JP2015170575A - Substrate unit, electrochemical cell unit and manufacturing method for electrochemical cell unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate unit, occurrence of manufacturing failure of which can be suppressed, and to provide an electrochemical cell unit and a manufacturing method of an electrochemical cell unit.SOLUTION: A substrate unit includes a substrate 20 having a wiring pattern 26 and lands 30, and on which an electronic element is mounted, and a positive electrode tab 15 and a negative electrode tab 16 having a joint 17 extending from an electrochemical cell, and joined to the lands 30 by resistance-welding. The land 30 includes a first layer 31 formed of a material mainly composed of copper, and a second layer 32 formed of a material mainly composed of nickel, and phosphorus is added to the second layer 32.

Description

  The present invention relates to a substrate unit, an electrochemical cell unit, and an electrochemical cell unit manufacturing method.

  Electrochemical cells such as non-aqueous electrolyte secondary batteries and electric double layer capacitors are used as power sources for various devices. As one form of the electrochemical cell, for example, a battery as described in Patent Document 1 has been proposed.

  In Patent Document 1, a positive electrode tab as a conductor is connected to a positive electrode of an electrochemical cell that stores electric charge, a negative electrode tab as a conductor is connected to a negative electrode of a battery cell, and a rectangular positive electrode as a conductor is connected to the positive electrode tab. The plate is connected, a rectangular negative electrode plate that is a conductor is connected to the negative electrode tab, the positive electrode plate and the negative electrode plate are connected to the protection circuit board, and formed at the four corners of the rectangular area corresponding to the positive electrode plate in the protection circuit board. An electrochemical cell unit is described in which a positive electrode plate is soldered to a land of the same shape, and the negative electrode plate is soldered to lands of the same shape formed at the four corners of a rectangular area corresponding to the negative electrode plate in the protection circuit board. ing.

  According to the electrochemical cell unit described in Patent Document 1, since the lands are arranged at the four corners or the four sides of the rectangular region, the positive electrode plate and the negative electrode plate can be placed on the lands formed on the protection circuit board without being displaced. It is said that it can be soldered to the land.

JP 2005-183092 A

However, the above-described prior art has the following problems.
In the prior art, the positive electrode tab and the negative electrode tab of the electrochemical cell are joined to the positive electrode plate and the negative electrode plate by resistance welding such as spot welding by the direct method, respectively. At this time, the solder interposed between the positive electrode plate and the negative electrode plate and the land melts and flux (pine resin or the like) bumps, and at that time, scattered solder may be generated in a ball shape. The solder balls formed at this time, for example, short-circuit the tabs of the electrochemical cell and the protection circuit board, causing malfunctions.

  Thus, in the prior art, there is a possibility that a manufacturing defect may occur in the electrochemical cell unit due to the solder balls.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a substrate unit, an electrochemical cell unit, and an electrochemical cell unit manufacturing method capable of suppressing the occurrence of manufacturing defects.

  In order to solve the above problems, a board unit according to the present invention has a wiring pattern and a land, is extended from an electric component and a board on which an electronic element is mounted, and is joined to the land by resistance welding. A tab having a joint portion, and the land includes a first layer formed of a material mainly containing copper, and a second layer formed of a material mainly containing nickel, The second layer is characterized in that phosphorus is added.

According to the present invention, since the joint portion of the tab extended from the electric component is directly joined to the land by resistance welding, no solder ball is generated. Therefore, it is possible to suppress the occurrence of manufacturing defects due to solder balls.
The land to which the tab of the electrical component is joined includes a first layer formed of a material containing copper as a main component and a second layer formed of a material containing nickel as a main component. Since phosphorus is added to the layer, it becomes possible to reduce the melting point compared to pure nickel, enabling welding with low thermal energy, and at least compared with the case of using conventional pure nickel Can sufficiently secure the bonding strength.
In addition, since joining by resistance welding can greatly reduce the heating time compared to joining by solder, for example, an electrical component, a laminate film covering the electrical component, a film-like member positioned between the laminate film and the tab, Further, it is possible to suppress thermal damage to the electronic element mounted on the substrate.
Furthermore, unlike the prior art, no metal plate is required, so the board unit is reduced in size, thickness and cost by reducing the number of parts, and the manufacturing lead is simplified by reducing the manufacturing process. Time reduction and cost reduction are possible.

  The tab has Ni-P plating.

  According to the present invention, the bonding strength between the tab and the land can be sufficiently secured by adding phosphorus (P).

  The tab has a bent portion.

  According to the present invention, a strong joint can be obtained by providing the tab with a bent portion.

  Further, the joint portion of the tab is formed with a convex portion protruding toward the land.

  According to the present invention, since the current during resistance welding can be concentrated and pressed on the convex portion of the tab, the tab can be efficiently and reliably resistance welded to the land.

  In addition, the tab is joined to the land in a state of being folded back to the electric component side.

  According to the present invention, the total length of the substrate unit can be shortened and downsized by folding the tab.

  Moreover, it has the thermal radiation part extended toward the said electrical component in the said electrical component side from the said junction part of the said tab, It is characterized by the above-mentioned.

  According to the present invention, since heat generated during resistance welding can be released from the heat radiating portion, for example, an electrical component, a laminate film covering the electrical component, a film-like member positioned between the laminate film and the tab, and a substrate It is possible to reliably suppress thermal damage to the electronic elements and the like mounted on the board.

