JP3460933B2 - Electrode element for polymer battery and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer battery electrode element and a method for manufacturing the same, and more particularly to a polymer battery electrode element with a reduced lead space and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electronic devices such as mobile phones and portable notebook computers have been remarkably made cordless and have high performance. Even in secondary batteries which are the power source of these electronic devices,
Small size, light weight, thinness, large capacity, and high voltage are required. In order to meet such demands, a lithium non-aqueous solvent having a thickness of about 0.5 mm is provided with an electrode element in which a positive electrode layer, a polymer electrolyte layer and a negative electrode layer are superposed and integrated into a sheet shape (thin type). Batteries are also known (eg US Pat. No. 5,296,318).

FIG. 4 is a cross-sectional view showing a main part of a constitutional example of the electrode element for the polymer electrolyte battery. Figure 4
In the above, 1 is an electrolyte-retaining polymer-electrolyte sheet that functions as a separator (for example, a polymer such as hexafluoropropylene-vinylidene fluoride copolymer and an ethylene carbonate solution such as a lithium salt ... a non-aqueous electrolyte solution). System), 2 is a positive electrode sheet formed by laminating an active material such as a metal oxide, a positive electrode layer containing a non-aqueous electrolyte and an electrolyte retaining polymer on a current collector, 3 is an active material that absorbs and releases lithium ions, It is a negative electrode sheet formed by laminating a negative electrode layer containing a non-aqueous electrolytic solution and an electrolyte retaining polymer on a current collector.

The positive electrode sheet 2 and the negative electrode sheet 3
Is a positive electrode sheet containing a positive electrode active material on both main surfaces of a current collector layer having a current collector terminal projecting at one end edge when pressure contact between metal or ceramic pressure rollers is made, or After the negative electrode sheets containing the negative electrode active material are pressure-bonded and integrated with each other, lead terminals are welded to the current collector terminals protruding at the edges.

Examples of the active material of the positive electrode sheet 2 include lithium manganese oxide, manganese dioxide, lithium-containing cobalt oxide, lithium-containing nickel cobalt oxide, and lithium-containing amorphous vanadium pentoxide.
Examples thereof include chalcogen compounds. Examples of the negative electrode active material include bisphenol resin, polyacrylonitrile, a calcined product such as cellulose, and a calcined product of coke and pitch, which are natural or artificial graphite, carbon black, acetylene black, Ketjen black, nickel powder. Alternatively, a form containing nickel powder or the like may be adopted.

Further, the electrolyte-based sheet 1 is made of a non-aqueous solvent such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, lithium perchlorate, lithium hexafluorophosphate, and boron. Lithium tetrafluoride, lithium arsenic hexafluoride, lithium trifluoromethanesulfonate, etc. dissolved in 0.2 to 2 mol / l can be mentioned.

In manufacturing such a lightweight and flexible lithium polymer battery, the lamination of the electrode elements is premised. That is, the positive electrode sheet 2, the separator (polymer-electrolyte system) sheet 1, and the negative electrode sheet 3, which are electrode elements, are combined in a laminated form, and the laminated body is integrated in the process of passing between rigid pressure rollers (laminator rollers). To do. In pressing and unifying by the pressing roller, the laminated body is heated and heated to a required temperature in the process of being conveyed by the endless belt so that the pressing and unifying can be easily performed.

Thereafter, the integrated electrode element is cut and separated into a predetermined shape and size, and a required external lead is attached.
The back side of the positive electrode sheet 2 and the negative electrode sheet 3 is covered with a resin film for protection / seal layer (sealing layer) or the plasticizer contained in the electrode element is extracted and then wound to form a battery outer can. Enclose inside. Then, if necessary, supply electrolyte.
After the injection, the battery is made by sealing the opening of the battery outer can while pulling out the external leads.

