JP4304716B2 - How to install the battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for installing an assembled battery formed by connecting a plurality of batteries.
[0002]
[Prior art]
Conventionally, as a laminated laminated battery, a film in which a metal layer and a heat-fusible resin layer are laminated, that is, a power generation body is encapsulated by a laminate film, and the heat-fusible resin layers are heat-sealed. What is hermetically sealed is known, and a configuration in which the positive electrode lead terminal and the negative electrode lead terminal are extended from a sealing portion of a laminate film that is an exterior body is known. An assembled battery is obtained by connecting a plurality of the laminated laminate batteries. The assembled battery is configured by connecting lead terminals of a laminated laminate battery with a conductive material. Moreover, this assembled battery is often used by being covered with a case of metal or the like.
[0003]
[Problems to be solved by the invention]
In the battery, the positive electrode lead terminal is at a higher potential than the negative electrode lead terminal, and generally it can be said that the metal ions are likely to elute electrochemically. For this reason, the surface of the positive electrode lead terminal is generally deteriorated before the negative electrode lead terminal, and the positive electrode lead / exterior body is likely to be peeled off. If the lead / exterior body peels and deteriorates at either the positive electrode lead or the negative electrode lead and a leak occurs, the battery has a sealing life at that time, so the battery's sealing life is substantially It is determined by the positive electrode lead sealing life. In particular, in the case of an assembled battery that is covered with a metal case so that the battery is sandwiched in a pressurized state, the outer body made of a laminate film of the battery is pressed down, so the internal pressure rises due to gas generation inside the battery. However, the lead sealing is pressed, and the deterioration of the sealing reliability is accelerated.
[0004]
The present invention has been made to solve the above-described problems, and provides an assembled battery installation method that improves sealing reliability by preventing deterioration of the positive electrode lead terminal of the battery. With the goal.
[0005]
[Means for Solving the Problems]
The battery pack installation method of the present invention is a battery pack installation method in which the lead terminals of a plurality of laminated laminate batteries that are externally sealed and sealed with a film of a power generator are installed in the battery pack installation method . The positive electrode lead terminal is installed with the upper side direction.
[0006]
That is, the present invention seals and seals a battery body in which a lead terminal is provided on a power generating body in which at least electrode plates are laminated so that the lead terminal can be electrically connected to the outside and sandwiched with a film. An assembled battery installation method including a plurality of laminated laminate batteries,
A plurality of the stacked laminate batteries are stacked in the stacking direction,
When connecting the lead terminals to each other, an installation method of an assembled battery for all the positive electrode lead side terminals is extended, it characterized that you placed in the upper as viewed in the direction of gravity.
[0007]
In the assembled battery installation method of the present invention, since the side where the positive electrode lead terminal is extended is installed on the upper side, the deterioration of the positive electrode lead terminal is alleviated, and the positive electrode lead / exterior body peeling deterioration hardly occurs, An assembled battery having excellent sealing reliability can be obtained.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a laminated laminate battery as an example of the embodiment of the present invention, and the feature thereof is that the battery pack 1 is installed so that the positive electrode lead terminal 11 is directed upward.
[0009]
FIG. 2 shows an example of a laminated laminate battery 21 used in the assembled battery 1, and a cross-sectional view thereof is shown in FIG. Referring to FIG. 3, the laminated laminate battery 21 is capable of energizing the battery body 14 in which the lead terminals 11 and 12 are provided on the power generating body 3 in which at least the electrode plates are laminated, and the lead terminals 11 and 12 are externally energized. The film is hermetically sealed with a film so as to extend and sandwich. That is, the power generation body 3 is encapsulated by the lower exterior body 5 and the upper exterior body 6 both made of a film, and the exterior bodies around the power generation body are heat sealed to be hermetically sealed. The film refers to a thin member having flexibility with respect to bending deformation. In the present invention, a metal foil alone or a laminate of a metal foil and a resin film generally called a laminate film is preferable. The battery of this embodiment is sealed under reduced pressure by heat sealing the exterior body under reduced pressure.
