JP4304715B2 - 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]
The battery may be installed in various vertical directions, and may be installed with the positive lead terminal lead-out portion facing downward. In particular, in the case of a battery in which the positive electrode and the negative electrode lead are drawn out in opposite directions (hereinafter referred to as a double-sided lead-out battery), the positive electrode lead may be forced to face downward. For example, when this type of battery is stacked and connected in series and installed vertically, the positive and negative electrode leads must be staggered, so one of the two batteries has the positive electrode lead facing down. The
[0004]
In the laminated laminate battery, the electrolytic solution accumulates on the lower side in the direction of gravity. For this reason, the lead terminal located in the lower direction is liable to deteriorate due to contact with the electrolytic solution, and the lead / exterior body peeling deterioration occurs, and the sealing reliability is likely to deteriorate. In particular, in the battery, the positive electrode lead terminal is at a higher potential than the negative electrode lead terminal, and generally metal ions are likely to elute electrochemically, so that deterioration due to contact with the electrolytic solution is likely to occur. In particular, in the case of an assembled battery covered with a metal case so that the battery is clamped in a pressurized state, the laminate outer body of the battery is pressed down, so that an increase in internal pressure due to gas generation inside the battery leads. Sealing is pressed and deterioration of sealing reliability is accelerated.
[0005]
The present invention has been made in order to solve the above-described problems. The present invention has been made to alleviate the deterioration of the positive electrode lead terminal, and even when the positive electrode lead terminal is installed downward, the lead / exterior body is less likely to deteriorate. An object of the present invention is to provide an assembled battery installation method having excellent sealing reliability.
[0006]
[Means for Solving the Problems]
In the battery assembly installation method of the present invention, the lead terminals of a plurality of laminated laminate batteries that are hermetically sealed with a film of a power generator are connected to each other, and the positive electrode lead terminals are directed downward. In the method for installing a battery pack including at least one battery, the positive electrode lead terminal installed at least downward is subjected to a surface treatment.
[0007]
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,
Laminating a plurality of the laminated laminate batteries in the lamination direction,
When connecting the lead terminals to each other, arrange the positive electrode lead terminal of at least one battery facing downward in the direction of gravity,
A method of installing the battery pack, wherein to Rukoto the front surface process to the positive electrode lead terminal arranged towards the lower side.
[0008]
In addition, the present invention provides a battery body in which a lead terminal is provided on a power generating body in which at least electrode plates are laminated, and is sealed and sealed with a film so that the lead terminal is extended and sandwiched so as to be able to conduct electricity to the outside. An assembled battery installation method including a plurality of laminated laminate batteries,
When connecting the lead terminals to each other and connecting the plurality of laminated laminate batteries in series, the positive electrode lead terminal of at least one battery is arranged facing downward as seen in the direction of gravity,
A method of installing the battery pack, wherein to Rukoto the front surface process to the positive electrode lead terminal arranged towards the lower side.
[0009]
According to the present invention, since the positive electrode lead terminal facing downward is subjected to surface treatment, the deterioration of the positive electrode lead terminal installed in the lower direction is alleviated, and the lead / exterior body peeling deterioration hardly occurs. An assembled battery having excellent sealing reliability can be obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) are perspective views of a laminated laminate battery as an example of the embodiment of the present invention. The feature is that at least the positive electrode lead terminal 11 located in the lower direction is subjected to surface treatment. It has been done.
[0011]
2 (a) and 2 (b) are examples 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 can be electrically connected to the battery body 14 in which the lead terminals 11 and 12 are provided on the power generation body 3 in which at least the electrode plates are laminated, and the lead terminals 11 and 12 can be energized to the outside. 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.
[0012]
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.
[0013]
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. 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.
[0014]
In the present invention, as shown in FIG. 1, in the assembled battery installed with at least one lead terminal facing downward, the positive electrode lead terminal 11 extended downward is subjected to surface treatment.
