JP3959448B2 - Batteries, composite batteries and vehicles - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a battery such as an assembled battery in which a unit cell is accommodated, a composite assembled battery having a plurality of such batteries, and a vehicle including such a battery or a composite assembled battery, and in particular, from the outside. The present invention relates to a battery, a composite assembled battery, and a vehicle that can reduce vibration transmitted to the battery and reduce the possibility of the battery being damaged by vibration.
[0002]
[Background]
An electric vehicle driven by an electric motor, a conventional hybrid vehicle of an internal combustion engine and an electric motor, and the like have been developed and are gradually being used in recent years. In a vehicle to which such an electric motor is applied, the configuration of a battery that stores electricity as a power source is very important. In such a battery mounted on a vehicle, it is generally required to have a large capacity, a small size, and be able to be charged quickly, but in addition, since it is used in a vehicle with a lot of vibration, It is a very important condition that sufficient durability against vibration, that is, vibration resistance is ensured.
[0003]
However, in an assembled battery in which a plurality of unit cells that have been widely used as in-vehicle batteries are connected in the past, when used in an environment with vibrations, the terminals and busbars that connect the battery and the battery have their vibrations. There was a possibility that the fatigue would increase, the resistance would increase, and the fatigue could break.
In order to avoid such a situation, for example, in the assembled battery described in Japanese Patent Application Laid-Open No. 2001-229896, the battery is firmly fixed to the vehicle body to maintain durability against vibration. . However, since this method has no damping effect, vibrations cannot be damped. In some cases, there is a problem that the assembled battery resonates with the vibrations of the vehicle body, resulting in large vibrations, and sufficient vibration resistance is ensured. It was hard to say.
[0004]
DISCLOSURE OF THE INVENTION
The present invention has been made in view of such problems, and the object thereof is vibration resistance capable of exhibiting its performance with high durability without being destroyed even in an environment with a lot of vibration. The object is to provide a battery such as an assembled battery, which is sufficiently secured.
Another object of the present invention is to further combine an assembled battery having sufficient vibration resistance that can exhibit its performance with high durability without being destroyed even in an environment with a lot of vibration. It is providing the composite assembled battery comprised.
Furthermore, another object of the present invention is to provide a vehicle in which a battery such as an assembled battery or a composite assembled battery having sufficient vibration resistance is mounted, and thereby, for example, an electric motor can be driven appropriately. .
[0005]
In order to solve the above-described problems, according to a first aspect of the present invention, a battery of the present invention includes at least one unit cell, an outer case that houses the unit cell, and the element in the outer case. A resin group that covers the battery and is supported by the outer case, and at least one external elastic body that supports the outer case and is installed at a predetermined location.
[0006]
In a battery having such a configuration, first, the unit cell is supported by two elastic bodies, a resin formed inside and an external elastic body, and vibrations applied from the outside of the battery are sufficiently damped. It can be transmitted to the unit cell or its junction with the tab or bus bar.
In addition, the battery having such a structure supports a unit cell having a predetermined mass and an outer case with two elastic bodies, a resin formed inside and an external elastic body, and has two or more degrees of freedom. It can be considered as a mass spring model. Therefore, by controlling the mass and the spring constant and damping of each elastic body, the frequency of the resonance peak of the mass spring system can be shifted to an arbitrary frequency. Normally, the vibration generated in a vehicle such as an automobile is 100 Hz or less. Therefore, by shifting the resonance frequency of the mass spring system to a region higher than 100 Hz, the battery having such a configuration mounted on the vehicle reaches the resonance frequency. Nevertheless, the possibility of damage to the interior of the battery due to vibration is significantly reduced.
[0007]
According to the second aspect of the present invention, the composite assembled battery of the present invention includes a plurality of batteries according to the present invention, and the plurality of batteries are connected in series, in parallel, or in series and parallel composite connection. It is.
[0008]
Moreover, according to the 3rd viewpoint of this invention, the vehicle of this invention has the battery which concerns on this invention, or the composite assembled battery which concerns on this invention.
[0009]
As described above, according to the present invention, a battery such as an assembled battery having sufficient vibration resistance that can exhibit its performance with high durability without being destroyed even in an environment with a lot of vibrations. Can be provided.
In addition, a composite assembled battery that is configured by further combining an assembled battery with sufficient vibration resistance that can exhibit its performance with high durability without being destroyed even in an environment with a lot of vibration. Can be provided.
Furthermore, it is possible to provide a vehicle that is equipped with a battery such as an assembled battery or a composite assembled battery with sufficient vibration resistance, and can appropriately drive an electric motor, for example.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An assembled battery, a composite assembled battery, and a vehicle according to an embodiment of the present invention will be described with reference to FIGS.
First, an assembled battery according to an embodiment of the present invention will be described with reference to FIGS.
[0011]
FIG. 1 is a perspective view for explaining a schematic configuration of the assembled battery 20 of the present embodiment.
2 is a diagram showing the configuration of the assembled battery 20 shown in FIG. 1. FIG. 2 (A) is a plan view, FIG. 2 (B) is a front view, and FIG. 2 (C) is a side view. is there.
As illustrated, the assembled battery 20 includes 24 thin batteries (unit cells) 10, bus bars 21, terminals 22 and 23, an internal filling resin (resin group) 24, an external case 25, and an external elastic body 26.
[0012]
Each of the thin batteries (unit cells) 10 is a unit battery constituting the assembled battery 20 and is a lithium secondary battery having a predetermined voltage and a predetermined capacity. In the present embodiment, the 24 thin batteries are connected so as to ensure a predetermined voltage and a predetermined capacity as a whole.
The 24 unit cells 10 are sequentially stacked with an interval of about 1 to 2 mm, and the lower case unit cell 10 is arranged 1 to 2 mm away from the inner wall surface of the outer case 25. 25 is housed and installed.
[0013]
The unit cell 10 is effectively a thin laminate battery.