[0010]
Then, an example of the manufacturing method of a lamination type laminated battery is demonstrated using FIG. First, the power generator 3 is placed in the recess 22 of the lower exterior body 5 in which the recess 22 is formed in advance. Leads 11 and 12 are previously welded to the current collector foil 23 extending from the power generator 3 at a portion 4 (welded portion). Next, a flat film having no recess is applied as the upper exterior body 6 from above. Thereafter, heat sealing is performed under reduced pressure to obtain the laminated type single cell 21 of FIG.
[0011]
Next, an embodiment of the assembled battery of the present invention will be described. A plurality of stacked laminate batteries 21 obtained as described above are stacked in the stacking direction of the electrode plates, and the positive electrode lead terminal 11 and the negative electrode lead terminal 12 are connected by the lead connection portion 2 in parallel, respectively. 1 is obtained. The lead connection portion 2 is made of a conductive material, and generally a copper plate is often used. Connection is performed by ultrasonic welding, resistance welding, rivet caulking, or the like. In the present invention, as shown in FIG. 1, the assembled battery 1 is installed so that the positive electrode lead terminal 11 faces upward. Generally, this assembled battery is covered with a case of metal or the like so that the power generator is sandwiched in a pressurized state. By doing so, the electrode plate adhesion of the battery power generator can be maintained.
[0012]
If the assembled battery is installed so that the positive electrode lead terminal 11 is on the lower side as shown in FIG. 4, the electrolyte accumulates on the positive electrode lead terminal 11 side in the direction of gravity in the laminated laminate battery 21, and the positive electrode lead terminal In contact with the electrolyte. In the battery, the positive electrode lead terminal is at a higher potential than the negative electrode lead terminal, and generally it can be said that the metal ions are likely to elute electrochemically. For this reason, the surface of the positive electrode lead terminal is generally deteriorated before the negative electrode lead terminal, and the positive electrode lead / exterior body is likely to be peeled off. If the lead / exterior body peels and deteriorates at either the positive electrode lead or the negative electrode lead and a leak occurs, the battery has a sealing life at that time, so the battery's sealing life is substantially It is determined by the positive electrode lead sealing life.
[0013]
In the present invention, as shown in FIG. 1, by installing the laminated battery pack 1 with the positive electrode lead terminal 11 facing upward, sealing deterioration of the positive electrode lead terminal that is generally more susceptible to surface deterioration than the negative electrode lead 12. , Thereby improving the sealing life of the battery itself and providing an assembled battery with excellent sealing reliability.
[0014]
The present invention is particularly effective when a stacked laminate battery in which the positive electrode lead and the negative electrode lead as shown in FIG. When both leads are pulled out in the opposite direction, when one lead is directed upward, the other lead is directed downward. Even if the lead terminal sealing portion of either the positive electrode or the negative electrode causes deterioration due to peeling, the sealing life of the assembled battery as a whole is reached at that time. Therefore, the positive electrode lead terminal that is at a higher potential than the negative electrode lead terminal in the battery and is likely to cause surface degradation due to electrochemical elution of metal ions, and the negative electrode lead terminal that is at a lower potential than the positive electrode lead. By installing the assembled battery toward the lower side, it is possible to extend the sealing life as the assembled battery, and to provide an assembled battery with excellent sealing reliability.
[0015]
Hereinafter, embodiments of each component will be described in detail.
[Lead terminal]
As the material of the lead terminal, Al, Ti, etc. can be used for the positive electrode lead terminal, Ni, Cu, phosphor bronze, Fe, brass, stainless steel, etc. can be used for the negative electrode lead terminal, and annealing treatment may be performed if necessary. . The lead terminal is preferably flat and has a thickness in the range of 20 μm to 2 mm. As for the lead terminal, the positive electrode lead and the negative electrode lead are drawn out to the same side or facing each other as shown in FIG.
