JP7262637B1 - bipolar battery - Google Patents

Abstract

Kind Code: A1 A bipolar battery capable of measuring the voltage of each of a plurality of stacked single cells, being easily manufactured, and having a high yield is provided. Kind Code: A1 A bipolar battery has a connector formed of a printed circuit board having insulating properties and flexibility. The connector includes a main body, a plurality of comb tooth portions arranged in a comb shape, a plurality of contact portions provided at the ends of each of the comb tooth portions and exposed to the outside from both sides in the thickness direction, and the and a pattern wiring that electrically connects the contact portion and the terminal portion at the end portion of the body portion. Some of the plurality of contact portions are in contact with the current collectors arranged at both ends in the stacking direction, and the rest are sandwiched between the current collectors adjacent to each other in the stacking direction. It is electrically connected to the electrical body. [Selection drawing] Fig. 2

Description

The present invention relates to bipolar batteries.

Laminated batteries in which single cells are connected in series are widely used. In a stacked battery, when the voltage of the single cell varies beyond a certain range, the load concentrates on the single cell with the higher voltage and deteriorates. Then, the voltage of the degraded cell further increases due to the degradation, and the load is further concentrated on the degraded cell. As a result, the deterioration of the deteriorated single battery progresses. As a result, the life of the laminated battery is shortened.

Japanese Laid-Open Patent Application Publication No. 2002-100000 discloses a configuration for measuring variations in the voltages of single cells in a stacked battery.

In Patent Document 1, a unit cell comprising a positive electrode active material layer and a negative electrode active material layer sandwiching an ion conductive layer, current collecting foils facing each other, and an insulating seal material electrically insulating the current collecting foils facing each other is disclosed. , in a laminated electric storage device, a laminated electric storage device having a comb tooth-shaped FPC, in which each tooth is sandwiched and thermally bonded between the collector foil of the laminated unit cell and the sealing material is disclosed. ing.

In this layered electricity storage device, a positive electrode active material layer, an ion conductive layer, a negative electrode active material layer, and a sealing material are placed on top of a collector foil, and then the current collector foil is placed thereon for lamination. Then, when the collector foil is arranged on the sealing material, the teeth of the FPC are arranged on the sealing material and laminated, thereby incorporating the FPC into the laminated electric storage device.

Japanese Patent Application Laid-Open No. 2008-160060

However, in the stacked energy storage device of Patent Document 1, since the unit cells cannot be handled individually, it is not possible to measure the variation in the voltage of the unit cells in advance before stacking, and it is possible to remove defects before manufacturing. Can not. Therefore, there is a possibility that the yield of the stacked power storage device may decrease.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a bipolar battery that can measure the voltage of each of a plurality of stacked single cells, is easy to manufacture, and has a high yield.

In an exemplary bipolar battery of the present invention, single cells having current collectors disposed on both sides are stacked such that the current collectors of different polarities are in contact. The bipolar battery has a connector formed of a printed circuit board having insulation and flexibility. The connector includes a body portion, a plurality of comb tooth portions protruding from the body portion and arranged in a comb tooth shape apart from each other, and a tip end of each of the comb tooth portions having conductivity and having conductivity. a plurality of contact portions exposed to the outside from both sides in the thickness direction of the comb tooth portion; and pattern wiring for electrical connection. Some of the plurality of contact portions are in contact with the current collectors arranged at both ends in the stacking direction, and the rest are sandwiched between the current collectors adjacent in the stacking direction. is electrically connected to the current collector.

Exemplary bipolar batteries of the present invention are easy to manufacture and have high yields. Then, the voltage of each of the stacked cells can be measured, and partial deterioration of the bipolar battery can be suppressed.

1 is a partially cutaway perspective view schematically showing an example of a bipolar battery according to the present invention; FIG. FIG. 2 is a partially cutaway side view of an exterior body of an example of a bipolar battery; 1 is a partially cutaway perspective view schematically showing an example of a cell included in a bipolar battery; FIG. 1 is an exploded perspective view of a cell; FIG. It is a top view of a connector. FIG. 10 is a plan view schematically showing an example of a connector used in the bipolar battery of the first modified example; FIG. 4 is a partially cutaway perspective view schematically showing an example of a bipolar battery of a first modified example; FIG. 11 is a plan view schematically showing an example of a connector used in a bipolar battery of a second modified example; FIG. 11 is a partially cutaway perspective view schematically showing an example of a bipolar battery of a third modified example;

Exemplary embodiments of the invention are described in detail below with reference to the drawings. FIG. 1 is a partially cutaway perspective view schematically showing an example of a bipolar battery 10 according to the present invention. FIG. 2 is a side view of an example of the bipolar battery 10 with a part of the exterior body 11 cut away. In the description of this specification, it is assumed that the unit cells 20 are stacked vertically. That is, the thickness direction of the cell 20 is also the vertical direction. The vertical direction described above is set for convenience of explanation, and may differ from the vertical direction in actual use.

