Electrochemical Cell

Abstract

To provide an electrochemical cell that can be mounted while its posture is stably maintained and can maintain the airtightness of an exterior body.SOLUTION: There is provided an electrochemical cell 10 comprising: an electrode body 11 that has a positive electrode and a negative electrode; and an exterior body 12 that has at least a first wall part 65 and a second wall part 66 opposite to each other in the direction of a battery axis O with the electrode body therebetween and accommodates the electrode body therein. The first wall part is provided with a first terminal part 72 in conduction with one of the positive electrode and the negative electrode. The second wall part is provided with a second terminal part 73 in conduction with the other of the positive electrode and the negative electrode. The first wall part is provided with a buffer member 80 that is elastically deformed in the battery axis direction and has insulating properties with the first terminal part exposed to the outside.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to electrochemical cells. [Background technology]

[0002] Conventionally, electrochemical cells such as lithium ion secondary batteries and electrochemical capacitors have been widely used. Known examples of this type of electrochemical cell include a so-called coin-type (button-type) electrochemical cell that uses a metal case for an exterior body that houses an electrode body therein, as shown in Patent Document 1 below, and a so-called laminate-type electrochemical cell that uses a laminate film for an exterior body that houses an electrode body therein, as shown in Patent Document 2 below.

[0003] Coin-type electrochemical cells (e.g., nonaqueous electrolyte secondary batteries) are known to have high voltage, high energy density, excellent charge / discharge characteristics, long cycle life, and high reliability. Therefore, this type of electrochemical cell is suitably used as a backup power source for semiconductor memory or clock function in various small electronic devices such as smartphones, wearable devices, hearing aids, portable game consoles, and digital cameras. Laminate-type electrochemical cells have the advantages of being small and having a high degree of freedom in shape, and are known as electrochemical cells that can lead to even higher capacities. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-298803 A [Patent Document 2] JP 2018-85214 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when mounting an electrochemical cell in various devices, electronic devices, and the like, the electrochemical cell may be held in a state in which external terminals are electrically connected to the positive electrode terminal portion and the negative electrode terminal portion arranged in the battery axial direction (up and down direction). In this case, when spring terminals are used as the external terminals, the electrochemical cell is held at two points, sandwiching it from both sides in the battery axis direction, making it difficult to hold the electrochemical cell stably, and there was room for improvement. In particular, when the electrochemical cell is mounted between two mounting boards using spring terminals, the position of the electrochemical cell is likely to become unstable.

[0006] In this regard, it is conceivable to fix the outer casing of the electrochemical cell using, for example, a holder case or the like. However, if the outer casing is formed from a laminate film, there is a risk of the outer casing being scratched, making it difficult to firmly fix the outer casing itself using a holder case or the like.

[0007] Furthermore, the laminate film often has a multi-layer structure including a metal layer, and the metal layer is exposed to the outside at the end of the laminate film. Therefore, the exposed part of the metal layer is likely to come into contact with the outside. Under such circumstances, if the laminate film is scratched for some reason, the electrolyte and the metal layer may come into contact inside the electrochemical cell. In this state, if the metal layer becomes lower than the reduction potential with respect to, for example, lithium in the electrolyte due to external contact, an alloying reaction of the metal layer (for example, an alloying reaction between aluminum and lithium) may occur. If an alloying reaction of the metal layer occurs, for example, the alloy precipitated in a needle shape may penetrate the laminate film, or the metal layer may expand due to the alloying reaction, damaging the laminate film, and other inconveniences may occur, making it difficult to maintain the airtightness of the exterior body.

[0008] Therefore, it is required to mount the electrochemical cell while stably holding it and preventing the above-mentioned inconveniences. The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an electrochemical cell that can be mounted while maintaining a stable posture and that can maintain the airtightness of the exterior body. [Means for solving the problem]

[0009] (1) The electrochemical cell according to the present invention comprises: An electrochemical cell is mounted so as to be sandwiched between a first mounting substrate and a second mounting substrate arranged at an interval in a battery axis direction, An electrode assembly having a positive electrode and a negative electrode, and a The above and an exterior body having at least a first wall portion and a second wall portion facing each other in a battery axis direction and housing the electrode body therein, wherein the first wall portion is provided with a first terminal portion electrically connected to one of the positive electrode and the negative electrode, and the second wall portion is provided with a second terminal portion electrically connected to the other of the positive electrode and the negative electrode, and the first wall portion is elastically deformable in the battery axis direction and has insulating properties. Made of porous material A buffer member is provided with the first terminal portion exposed to the outside. The cushioning member is fixed to the first wall portion via an adhesive layer so as to overlap the first wall portion, and is sandwiched between the cushioning member and the first mounting substrate while being elastically deformed so as to be compressed. It is characterized by:

[0010] According to the electrochemical cell of the present invention, when mounting, external connection terminals such as spring terminals are brought into contact with the first terminal portion and the second terminal portion, respectively, so that the electrochemical cell can be sandwiched and held from both sides in the battery axis direction while achieving electrical continuity with the outside. In particular, since the first wall portion is provided with a buffer member, the buffer member can play a role of a spacer between the first wall portion and a mounting substrate on which the external connection terminals and the like are provided, and the electrochemical cell can be mounted while elastically deforming the buffer member so as to be compressed. This makes it possible to mount the electrochemical cell by placing it on the mounting substrate via the buffer member, and mounting can be performed while the attitude of the electrochemical cell is stably maintained. Furthermore, since the buffer member has insulating properties, it does not affect the electrical continuity between the external connection terminals and the first terminal portion.

[0011] The exterior body may be, for example, a metal container in which a positive electrode can and a negative electrode can are crimped together, or may be formed of a laminate film including a metal layer. In particular, even if the exterior body is formed of a laminate film including a metal layer, the use of an elastically deformable buffer member makes it difficult to scratch the exterior body. Furthermore, the use of the buffer member allows the exterior body to be separated from, for example, a mounting substrate, so that contact with the exposed portion of the metal layer from the outside can be suppressed. Therefore, various inconveniences caused by contact between the metal layer and the outside (e.g., alloying of the metal layer, etc.) can be suppressed, the airtightness of the exterior body can be maintained, and an electrochemical cell with improved operational reliability over a long period of time can be obtained.

[0012] (2) The buffer member is further provided on the second wall portion in a state where the second terminal portion is exposed to the outside. The second mounting substrate is sandwiched between the second mounting substrate and the second wall portion while being elastically deformed to be compressed. That's fine.

[0013] In this case, since the buffer member is provided not only on the first wall but also on the second wall, it is possible to mount the electrochemical cell by sandwiching it between two mounting substrates using the buffer member, for example. Therefore, the electrochemical cell can be mounted while maintaining its posture more stably.

[0014] (3) The outer casing is formed by arranging a first laminate member and a second laminate member in the battery axial direction on either side of the electrode body, and includes a storage section that stores the electrode body inside, and a sealing section in which the first laminate member and the second laminate member are joined to each other in an overlapping state and seal the inside of the storage section, the storage section includes the first wall portion and the second wall portion, and a cylindrical peripheral wall portion that surrounds the electrode body from the outside in the radial direction, the sealing portion is folded from the second wall portion side toward the first wall portion side along the peripheral wall portion and is formed in a cylindrical shape that surrounds the peripheral wall portion from the outside in the radial direction around the entire circumference, the first laminate member and the second laminate member are each formed of a laminate film having a metal layer and a resin layer covering both sides of the metal layer, and the cushioning member may be provided so as to cover a leading edge of the sealing portion.