[0009]

However, in the case of an electrode element for a polymer battery constructed by laminating and integrating the above electrode members, there are the following inconveniences. That is, when stacking and integrating the positive electrode sheet 2, the separator sheet 1, and the negative electrode sheet 3, the edge portions of the separator sheet 1 are projected in order to ensure electrical insulation separation between the two electrode sheets 2 and 3. The size and shape are set so that

FIG. 5 schematically shows this state, in which the width (height) of the positive electrode sheet 2 and the negative electrode sheet 3 is
It is selected and set to be smaller than the width (height) of the separator sheet 1, and the current collector terminal 2a of the positive electrode sheet 2 and the current collector terminal 3a of the negative electrode sheet 3 are attached to the edge portion of the separator sheet 1. It is protruding. That is, when packaging the electrode element for the polymer battery, it is necessary to avoid contact or short circuit between the current collector terminal 2a and the current collector terminal 3a. Therefore, when positioning along the positive electrode sheet 2 group and the negative electrode sheet 3 group respectively, the current collector terminals 2a and 3a are pulled out horizontally, the lead space becomes large, and as a result, the volume energy density It will be reduced.

The present invention has been made in view of such circumstances, and at least one of the electrode sheets is covered with a separator sheet on the surface of the region where the connection terminals are led out, so that the electrical connection between the connection terminals is improved. It is an object of the present invention to provide a polymer electrode element capable of reducing the lead space while ensuring electrical insulation, and consequently improving the volumetric energy density of a battery, and a method for manufacturing the same.

[0012]

According to a first aspect of the present invention, an end projecting to the outside of the electrode element body is pressure-bonded integrally with one main surface side of a separate sheet made of a polymer having an electrolyte retention property.
A positive electrode sheet for a polymer battery including a current collector having a child portion, and a terminal portion that is pressure-bonded integrally to the other main surface side of the separate sheet and projects to the outside of the electrode element body.
A polymer battery electrode element comprising a negative electrode sheet for a polymer battery including a current collector , wherein the separate sheet
The polymer battery positive electrode sheet and the polymer
Cover at least one of the terminals of the battery negative electrode sheet
It is an electrode element for polymer batteries, which has a protrusion . A second aspect of the present invention, the electrode main terminal portions on one main surface side of the separate sheet consisting of electrolyte retention polymer
Heating the positive electrode sheet for a polymer battery which is protruded to the outside of the unit body, a laminate formed by placing a negative electrode sheet for a polymer battery is protruded to the outside of the electrode main portion of the terminal portion on the other principal surface side from both sides And a step of passing the outer peripheral surface of a pair of rotating pressure rollers, which are arranged in parallel with each other, and pressure-bonding / integrating the heated laminated body, wherein the pressure is applied. The polymer is characterized in that the roller has an outer peripheral surface formed of an elastic layer, and the edges of the separate sheet are selected and set so as to extendably cover the projecting surfaces of the terminal portions of the two electrode sheets. It is a manufacturing method of a battery electrode element.

In the invention of claim 1, an electrolyte-retaining polymer-electrolyte sheet functioning as a separator, an active material such as a metal oxide, a non-aqueous electrolyte and a positive electrode layer containing an electrolyte-retaining polymer are used as a current collector. Conventionally, a positive electrode sheet formed by laminating a negative electrode layer containing an active material that absorbs and releases lithium ions, a non-aqueous electrolyte solution and an electrolyte retaining polymer on a current collector It is used. Here, the edge portion of the separate sheet needs to extendably cover the protruding surface of the collector terminal of at least one of the electrode sheets. That is, in order to improve the volume energy density, both electrode sheets lead (project) the current collector terminals they have to one end edge side. At this time, since contact between adjacent current collector terminals or another adjacent electrode sheet is likely to occur, in order to prevent or eliminate this, the projecting surface of the current collector terminal is extendedly covered. It Therefore, the entire surface of one of the electrode sheets may be covered with a separate sheet, or the protruding surfaces of the collector terminals of both electrode sheets and the entire surfaces of both electrode sheets may be covered with separate sheets. In this sense, at least one of the current collector terminal projecting surface of the positive electrode sheet and the current collector terminal projecting surface of the negative electrode sheet may be extendedly covered. Good. The above-mentioned extensional coating of the current collector terminal projecting surface with the separate sheet corresponds to pressure-bonding and integration with the pressure roller in the process of manufacturing the polymer battery electrode element, and the outer peripheral surface is subjected to elastic body lining. This can be easily achieved by using a pressure roller and enhancing the load followability with respect to the heated electrode member laminate. In the invention of claim 2, the laminated / integrated body of the polymer battery electrode member is
Generally, the procedure is as follows. First, an endless belt that requires heat resistance to withstand a temperature of at least 40 to 200 ° C. is prepared as a transport mechanism. Here, the endless belt conveys the laminated body of the polymer battery electrode member to the pressure roller while reinforcing, so to speak, without causing deformation of the polymer battery electrode member. A thickness, a material, a structure, or the like that can transmit a required temperature to the laminated body is desired. For example, if the material is tetrafluoroethylene fiber, the thickness
A tape or sheet of about 0.1 to 0.5 mm is preferable.