<Bipolar battery 10>
As shown in FIG. 1, the bipolar battery 10 is formed by stacking unit cells 20 having current collectors 24 and 26 on both sides so that the current collectors 24 and 26 of different polarities are in contact with each other. The bipolar battery 10 has an assembled battery 30 in which a plurality of single cells 20 are stacked so as to be connected in series. Here, a bipolar battery is a battery having a configuration in which a positive electrode is arranged on one surface in the thickness direction and a negative electrode is arranged on the other surface. Strictly speaking, the unit cell 20 in which one end surface in the thickness direction is a positive electrode and the other is a negative electrode is also a bipolar battery. Therefore, in this document, a battery unit having an assembled battery 30 formed by stacking the cells 20 may be referred to as a bipolar battery 10, and the cells 20 may be referred to as bipolar cells.

The bipolar battery 10 has an outer package 11 , an assembled battery 30 , a positive electrode conductive sheet 12 , a negative electrode conductive sheet 13 , and a connector 40 . The assembled battery 30 is housed inside the exterior body 11 .

As shown in FIG. 1, in the assembled battery 30, 11 unit cells 20 are stacked so as to be connected in series. The voltage of the assembled battery 30 is determined by the number of stacked cells 20 . In other words, the number of stacked cells 20 is determined based on the required output voltage of the bipolar battery 10 . Details of the cell 20 and the assembled battery 30 will be described later.

In the bipolar battery 10 , the positive electrode conductive sheet 12 is placed in contact with the lower surface of the unit cell 20 stacked at the bottom of the assembled battery 30 . Moreover, the negative electrode conductive sheet 13 is arranged in contact with the upper surface of the unit cell 20 stacked on the top of the assembled battery 30 . The positive electrode conductive sheet 12 and the negative electrode conductive sheet 13 are electrode terminals during charging and discharging.

As the positive electrode conductive sheet 12 and the negative electrode conductive sheet 13, for example, materials such as metal materials such as copper, aluminum, titanium, stainless steel, nickel and alloys thereof, calcined carbon, conductive polymer materials, and conductive glass are appropriately used. It can be selected and used. Moreover, the positive electrode conductive sheet 12 and the negative electrode conductive sheet 13 are not limited to these, and a wide range of conductive materials can be used. The positive electrode conductive sheet 12 and the negative electrode conductive sheet 13 may be made of the same material or may be made of different materials.

As shown in FIG. 1 , the exterior body 11 has a base portion 111 and a cover portion 112 . The base portion 111 has a substantially rectangular plate shape. The cover part 112 has a box-like shape with a lid-like portion at the top and an opening at the bottom. After the member constituting the bipolar battery 10 such as the assembled battery 30 is accommodated in the concave portion of the cover portion of the cover portion 112 , the base portion 111 covers the opening of the lower surface of the cover portion 112 . At this time, the cover portion 112 and the base portion 111 are in close contact with each other. As a result, foreign substances such as water, dust, and dirt are prevented from entering the interior of the exterior body 11, and problems of the bipolar battery 10 caused by these foreign substances are suppressed.

In the exterior body 11 , the lower end portion of the cover portion 112 is arranged so as to be in contact with the outer edge portion of the base portion 111 . At least one side of the cover portion 112 and the base portion 111 is a thermal bonding portion 113 that is bonded (hereinafter referred to as thermal bonding) by applying heat and pressure in the vertical direction.

The positive electrode conductive sheet 12 and the negative electrode conductive sheet 13 are used as electrode terminals of the bipolar battery 10 . Therefore, a part of the positive electrode conductive sheet 12 is pulled out from the exterior body 11 to form the positive electrode lead-out terminal 121 . A portion of the negative electrode conductive sheet 13 is pulled out from the outer package 11 to form a negative electrode lead terminal 131 .