Since the laminated battery does not have a useless space in the battery itself, it is very effective for making the assembled battery 20 compact. In addition, since the outer wall of the laminated battery is a polymer film such as nylon, the dynamic spring constant of the unit cell is lower than that of the can battery, and the efficiency of vibration reduction is increased.
The thickness of the laminated battery is preferably 1 mm to 10 mm. If the thickness is greater than 10 mm, heat tends to be trapped inside the unit cell, which is not appropriate from the viewpoint of heat dissipation. If the thickness is less than 1 mm, sufficient capacity cannot be ensured. In the range of 1 mm to 10 mm, in addition to such heat dissipation and efficiency, the effect of reducing vibrations and the effect of easy manufacturing are sufficiently exhibited, which is very effective. is there.
[0014]
The configuration of the thin battery 10 and the connection method of the 24 thin batteries 10 will be described in more detail with reference to FIGS.
FIG. 3 is a diagram showing the configuration of one thin battery 10, FIG. 3 (A) is a plan view showing the whole, and FIG. 3 (B) is a sectional view taken along the line II-II in FIG. 3 (A). is there.
As described above, the thin battery 10 is a lithium-based thin secondary battery, and includes two positive plates 101, five separators 102, two negative plates 103, a positive terminal 104, a negative terminal 105, and an upper battery exterior. It has the member 106, the lower battery exterior member 107, and the electrolyte which is not shown in figure.
Among these, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 109.
The number of the positive electrode plate 101, the separator 102, and the negative electrode plate 103 is not limited at all. For example, the power generation element 109 can be configured by one positive electrode plate 101, three separators 102, and one negative electrode plate 104. it can. The number of positive plates, negative plates and separators may be selected as appropriate.
[0015]
The positive electrode plate 101 constituting the power generation element 109 is preferably, for example, a Li—Mn composite oxide.
Specifically, the positive electrode plate 101 is made of a positive electrode active material such as a metal oxide, a conductive material such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene in a weight ratio of, for example, 100: What was mixed at a ratio of 3:10 was applied to both surfaces of a metal foil such as an aluminum foil as a positive electrode side current collector, dried, rolled, and then cut into a predetermined size. The mixing ratio of the polytetrafluoroethylene aqueous dispersion is its solid content. As the positive electrode active material, for example, lithium nickelate (LiNiO)₂), Lithium manganate (LiMnO)₂), Lithium cobaltate (LiCoO)₂Lithium composite oxide such as), chalcogen (S, Se, Te) compounds and the like are suitable.
These materials are relatively easy to diffuse the heat generated in the thin battery, reduce the expansion due to the expansion of the terminal due to the heat transfer to the terminal, and can suppress the tensile stress transmitted from the terminal to the battery exterior member described later as much as possible. It becomes. Specifically, it is possible to reduce the possibility of applying a tensile stress to the interface between the tab and the resin by extending the tab by electrically heating the tab portion.
[0016]
The negative electrode plate 103 constituting the power generation element 109 is preferably a crystalline carbon material or an amorphous carbon material.
Specifically, the negative electrode plate 103 is made of, for example, an organic material such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of the fired body is mixed, for example, at a solid content ratio of 100: 5, dried, and pulverized to support carbonized styrene butadiene rubber on the carbon particle surfaces. In this case, a binder such as an acrylic resin emulsion is mixed in a weight ratio of, for example, 100: 5, and this mixture is mixed with a metal foil such as a nickel foil or a copper foil as a negative electrode side current collector. It is applied to both sides, dried, rolled, and then cut into a predetermined size.
In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. However, when used as a power source for an electric vehicle or the like, it is advantageous because there is no sudden drop in output.
[0017]
In addition, the separator 102 of the power generation element 109 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 and may have a function of holding an electrolyte. The separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation, thereby blocking the current. It also has.
Note that the separator 102 of the present embodiment is not limited to a single layer film such as a polyolefin, and a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic non-woven fabric is used. Can do. By forming the separator 102 in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided. Further, instead of the separator 102, a gel electrolyte or an intrinsic polymer electrolyte can be used.
[0018]
The above power generation element 109 is laminated in such an order that the positive electrode plate 101 and the negative electrode plate 103 are alternately arranged from above and the separator 102 is positioned between the positive electrode plate 101 and the negative electrode plate 103. One separator 102 is laminated on each of the upper and lowermost parts. Each of the two positive plates 101 is connected to the positive terminal 104 made of metal foil via the positive current collector 104a, while the two negative plates 103 are connected to the negative current collector 105a. Is connected to the negative electrode terminal 105 which is also made of metal foil.
The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include aluminum, an aluminum alloy, copper, and nickel. Can include nickel, copper, stainless steel or iron. These metals are particularly suitable as components of thin batteries in terms of the resistance value, linear expansion coefficient, and resistivity of the metal, and even when the operating temperature is changed, the tensile stress transmitted from the terminal to the battery exterior member described later is transmitted. It is possible to suppress as much as possible.
Further, both the positive electrode side current collector 104a and the negative electrode side current collector 105a in this example extend the aluminum foil, nickel foil, copper foil, and iron foil that constitute the current collector of the positive electrode plate 104 and the negative electrode plate 105. However, the current collectors 104a and 105a can be formed of separate materials and parts.
The power generation element 109 is sealed by the upper battery exterior member 106 and the lower battery exterior member 107 (sealing means).
[0019]
  A method of connecting such a thin battery 10 will be described with reference to FIGS.
  Figure4These are 1st figures which show the connection method of the thin battery 10.4(A) is a diagram showing parallel connection,4(B) is a figure which shows the serial connection for a comparison.
  Figure5These are 2nd figures which show the other connection methods of the thin battery 10.5(A) is a diagram showing parallel connection,5(B) is a figure which shows the serial connection for a comparison.