Further, the traveling drive mechanism for traveling the pair of endless belts has a drive roller as a drive source and a guide roller for guiding the traveling. The pair of heat-resistant endless belts are fixed. By traveling at approximately the same speed in the direction, it is possible to avoid the occurrence of frictional damage on the outer peripheral surface of the laminate.

The laminated body of the polymer battery electrode members conveyed and supplied by the endless belt is sandwiched and held by the endless belt, and is opposed to each other so as not to cause deformation or damage. It is desirable to have a structure in which the distance between the main surfaces of the endless belt can be adjusted. That is, in the form of pressing one endless type belt, the movable type pressure unit is arranged so as to be able to move forward and backward, and by the movement of the movable type pressure unit, the facing distance of the pair of endless type belts is adjusted, It is preferable to adopt a configuration in which the laminated body of the electrode members is reinforced by an endless belt while being held and conveyed in a sandwiched manner.

In a second aspect of the present invention, the pair of heating units for heating the laminated body of the electrode members for the polymer battery sandwiched and conveyed by the endless belt from both sides are, for example, electric resistance heat generation, hot water or steam. It was used as a heat source.

The pair of pressure rollers that integrate the laminated body of the polymer battery electrode members that have passed (conveyed) through the endless belt are made of, for example, ceramic or metal with an outer peripheral surface lined with silicone rubber. Alternatively, it is made of heat-resistant resin. The width and diameter of the pressure roller are set in accordance with the laminated body of the polymer battery electrode members to be pressure-integrated. The pressure roller is arranged adjacently in the running direction of the endless belt, and a stack of electrode members for polymer batteries, which is held and conveyed by the endless belt, is continuously supplied.

Therefore, by rotating the endless belt at substantially the same speed, it becomes possible to avoid the occurrence of frictional damage on the outer peripheral surface of the laminated body while integrating them. The rotation and drive of the pressure roller may be performed by an independent rotation drive source, but a configuration using the transport drive source of the endless belt may be used.

According to the first aspect of the invention, in the polymer battery electrode element, at least one of the electrode layers has a lead-out (projecting) surface of the collector terminal insulated by the extension of the separate sheet, and the corresponding connecting terminal or Contact with the other electrode layer is easily suppressed or avoided. In other words, the possibility of contact with another adjacent current collector terminal or the other electrode layer is largely eliminated, so there is no need to bend and horizontally lead the current collector terminal, and the lead space can be reduced.

According to the second aspect of the present invention, due to the pressure contact of the pressure roller having the elastic layer as the pressure-bonding surface and the followability of the load, the lead-out surface of the current collector terminal can be made easier by the protruding edge portion of the separate sheet. And the lead-out surfaces of the current collector terminals are insulated from each other and covered. Therefore, in order to avoid mutual contact, the bending and
Since horizontal derivation is unnecessary, the lead space can be reduced, and it is possible to provide a polymer electrolyte battery having a large volume energy density.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments will be described below with reference to FIGS.

FIG. 1 is an enlarged perspective view showing the essential structure of the electrode element according to the embodiment. In FIG. 1, 4 is a separate sheet made of a polymer having an electrolyte retention property, 5 is a positive electrode sheet for polymer battery which is pressure-bonded to one main surface side of the separate sheet 4, and 6 is the separate sheet 4.
It is a negative electrode sheet for a polymer battery, which is pressure-bonded integrally with the other main surface side.