More specifically, the positive electrode lead-out terminal 121 of the positive electrode conductive sheet 12 is led out from the side where the base portion 111 and the cover portion 112 of the exterior body 11 are thermally welded. The negative electrode lead-out terminal 131 of the negative electrode conductive sheet 13 is arranged from the upper surface of the assembled battery 30 along the side surface of the assembled battery 30, and then extends outside from the thermally welded side between the base portion 111 and the cover portion 112 of the exterior body. pulled out.

The positive lead-out terminal 121 and the negative lead-out terminal 131 are thermally welded together with the base portion 111 and the cover portion 112 . It is preferable that the positive electrode lead terminal 121 and the negative electrode lead terminal 131 are formed as thin as possible in order to prevent the formation of gaps during thermal welding. A connector 40, which will be described later, is attached to the assembled battery 30. As shown in FIG.

The sides of the exterior body 11 other than the sides to be thermally welded may be closely attached by, for example, press fitting. Also, it may be fixed by heat welding in the same manner as the side to be heat welded. As a method for fixing the base portion 111 and the cover portion 112, a fixing method that can be fixed in close contact so as to prevent foreign substances such as water, dirt, dust, etc. from entering can be widely adopted.

<Cell 20>
The cell 20 will be described below with reference to the drawings. FIG. 3 is a partially cutaway perspective view schematically showing an example of the cell 20. As shown in FIG. 4 is an exploded perspective view of the cell 20. FIG. As shown in FIG. 3, the unit cell 20 has a substantially rectangular flat plate shape in a plan view, and the upper surface in the thickness direction is the negative electrode, and the lower surface is the positive electrode.

As shown in FIGS. 3 and 4, the cell 20 has a positive electrode 21, a negative electrode 22, and a separator 23. As shown in FIGS. A positive electrode 21 and a negative electrode 22 are laminated with a separator 23 interposed therebetween. That is, the cell 20 is formed by laminating the positive electrode 21, the separator 23, and the negative electrode 22 in this order from the bottom. The cell 20 is formed by stacking the positive electrode 21 and the negative electrode 22 . In addition, let the cell 20 be a lithium ion battery in this embodiment. The positive electrode 21, the negative electrode 22, and the separator 23 have, for example, the same configuration as that used in known lithium-ion batteries.

As shown in FIGS. 3 and 4 , the positive electrode 21 has a positive electrode current collector 24 and a positive electrode active material layer 25 . The positive electrode current collector 24 is made of conductive resin and has a substantially rectangular shape when viewed from the thickness direction of the cell 20 . Also, the positive electrode active material layer 25 is laminated on the surface (here, the upper surface) of the positive electrode current collector 24 . The positive electrode active material layer 25 contains a positive electrode active material, a conductive aid, and a coating resin. Materials used in known lithium-ion batteries, for example, are used for the positive electrode active material, conductive aid, and coating resin.

Further, the negative electrode 22 has a negative electrode current collector 26 and a negative electrode active material layer 27 . The negative electrode current collector 26 is made of conductive resin and has a substantially rectangular shape when viewed from the thickness direction of the cell 20 . The positive electrode current collector 24 and the negative electrode current collector 26 may be made of the same material or may be made of different materials. At least one of the positive electrode current collector 24 and the negative electrode current collector 26 may be replaced with a current collector made of metal or the like.

The negative electrode active material layer 27 is laminated on the surface (here, the bottom surface) of the negative electrode current collector 26 . The negative electrode active material layer 27 contains a negative electrode active material, a conductive aid, and a coating resin. Materials used in known lithium-ion batteries, for example, are used for the negative electrode active material, conductive aid, and coating resin.

Also, the positive electrode active material layer 25 and the negative electrode active material layer 27 contain an electrolytic solution. As the electrolytic solution, for example, a known electrolytic solution containing an electrolyte and a non-aqueous solvent used in known lithium ion batteries is used.

The positive electrode 21 , negative electrode 22 and separator 23 are attached to an annular frame member 28 . More specifically, the positive electrode active material layer 25 is arranged inside the frame member 28 and the peripheral edge portion of the positive electrode current collector 24 is fixed to the lower surface of the frame member 28 . Also, the negative electrode active material layer 27 is arranged inside the frame member 28 , and the peripheral portion of the negative electrode current collector 26 is fixed to the upper surface of the frame member 28 . The separator 23 is arranged to separate the positive electrode active material layer 25 and the negative electrode active material layer 27 and fixed to the frame member 28 . That is, in the cell 20 , the positive electrode active material layer 25 , the separator 23 and the negative electrode active material layer 27 are sealed by the positive electrode current collector 24 , the negative electrode current collector 26 and the frame member 28 .