[0016]
[Exterior body]
As an exterior body of a laminated laminate battery, a film-like body, that is, a thin member having flexibility exemplified by a metal foil, a resin thin film, and a laminate thereof, and having a recess formed therein is preferable. Can be used. The thickness of the film is preferably 10 to 300 μm, more preferably 50 to 200 μm. If the thickness of the film is less than 10 μm, the mechanical strength as a battery exterior body is poor, causing inconvenience such as easy breakage, and if it exceeds 300 μm, the flexibility is poor and the gas is not increased without increasing the internal pressure. It becomes inconvenient in accepting. The formation of the recess is preferably drawing (deep drawing) in which the film around the part to be formed is pressed in a slidable state and the film is pressed and formed with a punch and a die. In addition, you may fix a film around a shaping | molding part without slipping, and you may form a recessed part with the overhanging molding method which stretches and stretches a film with a die | dye. Moreover, you may produce the exterior body which has a recessed part with the injection molding method.
[0017]
[Power generation element]
The configuration and form of the power generation body 3 are not particularly limited, and for example, a plate-shaped one, a simple laminate of two or more electrode plates, or the like made of a positive electrode, a negative electrode, and a separator is used. The positive electrode is not particularly limited as long as it absorbs positive ions during discharge or discharges negative ions. (I) Metal oxide such as LiMnO ₂ , LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₂ , (II ) Conductive polymers such as polyacetylene and polyaniline, (III) General formula (R-Sm) n (R is aliphatic or aromatic, S is sulfur, m, n is m ≧ 1 Secondary battery such as a disulfide compound (dithioglycol, 2,5-dimercapto-1,3,4-thiadiazole, S-triazine-2,4,6-trithiol, etc.) As the positive electrode material, conventionally known materials can be used. Alternatively, the positive electrode active material can be mixed with an appropriate binder or functional material in the positive electrode. These binders include halogen-containing polymers such as polyvinylidene fluoride, and functional materials include conductive polymers such as acetylene black, polypyrrole, and polyaniline to ensure electron conductivity, and ion conductivity. For example, a polymer electrolyte, a composite thereof, and the like. The negative electrode is not particularly limited as long as it is a material capable of occluding and releasing cations, natural graphite, crystalline carbon such as graphitized carbon obtained by heat treatment of coal / petroleum pitch at high temperature, coal, petroleum pitch coke, Conventionally known negative electrode active materials for secondary batteries, such as amorphous carbon obtained by heat treatment of acetylene pitch coke and the like, lithium alloys such as metallic lithium and AlLi, can be used.
[0018]
Examples of the non-aqueous electrolyte solution contained in the power generator include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, N, N′-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, Examples of highly polar basic solvents that can be used as electrolytes for secondary batteries such as m-cresol include alkali metal cations such as Li, K, and Na, ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , (C ₂ F ₅ SO ₂ ) ₃ C ^{− and the} like What melt | dissolved the salt which consists of the anion of the compound to contain is mentioned. Moreover, the solvent and electrolyte salt which consist of these basic solvents can also be used individually or in combination. Moreover, it is good also as a gel electrolyte made into the polymer gel containing electrolyte solution.
[0019]
【Example】
Hereinafter, although the detail of this invention is concretely demonstrated using an Example, this invention is not limited to these Examples.
[0020]
<Example>
A lithium manganate powder having a spinel structure, a carbonaceous conductivity imparting material, and polyvinylidene fluoride were mixed and dispersed in NMP at a weight ratio of 90: 5: 5 and stirred to form a slurry. The amount of NMP was adjusted so that the slurry had an appropriate viscosity. This slurry was uniformly applied to one side of an aluminum foil having a thickness of 20 microns serving as a positive electrode current collector using a doctor blade. At the time of application, the unapplied part (the part where the current collector was exposed) was made to be slightly streaked. Next, this was vacuum-dried at 100 ° C. for 2 hours. Similarly, the slurry was applied to the other surface and vacuum-dried. At this time, the uncoated portions on the front and back sides were made to coincide. Thus, the sheet | seat which apply | coated the active material on both surfaces was roll-pressed. Eight sheets were cut out into rectangles including uncoated portions. The active material uncoated portion is a portion to be connected to the lead terminal. In this way, a positive electrode having a total theoretical capacity of 3 Ah was prepared.
