JP2006190601A - Laminated cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain the mutual contact of unit cell elements, etc. to exhibit a full function as a cell even when a gas is generated in the interior of a laminated cell. <P>SOLUTION: A laminate (22) is configured such that the unit cell elements (18) each in which a layer of an electrolyte (16) is interposed between a sheet cathode (12) and a sheet anode (14) are laminated. In the laminated cell (10) in which the laminate (22) is degassed and sealed with laminate sheets (24), a buffer (20) is provided to collect the gas generated in the laminate body. A porous material (20a) or a hollow material (20b) whose interior is made to be in a vacuum state, or an elastic hollow pipe (20c) in a crushed state is used for the buffer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated battery, and more specifically, a laminate in which a unit battery element in which an electrolyte layer is interposed between a sheet-like positive electrode and a negative electrode is laminated to a laminate sheet (flexible exterior member). The present invention relates to a stacked battery provided with a structure for collecting a gas generated in the battery sealed in the above.

  FIG. 6 schematically shows a general structure of a sheet-type lithium secondary battery. As shown in this figure, a sheet-type lithium secondary battery includes a positive electrode (12) and a negative electrode current collector (12a) coated with a positive electrode mixture (12b) on one side of a positive electrode current collector (12a: aluminum current collector). 14a: a unit battery element (18) formed by laminating a negative electrode (14) coated with a negative electrode mixture (14b) on one side of a lithium current collector via an electrolyte (16) layer, In a state where the non-coated surface of the positive electrode current collector of the battery element and the non-coated surface of the negative electrode current collector are in contact with each other, the laminated body (22) is sequentially laminated to form a laminated body (22). ) And ventilated and sealed.

The laminate sheet (24) is formed by, for example, integrating aluminum foil as a middle layer, laminating a polypropylene film inside and laminating a polyethylene terephthalate film and a nylon film on the outside, and has flexibility. .
The laminate (22) sandwiched between the two laminate sheets is accommodated with the positive electrode lead (31) and the negative electrode lead (32) led out to the outside, and the outer peripheral portion of the laminate sheet is sealed by heat sealing or the like. As a result, the internal airtightness is secured.

In addition, the “stacked battery, assembled battery, and vehicle” of Patent Document 1 shown in FIG. 7 eliminates the need for a positive electrode lead and a negative electrode lead for taking out current from the laminate sheet (24), Among the current collectors (12a, 14a) included in the sheet-like electrodes (12, 14) stacked with the electrolyte (16) layer interposed therebetween for the purpose of preventing a decrease in battery output due to passing through A multilayer battery has been proposed in which a current collector in the outermost layer is exposed from a laminate sheet and this is used as an electrode terminal.
JP 2004-134210 A

  In such a stacked battery, although a plurality of unit battery elements can be connected in series by stacking to obtain an arbitrary battery voltage according to the number of stacks, decomposition that occurs mainly due to repeated charge / discharge Various gases such as gas and oxygen may interfere with the contact between the electrode in the unit cell element and the electrolyte or between the unit cell elements, thereby reducing the output of the battery, or they may completely peel off. In such a case, the stacked battery may not function as a battery.

  The present invention has been made to solve such problems, and even when gas is generated inside a laminated battery in which a laminated body in which a plurality of unit battery elements are laminated is sealed with a laminate sheet, It is an object of the present invention to provide a laminated battery capable of exhibiting a sufficient function as a battery by maintaining contact between the battery and an electrolyte and contact between unit battery elements.

  To achieve the above object, the invention according to claim 1 is a unit battery element (18) in which an electrolyte (16) layer is interposed between a sheet-like positive electrode (12) and a sheet-like negative electrode (14). In the laminated battery (10) in which the laminated body (22) laminated with air is hermetically sealed with the laminated sheet (24), a buffer (20) for collecting the gas generated in the laminated body is provided. It is characterized by.