The distance between the positive electrode current collector 24 and the separator 23 and the distance between the negative electrode current collector 26 and the separator 23 are adjusted according to the capacity of the cell 20 . That is, the positions of the positive electrode current collector 24, the negative electrode current collector 26, and the separator 23 are determined so that the unit cell 20 has a predetermined capacity.

In the unit cell 20 , the frame member 28 is used to appropriately maintain the gap between the positive electrode current collector 24 and the separator 23 and the gap between the negative electrode current collector 26 and the separator 23 .

The positive electrode current collector 24 and the negative electrode current collector 26 are resin current collectors made of a conductive polymer material. The shape of the resin current collector is not particularly limited, and may be a sheet-like current collector made of a conductive polymer material, a deposited layer made of fine particles made of a conductive polymer material, or the like.

Examples of the conductive polymer material that constitutes the resin current collector include conductive polymers and resins to which a conductive agent is added as necessary. Also, as the conductive agent that constitutes the conductive polymer material, the same one as the conductive aid contained in the positive electrode active material can be employed.

Examples of resins constituting the conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyethernitrile (PEN), poly Tetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), epoxy resin, silicone resin or mixtures thereof etc.

From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferred, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferred. (PMP).

The cell 20 has the configuration shown above. Note that the unit cell 20 of the present embodiment has a substantially rectangular shape when viewed from the thickness direction, but is not limited to this. For example, it may be square. Furthermore, it may be circular, elliptical, or polygonal (triangular, quadrangular, etc.). Although the shape of the unit cell 20 in plan view is not particularly limited, it is preferably substantially square or substantially rectangular in consideration of versatility such as transportation and installation of the assembled battery 30, which will be described later.

<Battery assembly 30>
Next, the details of the assembled battery 30 in which a plurality of cells 20 are stacked so as to be connected in series will be described with reference to the drawings. FIG. 5 is a plan view of the connector 40. FIG. As shown in FIGS. 1 and 2 , the assembled battery 30 has a plurality of unit cells 20 and connectors 40 . A plurality of unit cells 20 are stacked in the thickness direction.

More specifically, the plurality of cells 20 are arranged such that the positive electrode current collector 24 on the lower surface of the upper cell 20 and the negative electrode current collector 26 on the upper surface of the lower cell 20 are electrically connected. is laminated to Thereby, the cells 20 are connected in series. That is, the output voltage of the assembled battery 30 is the voltage obtained by connecting the cells 20 in series.

Connector 40 measures the voltage of cell 20 . As shown in FIG. 5 , the connector 40 has a body portion 41 , a plurality of comb tooth portions 42 , a plurality of contact portions 43 and pattern wiring 44 .

The body portion 41 has a lead portion 411 , a branch portion 412 and a plurality of terminal portions 413 . The lead-out portion 411 has a substantially rectangular shape in a plan view. A plurality of terminal portions 413 connected to a voltage measuring device (not shown) are provided at one end in the longitudinal direction of the body portion 41 . Each terminal portion 413 has the same shape. Each terminal portion 413 is conductive, and at least a portion thereof is exposed to the outside of the body portion 41 . Each of the plurality of terminal portions 413 is electrically insulated from other terminal portions 413 . Although the details will be described later, the number of the plurality of terminal portions 413 is “the number of stacked cells 20 +1”. In the connector 40 of the present embodiment, “the number of stacked cells 20 +1” is twelve.

A branch portion 412 is integrally connected to the other end of the lead portion 411 in the longitudinal direction. The branched portion 412 has an elongated shape extending in a direction intersecting with the drawn portion 411 . In the connector 40 according to this embodiment, the branch portion 412 has a rectangular shape, and the longitudinal direction thereof is orthogonal to the longitudinal direction of the lead portion 411 . In addition, the lead-out portion 411 is connected to the center of the branch portion 412 in the longitudinal direction. In other words, the lead-out portion 411 is connected to the intermediate portion of one of the long sides of the branch portion 412 .

The plurality of comb tooth portions 42 protrude from the main body portion 41 and are spaced apart from each other and arranged in a comb tooth shape. Specifically, the plurality of comb tooth portions 42 are integrally connected to the other long side of the branch portion 412 and extend outward from the branch portion 412 . The plurality of comb tooth portions 42 are independent of each other. The number of the plurality of comb tooth portions 42 is the same as that of the terminal portions 413, that is, "the number of laminated cells 20+1".