  When the assembled battery 20 having a plurality of thin batteries 10 is configured by electrically connecting the thin batteries 10,4(A) and figure5A parallel connection as shown in (A) is preferable because it can maintain a stronger structure against an applied external force.
[0020]
  Figure4The connection method shown in (A) is such that the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction, and the first thin battery 10a The second thin battery 10b is juxtaposed substantially on the same plane, and the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are electrically connected by the first bus bar 21a. Similarly, the negative terminal 105 of the first thin battery 10a and the negative terminal 105 of the second thin battery 10b are electrically connected by the second bus bar 21b.
[0021]
  Also figure5The connection method shown in (A) is such that the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction, and the first thin battery 10a The first thin battery 10a and the second thin battery 10b are stacked such that the vertically upward surface faces the vertically downward surface of the second thin battery 10b, and the positive electrode of the first thin battery 10a is stacked. The terminal 104 and the positive terminal 104 of the second thin battery 10b are welded and electrically connected. Similarly, the negative terminal 105 of the first thin battery 10a and the negative terminal 105 of the second thin battery 10b are connected. It is welded and electrically connected.
[0022]
When connected in series as shown in FIG. 4B and FIG. 5B, the positive terminal 104 of each thin battery 10a, 10b is reversed as indicated by the arrow due to the applied external force. Although twisting of the phase occurs, in the connection structure as shown in FIGS. 4A and 5A, since the positive terminals 104 and the negative terminals 105 of the thin batteries 10a and 10b are connected, The stress generated in the batteries 10a and 10b has the same phase, and the twist generated in the terminals 104 and 105 can be suppressed as much as possible.
As a result, it is possible to reduce the possibility of peeling at the interface between the terminal and the battery exterior member. In addition, when the metal of the positive electrode terminal and the metal of the negative electrode terminal are different, the tensile stress generated in the terminal lead-out portion is also different and may cause interface peeling. It is possible to make the tensile stress generated in the terminal lead-out portion of the battery substantially equal, and to prevent interface peeling.
[0023]
The bus bar 21 is a plate-like conductive member for connecting the terminals of the 24 thin batteries 10 and connecting them to the assembled battery terminals 22 and 23 led out from the external case 25 as described above.
The first bus bar 21 a connects each positive electrode terminal 104 of each thin battery 10 and the substantially cylindrical assembled battery positive electrode terminal 22 led out from the outer case 25.
The second bus bar 21 b connects each negative electrode terminal 105 of each thin battery 10 and the substantially cylindrical battery-assembled negative electrode terminal 23 led out from the outer case 25.
[0024]
The terminal 22 and the terminal 23 are terminals for voltage output from the assembled battery to the outside. The terminal 22 is a positive terminal and the terminal 23 is a negative terminal.
As described above, the positive terminal 22 is connected to the positive terminal 104 of each thin battery 10 in the assembled battery 20 via the first bus bar 21a, and the negative terminal 23 is connected to the second bus bar 21a. It is connected to the negative electrode terminal 105 of each thin battery 10 in the assembled battery 20.
[0025]
The internal filling resin (resin group) 24 is a resin that is densely filled between constituent parts of the 24 thin batteries (unit cells) 10 and the bus bar 21 in the outer case 25. Reduce the transmission of vibration to the part. As described above, in the outer case, the thin batteries 10 stacked at an interval of about 1 to 2 mm and the bus bar 21a for connecting them are arranged so that the lowermost thin battery 10 is 1 to 2 mm from the inner bottom surface of the outer case 25. It is accommodated and installed so as to be arranged at a position some distance away. The inner filling resin 24 is filled in the outer case 25 so as to fill the space between these components, and thus the thin battery 10 is sealed in the outer case 25.
Here, the hardness of the resin 24 is desirably 5 to 95 according to JIS-A. This is because if the hardness JIS-A is less than 5, the resin is too soft and the thin battery 10 or the bus bar 21 is likely to sink into the resin under its own weight.
[0026]
The resin 24 also has a function of protecting the components such as the unit cell 10 from the external environment. Specifically, the resin 24 is required to have performances such as waterproofness, moisture proofing, cold cycle performance, heat stability, insulation, and flame retardancy. In order to satisfy these performances, the resin 24 is preferably composed of, for example, an epoxy resin, a urethane resin, a nylon resin, an olefin resin, or the like. In particular, the urethane-based resin has excellent performance as described above and is suitable as the resin 24. In addition, the resin 24 may be a resin such as silicon rubber or an olefin-based elastomer, and any resin material can be used as the internal filling resin 24 as long as the above-described performances are satisfied.
[0027]
It is also effective to use a plurality of these resin materials in combination. With such a configuration, it is possible to arrange an appropriate resin for various parts of the outer case 25 and perform effective vibration isolation.
Specifically, for example, the type of resin formed between the inner wall of the outer case 25 and the lowermost unit cell 10 adjacent thereto, and the resin formed between the upper unit cells 10 above it. It is effective to adopt a configuration in which the resin formed between the outer case 25 and the unit cell 10 has a smaller absolute value of hardness than the resin formed between the unit cells 10. This is because, in order to reduce as much as possible that the vibration applied to the outer case 25 from the outside is transmitted to the unit cell 10, the entire 24 elementary electron groups may be vibrationally insulated from the outer case 25. Desirably, if the resin formed between the inner wall of the outer case 25 and the unit cell 10 and the resin formed between the unit cells are softer, even if the outer case 25 vibrates, the vibration is absorbed by the resin 24 therebetween. That is, the vibration is insulated and it is difficult to transmit the vibration.
[0028]
Similarly, when the elementary electrons 10 are configured in three or more layers as in the present embodiment, the resin group located in the center has the highest absolute value of hardness, and the absolute value of hardness as it goes to the outer case It is also effective to configure so that becomes smaller, that is, softer.
Of course, even in such a case, a resin having a larger absolute value than the hardness of the outermost resin, that is, a hard resin may be used in a unified manner other than the outermost resin.