  In addition, the substrate is characterized by being stacked and arranged in the thickness direction of the tab with respect to the extended tab.

  According to the present invention, the board unit can be thinned because the board is stacked and arranged in the thickness direction of the tab with respect to the extended tab.

  In addition, an end of the board on the electric component side is arranged on the electric component side with respect to an intermediate position between the joint portion of the tab and the electric component.

  According to the present invention, by arranging the board close to the electrical component side, the total length of the board unit can be shortened in addition to making the board unit thinner.

  The electrochemical cell unit of the present invention includes the above-described substrate unit, and the electrical component is an electrochemical cell.

  According to the present invention, since it is possible to suppress the occurrence of manufacturing defects due to solder balls, a highly reliable electrochemical cell unit can be obtained. Moreover, it can suppress that a thermal damage is added to the laminate film, an electronic element, etc. which cover an electrochemical cell. Furthermore, the electrochemical cell unit can be reduced in size, thickness and cost by reducing the number of parts.

  The electrochemical cell includes a pair of the tabs, and a positive electrode tab formed of a material mainly composed of aluminum as the one tab extends from the positive electrode of the electrochemical cell, and the electrochemical cell From the negative electrode of the cell, a negative electrode tab formed of a material containing nickel as a main component is extended as the other tab.

  According to the present invention, when the positive electrode tab and the negative electrode tab are each resistance-welded to the land, it is possible to suppress the production failure caused by the solder ball, so that the electrochemical cell unit is highly reliable. Can do.

  The electrochemical cell unit manufacturing method of the present invention is an electrochemical cell unit manufacturing method for manufacturing the above-described electrochemical cell unit, wherein the positive electrode tab is joined to the land by resistance welding. Including a positive electrode side resistance welding step, and in the positive electrode side resistance welding step, one of the welding electrode rods is brought into contact with the positive electrode tab and the other welding electrode rod is brought into contact with the land. It is characterized by being performed.

  According to the present invention, in the positive electrode side resistance welding step, the positive electrode tab is formed by a so-called indirect welding method in which one welding electrode rod is brought into contact with the positive electrode tab and the other welding electrode rod is brought into contact with the land. Can be securely bonded to the land.

  Moreover, the electrochemical cell unit manufacturing method of the present invention is an electrochemical cell unit manufacturing method for manufacturing the above-described electrochemical cell unit, wherein the negative electrode tab is joined to the land by resistance welding. Including the negative electrode side resistance welding step, the negative electrode side resistance welding step is characterized in that a pair of welding electrode rods are respectively brought into contact with the negative electrode tab.

  According to the present invention, in the negative electrode side resistance welding process, the negative electrode tab can be reliably joined to the land by a so-called series welding method in which a pair of welding electrode bars are brought into contact with the negative electrode tab, respectively.

According to the present invention, since the joint portion of the tab extended from the electric component is directly joined to the land by resistance welding, no solder ball is generated. Therefore, it is possible to suppress the occurrence of manufacturing defects due to solder balls.
The land to which the tab of the electrical component is joined includes a first layer formed of a material containing copper as a main component and a second layer formed of a material containing nickel as a main component. Since phosphorus is added to the layer, the bonding strength between the tab and the land can be sufficiently secured.
In addition, the joining by resistance welding can greatly shorten the heating time as compared with the joining by soldering, so that, for example, the laminate film covering the power generation element of the battery, the electronic element mounted on the substrate, etc. are thermally damaged. Can be suppressed.
Furthermore, unlike the prior art, since a metal plate is not required, the board unit can be reduced in size, thickness and cost by reducing the number of components.

It is explanatory drawing of the electrochemical cell unit which concerns on 1st embodiment. It is side surface sectional drawing of a land. It is explanatory drawing at the time of resistance welding a positive electrode tab with respect to a land. It is a schematic diagram of the one aspect | mode of resistance welding. It is a schematic diagram of the one aspect | mode of resistance welding. It is a schematic diagram of the one aspect | mode of resistance welding. It is a schematic diagram of the one aspect | mode of resistance welding. It is a schematic diagram of the one aspect | mode of resistance welding. It is explanatory drawing at the time of resistance welding a negative electrode tab with respect to a land. It is a schematic diagram of the other aspect of a land. It is explanatory drawing of the electrochemical cell unit which concerns on 2nd embodiment. It is explanatory drawing of the electrochemical cell unit which concerns on 3rd embodiment. It is explanatory drawing of the electrochemical cell unit which concerns on 4th embodiment.

(First embodiment)
Below, 1st embodiment of this invention is described using drawing.
FIG. 1 is an explanatory view of an electrochemical cell unit 1 according to the first embodiment. FIG. 1 (a) is a plan view of the electrochemical cell unit 1, and FIG. 1 (b) is an electrochemical cell unit 1. FIG. In addition, in FIG. 1, about the coating | coated member 40 mentioned later, it has illustrated with the dashed-two dotted line.
As shown in FIGS. 1A and 1B, the electrochemical cell unit 1 of the present embodiment mainly includes an electrochemical cell 11 (corresponding to “electrical part” in the claims) and a substrate unit 2. And is constituted by.