[0015] In this case, the first laminate member and the second laminate member formed of a thin laminate film are used to configure the exterior body, so that a laminate-type electrochemical cell that is small and has a high degree of freedom in shape can be obtained. In particular, the first laminate member and the second laminate member are joined by, for example, thermal welding, so that the sealing portion can be configured with high sealing properties (adhesion). In addition, since the sealing portion is folded along the peripheral wall portion, it is possible to effectively prevent disturbances such as dust and moisture from entering the housing portion from the outside through the gap between the first laminate member and the second laminate member. Therefore, an electrochemical cell with stable operational reliability can be obtained. Furthermore, since the leading edge of the sealing portion can be covered by using the buffer member, the leading edge can cover and conceal the metal layers of the first and second laminate members. This can further suppress contact with the metal layers from the outside, and effectively suppress various inconveniences (e.g., alloying of the metal layers) caused by contact between the metal layers and the outside. This makes it easier to maintain the airtightness of the exterior body, and can provide an electrochemical cell with improved operational reliability.

[0016] (4) The sealing portion may be in contact with the peripheral wall portion from the outside in the radial direction.

[0017] In this case, since the sealing portion is in contact with the peripheral wall portion from the outside in the radial direction, the sealing portion can be configured to surround the peripheral wall portion without leaving an annular gap between the sealing portion and the peripheral wall portion. Therefore, the diameter of the entire electrochemical cell can be reduced by the amount that the gap can be omitted. In particular, since the diameter of the entire electrochemical cell can be reduced without changing the size of the housing portion, this can contribute to improving the volume ratio of the electrode body to the volume of the entire electrochemical cell, which can lead to an improvement in volumetric efficiency. Note that volumetric efficiency refers to the ratio of the volume of the electrode to the volume of the entire battery, i.e., "electrode part volume / total battery volume."

[0018] (5) The tip end side of the sealing portion may be deformed so as to be curved radially inward toward the tip edge.

[0019] In this case, the tip side of the sealing portion bent along the peripheral wall toward the first wall is deformed so as to be curved radially inward toward the tip edge. This allows the tip side of the sealing portion formed by joining the first laminate member and the second laminate member to be forcibly curved radially inward around the entire circumference of the sealing portion. This makes it difficult for the metal layers of the first laminate member and the second laminate member to be exposed to the outside at the tip edge of the sealing portion. This further suppresses contact with the metal layers from the outside. Effect of the Invention

[0020] According to the present invention, it is possible to provide an electrochemical cell that can be mounted while maintaining a stable posture and that can maintain the airtightness of the exterior body. [Brief description of the drawings]

[0021] [Figure 1]FIG. 1 is a diagram showing a first embodiment of a secondary battery (electrochemical cell) according to the present invention, and is a vertical cross-sectional view showing a state in which the battery is mounted between a first mounting substrate and a second mounting substrate. [Diagram 2] FIG. 2 is a perspective view of the secondary battery shown in FIG. [Diagram 3] 3 is a vertical cross-sectional view of the secondary battery taken along line AA shown in FIG. 2. [Figure 4] 4 is an enlarged longitudinal sectional view of the secondary battery showing a portion surrounded by a virtual circle B shown in FIG. [Diagram 5] FIG. 4 is an exploded perspective view of the secondary battery shown in FIG. [Figure 6] 6 is a longitudinal sectional view of the electrode body taken along line CC shown in FIG. 5. [Figure 7] FIG. 4 is a vertical sectional view of a secondary battery showing a modified example of the first embodiment. [Figure 8] FIG. 4 is a vertical sectional view of a secondary battery showing another modified example of the first embodiment. [Figure 9] 9 is an enlarged longitudinal sectional view of the secondary battery showing a portion surrounded by an imaginary circle D shown in FIG. 8. [Figure 10] 10 is a vertical sectional view of a secondary battery showing still another modified example of the first embodiment. FIG. [Figure 11] 10 is a vertical sectional view of a secondary battery showing still another modified example of the first embodiment. FIG. [Figure 12] FIG. 11 is a diagram showing a second embodiment of a secondary battery (electrochemical cell) according to the present invention, and is a vertical cross-sectional view showing a state in which the secondary battery is mounted between a first mounting substrate and a second mounting substrate. [Figure 13] FIG. 11 is a vertical sectional view showing a mounted state of a secondary battery, illustrating a modification of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] (First embodiment) Hereinafter, an embodiment of an electrochemical cell according to the present invention will be described with reference to the drawings. In this embodiment, a lithium ion secondary battery (hereinafter simply referred to as a secondary battery), which is a type of non-aqueous electrolyte secondary battery, will be taken as an example of an electrochemical cell. Furthermore, in this embodiment, a so-called laminate type secondary battery, in which the exterior body is formed of a laminate film, will be taken as an example.

[0023] As shown in FIG. 1, the secondary battery 10 of this embodiment is mounted so as to be sandwiched between a first mounting board 2 and a second mounting board 3 that are spaced apart in the direction of a battery axis O, thereby constituting a part of an electronic device 1. The electronic device 1 is not particularly limited, but examples thereof include small portable electronic devices such as smartphones and wireless earphones such as TWS (True Wireless Stereo). The first mounting board 2 and the second mounting board 3 are, for example, printed circuit boards, on which various electronic components (not shown) constituting the electronic device 1 are mounted. However, the first mounting board 2 and the second mounting board 3 are not limited to printed circuit boards, and may be, for example, a part of a housing that constitutes the electronic device 1.

[0024] A first spring terminal 4, which is an external terminal, is mounted on a main surface 2a of the first mounting board 2 facing the second mounting board 3. The first spring terminal 4 has a first contact portion 4a that is biased toward the secondary battery 10 by an elastic restoring force of a spring member (not shown). As a result, the first contact portion 4a strongly presses against a first electrode terminal plate 72 (described later) of the secondary battery 10 and is electrically connected to the first electrode terminal plate 72. Similarly, a second spring terminal 5, which is an external terminal, is mounted on the main surface of the second mounting board 3 facing the first mounting board 2. The second spring terminal 5 has a second contact portion 5a that is biased toward the secondary battery 10 by an elastic restoring force of a spring member (not shown). As a result, the second contact portion 5a strongly presses against a second electrode terminal plate 73 (described later) of the secondary battery 10 and is electrically connected to the second electrode terminal plate 73.

[0025] Therefore, the secondary battery 10 is mounted between the first mounting board 2 and the second mounting board 3 in a state where it is sandwiched from both sides in the direction of the battery axis O by the first spring terminal 4 and the second spring terminal 5. Furthermore, the secondary battery 10 is electrically connected to the electronic device 1 via the first spring terminal 4 and the second spring terminal 5, and supplies power to the electronic device 1.