  The invention according to claim 2 is characterized in that the buffer (20) is accommodated in a laminate sheet, and a gas flow path (26) is formed between the laminate (22) and the buffer. And

  According to a third aspect of the present invention, the buffer (20) is a porous member (20a) or a hollow member (20b) whose inside is in a vacuum state, and the gas generated in the laminate (22) is porous. It collects in a member or a hollow member, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, the buffer (20) is an elastic hollow tube (20c), and utilizes a restoring force to restore the original shape from a collapsed state of the hollow tube. The gas generated in the laminate (22) is collected in a hollow tube.

  According to a fifth aspect of the present invention, the buffer (20) is a leaf spring (20d) manufactured by bending a plate-like member, and attempts to restore the original shape from the compressed state. The gas generated in the laminate (22) is collected in the gap between the leaf springs using a restoring force.

  The invention according to claim 6 is a laminate in which a unit cell element (18) in which an electrolyte (16) layer is interposed between a sheet-like positive electrode (12) and a sheet-like negative electrode (14) is laminated. A unit battery element in which a plate-type buffer (20) which is a mesh-like or lattice-like conductor having a predetermined thickness is laminated in a laminated battery (10) in which (22) is vented and sealed with a laminate sheet (24). The gas generated in each unit battery element is collected in a mesh or lattice gap.

According to the first aspect of the present invention, when various gases such as decomposition gas are generated mainly due to charge / discharge in a stacked battery in which a stacked body in which unit battery elements are stacked is vented and sealed with a laminate sheet. In addition, since this can be collected in the buffer, it is possible to avoid a decrease in battery output due to these gases separating unit battery elements and the like and hindering the contact.
In addition, even when the outermost current collector is used as an electrode terminal as in the multilayer battery of Patent Document 1, it is possible to prevent the electrode terminal surface from becoming uneven due to the generation of gas. Even when the battery units are stacked, a sufficient contact surface between the stacked batteries can be secured.

  According to the second aspect of the present invention, the buffer is accommodated in the laminate sheet, and the laminated body and the buffer are communicated with each other through the gas flow path, whereby the gas generated in the laminated body is guided to the buffer through the gas flow path. Can do. As a result, it is possible to avoid peeling of unit cell elements and the like due to generation of gas by a laminated battery having a simple and simple configuration.

  More specifically, as in the invention described in claim 3, the laminate and the hollow member (including the porous member) are evacuated and sealed with a film sheet, and the inside of the hollow member is brought into a vacuum state, or the claim As in the invention described in No. 4, the laminated body and the hollow tube having elasticity collapsed in the radial direction are sealed with a film sheet, so that the gas generated in the laminated body is contained inside the hollow member or the hollow tube. Can be collected. Further, as in the invention described in claim 5, even when the laminate and the compressed leaf spring are sealed with a laminate sheet, the gas generated in each unit cell element by utilizing the restoring force of the leaf spring is discharged to the leaf spring. It can be collected in the gaps between them.

  According to the sixth aspect of the present invention, in the state where the plate-type buffer, which is a mesh-like or lattice-like (or porous member) conductor having an appropriate thickness, is disposed between the unit battery elements to be stacked. By venting and sealing this with a laminate sheet, the volume of the buffer can be increased, and even when a large amount of gas is generated in the laminate, it can be quickly collected.

A thin type battery is formed by laminating a plurality of unit battery elements, each of which is formed by laminating a rectangular positive electrode and a negative electrode via a polymer electrolyte layer, and this is sealed with a laminate sheet. And has some flexibility.
For example, since a polymer lithium secondary battery is repeatedly charged and discharged several tens to several hundreds of times, various gases such as methane, ethane, carbon dioxide, and oxygen are generated from each unit battery element with the charge and discharge. Therefore, the multilayer battery of the present invention is characterized by having a buffer for collecting gas generated in the unit battery element.
Hereinafter, each example of the multilayer battery of the present invention will be described with reference to the drawings. In addition, the detailed description which overlaps about the same structure in each Example is abbreviate | omitted.