The electrochemical cell 11 is a so-called lithium ion battery including an electrode body 13 including a positive electrode and a negative electrode, and an exterior body 19 that houses the electrode body 13.
The electrode body 13 has a substantially rectangular shape in plan view. The electrode body 13 includes a positive electrode and a negative electrode (not shown) stacked on each other via a separator (not shown). The positive electrode and the negative electrode are in contact with a nonaqueous electrolyte such as an electrolytic solution.

The positive electrode of the electrode body 13 is obtained by, for example, attaching a positive electrode active material to a current collector such as a metal foil. The positive electrode active material is a complex oxide containing lithium and a transition metal, such as lithium titanate and lithium manganate. The negative electrode is obtained by attaching a negative electrode active material to a current collector such as a metal foil. Examples of the negative electrode active material include silicon oxide, graphite, hard carbon, lithium titanate, and LiAl. The separator has a property of passing lithium ions. The separator includes, for example, any one of a resin porous film, a glass nonwoven fabric, and a resin nonwoven fabric, or any combination of two or more. The electrode body 13 can accumulate (charge) charges or release (discharge) charges by moving lithium ions from one of the positive electrode and the negative electrode to the other.
Thus, the electrode body 13 is formed by winding or laminating the positive and negative electrodes and their current collectors and the separator separating the positive and negative electrodes. In addition to the liquid, a gel or a solid electrolyte can also be used as the electrolyte. In that case, the gel or the solid electrolyte can have a separator function.

  A positive electrode tab 15 and a negative electrode tab 16 (both corresponding to “tabs” in the claims) are provided in the longitudinal direction of the electrode body 13 from one side surface of the electrode body 13 along the short direction of the electrode body 13. Along the outside of the electrode body 13. The positive electrode tab 15 is electrically and mechanically connected to the positive electrode of the electrode body 13. The negative electrode tab 16 is electrically and mechanically connected to the negative electrode of the electrode body 13. Details of the positive electrode tab 15 and the negative electrode tab 16 will be described later.

  The electrochemical cell 11 includes an exterior body 19 that houses the electrode body 13. The exterior body 19 is formed with a cup-shaped recess so as to enclose the electrode body 13, and the electrode can be accommodated in the recess. Further, a sheet having a rectangular shape in plan view can be bent. The exterior body 19 is a laminate film having a metal layer laminated by sandwiching both surfaces of a metal foil with a resin film, for example. The metal foil is formed using a metal material that blocks moisture and oxygen such as aluminum and magnesium. The inner surface of the resin layer is formed using, for example, a thermoplastic resin such as polyethylene, polypropylene, ionomer, or ethylene-methacrylate copolymer resin. Specifically, the exterior body 19 of the present embodiment has an insulating characteristic of a three-layer structure including an inner layer made of a resin material such as polypropylene, an outer layer made of a resin material such as nylon, and an intermediate layer made of a metal material such as aluminum. It is an excellent laminate film. The electrode body 13 is sealed by heat welding the exterior body 19. Moreover, you may have a film-shaped member which pinches | interposes a tab between the exterior body 19, and the positive electrode tab 15 and the negative electrode tab 16. FIG. The film sandwiching the tab is made of a thermoplastic resin like the inner surface of the resin layer, and is sealed together with the laminate film.

The substrate unit 2 includes a substrate 20, a positive electrode tab 15 and a negative electrode tab 16.
The substrate 20 is a so-called glass epoxy substrate made of an epoxy resin containing glass, for example, and is formed in a substantially rectangular shape in plan view. The substrate 20 is disposed away from the base end portion 15 a of the positive electrode tab 15 and the base end portion 16 a of the negative electrode tab 16 in the thickness direction of the electrode body 13.
Of the main surface of the substrate 20, a wiring pattern (not shown) is routed on the first main surface 21 facing the base end portion 15 a of the positive electrode tab 15 and the base end portion 16 a of the negative electrode tab 16. Yes. The wiring pattern is formed in a laminated form by bonding metal materials such as copper (Cu), for example.

On the first main surface 21 of the substrate 20, a plurality of electronic elements 23 are mounted. The electronic element 23 is a so-called IC in which switching circuits such as resistors and transistors are packaged. Further, on the first main surface 21 of the substrate 20, a chip resistor, a capacitor, etc. (not shown) are mounted.
The electronic elements 23 and the wiring pattern mounted on the substrate 20 control the charging / discharging of the electrochemical cell 11 to prevent overcharging and overdischarging, and when the overcurrent occurs, the electrochemical cell 11 is electrically connected from an external device. The protection circuit for interrupting is formed.

A pair of electrode pads 24 </ b> A and 24 </ b> B are formed on the first main surface 21 of the substrate 20. The electrode pads 24A and 24B have a wiring formed by, for example, etching a metal material such as copper (Cu) after a pattern is printed on a metal material, and wiring is formed. Simultaneously when forming a wiring pattern (not shown). It is formed.
The core wires of the positive electrode conductor 25A and the negative electrode conductor 25B are electrically and mechanically connected to the electrode pads 24A and 24B, respectively. The positive electrode conductor 25A and the negative electrode conductor 25B are conductors for electrically connecting the electrochemical cell unit 1 to an external device.

  A pair of lands 30 are formed on the second main surface 22 opposite to the first main surface 21 of the substrate 20. A positive electrode tab 15 and a negative electrode tab 16 are joined to the pair of lands 30 by resistance welding, respectively.