[0026] (Secondary battery) The secondary battery 10 will be described in detail below. As shown in Fig. 1 to Fig. 5, the secondary battery 10 of this embodiment mainly comprises an electrode body 11 having a plurality of electrodes, i.e., a positive electrode 20 and a negative electrode 30, stacked on top of each other along the battery axis O, and an exterior body 12 that houses the electrode body 11 and has at least a top wall portion (first wall portion according to the present invention) 65 and a bottom wall portion (second wall portion according to the present invention) 66 that face each other in the battery axis O direction with the electrode body 11 in between. The exterior body 12 is formed of a laminate film. Note that in each drawing, the electrode body 11 is illustrated in an appropriately simplified form.

[0027] In this embodiment, the axis that passes through the center of the electrode body 11 and extends in the up-down direction is referred to as the battery axis O. In addition, in a plan view seen from the battery axis O direction, the direction that intersects with the battery axis O is referred to as the radial direction, and the direction that goes around the battery axis O is referred to as the circumferential direction. Furthermore, in describing the configuration of the secondary battery 10, the direction along the battery axis O from the second electrode terminal plate 73 functioning as an external connection terminal for the negative electrode 30 described later to the first electrode terminal plate 72 functioning as an external connection terminal for the positive electrode 20 is referred to as the upward direction, and the opposite direction is referred to as the downward direction. Therefore, as shown in FIG. 1, the first mounting board 2 is disposed above the secondary battery 10, and the second mounting board 3 is disposed below the secondary battery 10.

[0028] As shown in Figs. 5 and 6, the electrode assembly 11 is a so-called laminated electrode in which a positive electrode 20 and a negative electrode 30 are laminated with a separator (not shown) sandwiched therebetween. The electrode body 11 is formed so that its outer shape is circular in a plan view. However, the outer shape of the electrode body 11 is not limited to this case and may be other shapes, such as an ellipse, an oval shape, or a diamond shape, and may be changed as appropriate.

[0029] In this embodiment, the positive electrode 20 and the negative electrode 30 are alternately stacked by being wound with the separator sandwiched between them. However, this is not limited to this case, and for example, the positive electrode 20 and the negative electrode 30 may be alternately stacked by being folded in a zigzag shape from the direction in which they intersect each other. Furthermore, a so-called pellet-type electrode body having the positive electrode 20 and the negative electrode 30 on both sides of the separator may be used.

[0030] The structure of the electrode body 11 will now be briefly described. The positive electrode 20 includes a positive electrode current collector 21 formed in a strip shape in a developed state before being wound, and positive electrode active material layers (not shown) formed on both sides of the positive electrode current collector 21 .

[0031] The positive electrode current collector 21 is formed in a thin sheet shape from a metal material such as aluminum or stainless steel, and includes a plurality of positive electrode bodies 22 and a plurality of positive electrode connection pieces 23. The positive electrode bodies 22 are formed in a disk shape, for example, and are arranged at intervals so as to be aligned in a row in a developed state before winding. The positive electrode connection pieces 23 are arranged between adjacent positive electrode bodies 22 in a developed state before winding, and connect the adjacent positive electrode bodies 22 to each other. Of the multiple positive electrode bodies 22, a positive electrode terminal tab 24 is formed on the positive electrode body 22 that is arranged on the outermost periphery in a wound state.

[0032] The positive electrode active material layer is formed on both sides of the positive electrode current collector 21 except for the positive electrode terminal tab 24. The positive electrode active material layer contains a positive electrode active material, a conductive assistant, a binder, a thickener, and the like, and is formed of a composite metal oxide such as lithium cobalt oxide or lithium nickel oxide. Examples of the conductive assistant include carbon blacks, carbon materials, and metal fine powders. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

[0033] The negative electrode 30 includes a negative electrode current collector 31 formed in a band shape in a developed state before being wound, and a negative electrode active material layer (not shown) formed on both sides of the negative electrode current collector 31 .

[0034] The negative electrode current collector 31 is formed in a thin sheet shape from a metal material such as copper, nickel, or stainless steel, and includes a plurality of negative electrode bodies 32 and a plurality of negative electrode connection pieces 33. The negative electrode bodies 32 are formed in, for example, a disk shape like the positive electrode body 22, and are arranged at intervals in a developed state before winding. The negative electrode connection pieces 33 are arranged between adjacent negative electrode bodies 32 in a developed state before winding, and connect the adjacent negative electrode bodies 32 to each other. Of the multiple negative electrode bodies 32, a negative electrode terminal tab 34 is formed on the negative electrode body 32 that is arranged on the outermost periphery in a wound state.

[0035] The negative electrode 30 has an outer shape similar to that of the positive electrode 20 described above. However, the outer size of the positive electrode 20 is slightly smaller than that of the negative electrode 30 (slightly smaller).

[0036] The negative electrode active material layer is formed on both sides of the negative electrode current collector 31 except for the negative electrode terminal tab 34. The negative electrode active material layer contains a negative electrode active material, a conductive assistant, a binder, a thickener, and the like, and is formed of a carbon material such as graphite. Examples of the conductive assistant include carbon blacks, carbon materials, and metal fine powders. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

[0037] The positive electrode 20 and the negative electrode 30 configured as described above are wound with the separator therebetween, as described above, and are stacked alternately. Then, in the electrode body 11 obtained by winding, as shown in Figures 5 and 6, the positive electrode main body 22 on which the positive electrode terminal tab 24 is formed is located at the top, and the negative electrode main body 32 on which the negative electrode terminal tab 34 is formed is located at the bottom. Therefore, the electrode body 11 is accommodated in the exterior body 12 in a state in which the positive electrode terminal tab 24 faces upward and the negative electrode terminal tab 34 faces downward.

[0038] As shown in FIGS. 1 to 5, the exterior body 12 includes a first laminating member 40 and a second laminating member 50 formed from a laminate film. The exterior body 12 is formed by arranging the first laminate member 40 and the second laminate member 50 in the direction of the battery axis O with the electrode body 11 sandwiched therebetween, and includes a housing section 60 that houses the electrode body 11 therein, and a sealing section 61 in which the first laminate member 40 and the second laminate member 50 are joined to each other in an overlapping state and seal the inside of the housing section 60. As a result, the exterior body 12 houses the electrode body 11 in a sealed state inside the housing section 60. The inside of the housing section 60 is filled with an electrolyte solution (electrolyte solution) not shown.

[0039] The housing portion 60 includes a top wall portion 65 and a bottom wall portion 66 which face each other in the direction of the battery axis O with the electrode body 11 therebetween, and an annular peripheral wall portion 67 which surrounds the electrode body 11 from the outside in the radial direction. The sealing portion 61 is bent (upward) along the peripheral wall portion 67 from the bottom wall portion 66 side toward the top wall portion 65 side, and is formed in a ring shape that surrounds the peripheral wall portion 67 from the radial outside all around, and is in contact with the peripheral wall portion 67 from the radial outside.