[0021]
On the other hand, amorphous carbon powder and polyvinylidene fluoride were mixed in NMP at a weight ratio of 91: 9, dispersed and stirred to obtain a slurry. The amount of NMP was adjusted so that the slurry had an appropriate viscosity. This slurry was uniformly applied to one side of a copper foil having a thickness of 10 microns serving as a negative electrode current collector using a doctor blade. At the time of application, the unapplied part (the part where the current collector was exposed) was made to be slightly streaked. Next, this was vacuum-dried at 100 ° C. for 2 hours. At this time, the film thickness of the active material layer was adjusted so that the theoretical capacity per unit area of the negative electrode layer and the theoretical capacity per unit area of the positive electrode layer were 1: 1. Similarly, the slurry was applied to the other surface and dried in vacuum. Thus, the sheet | seat which apply | coated the active material on both surfaces was roll-pressed. Nine sheets were prepared by cutting this into a size 2 mm longer and wider than the size of the positive electrode, including a non-coated portion, in a rectangular shape. The active material uncoated portion is a portion to be connected to the lead terminal. In this way, a negative electrode was prepared.
[0022]
Between the positive electrode and the negative electrode prepared as described above, a microporous separator having a three-layer structure of polypropylene / polyethylene / polypropylene having a size larger by 2 mm in length and width than the size of the negative electrode (manufactured by Hoechst Celanese, Cellguard) 2300). The outermost side of the electrode was a negative electrode, and a separator was placed on the outer side of the negative electrode (in the order of separator / negative electrode / separator / positive electrode / separator /.../ negative electrode / separator). The positive electrode active material uncoated portion and the negative electrode active material uncoated portion were aligned in the opposite direction. Next, an aluminum plate having a thickness of 0.1 mm, a width of 50 mm, and a length of 50 mm serving as a positive electrode lead terminal and eight positive electrode active material uncoated portions were collectively ultrasonically welded. Similarly, a nickel plate having a thickness of 0.1 mm, a width of 50 mm, and a length of 50 mm serving as a negative electrode lead terminal and nine negative electrode active material uncoated portions were ultrasonically welded together. In addition, the positive electrode lead terminal and the negative electrode lead terminal were heat-sealed with a sealing material made of a film-like acid-modified polypropylene having a thickness of 30 μm in advance on a portion to be sealed by the exterior body prior to the above-described welding connection.
[0023]
On the other hand, a film made of a laminate of 25 μm nylon, 40 μm soft aluminum, and 30 μm acid-modified polypropylene was prepared as a laminate film for an exterior body, cut into a predetermined size, and deep-drawn into a cup shape. The electrode laminate was housed in the cup molding portion of this laminate film. Next, place the above laminated film that has been cut into a predetermined size without being molded on the cup molding part containing the power generating element so that the sealing surface faces inward. It was.
[0024]
Next, the lead terminals drawn out via the cup collars are sandwiched between the film collars and the lid, the lead terminal lead parts 2 are heat-sealed, and then the lead terminal lead parts One side (hereinafter referred to as “long side A”) of the long sides (hereinafter referred to as “long side A” and “long side B”) was not heat-sealed. The lead terminal lead-out part was heat-sealed under slightly weaker conditions so that the seal strength of the lead terminal sealing part could be easily compared between levels.
[0025]
Next, the long side A was inclined downward, and an electrolyte solution was injected into the electrode laminate from the gap between the long side B, which was the last unsealed portion. The electrolytic solution uses 1 mol / liter LiPF ₆ as a supporting salt and a mixed solvent of propylene carbonate and methyl ethyl carbonate (weight ratio 50:50) as a solvent. The amount of liquid injection was an amount corresponding to 5% of the volume of the power generation element. After pouring, vacuum degassing was performed. Finally, the long side B was heat-sealed in a reduced pressure state using a vacuum sealing machine to complete the unit cell.