FIG. 2 is a side sectional view of the land 30. In FIG. 2, illustrations are omitted except for the substrate 20, the land 30, and the positive electrode tab 15 for easy understanding. In FIG. 2, the thicknesses of the land 30 and the positive electrode tab 15 are exaggerated.
As shown in FIG. 2, the land 30 is formed by being laminated on the wiring pattern 26 laid on the second main surface 22 with, for example, copper (Cu), and the copper (Cu) is a main component. A first layer 31 formed of a material having nickel (Ni) as a main component, a second layer 32 formed of a material having nickel (Ni) as a main component, and a third layer formed of a material having gold (Au) as a main component. 33.

The wiring pattern 26 arranged on the second main surface 22 has a thickness of at least 10 μm, for example. The thickness of the wiring pattern 26 is more preferably 30 μm or more, and further preferably 60 μm or more.
The wiring pattern 26 on the second main surface 22 is routed on the first main surface 21 by an intermediate via 28 (see FIG. 1) formed in the substrate 20 along the thickness direction of the substrate 20. The wiring pattern is electrically connected.

The first layer 31 is laminated with respect to the wiring pattern 26 on the second main surface 22. For example, an alloy of copper (Cu) and tin (Sn) (Cu—Sn, hereinafter referred to as “copper tin alloy”). Or an alloy of copper (Cu) and nickel (Ni) (Cu—Ni, hereinafter referred to as “copper nickel alloy”).
The method for forming the first layer 31 is not particularly limited.
The first layer 31 is formed, for example, by plating a surface of the wiring pattern 26 with nickel (Ni) and then heating to partially become a copper nickel alloy.
The first layer 31 may be formed by, for example, plating the surface of the wiring pattern 26 with a copper nickel alloy or a copper tin alloy.

In addition, when forming the 1st layer 31 with a copper tin alloy, it is desirable that the content rate of tin (Sn) shall be 20% or less. In particular, when the content ratio of tin (Sn) is increased to 20% or more, the first layer 31 cannot maintain its shape under the influence of temperature when the positive electrode tab 15 and the negative electrode tab 16 are resistance welded. For this reason, when the positive electrode tab 15 and the negative electrode tab 16 are resistance-welded, misalignment, a short circuit, etc. may occur, and stable bonding may not be possible.
Moreover, when forming the 1st layer 31 with a copper nickel alloy, it is desirable for the content rate of copper (Cu) to be 50% or less. This is because if the ratio of copper (Cu) is increased, the surface is oxidized after the first layer 31 is formed, and resistance welding may not be stably performed.

  The second layer 32 is laminated so as to cover the surfaces of the wiring pattern 26 and the first layer 31. For example, an alloy of Sn (Sn) and nickel (Ni) (Sn—Ni, hereinafter referred to as “copper nickel alloy”). ), An alloy of zinc (Zn) and nickel (Ni) (Zn—Ni, hereinafter referred to as “zinc nickel alloy”), an alloy of copper (Cu) and nickel (Ni) (Cu—Ni). , Hereinafter referred to as “copper nickel alloy”), an alloy of gold (Au) and nickel (Ni) (Au—Ni, hereinafter referred to as “gold nickel alloy”), phosphorus (P) and nickel (Ni). (Ni—P, hereinafter referred to as “phosphorus nickel alloy”) and the like. In particular, by adding phosphorus (P) to the material forming the second layer 32, the bonding strength between the positive electrode tab 15 and the negative electrode tab 16 and the land 30 can be sufficiently ensured. Further, the metal added to nickel (Ni) can be added up to 1 wt% to 49 wt%. Particularly in the case of phosphorus (P), the content is preferably 1 wt% to 15 wt%. The second layer 32 may have a crystallite size of 10 μm or less. More preferably, it is 0.1 μm or less, and further preferably 0.02 μm or less, so that a sufficient bonding strength can be secured.

The method for forming the second layer 32 is not particularly limited.
The second layer 32 is formed by, for example, an electrolytic plating method or an electroless plating method. The second layer 32 is more preferably formed by an electroless plating method. Further, it can be confirmed by using XRD analysis that a broad-shaped nickel alloy layer having extremely small crystallites and no peaks can be formed by electroless plating. However, when the second layer 32 is formed by an electroless plating method, it is not preferable to include boron (B). This is because in a state where boron (B) is added to nickel (Ni), the melting point of nickel (Ni) increases and welding cannot be performed at an appropriate temperature. For this reason, the content of boron (B) in the second layer 32 needs to be suppressed to, for example, 1% or less.
Here, phosphorus (P) is added to the material forming the second layer 32. Thereby, the joining strength of the positive electrode tab 15 and the negative electrode tab 16 and the land 30 is fully securable.

  The third layer 33 is provided to prevent oxidation on the surface of the second layer 32. The third layer 33 is laminated so as to cover the surface of the second layer 32. For example, an alloy of gold (Au) and tin (Sn) (Au—Sn, hereinafter referred to as “gold-tin alloy”) or the like. , An alloy of gold (Au) and copper (Cu) (Au—Cu, hereinafter referred to as “gold-copper alloy”), or an alloy of gold (Au) and nickel (Ni) (Au—Ni, hereinafter referred to as “gold”). Nickel alloy "). The third layer 33 is formed by, for example, an electrolytic plating method or an electroless plating method.