[0040] The exterior body 12 will be described in detail below. 3 and 4, the first laminate member 40 is a member that mainly covers the electrode body 11 from above, and has a metal layer 41, and an inner resin layer 42 and an outer resin layer 43 that cover both sides of the metal layer 41. The inner resin layer 42 and the outer resin layer 43 are tightly bonded to both sides of the metal layer 41, for example, by heat fusion or adhesion, via a bonding layer (not shown). In each drawing, the metal layer 41, the inner resin layer 42, and the outer resin layer 43 are appropriately omitted from illustration.

[0041] The metal layer 41 is made of a metal material suitable for blocking outside air and water vapor, such as stainless steel or aluminum. The inner resin layer 42 is formed using a thermoplastic resin such as polyolefin polyethylene or polypropylene. As the polyolefin, any of the following materials can be used: high-pressure low-density polyethylene (LDPE), low-pressure high-density polyethylene (HDPE), inflation polypropylene (IPP) film, non-oriented polypropylene (CPP) film, biaxially oriented polypropylene (OPP) film, linear short-chain branched polyethylene (L-LDPE, metallocene catalyst type). In particular, polypropylene resin is preferable. The outer resin layer 43 is formed using, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

[0042] The first laminate member 40 is formed in a double-tube shape with an upper end, and includes a top wall portion 45 that is circular in plan view and covers the electrode body 11 from above, a cylindrical peripheral wall portion 46 that extends downward from the outer periphery of the top wall portion 45 and surrounds the electrode body 11 from the radial outside, and a cylindrical first sealing portion 47 that is folded upward from the lower end portion of the peripheral wall portion 46 and surrounds the peripheral wall portion 46 from the radial outside.

[0043] The second laminate member 50 is a member that mainly covers the electrode body 11 from below, and has a metal layer 51, and an inner resin layer 52 and an outer resin layer 53 that cover both sides of the metal layer 51. The inner resin layer 52 and the outer resin layer 53 are each tightly joined to both sides of the metal layer 51 via a joining layer (not shown), for example, by heat fusion or adhesion. The materials and the like of the metal layer 51, the inner resin layer 52, and the outer resin layer 53 are similar to those of the metal layer 41, the inner resin layer 42, and the outer resin layer 43 in the first laminate member 40. Moreover, in each drawing, illustration of the metal layer 51, the inner resin layer 52, and the outer resin layer 53 is appropriately omitted.

[0044] The second laminate member 50 is formed in a bottomed cylindrical shape having a bottom wall portion 55 that covers the electrode body 11 from below, and a cylindrical second sealing portion 56 that extends upward from the outer circumferential edge portion of the bottom wall portion 55 and further surrounds the first sealing portion 47 from the radial outside.

[0045] The exterior body 12 is constituted by the first laminating member 40 and the second laminating member 50 configured as described above. Specifically, the top wall portion 45 and the peripheral wall portion 46 of the first laminate member 40 function as a top wall portion 65 and a peripheral wall portion 67, respectively, of the storage portion 60. In addition, the bottom wall portion 55 of the second laminate member 50 functions as a bottom wall portion 66 of the storage portion 60. Furthermore, the first sealing portion 47 of the first laminate member 40 and the second sealing portion 56 of the second laminate member 50 function as a sealing portion 61. Depending on the size of the electrode body 11 to be housed, the second laminate member 50 may be provided with a peripheral wall portion.

[0046] The first sealing portion 47 and the second sealing portion 56 functioning as the sealing portion 61 are integrally joined to each other, thereby sealing the inside of the storage portion 60 in an airtight state. Specifically, the inner resin layer 42 in the first sealing portion 47 and the inner resin layer 52 in the second sealing portion 56 are integrally joined together by, for example, ultrasonic welding or heat welding. However, the joining method is not limited to ultrasonic welding or heat welding, and may be, for example, high-frequency welding or adhesion using an adhesive.

[0047] In this embodiment, the height position of the upper end portion 61a of the sealing portion 61 is set to be equal to the height position of the top wall portion 65 of the storage portion 60. As a result, the sealing portion 61 is formed without protruding above the top wall portion 65. However, this is not limited to this case, and for example, the height position of the upper end portion 61a of the sealing portion 61 may be formed to be located above or below the top wall portion 65.

[0048] The first sealing portion 47 and the second sealing portion 56 are integrally joined together, then bent and molded by a molding die (not shown), and then drawn to reduce their diameter by a molding die (not shown). As a result, the sealing portion 61 formed by the first sealing portion 47 and the second sealing portion 56 is in intimate contact with the outer circumferential surface of the peripheral wall portion 67, being tightly pressed from the outside in the radial direction all around the circumference.

[0049] The connection portion between the lower end of the first sealing portion 47 and the lower end of the peripheral wall portion 46 functions as an inner bent portion 62 (see FIG. 3) generated by the drawing. The connection portion between the lower end of the second sealing portion 56 and the outer peripheral edge of the bottom wall portion 55 functions as an outer bent portion 63 (see FIG. 3) generated by the drawing.

[0050] Furthermore, as shown in Figures 3 and 5, the secondary battery 10 of this embodiment includes a first electrode plate 70 and a second electrode plate 71, a first electrode terminal plate (first terminal portion according to the present invention) 72 and a second electrode terminal plate (second terminal portion according to the present invention) 73, a first sealant film 74 and a second sealant film 75. The first electrode plate 70, the second electrode plate 71, the first electrode terminal plate 72, the second electrode terminal plate 73, the first sealant film 74 and the second sealant film 75 are accommodated together with the electrode body 11 inside the accommodation portion 60 in the exterior body 12.

[0051] The first electrode plate 70 is formed, for example, in a circular shape in a plan view, and is integrally connected to the positive electrode 20 in the electrode body 11. The first electrode plate 70 is formed, for example, from a metal material such as aluminum or stainless steel, with a diameter smaller than that of the electrode body 11, and is arranged coaxially with the battery axis O. The first electrode plate 70 is arranged overlapping the positive electrode main body 22 on which the positive electrode terminal tab 24 is formed, and the positive electrode terminal tab 24 is welded to the lower surface facing the electrode body 11 side, for example, by ultrasonic welding. As a result, the first electrode plate 70 is integrally connected to the positive electrode 20.

[0052] The first electrode terminal plate 72 is made of a metal material such as nickel and is circular in plan view with a smaller diameter than the first electrode plate 70, and is disposed so as to overlap the upper surface of the first electrode plate 70 facing the first laminate member 40. The first electrode terminal plate 72 is integrally fixed to the upper surface of the first electrode plate 70 by welding, for example, by resistance welding. As a result, the first electrode terminal plate 72 is electrically connected to the positive electrode 20 and functions as an external connection terminal for the positive electrode 20 .

[0053] A first through hole 45a having a circular shape in a plan view and exposing the first electrode terminal plate 72 to the outside is formed in the top wall portion 45 of the first laminate member 40. The first through hole 45a is formed so as to vertically penetrate the center of the top wall portion 45 and is formed coaxially with the battery axis O. That is, a first electrode terminal plate 72 is provided on the top wall portion 65 of the housing portion 60 and is exposed to the outside through the first through hole 45a.