  FIG. 1A is an exploded perspective view for showing the internal structure of the multilayer battery of this example, and FIG. 1B is an enlarged view of the XX cross section in the vicinity of the outer edge portion of the prepared multilayer battery. is there. The laminated battery 10 of this embodiment shown in the figure has a laminated body 22 in which 12 unit battery elements 18 are laminated, and the thickness thereof is about 5 mm. In this embodiment, the length and width of the laminate 22 are both about 30 cm. However, the length of each side and the number of layers can be freely set depending on the application of the battery.

  A buffer 20 is attached to the outer periphery of the laminated body 22 in a frame shape so as to surround the side surface of the laminated body. The buffer 20 is a porous member 20a having a square cross section with a side of about 5 mm (that is, the same thickness as the laminate 22) made of an insulating hard plastic or ceramic. The cross-sectional shape of the porous member is not limited to a square, and may be a suitable shape such as a rectangle, a triangle, a circle, or a semicircle.

  The laminate 22 and the buffer 20 are sandwiched and packaged by two aluminum laminate sheets 24 each having a length of about 32 cm in length and width, and the two aluminum laminate sheets are about 4 cm in the entire circumference of the outer peripheral edge. It is heat-sealed in width. Further, at the center of the aluminum laminate sheet 24, a window 33 having a length and width of about 24 cm is formed so that the current collectors 12a and 14a in the outermost layer are exposed to the outside and function as electrode terminals. The circumference is also heat-sealed with the current collectors 12a and 14a and sealed.

The manufacturing process for packaging the laminate 22 and the buffer 20 with the aluminum laminate sheet 24 is performed in a vacuum chamber, or three sides of the outer periphery of the aluminum laminate sheet 24 are sealed in advance and then the inside is vacuumed and sealed. As a result, the interior of the completed stacked battery 10 is evacuated. Therefore, even when gas is generated from the laminate 22 with charge / discharge, a certain amount of gas is collected in the gap of the buffer 20 that is a porous member. Thereby, it can prevent that the unit battery element 18 laminated | stacked produces peeling, and can avoid the fall of the battery output by contact inhibition. In addition, since deformation of the stacked battery due to gas generation can be avoided, even when a plurality of stacked batteries 10 are stacked to form a battery unit, a sufficient contact surface between the stacked batteries can be secured.
As in this embodiment, the buffer 20 is formed in a frame shape, and the laminated body 22 is fitted therein, so that there is also a secondary effect that the shape of the laminated battery is maintained flat.

  2 is an enlarged cross-sectional view of the vicinity of the outer edge of the stacked battery of Example 2. FIG. The configuration of the stacked battery 10 of the present embodiment shown in the figure is similar to the configuration of the stacked battery of the first embodiment, but instead of using a porous member as the buffer 20, a square cross section having a side of about 5 mm. The hollow member 20b is used.

  The hollow member 20b is made of an insulating material that does not easily collapse, and a plurality of small holes are formed in a line in the axial direction in a portion facing the side surface of the laminate 22. These small holes serve as gas flow paths 26 for guiding the gas generated in the laminate 22 to the hollow member 20b. The cross-sectional shape of the hollow member is not limited to a square, and may be an appropriate shape such as a general rectangle, a triangle, or a circle.

  The laminated body 22 and the hollow member 20b are packaged with an aluminum laminate sheet 24 in the vacuum chamber in the same manner as described above, or three sides of the outer peripheral portion of the aluminum laminate sheet 24 are sealed in advance and then the inside is vacuumed to seal As a result, the interior of the completed multilayer battery 10 is evacuated. Therefore, the gas generated from the laminated body 22 is sucked into the space in the hollow member through the gas flow path 26 and collected.