Here, the separate sheet 4 is, for example, a polymer sheet having an electrolyte retaining property such as a hexafluoropropylene-vinylidene fluoride copolymer, and the positive electrode sheet 5 is
For example, a positive electrode layer 5a containing an active material such as a metal oxide and an electrolyte retaining polymer is laminated on a current collector 5b. The negative electrode sheet 6 is, for example, a negative electrode layer 6a containing an active material that absorbs and releases lithium ions and an electrolyte retaining polymer, and is laminated on a current collector 6b.

In FIG. 1, 5c is a connecting terminal for the positive electrode which is electrically connected / projected to the current collector 5b, and 6c is electrically connected / projected (projects) to the current collector 6b. This is a connection terminal for the negative electrode. In the configuration of the electrode element for polymer battery, the edge portion of the separate sheet 4 is connected to the current collectors 5b (6b) of at least one of the electrode sheets 5 (6), and the connection terminals 5c (6c) are connected. ) Is extendedly covered with 4a.

Next, a manufacturing example of the electrode element according to the present invention will be described.

FIG. 2 is a side view showing a schematic structure of an electrode element manufacturing apparatus used in this manufacturing example. In FIG.
7a and 7b are a pair of heat-resistant endless belts that are drivably arranged by a pair of supports fixedly arranged on a base (not shown). , Drive to drive.

Here, a pair of heat-resistant endless belts
7a and 7b are made of, for example, tetrafluoroethylene fiber, have a thickness of about 0.2 mm, a width of 27 cm, and a total length of about 70 cm, and run in a fixed direction by a rotation driving roller 8a and rotation guide rollers 8b, 8c. Is configured. Further, the pair of heat-resistant endless belts 7a and 7b are arranged substantially parallel to each other so that the facing distance can be arbitrarily set, and the laminated body 9 of the polymer battery electrode members is sandwiched and held and conveyed. There is.

Further, the distance between the surfaces of the endless belts 7a, 7b corresponds to the thickness of the laminated body 9 of the electrode members for the polymer battery sandwiched and held by the endless belts 7a, 7b. In order to heat the laminated body 9 of the polymer battery electrode members sandwiched and held by the endless belts 7a and 7b from both sides, a pair of endless belts 7a and 7b are provided on the back surface side. Heating unit
10a and 10b are arranged. Where heating unit 1
0a and 10b are, for example, electric heating elements and are set so that the endless belts 7a and 7b can be heated and maintained at a temperature of about 80 to 180 ° C.

The means for adjusting the distance between the surfaces of the endless belts 7a, 7b is, for example, an air cylinder to move the pressing body forward and backward so as to face the endless belts 7a, 7b. In other words, the air cylinder supported by the cylinder fixing plate is mounted and arranged on the opposite surface side of the pressure unit, and the air cylinder is moved forward and backward by adjusting the cylinder fixing plate, so that the pressure unit is moved forward and backward, and thus the endless type. Adjust the distance between belts 7a and 7b.

Further, 11a and 11b are a pair of pressure rollers (laminating rollers) for integrating the laminated body 9 of the polymer battery electrode members that have passed through the endless belts 7a and 7b. The pressure rollers 11a and 11b are made of, for example, tool steel and have a diameter of 7 to 15 cm, a roller width of 25 to 50 cm, and an outer peripheral surface lined with a silicone rubber having a thickness of 0.5 to 10 mm. It adopts a structure that rotates at speed.

If necessary, the pressure rollers 11a and 11b have an electrically heating body electrically connected to the temperature control mechanism built therein so that the pressure rollers 11a and 11b can be heated and held at about 30 to 100 ° C. It may be configured. Also, for example, a pressure roller
It is also possible to adopt a bearing mechanism in which the rotary bearing of 11a is fixed and the rotary bearing of the pressure roller 11b can be slightly slidably moved to the pressure roller 11a side by the load.