[0054] The first sealant film 74 is formed in a ring shape surrounding the first electrode terminal plate 72 from the radially outer side, and is disposed coaxially with the battery axis O between the first electrode plate 70 and the top wall portion 45 of the first laminate member 40 while surrounding the first electrode terminal plate 72. The first sealant film 74 is heat-welded to the inner resin layer 42 of the top wall portion 45 of the first laminate member 40 and to the upper surface of the first electrode plate 70. As a result, the first electrode plate 70 is heat-welded to the top wall portion 45 of the first laminate member 40 via the first sealant film 74. The first sealant film 74 is formed of, for example, a thermoplastic resin such as polyethylene or polypropylene, which is a polyolefin, or polypropylene reinforced with nonwoven fabric.

[0055] As shown in Figures 3 and 5, the second electrode plate 71, the second electrode terminal plate 73 and the second sealant film 75 are formed and arranged in the same manner as the first electrode plate 70, the first electrode terminal plate 72 and the first sealant film 74 described above.

[0056] The second electrode plate 71 is formed, for example, in a circular shape in a plan view, and is integrally connected to the negative electrode 30 of the electrode body 11. The second electrode plate 71 is formed, for example, from a metal material such as copper with a diameter smaller than that of the electrode body 11, and is disposed coaxially with the battery axis O. The second electrode plate 71 is disposed so as to overlap the negative electrode 30 on which the negative electrode terminal tab 34 is formed, and the negative electrode terminal tab 34 is welded to the upper surface facing the electrode body 11 side, for example, by ultrasonic welding. As a result, the second electrode plate 71 is integrally connected to the negative electrode 30.

[0057] The second electrode terminal plate 73 is made of a metal material such as nickel and has a circular shape in plan view with a smaller diameter than the second electrode plate 71, and is disposed on the lower surface of the second electrode plate 71 facing the second laminate member 50. The second electrode terminal plate 73 is integrally fixed to the lower surface of the second electrode plate 71 by welding such as resistance welding. As a result, the second electrode plate 71 is electrically connected to the negative electrode 30 and functions as an external connection terminal for the negative electrode 30 .

[0058] A second through hole 55a having a circular shape in a plan view and exposing the second electrode terminal plate 73 to the outside is formed in the bottom wall portion 55 of the second laminate member 50. The second through hole 55a is formed so as to vertically penetrate the center of the bottom wall portion 55 and is formed coaxially with the battery axis O. That is, a second electrode terminal plate 73 is provided on the bottom wall portion 66 of the accommodation portion 60 and is exposed to the outside through the second through hole 55a.

[0059] The second sealant film 75 is formed in a ring shape surrounding the second electrode terminal plate 73 from the radially outer side, and is disposed coaxially with the battery axis O between the second electrode plate 71 and the bottom wall portion 55 of the second laminate member 50 while surrounding the second electrode terminal plate 73. The second sealant film 75 is heat-welded to the inner resin layer 52 of the bottom wall portion 55 of the second laminate member 50 and to the lower surface of the second electrode plate 71. As a result, the second electrode plate 71 is heat-welded to the bottom wall portion 55 of the second laminate member 50 via the second sealant film 75. Like the first sealant film 74, the second sealant film 75 is made of a thermoplastic resin such as polyolefin polyethylene or polypropylene, or polypropylene reinforced with nonwoven fabric.

[0060] Furthermore, as shown in Figures 1 to 5, in the secondary battery 10 of this embodiment, a first buffer sheet (a buffer member according to the present invention) 80 is provided on the top wall portion 65 of the storage section 60, and a second buffer sheet (a buffer member according to the present invention) 81 is provided on the bottom wall portion 66.

[0061] The first buffer sheet 80 is an insulating cushion sheet that is elastically deformable at least in the direction of the battery axis O, and is provided so as to overlap the top wall portion 65 with the first electrode terminal plate 72 exposed to the outside. The first buffer sheet 80 is formed from a porous material such as polypropylene foam, acrylic foam, urethane foam, or nonwoven fabric of various resins, and is formed into a ring shape in a plan view having a predetermined thickness. However, the material of the first buffer sheet 80 is not limited to this case, and other materials may be used as long as they are elastically deformable in the direction of the battery axis O and have insulating properties.

[0062] 3 and 4, an adhesive layer 82 is formed on the lower surface of the first buffer sheet 80. The first buffer sheet 80 is adhered and fixed to the top wall portion 65 via the adhesive layer 82 so as to overlap the top wall portion 65. The adhesive layer 82 can be formed using, for example, an acrylic adhesive or a rubber-based solvent-based adhesive. However, the adhesive is not limited to this case, and other adhesives may be used.

[0063] The first buffer sheet 80 is formed in a ring shape having an outer diameter equal to the outer diameter of the exterior body 12 and an inner diameter equal to the inner diameter of the first sealant film 74. As a result, the first buffer sheet 80 is formed such that its outer peripheral edge covers and coats the upper edge of the upper end portion 61a of the sealing portion 61 from above, and its inner peripheral edge protrudes radially inward beyond the first through-hole 45a formed in the top wall portion 65. Therefore, the outer peripheral edge of the first buffer sheet 80 covers and conceals the metal layers 41, 51 of the first laminate member 40 and the second laminate member 50 on the upper end portion 61a side of the sealing portion 61. Furthermore, the inner peripheral edge of the first buffer sheet 80 covers and hides the metal layer 41 of the first laminate member 40 at the first through-hole 45a.

[0064] The second buffer sheet 81, like the first buffer sheet 80, is an insulating cushion sheet that is elastically deformable at least in the direction of the battery axis O, and is provided so as to overlap the bottom wall portion 66 with the second electrode terminal plate 73 exposed to the outside. The second buffer sheet 81 is made of the same porous material as the first buffer sheet 80, and is formed in a ring shape in a plan view having a predetermined thickness. An adhesive layer 82 similar to that of the first buffer sheet 80 is formed on the upper surface of the second buffer sheet 81. The second buffer sheet 81 is adhered and fixed onto the bottom wall portion 66 via the adhesive layer 82 so as to overlap therewith.

[0065] The second buffer sheet 81 is formed in a ring shape having an outer diameter equal to the outer diameter of the exterior body 12 and an inner diameter equal to the inner diameter of the second sealant film 75. As a result, the second buffer sheet 81 is formed such that its inner peripheral edge portion protrudes radially inward beyond the second through hole 55a formed in the bottom wall portion 66. Therefore, the inner peripheral edge portion of the second buffer sheet 81 covers and conceals the metal layer 51 of the second laminate member 50 at the second through hole 55a.

[0066] (Function of secondary batteries) According to the secondary battery 10 configured as described above, as shown in FIG. 3, the first electrode terminal plate 72 fixed to the first electrode plate 70 is exposed to the outside through the first through hole 45a, and the second electrode terminal plate 73 fixed to the second electrode plate 71 is exposed to the outside through the second through hole 55a. Therefore, the first electrode terminal plate 72 and the second electrode terminal plate 73 can be utilized to establish electrical conductivity with the outside.