  The thickness of the land 30 excluding the wiring pattern 26 (that is, the total thickness of the first layer 31, the second layer 32, and the third layer 33) is preferably 20 μm or more, and more preferably 40 μm or more and 100 μm or less.

  As shown in FIG. 1 (a) and FIG. 1 (b), the positive electrode tab 15 and the negative electrode tab 16 extend from the electrochemical cell 11, respectively, and are electrochemically curved so as to be U-shaped when viewed from the side. The tip portions 15 b and 16 b are resistance-welded to the land 30 in a state where the cell 11 is folded back. The positive electrode tab 15 is made of, for example, a material mainly composed of aluminum (Al). Further, the negative electrode tab 16 is formed of a material mainly composed of nickel (Ni), for example. When the electrochemical cell is a capacitor type, both the positive electrode tab 15 and the negative electrode tab 16 can be mainly composed of aluminum.

  Here, as shown in FIG. 2, the front end portions 15 b and 16 b of the positive electrode tab 15 and the negative electrode tab 16 are joint portions 17 that are joined to the land 30 by resistance welding. In each joint portion 17 of the positive electrode tab 15 and the negative electrode tab 16, a convex portion 17 a that protrudes toward the land 30 is formed. By forming the convex portion 17a in the joint portion 17, when performing resistance welding as will be described later, the current can be concentrated and pressurized on the convex portion 17a of the positive electrode tab 15 and the negative electrode tab 16, so that the positive electrode tab 15 and the negative electrode tab 16 can be resistance-welded to the land 30 efficiently and reliably.

  The substrate unit 2 including the positive electrode tab 15, the negative electrode tab 16, and the substrate 20 is covered with a covering member 40. The covering member 40 is, for example, a laminate film having an excellent insulating property of a three-layer structure including an inner layer made of a resin material such as polypropylene, an outer layer made of a resin material such as nylon, and an intermediate layer made of a metal material such as aluminum, It is formed by winding an adhesive tape or the like formed of a resin material or the like around the substrate unit 2 and the end portions of the electrochemical cell 11 by being wound a plurality of times.

(Electrochemical cell unit manufacturing method)
Then, the electrochemical cell unit manufacturing method for manufacturing the above-mentioned electrochemical cell unit 1 is demonstrated.
FIG. 3 is an explanatory diagram when the positive electrode tab 15 is resistance-welded to the land 30. FIG. 3 illustrates a state in which the substrate 20 is viewed from the second main surface 22 side. In FIG. 3, only the peripheral portion of the positive electrode tab 15 and the land 30 is shown in an enlarged manner.
As shown in FIG. 3, the electrochemical cell unit manufacturing method includes a positive electrode side resistance welding process for joining the positive electrode tab 15 to the land 30 by resistance welding.
In the positive electrode side resistance welding step, one of the pair of welding electrode rods 61 and 62 is brought into contact with a position corresponding to the convex portion 17a in the positive electrode tab 15 from the second main surface 22 side, and the other The positive electrode tab 15 is joined to the land 30 by a so-called indirect method in which the welding electrode rod 62 is brought into contact with the land 30 to perform resistance welding.

  In the case of the indirect method, it is preferable that a resistance chip is bonded to the tip of the positive electrode tab 15 in advance by diffusion bonding such as ultrasonic welding or hot press, so that strong bonding can be obtained. As the material of the resistor chip, pure aluminum (99.9% or more) or an aluminum alloy may be used, and more preferably, nickel foil or stainless steel plated with nickel may be used. The thickness is preferably 10 μm to 200 μm. As a simple manufacturing method, the positive electrode tab 15 made of aluminum may be bent at least once and the bent portion may be used as a resistance chip.

FIG. 4 is a schematic diagram of one embodiment of resistance welding. In addition, in FIG. 4, the welding part is illustrated with the dashed-two dotted line.
Further, as shown in FIGS. 4A and 4B, the positive electrode tab 15 may have a bent portion 18. The bent portion 18 may be such that the positive electrode tab 15 at the tip of the bent portion is separated and an insulating member 38 is sandwiched therebetween. Here, as the insulating member 38, for example, polyimide (PI), polyamide (polyaramide is particularly preferable among polyamides), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), etc. In general, it is preferable to use a material having high flame retardancy called engineering plastic. Of the polyamides, polyaramid is particularly preferable. In order to improve workability, an adhesive layer may be disposed on the non-woven fabric or sheet and bonded to the tab. In this case, the adhesive material is preferably a silicone resin system. The thickness of the nonwoven fabric or sheet and the adhesive layer is preferably about 10 μm to 100 μm.
As shown in FIG. 4A, after the separated positive electrode tabs 15 are welded by the indirect method, the separated positive electrode tabs 15 are welded to each other, whereby a stronger bond can be obtained. Moreover, welding becomes easier by making one side of the separated positive electrode tab 15 long in advance. Further, as shown in FIG. 4B, the bent portion 18 may be further bent.

  As another method, it is also preferable to use a so-called series system in which a pair of welding electrode rods 61 and 62 (see FIG. 3) are brought into contact with and joined to the positive electrode tab 15. With the series method, it is possible to obtain a strong joint even when the electrode width is narrow or the welding area is small.