[0015]
As shown in FIGS. 4A and 4B, when the assembled battery is installed so that the positive electrode lead terminal 13 that has not been subjected to surface treatment is on the lower side, the electrolyte solution is on the lower side in the laminated laminate battery 21. Accumulate on the lead terminal side. Since the positive electrode lead terminal is at a higher potential than the negative electrode lead terminal, and generally metal ions are likely to elute electrochemically, the positive electrode lead terminal not subjected to surface treatment deteriorates due to contact with the electrolyte. As a result, the lead / exterior body peels off and the sealing reliability deteriorates.
[0016]
In the present invention, as shown in FIG. 1, at least the positive electrode lead terminal 11 positioned in the lower direction is subjected to surface treatment and the laminated laminate battery 1 is installed, thereby avoiding these problems. An assembled battery having excellent stopping reliability can be provided.
[0017]
As shown in FIG. 1 (a), when a double-sided lead-out type laminated laminate battery is installed vertically with the positive electrode lead down, and the positive electrode lead and the negative electrode lead are the same as shown in FIG. 1 (b). The present invention is effective when the stacked laminated battery drawn out in the direction is installed vertically with the lead portion facing 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, at least the positive electrode lead terminal installed on the lower side is subjected to a surface treatment that does not deteriorate even when it comes into contact with the electrolytic solution, so that the sealing life as an assembled battery can be extended, and the sealing reliability It is possible to provide an excellent assembled battery.
[0018]
In the above example, an assembled battery in which batteries are connected in parallel has been described. However, the present invention is also effective for an assembled battery in which double-sided lead-out type laminated laminated batteries are connected in series and installed vertically. In this case, since the directions of the positive and negative electrode leads must be alternated, the positive electrode lead of each of the two batteries is installed downward. By applying a surface treatment to at least the positive electrode lead placed downward, the above-mentioned problems can be avoided, and an assembled battery with excellent sealing reliability can be provided.
[0019]
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. It is not preferable that the surface is contaminated with oil or the like, and it is preferable to perform a degreasing treatment. The degreased lead terminal is subjected to a surface treatment in order to improve the adhesion of the lead terminal surface to the sealing material and to prevent the lead terminal from deteriorating due to contact with the electrolytic solution. There are roughly two types of surface treatment methods. One is roughening and the other is a corrosion-resistant coating. Examples of the former roughening treatment include chemical etching treatment, electrolytic etching treatment, and mechanical roughening treatment. Examples of the latter corrosion-resistant coating coating treatment include a coating comprising a partially aminated phenol polymer, a phosphoric acid compound and a titanium compound, a zinc phosphate coating, and a chromate treatment. In addition, a coupling agent system may be used, and examples thereof include a titanium coupling agent and an aluminate coupling agent. Since the tab sealing deterioration is often caused by corrosion of the tab surface, among the above, the corrosion-resistant coating coating treatment is preferable. As shown in FIG. 2 (a), the lead terminals are arranged so that the positive electrode lead 11 and the negative electrode lead 12 face each other, or as shown in FIG. 2 (b), the positive electrode lead 11 and the negative electrode lead 12 are drawn out to the same side. Go through the body seal. The positive electrode lead terminal 11 installed at least downward is subjected to surface treatment.
[0020]
[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.
[0021]
[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.
[0022]
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.
[0023]
【Example】
Hereinafter, although the detail of this invention is concretely demonstrated using an Example, this invention is not limited to these Examples.
[0024]
<Example 1>
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.
[0025]
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.
[0026]
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, a 0.1 mm thick, 50 mm wide, 50 mm long aluminum plate that has been subjected to a surface treatment with a corrosion-resistant film made of a partially aminated phenol-based polymer, a phosphoric acid compound, and a titanium compound, serving as a positive electrode lead terminal; Eight pieces of active material uncoated portions were ultrasonically welded together. 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.
[0027]
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.
[0028]
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.
[0029]
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 battery.
[0030]
The lead terminal portions of the plurality of batteries thus produced were connected by lead connection portions in parallel to produce a battery pack. 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 1 mm-thick aluminum plate case so that 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. The side surface portion of the battery and the heat seal portion of the laminate film were not in contact with the inner wall of the aluminum outer package so that no pressure was applied.