[0067] 1, by bringing the first contact portion 4a of the first spring terminal 4 into contact with the first electrode terminal plate 72 and bringing the second contact portion 5a of the second spring terminal 5 into contact with the second electrode terminal plate 73, the secondary battery 10 can be mounted between the first mounting board 2 and the second mounting board 3 while being held so as to be sandwiched from both sides in the direction of the battery axis O. This allows electrical continuity between the secondary battery 10 and the electronic device 1.

[0068] In particular, since the secondary battery 10 is provided with the first buffer sheet 80 and the second buffer sheet 81, the first buffer sheet 80 can act as a spacer between the first mounting board 2 on which the first spring terminal 4 is provided and the top wall portion 65, and the second buffer sheet 81 can act as a spacer between the second mounting board 3 on which the second spring terminal 5 is provided and the bottom wall portion 66. This allows the secondary battery 10 to be mounted so as to be sandwiched between the first mounting board 2 and the second mounting board 3 while the first buffer sheet 80 and the second buffer sheet 81 are elastically deformed so as to be compressed, respectively. Therefore, the secondary battery 10 can be mounted while its posture is stably maintained by utilizing the first buffer sheet 80 and the second buffer sheet 81. Furthermore, since the first buffer sheet 80 and the second buffer sheet 81 are insulating, they do not affect the electrical conductivity between the first spring terminal 4 and the second spring terminal 5 and the first electrode terminal plate 72 and the second electrode terminal plate 73.

[0069] Therefore, the secondary battery 10 can be mounted between the first mounting board 2 and the second mounting board 3 in a state in which it is stably held for a long period of time, and it is possible to supply power to the electronic device 1.

[0070] Furthermore, even if the exterior body 12 is formed of a laminate film, the elastically deformable first buffer sheet 80 and second buffer sheet 81 are used, so that the exterior body 12 is less likely to be scratched. Furthermore, as shown in Fig. 1, the first buffer sheet 80 can be used to separate the upper edge of the sealing portion 61 from the first mounting substrate 2, so that external contact with the exposed metal layers 41, 51 can be suppressed. Therefore, it is possible to suppress the occurrence of various inconveniences (e.g., alloying of the metal layers 41, 51, etc.) caused by contact between the metal layers 41, 51 and the outside, and the airtightness of the exterior body 12 can be maintained, and the secondary battery 10 can have improved operating reliability over a long period of time.

[0071] As described above, according to the secondary battery 10 of this embodiment, it is possible to mount the battery while maintaining a stable posture, and it is possible to maintain the airtightness of the exterior body 12, thereby providing a laminate-type secondary battery with improved operational reliability over the long term.

[0072] Furthermore, according to the secondary battery 10 of this embodiment, as shown in Fig. 4, the outer peripheral edge of the first buffer sheet 80 covers and coats the upper edge of the sealing portion 61, which further suppresses external contact with the metal layers 41, 51. Therefore, the above-mentioned effects can be achieved even more effectively.

[0073] 1, the inner peripheral edge of the first buffer sheet 80 covers and conceals the metal layer 41 of the first laminate member 40 at the first through hole 45a, and the inner peripheral edge of the second buffer sheet 81 covers and conceals the metal layer 51 of the second laminate member 50 at the second through hole 55a. Therefore, the metal layers 41, 51 can be protected even in the first through hole 45a and the second through hole 55a, and external contact with the metal layers 41, 51 can be suppressed.

[0074] 4, in the secondary battery 10 of this embodiment, the first laminate member 40 and the second laminate member 50 are joined by, for example, thermal welding, so that the sealing portion 61 can be configured with high sealing properties (adhesion). In addition, since the sealing portion 61 is folded along the peripheral wall portion 67, it is possible to effectively prevent disturbances such as dust and moisture from entering the housing portion 60 from the outside through the gap between the first laminate member 40 and the second laminate member 50. Therefore, in this respect as well, the secondary battery 10 can be made to have stable operational reliability.

[0075] Furthermore, since the exterior body 12 is constructed using the first laminate member 40 and the second laminate member 50 formed from thin laminate films, the thicknesses of the peripheral wall portion 67 and the sealing portion 61 themselves can be thin. This makes it easier to reduce the diameter of the secondary battery 10. In addition, since the sealing portion 61 is in contact with the peripheral wall portion 67 from the radially outer side, the sealing portion 61 can be disposed so as to surround the peripheral wall portion 67 without leaving an annular gap between the sealing portion 61 and the peripheral wall portion 67. Therefore, since the gap can be omitted, the diameter of the entire secondary battery 10 can be reduced. Moreover, since the diameter of the entire secondary battery 10 can be reduced without changing the size of the housing portion 60 that houses the electrode body 11, it is possible to improve the volume ratio of the electrode body 11 to the entire volume of the secondary battery 10. This can lead to improved volumetric efficiency.

[0076] (Modification of the first embodiment) In the first embodiment, the second electrode plate 71 is made of copper, but it may be made of nickel, for example. In this case, the second electrode terminal plate 73 may be omitted. In other words, an electrode terminal plate is not necessarily required for the negative electrode side, and it does not have to be provided. In this case, the second electrode plate 71 itself can function as an external connection terminal for the negative electrode side. In other words, the second electrode plate 71 can function as the second terminal portion according to the present invention.

[0077] Furthermore, in the above first embodiment, the secondary battery 10 is described as being circular in plan view, but the shape of the secondary battery 10 may be changed as appropriate. For example, the secondary battery 10 may be elliptical in plan view, combining straight lines and semicircular portions. In this case, the shape of the electrode body 11 may be elliptical in plan view in accordance with the external shape of the secondary battery 10.

[0078] Furthermore, in the above-described first embodiment, the case where the sealing portion 61 contacts the peripheral wall portion 67 from the outside in the radial direction has been described as an example, but the present invention is not limited to this case. For example, the secondary battery may have an annular gap between the peripheral wall portion 67 and the sealing portion 61. However, in terms of reducing the diameter and size of the secondary battery, it is preferable to bring the sealing portion 61 into contact with the peripheral wall portion 67 from the outside in the radial direction as in the first embodiment.

[0079] 7, an adhesive layer 82 may be further formed on the upper surface of the first buffer sheet 80, and the adhesive layer 82 may be covered with a release sheet 91. Similarly, an adhesive layer 82 may be further formed on the lower surface of the second buffer sheet 81, and the adhesive layer 82 etc. may be covered with a release sheet 91. The release sheet 91 covers and protects the adhesive layer 82, for example, during distribution and storage of the secondary battery, and can be easily peeled off from the adhesive layer 82 when the secondary battery is mounted.

[0080] In the case of the secondary battery 90 configured in this manner, during mounting, the secondary battery 90 can be sandwiched between the first mounting substrate 2 and the second mounting substrate 3, and further adhered and fixed to the first mounting substrate 2 and the second mounting substrate 3 via the adhesive layer 82. Therefore, the secondary battery 90 can be mounted in a state in which it is held even more stably. Furthermore, since the release sheet 91 covers the adhesive layer 82 during distribution, storage, etc. of the secondary battery 90, unintentional adhesion to the adhesive layer 82 can be prevented, thereby improving product distribution, storage properties, etc.