  FIG. 3A is an exploded perspective view for showing the internal structure of the multilayer battery of this example, and FIG. 3B is an enlarged view of the XX cross section in the vicinity of the outer edge portion of the prepared multilayer battery. is there. The stacked battery 10 of Example 2 shown in the figure has a stacked body 22 in which 12 unit battery elements 18 are stacked in a vertical and horizontal length of about 30 cm and a thickness of about 5 mm. The two hollow tubes 20c (buffers 20) arranged adjacent to the two side surfaces are sandwiched between two aluminum laminate sheets 24 and packaged. As in the first and second embodiments, aluminum is used. The current collectors 12a and 14a in the outermost layer 33 are exposed to the outside from the window portion formed in the laminate sheet 24 and function as electrode terminals.

  The hollow tube 20c is an insulating resin-made hollow circular tube having a diameter of 1 cm having elasticity, and a portion of the laminated body 22 facing the side surface is used to introduce gas generated in the laminated body 22 into the hollow tube. A plurality of small holes to be the gas flow paths 26 are formed in a line in the axial direction.

  When stacking the stacked batteries 10 of this embodiment in order to obtain a desired voltage, even-numbered stacked batteries are arranged so that the hollow tubes 20c arranged adjacent to the side surfaces of the stacked batteries are staggered. The stacked batteries are stacked so as to have a positional relationship of 90 ° relative rotation with the odd-numbered stacked batteries (not shown).

When the laminate 22 and the hollow tube 20c are packaged with the aluminum laminate sheet 24, the laminate 22 and the hollow tube are sandwiched between the two aluminum laminate sheets 24 and then pressed, and the hollow tube is radially aligned. The aluminum laminate sheet 24 is sealed by heat-sealing in a state deformed so as to be crushed (FIG. 3B). The hollow tube 20c inside the completed laminated battery 10 is initially in a collapsed state, but tries to be restored to its original shape due to its elasticity. Therefore, even when gas is generated in the laminated body 22, the gas is sucked into the hollow tube through the gas channel 26 and collected. As the gas is collected, the cross-sectional shape of the hollow tube 20c gradually approaches a circle (FIG. 3 (b)), but the hollow tubes 20c are staggered when the stacked batteries 10 are stacked. Therefore, the deformation hardly affects the thickness of the entire battery unit.
In the stacked battery 10 of this example, the state of gas generation from the stacked body 22 can be confirmed by visually observing the deformation state of the hollow tube 20c, and this can be used as a guide for the battery life. .

FIG. 4 shows another embodiment of the stacked battery of this example.
In this laminated battery, a plate spring 20d produced by bending a plate-like member into a Z shape instead of a hollow tube is used as a buffer. The leaf spring 20d has a height of about 5 mm when no external force is applied. Similar to the cylindrical tube 20 c, this leaf spring is also arranged adjacent to two opposing side surfaces of the laminate 22, and is compressed by the two aluminum laminate sheets 24 together with the laminate 22 and hermetically packaged.
The gas generated from the laminated body 22 is collected in the gap between the leaf springs by a restoring force for restoring the original shape from the state in which the leaf spring 20d is compressed.

In the stacked battery 10 of this embodiment shown in FIG. 5, a stacked body 22 in which a thin plate-like buffer 20 is arranged between each of six stacked unit battery elements 18 is a current collector 12a in the outermost layer. , 14a are exposed to the outside and sandwiched between two aluminum laminate sheets 24 in which window portions 33 are formed to form electrode terminals, and are packaged in a hermetically sealed state. The total thickness of the laminate 22 is about 10 mm. It has become.
The buffer 20 is made of conductive metal and has a lattice shape having the same length and width as the unit battery elements 18 and a thickness of about 1 mm. Note that the shape of the buffer 20 is not limited to the lattice shape, but may be a mesh shape, or a thin plate made of an electrically conductive porous member may be used.

The manufacturing process for packaging the laminate 22 with the aluminum laminate sheet 24 is performed in a vacuum chamber as in the first embodiment or the like, or after sealing three sides of the outer periphery of the aluminum laminate sheet 24 in advance, the inside is vacuumed. This is done by pulling and sealing, and the interior of the completed multilayer battery 10 is evacuated. Therefore, even when gas is generated from each unit battery element 18 due to charge / discharge, a relatively large amount of gas can be collected in the gaps of the lattice-shaped buffer 20. Thereby, electricity supply between the laminated unit battery elements etc. can be ensured, and the fall of a battery output can be avoided. The buffer 20 is not necessarily arranged between the unit battery elements, and it is of course possible to arrange only an appropriate number.
According to the multilayer battery of this example, although the thickness of the multilayer battery is increased, the volume of the gap in the buffer can be increased. Therefore, even when a large amount of gas is generated from each unit battery element. Can deal with.