[0029]
The resin 24 has a dielectric loss tangent of 10 to 1 kHz in a temperature range of −30 to 80 ° C.^-3~ 5.0 × 10^-1It is desirable to be in the range. 1.0 × 10^-3In a lower state, since the resin is too soft and vibration is transmitted, there is a high possibility that the unit cell will lose its own weight.^-1This is because a sufficient damping effect cannot be obtained in a larger state.
The vibration reducing effect depends on the loss tangent, and this loss tangent can be obtained by a dynamic viscoelasticity test. However, in this test, it is difficult to accurately measure the loss tangent for a relatively soft resin. Therefore, the characteristic is predicted by using a dielectric loss tangent that is substantially equivalent to the loss tangent, and here the characteristic is defined.
When the loss tangent can be accurately measured, the loss tangent is also 1.0 × 10^-3~ 5.0 × 10^-1It is desirable to be in the range.
[0030]
Further, like the hardness, this dielectric loss tangent is equal to the resin formed between the inner wall of the outer case 25 and the unit cell 10 and the resin formed between the unit cells. However, it is desirable that the absolute value is smaller than the resin between the batteries. This is also the same as the reason for the hardness described above.
[0031]
  The absolute value of the dynamic spring constant of the resin 24 is preferably smaller than the dynamic spring constant of the mass spring system in which the unit cell 10 is connected to the external case via a tab.
  Dynamic spring of resin 24constantIn the mass spring system in which the bus bar connected to the outer case 25 is a spring and the unit cell 10 is a mass, an extremely small spring of air that exists when there is no resin 24 group.constantA spring such as a bus barconstantIt has the effect of reducing the stress relating to the bus bar and the terminal. Therefore, when the absolute value is larger than the dynamic spring constant of the mass spring system in which the unit cell 10 is connected to the external case 25 via the tab, the possibility that the stress is related to the tab portion and the bus bar increases. This is because it is difficult to say that the proper resin 24 is selected.
  In general, the smaller the vibration transmissibility, the greater the effect on vibration isolation. However, the vibration transmissibility greatly depends on the dynamic spring constant of the object. Therefore, it is effective to reduce the dynamic spring constant in order to improve the vibration isolation performance.
[0032]
In the present embodiment, the resin 24 is filled in the outer case 25, but basically, in the space other than the unit cell 10 in the outer case 25, the resin 24 is only applied to a part thereof. It may be configured such that is formed.
The resin 24 needs to be formed so as to support these components in the outer case 25 in the vicinity of the unit cell 10, etc., but the other space portion may be formed in a part thereof. Even if it is formed entirely, the effects and effects related to the present invention are produced, and the object of the present invention is achieved.
For example, to reduce vibration, it is effective to set a resin group in a part where the amplitude of the unit cell and the bus bar is large. However, especially when it is desired to reduce the vibration of the unit cell, it is only applied to the part around the unit cell. The resin 24 may be formed. It is also effective to wrap only the bus bar portion with resin in order to reduce the vibration of the bus bar portion.
In any case, forming the resin 24 only partially as such can reduce the mass of the entire assembled battery and is effective in that respect.
[0033]
However, on the other hand, in consideration of the purpose of reduction of vibration transmission rate of the resin 24 as described above, waterproof property, moisture proof property, thermal cycle property, heat stability, insulation property, flame retardancy, etc., in the assembled battery 20, In the space other than the unit cell 10 in the outer case 25, it is desirable that the resin 24 is formed in 95 to 100 vol%. In particular, when considering the heat dissipation of the assembled battery 20, the heat dissipation is deteriorated if air exists in the space. Therefore, the resin 24 may be formed in a space of 95 vol% or more as much as possible. desirable.
[0034]
The outer case 25 is a metal case that accommodates the 24 thin batteries 10 and the bus bars 21 having the above-described structure and is filled with the resin 24 and sealed.
[0035]
The external elastic body 26 is an elastic body provided at the four corners of the lower surface of the external case 25 in order to reduce vibration between thin batteries as much as possible.
As the external elastic body 26, an elastic body having a hardness lower than that of the internal filling resin 24 is used. With such a configuration, the thin battery 10 and the inner filling resin 24 in the outer case 25 move as a unit with respect to the outer elastic body 26, for example, a tab portion of the thin battery 10 in the outer case 25 or the like. In particular, it is possible to prevent vibration from being applied as much as possible to a portion that is vulnerable to vibration. In addition, it is possible to shift the frequency of the assembled battery 20 as a whole, which is preferable.
Note that any number of external elastic bodies can be set at any location of the case.
[0036]
The external elastic body is preferably a member such as a mechanical spring, a rubber-based elastic body, or an elastomer-based elastic material.
The external elastic body is required to be able to arbitrarily change its absolute value in addition to exhibiting the action of spring and damping. Therefore, a mechanical spring that can set this freely is effective. The mechanical spring includes a structural spring such as a spring spring, a leaf spring, or a disc spring.
Also, rubber-based materials and elastomer-based materials are sufficiently effective because these physical quantities can be changed freely to some extent.
Therefore, these materials are preferable as the external elastic body.
[0037]
The assembled battery 20 having such a configuration forms a mass-spring system having two or more degrees of freedom with a unit cell as a mass portion and a tab portion and a resin group as a spring portion.
Now, this mass-spring system is simplified, the unit cell is mass M1, the mass of the outer case is M2, the spring constant K1 of the internal elastic body of the internal filling resin, the damping C1, and the spring constant of the external elastic body installed in the external case Considering a two-degree-of-freedom mass spring model comprising K2 and damping C2 as shown in FIG. 6, the natural angular frequencies (resonant vibration frequencies) ω1 and ω2 of this mass-spring system are substantially determined by the following equation (1). Is done.