[0081] Furthermore, in the first embodiment, as shown in Figures 8 and 9, the upper end 61a side of the sealing portion 61 may be deformed so as to be curved radially inward toward the upper edge over the entire circumference. As a result, the upper end 61a side of the sealing portion 61 is forcibly curved and deformed so as to follow the curvature of the curved connection portion 68 (R portion) that connects the top wall portion 65 and the peripheral wall portion 67. In the illustrated example, the upper end 61a side of the sealing portion 61 is deformed so as to be slightly crushed, but as long as it is curved, it does not matter whether it is crushed or not. When the upper end portion 61a of the sealing portion 61 is curved radially inward, this can be achieved by molding using a molding die (not shown).

[0082] In the case of the secondary battery 100 configured in this manner, in addition to the effects of the first embodiment described above, the metal layers 41, 51 of the first laminate member 40 and the second laminate member 50 can be made less likely to be exposed to the outside at the upper edge of the sealing portion 61. This makes it possible to further suppress contact with the metal layers 41, 51 from the outside. This makes it possible to effectively suppress the occurrence of various inconveniences (e.g., alloying of the metal layers 41, 51, etc.) caused by contact between the metal layers 41, 51 and the outside, thereby making it possible to provide a secondary battery 100 with further improved operating reliability over a long period of time.

[0083] Furthermore, in the above first embodiment, the first buffer sheet 80 is provided on the top wall portion 65 side, and the second buffer sheet 81 is provided on the bottom wall portion 66 side. However, it is not necessary to provide both the first buffer sheet 80 and the second buffer sheet 81, and it is also acceptable to provide only one of the buffer sheets. For example, as shown in FIG. 10, a first buffer sheet 80 may be provided on the top wall 65 side, and an insulating protective sheet 111 may be provided on the bottom wall 66 side instead of the second buffer sheet 81.

[0084] The protective sheet 111 is, for example, a polyimide tape or a PET tape in which an adhesive is applied to a PET (polyethylene terephthalate) film base material, and is formed in a ring shape in a plan view. The protective sheet 111 is fixed by adhesion or the like so as to overlap the bottom wall portion 66, and the inner peripheral edge side protrudes radially inward from the second through hole 55a and is folded back upward. As a result, the inner peripheral edge side of the protective sheet 111 covers and protects the inner peripheral surface of the second through hole 55a from the radially inner side over the entire circumference. Therefore, the protective sheet 111 plays a role of covering and hiding the metal layer 51 of the second laminate member 50 at the second through hole 55a.

[0085] In the illustrated example, the inner peripheral edge side of the protective sheet 111 is folded upward to block the inner peripheral surface of the second through hole 55a from the inside in the radial direction, but the present invention is not limited to this case, and it is not necessary to fold the inner peripheral edge side of the protective sheet 111 upward. However, since the metal layer 51 of the second laminate member 50 can be covered and hidden in the second through hole 55a, it is preferable to fold the inner peripheral edge side of the protective sheet 111 upward.

[0086] The secondary battery 110 thus configured can also achieve the same effects as those of the first embodiment.

[0087] Furthermore, in the above first embodiment, the first buffer sheet 80 is formed in a ring shape having an inner diameter equal to the inner diameter of the first sealant film 74, but this is not limited to this case, and it may be formed in a ring shape having an inner diameter larger than the inner diameter of the first sealant film 74, for example, as shown in Figure 11. In addition, an insulating protective sheet 121 similar to the protective sheet 111 shown in FIG. 10 may be fixed by adhesion or the like onto the top wall portion 65 so as to be positioned inside the first buffer sheet 80.

[0088] The protective sheet 121 is formed in a ring shape in a plan view, and the inner peripheral edge side protrudes radially inward from the first through hole 45a and is folded back downward. As a result, the inner peripheral edge side of the protective sheet 121 covers and protects the inner peripheral surface of the first through hole 45a from the radially inner side over the entire circumference. Therefore, the protective sheet 121 plays a role of covering and hiding the metal layer 41 of the first laminate member 40 at the first through hole 45a.

[0089] In the illustrated example, the inner peripheral edge side of the protective sheet 121 is folded downward to block the inner peripheral surface of the first through hole 45a from the inside in the radial direction, but the present invention is not limited to this case, and it is not necessary to fold the inner peripheral edge side of the protective sheet 121 downward. However, since the metal layer 41 of the first laminate member 40 can be covered and hidden in the first through hole 45a, it is preferable to fold the inner peripheral edge side of the protective sheet 121 downward.

[0090] The secondary battery 120 thus configured can also achieve the same effects as those of the first embodiment.

[0091] Second embodiment Next, a second embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0092] In the first embodiment, a laminate-type secondary battery 10 has been described as an example of an electrochemical cell. However, the electrochemical cell of this embodiment is a secondary battery (nonaqueous electrolyte secondary battery) having a metal container in which an exterior body comprises a positive electrode can and a negative electrode can which are crimped together.

[0093] As shown in FIG. 12, the secondary battery 130 of this embodiment is a so-called coin (button) type battery, and mainly comprises a container (exterior body according to the present invention) 131 and an electrode body 132 housed inside the container 131.

[0094] Storage container 131 mainly comprises a metallic positive electrode can 140 formed into a cylindrical shape with a bottom, and a metallic negative electrode can 160 formed into a cylindrical shape with a top and crimped to positive electrode can 140 via gasket 150. Positive electrode can 140 and negative electrode can 160 are fixed such that a bottom wall portion (second wall portion according to the present invention) 141, which will be described later, of positive electrode can 140 and a top wall portion (first wall portion according to the present invention) 161, which will be described later, of negative electrode can 160 face each other in the direction of battery axis O. In this embodiment, the direction from the bottom wall portion 141 toward the top wall portion 161 along the battery axis O is referred to as the upward direction, and the opposite direction is referred to as the downward direction.

[0095] The electrode body (power generating element) 132 mainly comprises a positive electrode 170 provided on the positive electrode can 140 side, a negative electrode 180 provided on the negative electrode can 160 side, and a separator 190 arranged between the positive electrode 170 and the negative electrode 180, and contains an electrolyte 133. The electrode body (power generating element) 132 is accommodated in a storage space S formed inside the storage container 131.

[0096] Positive electrode can 140 is formed in a cylindrical shape with a bottom, and includes bottom wall 141 formed in a circular shape in a plan view, and an annular outer wall 142 formed on the outer peripheral edge of bottom wall 141 along the circumferential direction of bottom wall 141 and extending upward. A portion of outer wall 142 located on the side of top wall 161 of negative electrode can 160 is formed as crimped portion 143 curved radially inward (toward the inner wall of negative electrode can 160) from the bottom wall 141 side toward the open end edge of outer wall 142.

[0097] Negative electrode can 160 is formed in a cylindrical shape with a top, including top wall 161 formed in a circular shape in a plan view, and an annular inner wall 162 formed on the outer peripheral edge of top wall 161 along the circumferential direction of top wall 161 and extending downward. Negative electrode can 160 is assembled to positive electrode can 140 from above so that inner wall 162 fits inside outer wall 142, and then assembled integrally with positive electrode can 140 by crimping and fixing via gasket 150.