FIG. 5 to FIG. 8 are schematic diagrams of one mode of resistance welding. In FIGS. 7 and 8, the welded portion is indicated by a two-dot chain line.
As shown in FIG. 5, when using the series method, the bent portion 18 may be provided in the positive electrode tab 15 in advance. By providing the bent portion 18, the current flowing inside the positive electrode tab 15 can be reduced. As a result, the path of the current flowing between the positive electrode tab 15 and the land 30 becomes longer, so that the positive electrode tab 15 easily generates heat. Accordingly, a strong bond between the positive electrode tab 15 and the land 30 can be obtained. As shown in FIG. 6, the bent portion 18 may further be provided with an insulating member 38. Further, as shown in FIG. 7, the bent portion 18 may be further bent.
In addition, as shown in FIG. 8, the bent portion 18 may have the positive electrode tab 15 at the distal end of the bent portion spaced apart and a resistance chip sandwiched therebetween. As the material of the resistor chip, pure aluminum (99.9% or more) or an aluminum alloy may be used, and more preferably, nickel foil or stainless steel plated with nickel may be used. The thickness is preferably 10 μm to 200 μm. As a simple manufacturing method, the positive electrode tab 15 made of aluminum may be bent at least once and the bent portion may be used as a resistance chip.

FIG. 9 is an explanatory diagram when the negative electrode tab 16 is resistance-welded to the land 30. FIG. 9 illustrates a state in which the substrate 20 is viewed from the second main surface 22 side. In FIG. 9, only the peripheral portions of the negative electrode tab 16 and the land 30 are illustrated in an enlarged manner.
As shown in FIG. 9, the electrochemical cell unit manufacturing method includes a negative electrode side resistance welding process for joining the negative electrode tab 16 to the land 30 by resistance welding.
In the negative electrode side resistance welding process, a pair of welding electrode rods 61 and 62 are brought into contact with the positions corresponding to the convex portions 17a of the negative electrode tab 16 from the second main surface 22 side, respectively, so that resistance welding is performed by a so-called series method. The tab 16 is joined to the land 30.

FIG. 10 is a schematic diagram of another aspect of the land 30. In FIG. 10, the positive electrode tab 15 and the negative electrode tab 16 are illustrated by two-dot chain lines.
As shown in FIG. 10, the land 30 may have a slit portion 30a at this time. Specifically, the slit portion 30a is provided at a place where a pair of welding electrode rods 61 and 62 respectively brought into contact with the positive electrode tab 15 and the negative electrode tab 16 are connected by a straight line. As a result, the current during energization from the first welding point to the next welding point (from one welding electrode rod to the other welding electrode rod) is accompanied by at least one bend (meander in multiple times). (See arrow in FIG. 10). Thereby, the path of the current flowing through the positive electrode tab 15 and the land 30 and between the negative electrode tab 16 and the land 30 becomes long, and the positive electrode tab 15 and the negative electrode tab 16 easily generate heat. Thus, a strong bond can be obtained. Similarly to the positive electrode tab 15 described above, the negative electrode tab 16 may have a bent portion 18 (see FIGS. 4 to 8).

According to this embodiment, since the joint 17 of the positive electrode tab 15 and the negative electrode tab 16 extended from the electrochemical cell 11 is directly joined to the land 30 by resistance welding, a solder ball may be generated. Absent. Therefore, it is possible to suppress the occurrence of manufacturing defects due to solder balls.
The land 30 to which the positive electrode tab 15 and the negative electrode tab 16 of the electrochemical cell 11 are joined includes a first layer 31 formed of a material mainly containing copper (Cu), and nickel (Ni) as a main component. And the second layer 32 is made of phosphorus (P), so that the bonding strength of the positive electrode tab 15 and the negative electrode tab 16 and the land 30 is sufficiently secured. it can.
In addition, since the heating time can be greatly shortened in the joining by resistance welding as compared with the joining by soldering, it is mounted on the exterior body 19 such as a laminate film covering the electrochemical cell 11 or the electrochemical cell 11 and the substrate 20, for example. It is possible to suppress thermal damage to the electronic element 23 and the like.
Furthermore, unlike the prior art, since a metal plate is not required, the board unit 2 can be reduced in size, thickness, and cost by reducing the number of components.

  Moreover, since the convex part 17a which protrudes toward the land 30 is formed in the junction part 17 of the positive electrode tab 15 and the negative electrode tab 16, the electric current at the time of resistance welding is made into the convex part 17a of the positive electrode tab 15 and the negative electrode tab 16. It is possible to concentrate and pressurize. Therefore, the positive electrode tab 15 and the negative electrode tab 16 can be efficiently and surely resistance welded to the land 30.

  Further, since the positive electrode tab 15 and the negative electrode tab 16 are joined to the land 30 in a state of being folded back toward the electrochemical cell 11, the total length of the substrate unit 2 and the electrochemical cell unit 1 is shortened and the size is reduced. be able to.

  Moreover, since the electrochemical cell unit 1 of this embodiment can suppress the production defect due to the solder balls, the electrochemical cell unit 1 can be made highly reliable. Further, it is possible to suppress thermal damage to the exterior body 19 such as a laminate film covering the electrochemical cell 11, a film-like member in contact with the tab, and the electronic element 23. Furthermore, the electrochemical cell unit 1 can be reduced in size, thickness and cost by reducing the number of parts.