Further, the pressure rollers 11a, 11b are the chain sprocket with an overload safety device mounted on the rotary shafts of the driving rollers 8a of the endless belts 7a, 7b, the chain, and the pressure rollers 11a, 11b. It is configured to rotate via a chain sprocket attached to the rotating shaft of 11b, and in synchronization with the rotation conveyance of the endless belts 7a and 7b,
The pressure rollers 11a and 11b are driven to rotate.

On the other hand, an electrolyte-retaining polymer-electrolyte sheet (for example, polymer system such as hexafluoropropylene-vinylidene fluoride copolymer) sheet 4 having a function of a separator and a collector terminal 5c are projected at one end. A positive electrode sheet (for example, a positive electrode layer containing an active material such as a metal oxide and an electrolyte retaining polymer laminated on a current collector) 5 and a negative electrode having a current collector terminal 6c protruding and provided at one end edge. A laminate 9 is prepared by laminating a sheet (for example, a negative electrode layer containing an active material that absorbs and releases lithium ions and an electrolyte retaining polymer on a current collector) 6.
Here, the separate sheet 4 has a thickness of about 0.4 to 0.9 mm,
Both electrode electrode sheets 5 and 6 have a thickness of 0.1 to 0.2 mm and a width of 20 to 60
at about mm, the current collector terminal 5c, the length of projection 6c is about 5 to 20 mm.

Next, the pressure unit is moved forward and backward corresponding to the laminate 9 forming the electrode element for the polymer battery to set the facing surface distance between the endless belts 7a and 7b. afterwards,
While driving and rotating each drive roller 8a of the traveling mechanism to drive the endless belts 7a and 7b in a predetermined direction, the laminated body 9 forming the electrode element is moved to the endless belts 7a and 7b.
Then, the sheet is supplied between the opposing surfaces and the holding and conveying is started.

In the carrying process, the endless belts 7a and 7b are held at a predetermined temperature (generally 80 to 180 ° C.) by the heating units 10a and 10b whose heat generation is adjusted in advance.
The laminated body 9 forming the electrode element is heated via. In addition,
At this point in time, since the pressure of the pressure unit is maintained at a proper interval between the facing surfaces of the endless belts 7a and 7b, there is no fear of friction or damage to the electrodes located on the outer peripheral surface, and The occurrence of collapse and deformation is also prevented and suppressed.

The laminated body 9 which is primarily heated in the process of conveying the endless belts 7a, 7b is rotated by the pressure rollers 11a, 11b in synchronism with the driving / running of the endless belts 7a, 7b. The pressure rollers 11a and 11b are supplied to the pressurizing rollers 11a and 11b to perform pressure integration. At this time, since the outer peripheral surfaces of the pressure rollers 11a and 11b are composed of the elastic bodies 11a 'and 11b', the elastic bodies 11a and 11b of the pressure rollers 11a and 11b are formed.
The outer peripheral surface composed of a ′ and 11b ′ follows the pressure force (load) applied between the opposing outer peripheral surfaces, so that the protruding edge of the separate sheet 4 covers the end surfaces of the electrode sheets 5 and 6 while covering them. The laminated body 9 is pressed and integrated.

FIG. 3 is a cross-sectional view showing the structure of a main part of a polymer electrolyte battery constructed by packaging the electrode element thus manufactured. In FIG. 3, 4 is a separate sheet, 5 is a positive electrode sheet, 6 is a negative electrode sheet, 5c is a current collector terminal of the positive electrode sheet 5, 6c is a current collector terminal of the negative electrode sheet 6, and 12a and 12b are lead wires. Reference numeral 13 is an exterior resin sheet in which the electrode elements are liquid-tightly packaged while leading out the lead wires 12a and 12b. In this configuration example, the negative electrode sheet 6 is entirely covered with the separate sheet 4.

In the structure of the above electrode element, each collector terminal 5
c and 6c are sufficiently or reliably electrically insulated / separated from the adjacent collector terminals 6c and 5c and the collectors 6b and 5b of the other electrode sheets 6 and 5, respectively. , Electrode sheet 5,
It can be derived and packaged according to 6. That is, it is possible to adopt a sufficient or reliable electrical insulation / separation configuration without bending the current collectors 6b and 5b in a direction intersecting the electrode sheets 5 and 6 (for example, in a plane). The lead space of, for example, 5 to 10 mm can be reduced by the space required for bending the current collectors 6b and 5b.