[0098] Gasket 150 is formed in a double annular shape so as to completely surround inner wall portion 162 of negative electrode can 160 from the radially outer side and the radially inner side. Gasket 150 is firmly sandwiched between positive electrode can 140 and negative electrode can 160 by crimping with crimping portion 143, and combines positive electrode can 140 and negative electrode can 160 together in a state in which a sealed storage space S is formed between positive electrode can 140 and negative electrode can 160.

[0099] The positive electrode 170 and the negative electrode 180 are disposed in the storage space S in a state in which they are disposed opposite each other in the direction of the battery axis O via the separator 190. The positive electrode 170, the negative electrode 180, and the separator 190 are impregnated with the electrolyte 133 filled in the storage container 131.

[0100] Positive electrode 170 is electrically connected to the upper surface of bottom wall 141 of positive electrode can 140 via positive electrode current collector 171. Negative electrode 180 is electrically connected to the lower surface of top wall 161 of negative electrode can 160 via negative electrode current collector 181. However, this is not limited to this case, and for example, positive electrode current collector 171 and negative electrode current collector 181 may be omitted and positive electrode 170 may be directly connected to positive electrode can 140 to give positive electrode can 140 the function of a current collector, or negative electrode 180 may be directly connected to negative electrode can 160 to give negative electrode can 160 the function of a current collector. The separator 190 is held by the gasket 150 inside the container 131 as the outer periphery of the separator 190 comes into contact with the gasket 150 .

[0101] In secondary battery 130 configured as described above, positive electrode can 140 including bottom wall 141 itself functions as a positive electrode side external connection terminal, and negative electrode can 160 including top wall 161 itself functions as a negative electrode side external connection terminal. However, in this embodiment, the center portion of top wall 161 functions as first terminal 161a with which first contact 4a of first spring terminal 4 comes into contact. Also, the center portion of bottom wall 141 functions as second terminal 141a with which second contact 5a of second spring terminal 5 comes into contact.

[0102] The first buffer sheet 80 is provided on the top wall 161 with the first terminal portion 161a exposed to the outside, and serves as a spacer between the top wall portion 161 and the first mounting substrate 2. Similarly, the second buffer sheet 81 is provided on the bottom wall 141 with the second terminal portion 141a exposed to the outside, and serves as a spacer between the bottom wall portion 141 and the second mounting substrate 3.

[0103] (Function of secondary batteries) Similarly to the first embodiment, the secondary battery 130 of this embodiment can be mounted so as to be sandwiched between the first mounting board 2 and the second mounting board 3, and can be mounted while maintaining a stable posture. Therefore, the coin-type secondary battery 130 can have improved operational reliability over a long period of time.

[0104] (Modification of the second embodiment) When exterior body 12 is made of metal, container 131, the structure is not limited to the second embodiment in which positive electrode can 140 and negative electrode can 160 are fixed to each other by crimping. 13, a secondary battery 200 may be provided with a storage container 201 configured such that the opening of a bottomed cylindrical metallic case body 202 is closed with a metallic electrode plate 203. In this case, the electrode plate 203 is thermally welded to the case body 202 via an insulating resin 204 such as a sealant film, thereby making it possible to provide a storage container 201 with high airtightness.

[0105] In this case, the electrode body 210 is only required to have at least a positive electrode and a negative electrode, and may be, for example, a so-called all-solid-state electrode body that uses an electrolyte containing a solid electrolyte. In the secondary battery 200, the electrode plate 203 functions as a top wall of the container 201 and corresponds to a first wall and a first terminal according to the present invention. Furthermore, the bottom wall 202a of the bottomed cylindrical case body 202 corresponds to a second wall and a second terminal according to the present invention.

[0106] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications include, for example, those that can be easily imagined by a person skilled in the art, those that are substantially the same, those that are within the scope of the equivalents, and the like.

[0107] For example, in each of the above embodiments, a secondary battery has been described as an example of an electrochemical cell, but this is not limited to this case, and the electrochemical cell may be, for example, a capacitor (e.g., a lithium ion capacitor) or a primary battery. [Explanation of symbols]

[0108] O…Battery axis 10, 90, 100, 110, 120, 130, 200...Secondary batteries (electrochemical cells) 11, 132, 210...electrode body 12…Exterior body 20, 170...Positive electrode 30, 180...Negative electrode 40…First laminate member 50...Second laminate member 60…Storage section 61...Sealing part 65, 161...Top wall part (first wall part) 66, 141...Bottom wall portion (second wall portion) 67...Peripheral wall part 72...First electrode terminal board (first terminal part) 73…Second electrode terminal board (second terminal part) 80...First cushioning sheet (cushioning member) 81...Second buffer sheet (buffer material) 131, 202...container (outer body) 141a...Second terminal section 161a...First terminal part 202a...Bottom wall part (second wall part, second terminal part) 203...Electrode plate (first wall part, first terminal part)

Claims

1. An electrochemical cell mounted so as to be sandwiched between a first mounting substrate and a second mounting substrate arranged at a distance in a battery axial direction, An electrode assembly having a positive electrode and a negative electrode; an exterior body that has at least a first wall portion and a second wall portion that face each other in the battery axis direction with the electrode body therebetween and that houses the electrode body therein; The first wall portion is provided with a first terminal portion that is electrically connected to one of the positive electrode and the negative electrode, The second wall portion is provided with a second terminal portion that is electrically connected to the other of the positive electrode and the negative electrode, a buffer member that is elastically deformable in the battery axial direction and is made of an insulating porous material is provided on the first wall portion with the first terminal portion exposed to the outside; The buffer member is fixed to the first wall portion via an adhesive layer so as to overlap the first wall portion, and is sandwiched between the buffer member and the first mounting substrate while being elastically deformed so as to be compressed.

2. 2. The electrochemical cell of claim 1 , The buffer member is further provided on the second wall portion with the second terminal portion exposed to the outside, and is fixed so as to overlap on the second wall portion via an adhesive layer, and the electrochemical cell is sandwiched between the second mounting substrate and the buffer member while elastically deforming to be compressed.

3. 3. The electrochemical cell according to claim 1 or 2, The exterior body is a housing portion that is formed by disposing a first laminate member and a second laminate member in the battery axial direction with the electrode body therebetween, and that houses the electrode body therein; a sealing portion in which the first laminate member and the second laminate member are joined to each other in an overlapping state, and which seals the inside of the storage portion; The housing portion includes the first wall portion, the second wall portion, and a cylindrical peripheral wall portion that surrounds the electrode body from the outside in the radial direction, The sealing portion is bent along the peripheral wall portion from the second wall portion side toward the first wall portion side and is formed into a cylindrical shape surrounding the peripheral wall portion from the radially outer side thereof, The first laminating member and the second laminating member are each formed of a laminating film having a metal layer and a resin layer covering both sides of the metal layer, The buffer member is provided so as to cover a leading edge of the sealing portion.

4. 4. The electrochemical cell of claim 3, The sealing portion is in contact with the peripheral wall portion from the outside in the radial direction.

5. 5. The electrochemical cell of claim 4, An electrochemical cell, characterized in that a tip end side of the sealing portion is deformed so as to be curved radially inward as it approaches the tip edge.

Images