  Further, according to the electrochemical cell unit manufacturing method of the present embodiment, in the positive electrode side resistance welding process, one welding electrode rod 61 is brought into contact with the positive electrode tab 15 and the other welding electrode rod 62 is brought into contact with the land 30. The positive electrode tab 15 can be reliably joined to the land 30 by a so-called indirect welding method performed in contact. Further, in the negative electrode side resistance welding process, the negative electrode tab 16 can be reliably joined to the land 30 by a so-called series welding method in which the pair of welding electrode rods 61 and 62 are respectively brought into contact with the negative electrode tab 16.

(Second embodiment)
Next, the electrochemical cell unit 1 according to the second embodiment will be described.
FIG. 11 is an explanatory view of the electrochemical cell unit 1 according to the second embodiment. FIG. 11 (a) is a plan view of the electrochemical cell unit 1, and FIG. 11 (b) is an electrochemical cell unit 1. FIG. In FIG. 11, the covering member 40 is indicated by a two-dot chain line.
In the electrochemical cell unit 1 according to the first embodiment, the tip portions 15b and 16b of the positive electrode tab 15 and the negative electrode tab 16 are the joint portions 17 (see FIG. 1).
On the other hand, as shown in FIGS. 11A and 11B, the electrochemical cell unit 1 according to the second embodiment is more electrochemical than the junction 17 of the positive electrode tab 15 and the negative electrode tab 16. 11 differs from the first embodiment in that the tip portions 15b, 16b of the positive electrode tab 15 and the negative electrode tab 16 are arranged on the 11 side. In the following, description of the same configuration as in the first embodiment is omitted.

A pair of lands 30 are formed on the first main surface 21 of the substrate 20. A positive electrode tab 15 and a negative electrode tab 16 are joined to the pair of lands 30 by resistance welding, respectively.
A pair of electrode pads 24 </ b> A and 24 </ b> B are formed on the second main surface 22 of the substrate 20. The core wires of the positive electrode conductor 25A and the negative electrode conductor 25B are electrically and mechanically connected to the pair of electrode pads 24A and 24B, respectively.

Here, the tip portions 15 b and 16 b of the positive electrode tab 15 and the negative electrode tab 16 are arranged closer to the electrochemical cell 11 side than the joint portion 17 of the positive electrode tab 15 and the negative electrode tab 16, toward the electrochemical cell 11. It has been extended. The tip portions 15b and 16b of the positive electrode tab 15 and the negative electrode tab 16 are heat radiating portions 35 that can release heat generated when the positive electrode tab 15 and the negative electrode tab 16 are resistance-welded to the land 30, respectively.
According to the second embodiment, since heat generated during resistance welding can be released from the heat radiating portion 35, for example, a film-like member connected to a tab derived from the electrochemical cell 11 or the electrochemical cell 11, electrochemical It is possible to reliably suppress thermal damage to the exterior body 19 such as a laminate film covering the cell 11 and the electronic element 23 mounted on the substrate 20.

(Third embodiment)
Then, the electrochemical cell unit 1 which concerns on 3rd embodiment is demonstrated.
12A and 12B are explanatory diagrams of the electrochemical cell unit 1 according to the third embodiment, in which FIG. 12A is a plan view of the electrochemical cell unit 1 and FIG. 12B is an electrochemical cell unit 1. FIG. In FIG. 12, the covering member 40 is illustrated by a two-dot chain line.
The electrochemical cell unit 1 according to the first embodiment was joined to the land 30 with the positive electrode tab 15 and the negative electrode tab 16 folded back to the electrochemical cell 11 side (see FIG. 1).
On the other hand, as shown in FIGS. 12A and 12B, the electrochemical cell unit 1 according to the third embodiment is an electrochemical cell unit without the positive electrode tab 15 and the negative electrode tab 16 being folded back. 1 is different from the first embodiment in that the substrate 20 is laminated in the thickness direction of the positive electrode tab 15 and the negative electrode tab 16. In the following, description of the same configuration as in the first embodiment is omitted.

A pair of electrode pads 24 </ b> A and 24 </ b> B are formed on the first main surface 21 of the substrate 20. The core wires of the positive electrode conductor 25A and the negative electrode conductor 25B are electrically and mechanically connected to the pair of electrode pads 24A and 24B, respectively.
A pair of lands 30 are formed on the second main surface 22 of the substrate 20. The pair of lands 30 are formed at one end 20 a on the electrochemical cell 11 side in the second main surface 22 of the substrate 20.

  A positive electrode tab 15 and a negative electrode tab 16 are joined to the pair of lands 30 by resistance welding, respectively. At this time, the one end portion 20 a of the substrate 20 is stacked on the positive electrode tab 15 and the negative electrode tab 16 in the thickness direction of the positive electrode tab 15 and the negative electrode tab 16. Therefore, according to the third embodiment, the substrate unit 2 and the electrochemical cell unit 1 can be thinned.

(Modification of the third embodiment)
Then, the electrochemical cell unit 1 which concerns on the modification of 3rd embodiment is demonstrated.
FIG. 13 is an explanatory view of an electrochemical cell unit 1 according to a modification of the third embodiment. FIG. 13 (a) is a plan view of the electrochemical cell unit 1, and FIG. 13 (b) is an electrochemical. 3 is a side view of the cell unit 1. FIG. In FIG. 13, the covering member 40 is illustrated by a two-dot chain line.
In the electrochemical cell unit 1 according to the third embodiment, one end portion 20 a of the substrate 20 is stacked on the positive electrode tab 15 and the negative electrode tab 16 in the thickness direction of the positive electrode tab 15 and the negative electrode tab 16.
On the other hand, as shown in FIGS. 13A and 13B, the electrochemical cell unit 1 according to the modification of the third embodiment extends from one end 20a of the substrate 20 to the other end 20b. The third embodiment is different from the third embodiment in that the positive electrode tab 15 and the negative electrode tab 16 are stacked in the thickness direction of the positive electrode tab 15 and the negative electrode tab 16. In the following, description of the same configuration as that of the third embodiment is omitted.