[0038]
[Expression 1]
ω1, ω2 = (a + c) / 2 ± √ ((a / 2−b / 2) 2 + bc) (1)
However, ω1 <ω2,
a = (K1 + K2) / M1,
b = K2 / M1,
c = K2 / M2
And also
ω1: primary resonance frequency (natural angular frequency)
ω2: secondary resonance frequency (natural angular frequency)
M1: Mass of the unit cell
M2: Mass of the outer case
K1: Spring constant of internal resin
K2: Spring constant of the external elastic body
It is.
[0039]
Therefore, the resonance peak frequencies ω1 and ω2 control the unit cell mass M1, the outer case mass M2, the internal resin spring constant K1 and damping C1, and the external elastic body spring constant K2 and damping C2. This makes it possible to shift to an arbitrary frequency.
Since the assembled battery 20 of the present embodiment is not a complete two-degree-of-freedom type or multi-degree-of-freedom type mass-spring damping system, actually, the above equation (1) does not completely describe the characteristics and operations. Can not. However, it is possible to perform performance tuning with reference to this equation.
[0040]
  Therefore, specifically, the spring constant of the elastic body is obtained by experiments, the masses of the unit cells and the outer case are measured, and the resonance frequency is obtained from equation (1). Then, tuning is performed so that the resonance frequency is set to 100 Hz or higher so that it does not fall within the frequency range of vibration generated in the automobile. Note that the mass may be adjusted by adding an additional mass.
  If the number of external elastic bodies changes, the total springconstantAnd damping changes. Therefore, the number of external elastic bodies installedconstantIt is effective to control this. This is because after the assembled battery is formed, the resonance frequency control of the assembled battery can be finely adjusted by the number, thickness, material, and the like of the external elastic body.
[0041]
Thus, in the assembled battery 20 of the present embodiment, the external elastic body 26 is installed in the outer case 25, and the resin 24 is injected into the space formed when the thin battery 10 is accommodated in the outer case 25. Therefore, vibrations and the like input from the outside of the assembled battery 20 can be transmitted with sufficient attenuation to the thin battery 10, the tab, and the like constituting the assembled battery 20.
Furthermore, the unit cell thickness, unit cell surface density, resin group thickness, unit density, type, external case mass, external elastic body thickness, installation position, material, etc. are controlled. Thus, in the vibration system having at least two degrees of freedom with the unit cell of the assembled battery as the mass part and the tab part and the resin group as the spring part, the primary resonance frequency and the secondary resonance frequency are arbitrarily set, The resonance frequency of the assembled battery is removed from the frequency range of the vibration frequency generated in the automobile. Therefore, the assembled battery 20 does not reach the resonance frequency as long as it is used on a vehicle.
In particular, in the internal filling resin 24 and the external elastic body 26, vibration energy can be efficiently reduced because vibration energy is converted into heat energy by resin damping.
[0042]
Next, a composite assembled battery according to an embodiment of the present invention configured by combining a plurality of such assembled batteries 20 will be described with reference to FIGS. 7 and 8.
FIG. 7 is a perspective view of the composite battery pack 30, FIG. 8 (A) is a plan view, FIG. 8 (B) is a front view, and FIG. 8 (C) is a side view.
As shown in FIGS. 7 and 8A to 8C, the composite assembled battery 30 is configured by electrically connecting six assembled batteries 20. In the composite battery pack 30, six battery packs 20 are stacked such that the terminals 22 and 23 face the same direction. That is, the terminals 22 and 23 of the assembled battery 20 located at the m-th stage and the terminals 22 and 23 of the assembled battery 20 located at the (m + 1) -th stage are oriented in the same direction. The m + 1-stage assembled battery 20 is stacked.
[0043]
Then, the assembled battery positive terminals 22 of all the assembled batteries 20 facing in the same direction are electrically connected by an external connection positive terminal 31 that connects the composite assembled battery 30 and the outside. Similarly, the assembled battery negative terminals 23 of all the assembled batteries 20 facing in the same direction are electrically connected by the external connection negative terminal 32. The external connection positive electrode terminal 31 has a substantially rectangular flat plate shape, and the assembled battery 20 of the assembled battery 20 in which a plurality of terminal connection holes having diameters into which the assembled battery positive electrode terminal 22 can be inserted or press-fitted are stacked. It is processed at a pitch equal to the pitch between the positive electrode terminals 22 for use. Similarly, the external connection negative terminal 32 has a terminal connection hole.
In the composite battery 30, all the battery terminals 22, 23 to which the insulating cover 33 made of an insulating material is connected so that the battery terminals 22, 23 are not exposed to the outside of the composite battery 30. It is equipped so that it may cover. The insulating cover 33 is shown only in FIG. 7 in a transparent view for convenience of explanation.
Then, the six assembled batteries 20 stacked in this way are connected to both side surfaces by flat connecting members 34 and further fastened and fixed by fixing screws 35.
[0044]
According to the composite assembled battery configured as described above, since the composite assembled battery is configured by combining a plurality of assembled batteries, it is possible to easily realize a battery having a desired capacity and a desired voltage suitable for the purpose of use. it can.
At that time, since the composite battery pack is configured without complicated connection, the failure rate of the composite battery pack due to poor connection can be reduced.
In addition, when an equivalent relatively large-capacity battery is configured as one assembled battery, the number of connected unit cells increases extremely, and the entire assembled battery deteriorates due to deterioration of one cell. Although the possibility increases, if it is a composite battery pack that further combines battery packs in this way, even if one battery pack fails or deteriorates, it is easily repaired by replacing only that battery pack can do.
In the present embodiment, a composite assembled battery in which six assembled batteries are connected in parallel is illustrated. However, it may be connected in series, or a combination of series and parallel may be combined. .
[0045]
Next, a vehicle according to an embodiment of the present invention on which such a composite battery pack 30 is mounted will be described with reference to FIG.
FIG. 9 is a diagram schematically showing a vehicle equipped with the composite battery pack.