The plurality of contact portions 43 are provided at the tip of each comb tooth portion 42 and have conductivity, and are exposed on at least one surface of the comb tooth portion 42 in the thickness direction. In other words, the contact portion 43 is a conductive foil formed on the comb tooth portion 42 . The number of the plurality of contact portions 43 is the same as the number of comb tooth portions 42, that is, "the number of laminated cells 20+1". The contact portion 43 is made of a conductive material.

The contact portion 43 may have through holes provided in the comb tooth portion 42 and lands formed on both surfaces of the comb tooth portion 42 and electrically connected to the through holes. At this time, the pattern wiring 44 may come into contact with the through holes. Also, if the connector 40 is a single-sided board, the pattern wiring 44 may include a land as part of it.

In the connector 40, the body portion 41 and the comb tooth portion 42 are integrally formed. The body portion 41 and the comb tooth portion 42 of the connector 40 are made of flexible and insulating resin such as polyimide. The material is not limited to polyimide as long as it is flexible and insulating.

The pattern wiring 44 is a conductor arranged on the comb tooth portion 42 and the main body portion 41 . Each of the plurality of contact portions and the plurality of terminal portions 413 provided at the end portion of the body portion 41 are electrically connected. The pattern wiring 44 is, for example, a conductive foil made of a conductive material such as copper, aluminum, or alloys thereof. The pattern wiring 44 electrically connects the contact portion 43 and the terminal portion 413 one-to-one.

The connector 40 is formed of a printed circuit board having insulation and flexibility. The connector 40 may be a single-sided board. Note that the connector 40 has a body portion 41 and a comb tooth portion 42 made of polyimide, and a pattern wiring 44 made of metal foil. That is, the connector 40 is a flexible printed circuit (FPC). However, the connector 40 is not limited to this configuration, and a substrate obtained by combining a rigid substrate using epoxy resin, ceramic, or the like and a flexible substrate may be used. For example, the body portion 41 may be a rigid substrate, the comb tooth portion 42 may be a flexible substrate, and the comb tooth portion 42 may be flexible.

A pattern wiring 44 is formed on one side of the connector 40 . By forming the pattern wiring 44 on one side of the connector 40, the connector 40 can be formed thin, so that the flexibility is increased and the connector 40 can be easily attached. In addition, it is difficult to form a gap during heat welding for sealing the exterior body 11, and it is possible to tightly seal the exterior body.

The pattern wiring 44 preferably has a width of 0.3 mm or less. Moreover, it is preferable that the interval between the pattern wirings 44 in the lead-out portion 411 is 0.3 mm or less. By configuring in this way, the lead-out portion 411 tends to be smooth. Since a part of the lead-out portion 411 is arranged outside the exterior body 11 , it is difficult for a gap to be formed when the exterior body 11 is thermally welded. Moreover, it is preferable that the pattern wiring 44 is 0.05 mm or more. By doing so, disconnection of the pattern wiring 44 is suppressed.

The contact portion 43 may be made of the same material as the pattern wiring 44, or may be made of a different material. For example, if the pattern wiring 44 is made of copper, the contact portion 43 may be made of copper. Further, the contact portion 43 may have a configuration in which the surface of copper is plated with gold.

The connector 40 has the configuration shown above. Next, attachment of the connector 40 to the assembled battery 30 will be described with reference to the drawings. As shown in FIGS. 1, 2, etc., the assembled battery 30 is formed by stacking 11 unit cells 20 in the thickness direction. In FIG. 1, the main body portion 41 of the connector 40 protrudes from the assembled battery 30, but in the actual bipolar battery 10, it is arranged along the assembled battery 30 when housed in the exterior body 11. It can be folded like this. Even in this case, by forming the connector 40 with FPC, the pattern wiring 44 can be bent along the assembled battery 30 without disconnection. In particular, by using an FPC in which the pattern wiring 44 is arranged on one side, it is possible to easily bend the FPC and suppress disconnection of the pattern wiring 44 .

As shown in FIGS. 1 and 2, in all the cells 20 of the assembled battery 30, the positive electrode 21 is on the bottom surface and the negative electrode 22 is on the top surface. A connector 40 is attached to the assembled battery 30 . As described above, the number of comb tooth portions 42 and contact portions 43 is the number of cells 20 +1, that is, twelve.