[0031]
The assembled battery is fully charged at a voltage of 4.3 V, and the positive electrode lead terminal subjected to the surface treatment as shown in FIG. 1A is placed on the lower side, and it is 60 months at 90 ° C. for 2 months. When left for a while, no leakage occurred in the lead terminal sealing portion.
[0032]
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.
[0033]
<Example 2>
A laminated laminate battery in which a positive electrode lead terminal and a negative electrode lead terminal subjected to the same surface treatment as in Example 1 are drawn out in the same direction is fully charged at a voltage of 4.3 V, and the lead terminals are arranged as shown in FIG. When installed so as to be on the lower side and left for 2 months in an environment of 60 ° C. and 90%, no leakage occurred in the lead terminal sealing portion.
[0034]
<Comparative Example 1>
The laminated laminate battery in which the positive electrode lead terminal and the negative electrode lead terminal which are not subjected to surface treatment are drawn from opposite sides is fully charged at a voltage of 4.3 V, and the positive electrode lead terminal is placed on the lower side as shown in FIG. When this was left to stand for 2 months in an environment of 60 ° C. and 90%, leakage occurred in the positive electrode lead terminal sealing portion.
[0035]
<Comparative example 2>
The laminated laminate battery in which the positive electrode lead terminal and the negative electrode lead terminal not subjected to surface treatment are drawn in the same direction is fully charged at a voltage of 4.3 V so that the lead terminal is on the lower side as shown in FIG. And left in an environment of 60 ° C. and 90% for 2 months, leakage occurred at the positive electrode lead terminal sealing portion.
[0036]
<Discussion>
When the assembled batteries of Examples 1 and 2 and Comparative Examples 1 and 2 were left for 2 months in an environment of 60 ° C. and 90%, leaks did not occur in both lead terminals in Examples 1 and 2. On the other hand, in Comparative Examples 1 and 2, a leak occurred in the positive electrode lead terminal sealing portion having an untreated surface. Based on these results, surface treatment is performed on the positive electrode lead terminal located on the lower side in contact with the electrolytic solution, so that the deterioration of the positive electrode lead terminal is alleviated and the deterioration of the peeling of the lead / exterior body is suppressed. It was confirmed that it can be improved.
[0037]
【The invention's effect】
As described above, according to the present invention, since the deterioration of the positive electrode lead terminal located in the lower direction of the assembled battery is alleviated, the lead / exterior body is hardly deteriorated and the sealing reliability is excellent. An assembled battery can be obtained.
[Brief description of the drawings]
FIGS. 1A and 1B are schematic perspective views showing an embodiment of an assembled battery according to the present invention, respectively.
FIGS. 2A and 2B are schematic perspective views showing an example of a unit cell used in the present invention.
3 is a schematic cross-sectional view of the unit cell of FIG. 2 (a). FIG.
FIGS. 4A and 4B are schematic perspective views for explaining problems when the present invention is not applied. FIG.
[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 ... Surface treated positive electrode lead 12... Untreated surface negative electrode lead 13... Untreated surface positive electrode lead 14... Battery body 21... Laminated laminated battery 22. ..Collector foil

Claims (4)

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,
Laminating a plurality of the laminated laminate batteries in the lamination direction,
When connecting the lead terminals to each other, arrange the positive electrode lead terminal of at least one battery facing downward in the direction of gravity,
Installation of the battery pack, wherein to Rukoto the front surface process to the positive electrode lead terminal arranged towards the lower side. 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,
When connecting the lead terminals to each other and connecting the plurality of laminated laminate batteries in series, the positive electrode lead terminal of at least one battery is arranged facing downward as seen in the direction of gravity,
Installation of the battery pack, wherein to Rukoto the front surface process to the positive electrode lead terminal arranged towards the lower side. 3. The assembled battery installation method according to claim 1, wherein the surface treatment is a corrosion-resistant coating coating treatment. 4. The assembled battery installation method according to claim 1, 2, or 3, wherein the battery assembly comprises 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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