As shown in FIG. 9, the composite battery pack 30 is mounted, for example, under the floor of the vehicle 1 as shown in the figure, and is used as a power source for an electric motor for driving wheels or a power source for an on-vehicle electric circuit or the like.
In such an environment, as the vehicle 1 travels, a lot of vibration is generated in the vehicle, and there is a high possibility that a defective battery such as an interface peeling between the tab and the resin occurs. If the interface peeling between the tab and the resin occurs even in one of a large number of batteries, there is a possibility that the entire vehicle composite battery may become unusable.
However, in the terminal device 30 of the present embodiment, the vibration can be sufficiently reduced in each assembled battery, so that the possibility of the separation of the tab-resin interface due to the vibration is significantly reduced.
As described above, it is very effective to apply the composite battery pack of the present embodiment to a vehicle. In other words, the vehicle having the composite battery pack of the present embodiment is a highly reliable vehicle. I can say that.
[0046]
The embodiment described above is described in order to facilitate understanding of the present invention, and is not described in order to limit the present invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the present invention.
For example, the number of the thin batteries constituting the assembled battery, the number of the assembled batteries constituting the composite battery, the connection method of the thin batteries constituting the battery assembly, and the connection method of the assembled battery constituting the composite battery are described above. However, the number and connection method (series connection, parallel connection, series-parallel composite connection) may be selected and set as appropriate based on the required electric capacity, voltage, and the like. For example, in the above-described embodiment, the present invention has been described by exemplifying an assembled battery including two or more thin batteries. For example, only one unit cell is accommodated in an external case, or only one unit cell is included. In particular, when it is desired to prevent vibration from external vibrations, it is sufficiently effective to make only one unit cell the same configuration as that of the above-described embodiment, and such a case is also within the scope of the present invention. It is clear that there is.
[0047]
In the present embodiment, the case where the assembled battery and the composite assembled battery according to the present invention are applied to a vehicle has been mainly described. However, the present invention may be applied to any vehicle other than a vehicle. The battery according to the present invention is particularly effective in a place where high battery sealing reliability should be ensured or where vibration resistance is required, and may be applied to such an arbitrary object. .
[0048]
【Example】
The example of the more concrete structure of the assembled battery which concerns on this invention, the effect of the vibration reduction in each assembled battery, etc. are demonstrated more concretely, showing the three examples of Examples 1-3.
[0049]
Example 1
As shown in FIG. 10, in the assembled battery of Example 1, two laminated exterior cells are installed in parallel in a metal outer case, and resin B is used as an internal elastic body for all the spaces in the outer case. The resin A is provided as an external elastic body at the four corners of the outer case.
The mass of the outer case is 500 g, the mass of the unit cell is 80 g, the thickness of the unit cell is 5 mm, and the thickness of the external elastic body is 5 mm. Further, in the outer case, the lower unit cell is disposed at a position 2 mm away from the inner wall of the outer case in the thickness direction, and the Uekawa unit cell is also separated from the lower unit cell by 2 mm in the thickness direction. Placed in position. A resin B is filled between the inner wall of the outer case and the unit cell and between the unit cells.
[0050]
Resin B has a specific gravity of 1.2, a hardness of JIS-A90, a dielectric loss tangent (1 kHz) of 0.005, a glass transition temperature of 110 ° C., and a linear expansion coefficient of 5.0 × 10.^-5(1 / ° C.), volume resistivity 4.0 × 10¹⁶It is a two-component mixed room temperature solidification type epoxy resin having (Ω · cm) and dielectric breakdown strength of 25 (kVmm).
Resin A has a specific gravity of 0.98, a hardness of JIS-A21, a dielectric loss tangent (1 kHz) of 0.038, a glass transition temperature of −57 ° C., and a linear expansion coefficient of 2.2 × 10.^-4(1 / ° C), volume resistivity 1.0 × 10¹²This is a two-component mixed room temperature solidification type urethane resin having (Ω · cm) and dielectric breakdown strength of 23 (kV / mm).
A mass-spring system model of this assembled battery is shown in FIG. The ratio of the dynamic spring constant of the tab portion to the dynamic spring constant of the resin B in the system of the unit cell mass and the thickness of the resin B was 60%.
[0051]
Conventional structure having the same configuration as that of the assembled battery of Example 1 except for the spectrum of vibration transmissibility of the assembled battery of Example 1 having such a configuration, and the comparison target without including the internal elastic body and the external elastic body. FIG. 12 shows a spectrum of vibration transmissibility of the battery pack having the structure. As shown in FIG. 12, in the assembled battery of Example 1, it is confirmed that the resonance peak is shifted to the high frequency side and is 100 Hz or more.
[0052]
Further, for the assembled battery having such a configuration, the acceleration ratio was detected and the average reduction rate (average vibration reduction rate) was detected.
Here, the acceleration ratio is measured by measuring the acceleration value of the response vibration obtained when an acceleration pickup is installed at approximately the center of the upper part of the assembled battery and forcedly excited at 10 Hz, 50 Hz, and 100 Hz, respectively. It detects by comparing with the acceleration value obtained on the same conditions with respect to the assembled battery of a structure, and calculating the ratio. Therefore, when the acceleration ratio is 1.0, it means that the absolute value of the acceleration of the assembled battery of Example 1 having resin and the assembled battery not having resin is the same, and the acceleration ratio is 0.0. A value of .about.1.0 indicates that the vibration is reduced with respect to the forced excitation, and an acceleration ratio greater than 1.0 means that the vibration is amplified by resonating with the forced vibration.
The average reduction rate is detected by obtaining an average of the reduction amounts of the acceleration ratio detected when the vibration is applied in the range of 10 to 300 Hz, and the larger this value is, the more the vibration is reduced.
[0053]
As a result of detection, the acceleration ratio of the assembled battery of Example 1 is 0.25 when the frequency of forced excitation is 10 Hz, 0.30 when 50 Hz, and 0.33 when 100 Hz. Reduction of vibration was confirmed in the frequency.