In the description of the assembled battery 30, the individual cells 20 and the comb tooth portions 42 of the connectors 40 may be distinguished. In this case, the eleven cells 20 are referred to as a first cell 20_01 to an eleventh cell 20_11. The lowest cell is the first cell 20_01, and the top cell is the eleventh cell 20_11. Also, the twelve comb teeth 42 are referred to as a first comb tooth 42_01 to a twelfth comb tooth 42_12. The first comb tooth portion 42_01 to the twelfth comb tooth portion 42_12 are arranged in this order.

In the assembled battery 30, the positive electrode collector 24 arranged on the lower surface of the upper unit cell 20 and the negative electrode collector 26 arranged on the upper surface of the lower unit cell 20 are arranged in contact with each other. . The positive electrode current collector 24 and the negative electrode current collector 26 that are arranged in contact are electrically connected, that is, are in a conductive state with each other.

Among the plurality of contact portions 43, some contact the current collectors 24 and 26 arranged at both ends in the stacking direction, and the rest are sandwiched between the current collectors 24 and 26 adjacent in the stacking direction. . Each contact portion 43 is electrically connected to each current collector 24 , 26 . This configuration will be described in detail below.

The contact portions 43 arranged on the comb tooth portions 42 of the connector 40 are arranged between the unit cells 20 arranged vertically. The contact portions 43 arranged on the comb tooth portion 42 have conductive portions exposed on both sides in the thickness direction. Therefore, the contact portion 43 is electrically connected to both the positive electrode current collector 24 and the negative electrode current collector 26 . More specifically, the contact portion 43 is in contact with the inner portion of the collectors 24 and 26 from the outer edge thereof by a certain length or more. By configuring in this way, the contact portion 43 contacts the positive electrode current collector 24 and the negative electrode current collector 26 at a portion avoiding the undulation of the outer edge of the cell 20 . Therefore, the contact portion 43 and the positive electrode current collector 24 and the negative electrode current collector 26 are stably electrically connected.

As shown in FIGS. 1 and 2, the first comb tooth portion 42_01 is arranged in contact with the positive electrode current collector 24 on the lower surface of the first cell 20_01. Thereby, the contact portion 43 arranged on the first comb tooth portion 42_01 is electrically connected to the positive electrode current collector 24 of the first cell 20_01. The first comb tooth portion 42_01 may be fixed to the positive electrode current collector 24 of the first cell 20_01 using a conductive adhesive or adhesive tape. Alternatively, it may be fixed using a fixture using a screw or the like. It is possible to widely adopt a fixing method that enables reliable electrical connection between the first comb tooth portion 42_01 and the positive electrode current collector 24 of the first cell 20_01.

The second comb tooth portion 42_02 is sandwiched between the negative electrode current collector 26 on the top surface of the first cell 20_01 and the positive electrode current collector 24 on the bottom surface of the second cell 20_02. Similarly, the third comb-tooth portion 42_03 to the eleventh comb-tooth portion 42_11 are arranged so as to be sandwiched between unit cells arranged vertically. The comb tooth portion 42 sandwiched between the unit cells 20 may be fixed by the crimping force between the unit cells 20 when stacking the assembled battery 30 . Alternatively, a conductive adhesive, an adhesive tape, or the like may be used.

In this way, by arranging the comb tooth portion 42 sandwiched between the unit cells 20 of the assembled battery 30, the voltage of each unit cell 20 can be obtained. The assembled battery 30 is arranged inside the exterior body 11 with the connector 40 attached. At this time, the lead-out portion 411 of the main body portion 41 of the connector 40 is led out from the thermally welded side of the exterior body 11 together with the positive lead-out terminal 121 and the negative lead-out terminal 131 . The lead-out portion 411 is arranged side by side with the positive lead-out terminal 121 and the negative lead-out terminal 131 and welded together with the base portion 111 and the cover portion 112 of the exterior body 11 . In order to suppress the generation of gaps, it is preferable that the lead portion 411 is also formed thin.

As described above, the terminal portion 413 arranged on the lead portion 411 of the connector 40 is connected to a voltage measuring device (not shown). The voltage measurement device acquires the voltages of the contact portions 43 arranged in each of the first comb tooth portion 42_01 to the twelfth comb tooth portion 42_12. Then, the voltage difference between adjacent comb tooth portions 42 becomes the voltage of the cell 20 . For example, the difference between the voltage of the contact portion 43 of the fourth comb tooth portion 42_04 and the voltage of the contact portion 43 of the fifth comb tooth portion 42_05 is calculated as the voltage of the fourth cell 20_04.