[0026]
The lead terminal portions of the plurality of single cells produced in this way were connected by lead connection portions so as to be in parallel to produce an assembled battery. A copper plate, which is a conductive material, was used for the lead connection portion and connected by ultrasonic welding. The assembled battery was covered with a case of an aluminum plate having a thickness of 1 mm, and the power generation body was held in a pressurized state by the pressure of the aluminum exterior body. By doing so, the electrode plate adhesion of the battery power generator is maintained. In addition, the side part of the battery and the heat seal part of the laminate film were not in contact with the inner wall of the aluminum outer package so that no pressure was applied.
[0027]
When the above assembled battery is fully charged at a voltage of 4.3 V, the positive lead terminal is placed on the upper side as shown in FIG. 1, and left at 60 ° C. in a 90% environment for two months. There was no leak in the part.
[0028]
In the examples and comparative examples of the present specification, the presence or absence of leakage was confirmed by confirming the leakage trace (precipitate, etc.) at the root of the lead terminal lead portion.
[0029]
<Comparative example>
When the same assembled battery as in the example was fully charged at a voltage of 4.3 V, the positive electrode lead terminal was placed on the lower side as shown in FIG. 4, and left at 60 ° C. in a 90% environment for 2 months. Leakage occurred at the positive lead terminal sealing portion.
[0030]
<Discussion>
When the assembled batteries of Examples and Comparative Examples were allowed to stand for 2 months in an environment of 60 ° C. and 90%, no leakage occurred in both the positive electrode lead terminal and the negative electrode lead terminal in the example. On the other hand, in the comparative example, a leak occurred in the positive electrode lead terminal sealing portion. Based on these results, when a positive electrode lead terminal at a high potential in the battery is installed on the lower side where the electrolyte is accumulated, metal ions are eluted from the positive electrode lead terminal, resulting in surface deterioration, and peeling / deterioration of the lead / laminate outer package. It was confirmed that it is likely to occur. On the other hand, in the example, since the positive electrode lead terminal was placed on the upper side, no leakage occurred and it was confirmed that the sealing reliability was improved.
[0031]
【The invention's effect】
As described above, according to the present invention, since the deterioration of the positive electrode lead terminal is alleviated, it is difficult for the positive electrode lead / exterior body to be peeled and the assembled battery having excellent sealing reliability can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an embodiment of an assembled battery according to the present invention.
FIG. 2 is a schematic perspective view showing an example of a unit cell used in the present invention.
FIG. 3 is a schematic cross-sectional view of the unit cell of FIG.
FIG. 4 is a schematic perspective view for explaining a problem when the present invention is not applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery assembly 2 ... Lead connection part 3 ... Electric power generation body 4 ... Welding part 5 ... Lower exterior body 6 ... Upper exterior body 11 ... Positive electrode lead terminal 12 ... Negative electrode lead terminal 14 ... Battery body 21 ... Laminated laminate battery 22 ... Recess 23 ... Current collecting foil

Claims (2)

A laminated laminate in which a battery body provided with a lead terminal on at least a power generating body in which electrode plates are laminated is hermetically sealed with a film so that the lead terminal is extended and sandwiched so as to be able to conduct electricity to the outside. A method for installing an assembled battery including a plurality of batteries,
A plurality of the stacked laminate batteries are stacked in the stacking direction,
Said lead terminals to each other when connecting, installation method of an assembled battery for all the positive electrode lead side terminals is extended, it characterized that you placed in the upper as viewed in the direction of gravity. 2. The assembled battery installation method according to claim 1, comprising a laminated laminate battery in which a positive electrode lead terminal and a negative electrode lead terminal are drawn out in directions facing each other.

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