Moreover, the average reduction rate of 10-300 Hz of the assembled battery of Example 1 was 71% with respect to the assembled battery of the conventional structure, and the reduction of vibration was confirmed as a whole.
[0054]
Example 2
In the assembled battery of Example 2, as shown in FIG. 13, four laminated outer cells are installed in parallel in a metal outer case, and resin C is used as an internal elastic body in all spaces in the outer case. The resin A is solidified at room temperature, and the same resin A as in Example 1 is provided as an external elastic body at the four corners of the outer case.
The outer case has a mass of 550 g, the unit cell has a mass of 80 g, the unit cell has a thickness of 5 mm, and the external elastic body has a thickness of 5 mm. Further, in the outer case, the lowermost unit cell is disposed at a position 2 mm apart from the inner wall of the outer case in the thickness direction, and thereafter each unit cell is sequentially disposed at a position 2 mm apart from each other in the thickness direction. In addition, resin C is filled in the space between the inner wall of the outer case and the unit cells and between the unit cells.
[0055]
Resin C has a specific gravity of 1.0, a hardness of JIS-A60, a dielectric loss tangent (1 kHz) of 0.005, a glass transition temperature of 100 ° C., and a linear expansion coefficient of 1.0 × 10.^-4(1 / ° C), volume resistivity 1.0 × 10¹⁵(Ω · cm), dielectric breakdown strength 20 (kV / mm) two-component mixed room temperature solidification type olefin resin.
A mass-spring system model of this assembled battery is shown in FIG. In addition, the ratio of the dynamic spring constant of the tab part in the system of the unit cell mass and the thickness of the resin C and the dynamic spring constant of the resin C was 95%.
[0056]
Conventional structure having the same configuration as that of the assembled battery of Example 2 except for the spectrum of vibration transmissibility of the assembled battery of Example 2 having such a configuration, and the comparison target without including the internal elastic body and the external elastic body. FIG. 15 shows a spectrum of vibration transmissibility of the assembled battery having the structure. As shown in FIG. 15, also in the assembled battery of Example 2, it is confirmed that the resonance peak is shifted to the high frequency side and is 100 Hz or more.
Further, as a result of detecting the acceleration ratio and the average reduction rate as described above for the assembled battery having such a configuration, the acceleration ratio is 0.94 when the frequency of forced excitation is 10 Hz, and is 0 when the frequency is 50 Hz. It was 0.94 in the case of .90 and 100 Hz, and a reduction in vibration was confirmed at each excitation frequency.
Moreover, the average reduction rate of 10-300 Hz of the assembled battery of Example 1 was 7% with respect to the assembled battery of the conventional structure, and the reduction of vibration was confirmed as a whole.
[0057]
Example 3
As shown in FIG. 2, in the assembled battery of Example 3, 24 laminated unit cells are placed in 6 parallel-4 series in a metal outer case, and resin D is used as an internal elastic body in the outer case. Then, the resin A is solidified at room temperature, and the same resin A as in Examples 1 and 2 is provided as an external elastic body at the four corners of the outer case.
The external case has a mass of 1000 g, the unit cell has a mass of 80 g, the unit cell has a thickness of 5 mm, and the external elastic body has a thickness of 5 mm. Further, in the outer case, the lowermost unit cell is disposed at a position 2 mm apart from the inner wall of the outer case in the thickness direction, and thereafter each unit cell is sequentially disposed at a position 1 mm apart from each other in the thickness direction. The resin D is filled in the space between the outer case inner wall and the unit cells and between the unit cells.
[0058]
Resin D has a specific gravity of 1.03, a hardness of JIS-A35, a dielectric loss tangent (1 kHz) of 0.07, a glass transition temperature of −35 ° C., and a linear expansion coefficient of 2.0 × 10.^-4(1 / ° C), volume resistivity 0.6 × 10¹⁵It is a two-component mixed room temperature solidification type urethane-based resin having (Ω · cm) and dielectric breakdown strength of 18 (kV / mm).
A simplified and generalized mass-spring model for this assembled battery is as shown in FIG. The ratio of the dynamic spring constant of the tab portion to the dynamic spring constant of the resin D in the system of the unit cell mass and the thickness of the resin D was 90%.
[0059]
The vibration transmissibility spectrum of the assembled battery of Example 3 having the above-described configuration, and the conventional structure having the same configuration as that of the assembled battery of Example 3 except that the internal elastic body and the external elastic body are not provided. The spectrum of the vibration transmissibility of the assembled battery having the structure is shown in FIG.
As shown in FIG. 16, also in the assembled battery of Example 3, it is confirmed that the resonance peak is shifted to the high frequency side and is 100 Hz or more.
Further, as a result of detecting the acceleration ratio and the average reduction rate as described above for the assembled battery having such a configuration, the acceleration ratio is 072 when the forced excitation frequency is 10 Hz, and 0.80 when the forced excitation frequency is 50 Hz. In the case of 100 Hz, it was 0.97, and it was confirmed that the vibration was reduced at each excitation frequency.
Moreover, the average reduction rate of 10-300 Hz of the assembled battery of Example 1 was 19% with respect to the assembled battery of the conventional structure, and the reduction of vibration was confirmed as a whole.
[0060]
FIG. 17 shows the characteristics of the resins B, C and D as the internal elastic bodies and the resin A as the external elastic bodies used in Examples 1 to 3 described above.
Thus, in any of the assembled batteries of Examples 1 to 3, the resonance peak is shifted to 100 Hz or higher on the high frequency side, and the vibration is reduced at each frequency as a whole. Was confirmed.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a schematic configuration of an assembled battery according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of the assembled battery illustrated in FIG. 1;
FIG. 3 is a diagram illustrating a configuration of a unit cell housed in the assembled battery illustrated in FIG. 1;
4 is a first diagram showing a method for connecting a plurality of unit cells shown in FIG. 3; FIG.