Thus, in the bipolar battery 10 of this embodiment, the voltage of each single cell 20 can be checked during charging and discharging. With such a configuration, it is possible to detect defects such as a partial short circuit of the cell 20 and an increase in resistance value at an early stage, and it is possible to quickly deal with the defective assembled battery 30 . That is, charge/discharge control of the bipolar battery 10 can be performed efficiently.

The shape of the contact portion 43 preferably has an area of at least a 2 mm×5 mm rectangle. Alternatively, it is preferable that each side of the contact portion 43 has an area of a rectangle or more that is 1/200 or more of the length of the shortest side of the unit cell 20 . By doing so, even when the surface of the positive electrode current collector 24 or the negative electrode current collector 26 of the cell 20 is undulating, the contact portion 43 can be reliably brought into contact.

<First modification>
FIG. 6 is a plan view schematically showing an example of a connector 40a used in the bipolar battery of the first modified example. FIG. 7 is a partially cutaway perspective view schematically showing an example of a bipolar battery 10a of a second modified example. The connector 40a shown in FIG. 6 differs from the connector 40 shown in FIG. 5 in that the lengths of the comb tooth portions 42 are different. Other points of the connector 40a are the same as those of the connector 40, and substantially the same parts are denoted by the same reference numerals, and detailed description of the same parts is omitted.

The comb tooth portion 42 is formed longer in order toward one side in the arrangement direction. More specifically, as shown in FIG. 6, the connector 40a has 12 comb teeth 42. As shown in FIG. When the twelve comb teeth 42 are the first comb teeth 42_01 to the twelfth comb teeth 42_12 as described above, the first comb teeth 42_01 is the shortest and gradually becomes longer. The twelfth comb tooth portion 42_12 is the longest.

As shown in FIG. 7, each comb tooth portion 42 is sandwiched between the cells 20 stacked in the thickness direction. Therefore, the positions at which the comb tooth portions 42 are attached are different. In the connector 40a, the length of the comb tooth portion 42 is determined by the height at which the contact portion 43 is arranged. More specifically, the length is determined so that only the comb tooth portion 42 is wired upward while the branch portion 412 is kept in contact with the base portion 111 .

The branch portion 412 as a whole can reduce the space for arranging the base portion 111 to reduce the size of the exterior body 11. As a result, the size of the bipolar battery 10a can be reduced. Further, by configuring the connector 40a in this way, twisting of the main body 41 with respect to the base portion 111 during wiring of the comb tooth portion 42 can be suppressed. As a result, when the exterior body 11 is heat-sealed, a gap is less likely to form between the exterior body 11 and the connector 40a, thereby suppressing foreign matter such as water, dust, and dirt from entering the bipolar battery 10a.

<Second modification>
FIG. 8 is a plan view schematically showing an example of a connector 40b used in the bipolar battery of the second modified example. The connector 40b shown in FIG. 8 differs from the connector 40 shown in FIG. 5 in that the width of the comb tooth portion 42b and the pattern wiring 44b arranged in the comb tooth portion 42b are different. Other points of the connector 40b are the same as those of the connector 40, and substantially the same parts are denoted by the same reference numerals, and detailed description of the same parts is omitted.

As shown in FIG. 8 , the comb tooth portions 42 b are arranged in the longitudinal direction of the branch portion 412 . The lead-out portion 411 is arranged on the opposite side of the comb tooth portion 42 b in the intermediate portion in the longitudinal direction of the branch portion 412 . That is, the main body portion 41 has a drawer portion 411 extending on the side opposite to the comb tooth portion 42 . The comb tooth portion 42 b is formed so that the width thereof increases in the longitudinal direction of the branch portion 412 as the distance from the portion connected to the lead portion 411 increases. In the arrangement direction of the comb teeth 42, the pattern wiring 44b wired to the comb teeth 42 arranged far from the lead-out portion 411 is wider than the pattern wiring 44b wired to the comb teeth 42 arranged near. is wide.

That is, in the connector 40b, the pattern wiring 44b arranged in the branch portion 412 and the comb tooth portion 42b becomes wider as the pattern wiring 44b connected to the comb tooth portion 42b farther from the connection portion with the lead portion 411 is connected. By configuring in this way, the resistance difference of the pattern wiring 44b based on the length difference can be suppressed. Thereby, the voltage of the stacked unit cells 20 can be measured more accurately.