The reduction of the lead space is achieved by packaging the electrode element in which the electrode sheets 5 and 6 are laminated in three layers, respectively, and the polymer electrolyte battery has a length of 158 mm and a width.
When the size is 51 mm and the thickness is 6 mm, the capacity is increased by about 20.4%.

The present invention is not limited to the above examples, and various modifications can be made without departing from the spirit of the invention.

[0041]

According to the invention of claim 1, the lead-out (protruding) surface of the collector terminal of at least one of the electrode sheets is insulated by the extension of the separate sheet, and the corresponding connecting terminal or the other electrode. Contact with the seat is easily suppressed or avoided. That is, the fear that the current collector terminals adjacent to each other are electrically contacted with each other is eliminated, and the lead space is reduced, so that the volume energy density can be easily improved.

According to the second aspect of the present invention, due to the pressure contact of the pressure roller and the followability of the load, the lead-out surface of the current collector terminal is easily wrapped by the protruding edge portion of the separate sheet to insulate. To be covered. Further, since contact between the current collector terminals is avoided, the current collector terminals can be led out along the electrode sheet, so that the electrode element with reduced lead space can be easily provided. That is, it greatly contributes to the provision of a polymer electrolyte battery having a large volume energy density.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a main configuration of an electrode element according to an embodiment.

FIG. 2 is a side view showing a configuration of main parts of an electrode element manufacturing apparatus used in an embodiment.

FIG. 3 is a cross-sectional view showing the configuration of a main part of a polymer electrolyte battery in which an electrode element according to an embodiment is incorporated.

FIG. 4 is a sectional view showing a schematic configuration of an electrode element for a polymer battery.

FIG. 5 is an enlarged cross-sectional view showing a schematic configuration of a projecting portion of a collector terminal of an electrode element for a polymer battery.

[Explanation of symbols]

4 ... Separate sheet 5: Positive electrode sheet 5a ... Positive electrode layer 5b ... Current collector 5c …… Current collector terminal 6 ... Negative electrode sheet 6a ... Negative electrode layer 6b ... Current collector 6c …… Current collector terminal 7a, 7b ... Endless belt 6a …… Drive roller 9 ... Laminate for forming electrode element 10a, 10b ...... Heating unit 11a, 11b ...... Pressure roller 11a ', 11b' ... Elastic layer of pressure roller

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 6/18 H01M 10/40

Claims (2)

(57) [Claims] 1. An electrode element main body, which is integrally press-bonded to one main surface side of a separate sheet made of a polymer having electrolyte retention properties.
A positive electrode sheet for a polymer battery including a current collector having a terminal portion projecting to the outside of the sheet ,
A collector having a terminal portion protruding outside the electrode element body
A polymer battery negative electrode sheet comprising: a polymer battery negative electrode sheet, wherein the separate sheet is a polymer battery positive electrode sheet.
And the terminal portion of the polymer battery negative electrode sheet
An electrode element for a polymer battery, which has a protrusion that covers at least one side . 2. A terminal portion is provided outside the electrode element body on one main surface side of a separate sheet made of an electrolyte retaining polymer.
A positive electrode sheet for a polymer battery which is protruded end to the other main surface
Heating the laminate was placed a negative electrode sheet for a polymer battery is protruded to the outside of the electrode main portion of the terminal portion from both sides, arranged in parallel to the heated laminate and a pair of rotating pressure In the method of manufacturing an electrode element for a polymer battery, which comprises a step of passing through a pressure roller outer peripheral surface and pressure-bonding / integrating, the pressure roller has an outer peripheral surface formed of an elastic layer, and a separate sheet edge is A method for producing an electrode element for a polymer battery, wherein the electrode elements are selected and set so as to extendably cover the protruding surfaces of the terminal portions of both electrode sheets.