of the heat radiation fins.
[Explanation of symbols]
1 Electrode laminated battery 3,13 Press plate (press member)
3a, 13a protrusions 9,31,31a, 31b, 31c, 31d, 31e, 31f heat dissipation Fi down

Claims (3)

A positive electrode plate and a negative electrode plate are laminated with a separator between them, and both sides of the electrode laminate are sandwiched between a pair of laminate films provided with a metal layer and a resin layer, and the peripheral edges of the pair of laminate films are firmly fixed to each other. the electrode stacked batteries for sealing the interior Te, pressed by the pair of pressing members from both sides, the pressing member, is projected outward from the periphery of the electrode stacked type battery, the protruding portions cross on the outside of the pressing member A device for cooling an electrode laminated battery having a heat radiation fin interposed therebetween, wherein a plurality of the electrode laminated batteries are stacked along a thickness direction thereof, and the pressing member is interposed between the stacked electrode stacked batteries. The plurality of electrode laminated batteries are arranged in parallel so that the heat dissipating fins provided corresponding to the respective electrode laminated batteries are located in the same cooling medium flow path. The heat radiating area of the heat radiating fins of the body outlet side, the electrode stacked type battery cooling device being characterized in that larger than the heat dissipation area of the heat radiating fins of the inlet side. 2. The cooling apparatus for an electrode laminated battery according to claim 1, wherein the pressing member is constituted by a plate-like member. 3. The apparatus for cooling an electrode laminated battery according to claim 1, wherein the plurality of electrode laminated batteries arranged in parallel are simultaneously pressed by the pressing member.

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