FIG. 5 is a second diagram showing a method of connecting a plurality of unit cells shown in FIG. 3;
6 is a diagram illustrating a mass spring system model of the assembled battery illustrated in FIG. 2; FIG.
FIG. 7 is a perspective view for explaining a schematic configuration of a composite battery pack according to an embodiment of the present invention.
FIG. 8 is a diagram showing a configuration of the composite battery pack shown in FIG. 7;
9 is a diagram schematically showing a vehicle according to an embodiment of the present invention having the composite battery pack shown in FIG. 7. FIG.
FIG. 10 is a diagram showing a configuration of a more specific first example of an assembled battery according to the present invention.
11 is a diagram illustrating a mass spring system model of the assembled battery illustrated in FIG. 10;
FIG. 12 is a diagram showing a spectrum of vibration transmissibility of the assembled battery shown in FIG. 10 and the conventional assembled battery.
FIG. 13 is a diagram showing a configuration of a more specific first example of the battery pack according to the present invention.
14 is a diagram showing a mass spring system model of the assembled battery shown in FIG. 13; FIG.
FIG. 15 is a diagram showing a spectrum of vibration transmissibility of the assembled battery shown in FIG. 13 and the conventional assembled battery.
FIG. 16 is a diagram showing vibration transmissibility spectra of the assembled battery shown in FIG. 2 and a conventional assembled battery as a more specific third example of the assembled battery according to the present invention.
FIG. 17 is a table showing the characteristics of resins B, C, D as internal elastic bodies and resin A as external elastic bodies used in the first to third examples described above.
[Explanation of symbols]
1 ... Vehicle
10 ... Thin battery
10a: first thin battery
10b ... second thin battery
101 ... Positive electrode plate
102 ... Separator
103 ... Negative electrode plate
104: Positive terminal
105 ... Negative electrode terminal
106: Upper battery exterior member
107 ... Lower battery exterior member
109 ... Power generation element
110 ... heat fusion region
111 ... Terminal lead-out part
20 ... Battery
21a ... first bus bar
21b ... second bus bar
22 ... Positive terminal
23 ... Negative terminal
24. Internal filling resin
25 ... Outer case
26. External elastic body
30 ... Composite battery pack
31 ... Positive terminal for external connection
32 ... Negative terminal for external connection
33 ... Insulation cover
34. Connecting member
35 ... Fixing screw

Claims (18)

At least one unit cell;
An outer case for housing the unit cell;
A resin group formed so as to cover the unit cell in the outer case and to support the outer case;
At least one external elastic body for supporting the outer case and installing it in a predetermined place;
Have
The battery characterized in that the hardness of the external elastic body is smaller than the hardness of the resin group . The battery according to claim 1, wherein the resonance frequencies ω <b> 1 and ω <b> 2 calculated by the equation (2) are configured to be 100 Hz or more.
ω1, ω2 = ( a + c ) / 2 ± √ ((a / 2-b / 2) 2 + bc)   ... (2)
However, ω1 <ω2,
a = (K1 + K2) / M1,
b = K2 / M1,
c = K2 / M2
And also
ω1: primary resonance frequency (natural angular frequency)
ω2: secondary resonance frequency (natural angular frequency)
M1: Mass of the unit cell
M2: Mass of the outer case
K1: Spring constant of internal resin
K2: Spring constant of the external elastic body
It is. The resin groups, said filled inside the outer case, battery according to claim 1 or 2 for supporting the unit cells to the outside case The battery according to any one of claims 1 to 3, wherein the assembled battery includes at least two or more of the unit cells, and the two or more batteries are covered with the resin group and accommodated in the outer case. The battery according to claim 1, wherein the resin group has a hardness JIS-A of 5 or more and 95 or less. The 10-1 kHz dielectric loss tangent of the said resin group exists in the range of 1.0 * 10 < ^-3 > -5.0 * 10 < ^-1 > in the temperature range of -30-80 degreeC. The battery described. The battery according to claim 1, wherein the dynamic spring constant of the resin group has a smaller absolute value than a dynamic spring constant of a mass spring system in which a unit cell is connected to an external case via a tab. The battery according to claim 1, wherein the resin group includes one or a plurality of resins. The battery according to claim 8, wherein the resin group includes one or more resins selected from an epoxy resin, a urethane resin, a nylon resin, and an olefin resin. Having two or more of the unit cells,
The resin group includes a first resin formed between an inner wall of the outer case and a unit cell disposed opposite thereto, and a second resin formed between adjacent unit cells. The battery according to claim 8, wherein the absolute value of the hardness of the first resin is smaller than the absolute value of the hardness of the second resin. Having two or more of the unit cells,
The resin group includes a first resin formed between an inner wall of the outer case and a unit cell disposed opposite thereto, and a second resin formed between adjacent unit cells. The battery according to claim 8, wherein an absolute value of dielectric tangent of the first resin is smaller than an absolute value of hardness of the second resin. The battery according to any one of claims 1 to 11, wherein the resin group is formed in 95 to 100 vol% of a space other than the unit cell in the outer case. The battery according to claim 1, wherein the external elastic body is any one of a mechanical spring, a rubber-based elastic material, and an elastomer-based elastic material. The battery according to any one of claims 1 to 13, wherein the unit cell is a thin laminated battery having a thickness of 1 to 10 mm in the stacking direction of electrodes. The battery according to any one of claims 1 to 14, wherein a positive electrode material of the unit cell is a Li-Mn composite oxide. The battery according to claim 1, wherein the negative electrode material of the unit cell is either a crystalline carbon material or an amorphous carbon material. A composite assembled battery comprising a plurality of the batteries according to any one of claims 1 to 16, wherein the plurality of batteries are connected in series, in parallel, or in series and parallel composite connections. A vehicle equipped with the battery according to any one of claims 1 to 16 or the composite assembled battery according to claim 17.

Images