  As described above, according to the present invention, even when gas is generated from a laminated body (unit battery element) of a laminated battery in which a laminated body in which a plurality of unit battery elements are laminated is sealed with a laminate sheet, the buffer is provided. By collecting this, it is possible to ensure the energization between the unit battery elements and the like, and to provide a stacked battery that can ensure a sufficient function as a secondary battery even if charging and discharging are repeated.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. For example, the gas generated in the laminate can be guided and collected in a suction tank or the like provided outside without enclosing the buffer in the laminate sheet.

As described above, according to the present invention, there is provided a stacked battery that can ensure contact between unit cell elements and the like even when gas is generated inside mainly due to charge and discharge.
In the above description, the laminated battery is described as a thin secondary battery, but it is a laminated battery that is accommodated in a flexible container, and is not limited to this as long as gas is generated inside by use. The present invention can also be applied to a primary battery.

1 is a structural diagram of a stacked battery in Example 1. FIG. 3 is a structural diagram of a stacked battery in Example 2. FIG. 4 is a structural diagram of a stacked battery in Example 3. FIG. 4 is a structural diagram of another form of the stacked battery in Example 3. FIG. 6 is a structural diagram of a stacked battery in Example 4. FIG. It is the schematic diagram which showed the general structure of the sheet-type lithium secondary battery. 1 is a structural diagram of a stacked battery disclosed in Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stack type battery 12 Positive electrode 12a Positive electrode collector 12b Positive electrode mixture 14 Negative electrode 14a Negative electrode collector 14b Negative electrode mixture 16 Electrolyte 18 Unit battery element 20 Buffer 20a Porous member 20b Hollow member 20c Hollow tube 20d Leaf spring 22 Lamination Body 24 Laminate sheet 26 Gas flow path 31 Positive electrode lead 32 Negative electrode lead 33 Window

Claims (6)

A laminate (22) in which a unit battery element (18) having an electrolyte (16) layer interposed between a sheet-like positive electrode (12) and a sheet-like negative electrode (14) is laminated to a laminate sheet (24). In the laminated battery (10) ventilated and sealed at
A laminated battery comprising a buffer (20) for collecting gas generated in the laminate.   The laminate according to claim 1, wherein the buffer (20) is accommodated in a laminate sheet, and a gas flow path (26) is formed between the laminate (22) and the buffer. Type battery.   The buffer (20) is a porous member (20a) or a hollow member (20b) whose inside is evacuated, and traps the gas generated in the laminate (22) in the porous member or the hollow member. The stacked battery according to claim 2, wherein:   The buffer (20) is a hollow tube (20c) having elasticity, and is generated in the laminate (22) by using a restoring force to restore the original shape from a collapsed state of the hollow tube. The stacked battery according to claim 2, wherein the collected gas is collected in a hollow tube.   The buffer (20) is a leaf spring (20d) manufactured by bending a plate-like member, and the laminated body uses a restoring force to restore the original shape from a compressed state. The stacked battery according to claim 2, wherein the gas generated in (22) is collected in a gap between the leaf springs. A laminate (22) in which a unit battery element (18) having an electrolyte (16) layer interposed between a sheet-like positive electrode (12) and a sheet-like negative electrode (14) is laminated to a laminate sheet (24). In the laminated battery (10) ventilated and sealed at
A plate-type buffer (20), which is a mesh or lattice conductor having a predetermined thickness, is arranged between the stacked unit battery elements, and the gas generated in each unit battery element is trapped in the mesh or lattice gap. A stacked battery, characterized by being collected.

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