<Third modification>
FIG. 9 is a partially cutaway perspective view schematically showing an example of a bipolar battery 10c of a third modified example. Four connectors 40c are used in the bipolar battery 10c shown in FIG. Except for this point, the bipolar battery 10c is the same as the bipolar battery 10 shown in FIG. 1, and substantially the same parts are denoted by the same reference numerals, and detailed description of the same parts is omitted.

As shown in FIG. 9, the bipolar battery 10c has a plurality of connectors 40c. The bipolar battery 10c has four connectors 40c. Each connector 40 c has three comb tooth portions 42 . The comb tooth portions 42 of each connector 40c are arranged at different positions between different cells.

One connector 40 c is provided for every four cells 20 . A terminal portion 413 is provided on the body portion 41 of the connector 40c, and the terminal portion 413 of each connector 40c is connected to a voltage measuring device (not shown). The three comb tooth portions 42 of each connector 40c are sandwiched between the positive electrode current collector 24 and the negative electrode current collector 26, respectively. It is also connected to the lower end positive electrode current collector 24 and the upper end negative electrode current collector 26 of the assembled battery 30 .

The connector 40 c has a shorter branch portion 412 than the connector 40 . Therefore, the connector 40c is less likely to be twisted, and when the connector 40c is bent along the assembled battery 30, an unreasonable force is less likely to act. Therefore, disconnection or the like is less likely to occur, and the voltage of the cell 20 can be stably measured.

The bipolar batteries 10, 10a, and 10c may have a configuration in which the assembled battery 30 is covered only with the cover portion 112. FIG. In other words, in the bipolar batteries 10, 10a, and 10c, the exterior body 11 may have a configuration in which the base portion 111 is omitted.

The embodiments of the present invention have been described above, but each configuration and combination thereof in the embodiments are examples, and additions, omissions, substitutions, and other modifications of the configuration can be made without departing from the scope of the present invention. is possible. Moreover, the present invention is not limited by the embodiments.

The bipolar type battery according to the present invention is useful, for example, as a lithium ion battery used for mobile phones, personal computers, hybrid vehicles and electric vehicles.

Reference Signs List 10, 10a Bipolar type battery 11 Armor body 111 Base part 112 Cover part 12 Positive electrode conductive sheet 121 Positive electrode lead-out terminal 13 Negative electrode conductive sheet 131 Negative electrode lead-out terminal 20 Cell 21 Positive electrode 22 Negative electrode 23 Separator 24 Positive electrode current collector 25 Positive electrode active material layer 26 negative electrode current collector 27 negative electrode active material layer 28 frame member 30 assembled battery 40, 40a, 40b connector 41 body portion 411 lead portion 412 branch portion 413 terminal portion 42, 42b comb tooth portion 43 contact portion 44, 44b pattern wiring

Claims (5)

A bipolar battery in which single cells having current collectors arranged on both sides are stacked so that the current collectors of different polarities are in contact,
Having a connector formed of a printed circuit board having insulation and flexibility,
The connector is
a main body;
a plurality of comb teeth protruding from the main body and arranged in a comb shape apart from each other;
a plurality of contact portions provided at the tip of each of the comb teeth, having electrical conductivity and exposed on at least one side in the thickness direction of the comb teeth;
a pattern wiring arranged in the comb tooth portion and the main body portion and individually and electrically connecting the contact portion and a plurality of terminal portions at the end portion of the main body portion;
wherein the plurality of contact portions are in contact with a portion inside the outer edge portion of the current collector by a predetermined length or more;
Some of the plurality of contact portions are in contact with the current collectors arranged at both ends in the stacking direction, and the rest are sandwiched between the current collectors adjacent in the stacking direction. electrically connected to the current collector ;
The comb tooth portion is a bipolar battery in which the comb tooth portions are formed longer in order toward one side in the arrangement direction . 2. The bipolar battery according to claim 1, wherein the contact portion has a conductive foil formed on the comb tooth portion. Having a plurality of connectors,
3. The bipolar battery according to claim 1, wherein the comb tooth portions of the plurality of connectors are arranged at different positions between different cells. The main body portion has a drawer portion extending in a direction opposite to the comb tooth portion,
In the direction in which the comb teeth are arranged, the pattern wiring arranged in the comb teeth arranged farther from the lead-out portion is wider than the pattern wiring arranged in the comb teeth arranged nearby. 4. The bipolar battery according to any one of claims 1 to 3 , having a wide range. 5. The bipolar battery according to claim 1, wherein said connector is a single-sided substrate.

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