A pair of lands 30 are formed on the second main surface 22 of the substrate 20. The pair of lands 30 are formed on the other end 20 b of the second main surface 22 of the substrate 20 on the side opposite to the electrochemical cell 11. Therefore, by joining the positive electrode tab 15 and the negative electrode tab 16 to the land 30 by resistance welding, the tip portions 15b and 16b of the positive electrode tab 15 and the negative electrode tab 16 are positioned at the other end portion 20b of the substrate 20, respectively. As a result, the one end 20 a of the substrate 20 is closer to the electrochemical cell 11 than the intermediate position between the junction 17 of the positive electrode tab 15 and the negative electrode tab 16 and the electrochemical cell 11, and one end of the electrochemical cell 11 and the substrate 20. 20a is arranged in proximity.
According to the modification of the third embodiment, since the substrate 20 can be disposed close to the electrochemical cell 11 side, the substrate unit 2 and the electrochemical cell unit 1 can be reduced in addition to the thinning of the substrate unit 2. The overall length can be shortened.

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

  The arrangement of the substrate 20, the positive electrode tab 15, the negative electrode tab 16, the positive electrode conductor 25 </ b> A, the negative electrode conductor 25 </ b> B, the electronic element 23, and the like is not limited to each embodiment. Therefore, for example, the positive electrode tab 15, the negative electrode tab 16, the positive electrode conductor 25A, and the negative electrode conductor 25B may all be disposed on the first main surface 21 of the substrate 20, or the positive electrode tab 15, the negative electrode tab 16, the positive electrode conductor 25A, The negative electrode conductors 25 </ b> B may all be disposed on the second main surface 22 of the substrate 20. In each embodiment, the electronic element 23 is mounted on the first main surface 21 of the substrate 20, but the electronic element 23 may be mounted on the second main surface 22 of the substrate 20. The arrangement of the substrate 20, the positive electrode tab 15, the negative electrode tab 16, the positive electrode conductor 25A, the negative electrode conductor 25B, the electronic element 23, and the like can be variously changed.

  In each embodiment, the case where the electrical component is the electrochemical cell 11 has been described as an example, but the electrical component is not limited to the electrochemical cell 11. The present invention can be widely applied to an electrical component having a tab. In particular, when the electrical component is not the electrochemical cell 11, the material of the positive electrode tab 15 and the negative electrode tab 16 is not limited to the above-described embodiment.

  In each embodiment, a so-called lithium ion battery has been described as an example of the electrochemical cell 11, but the electrochemical cell 11 is not limited to a lithium ion battery. Therefore, the electrochemical cell 11 may be, for example, a nonaqueous electrolyte secondary battery other than a lithium ion battery, an electric double layer capacitor, a lithium ion capacitor, or the like.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electrochemical cell unit 2 ... Substrate unit 11 ... Electrochemical cell (electric part) 15 ... Positive electrode tab (tab) 16 ... Negative electrode tab (tab) 17 ... Joint part 17a ... Projection 18 ... Bending part 20 ... Substrate 23 ... Electronic element 26 ... Wiring pattern 30 ... Land 31 ... First layer 32 ... Second layer 35 ...・ Heat radiation part 61 ... Welding electrode rod 62 ... Welding electrode rod

Claims (12)

A substrate having a wiring pattern and a land, and an electronic element mounted thereon,
A tab having a joint extending from an electrical component and joined to the land by resistance welding;
With
The land is
A first layer formed of a copper-based material;
A second layer made of a nickel-based material;
Including
The substrate unit, wherein phosphorus is added to the second layer. The board unit according to claim 1,
The substrate unit is characterized in that the tab has Ni-P plating. The board unit according to claim 1 or 2,
The tab unit has a bent portion. The substrate unit according to any one of claims 1 to 3,
A projecting portion that protrudes toward the land is formed at the joint portion of the tab. The board unit according to any one of claims 1 to 4, wherein
The board unit, wherein the tab is joined to the land in a state of being folded back to the electrical component side. The board unit according to claim 5,
The board unit having a heat radiating portion extending toward the electric component on the electric component side of the joint of the tab. The board unit according to any one of claims 1 to 4, wherein
The board is laminated and arranged in the thickness direction of the tab with respect to the extended tab. The board unit according to claim 7,
An end of the board on the electric component side is disposed on the electric component side with respect to an intermediate position between the joint portion of the tab and the electric component.   An electrochemical cell unit comprising the substrate unit according to claim 1, wherein the electrical component is an electrochemical cell. The electrochemical cell unit according to claim 9, wherein
The electrochemical cell comprises a pair of the tabs,
From the positive electrode of the electrochemical cell, a positive electrode tab formed of a material mainly composed of aluminum is extended as one of the tabs, and from the negative electrode of the electrochemical cell, nickel is mainly formed as the other tab. An electrochemical cell unit, wherein a negative electrode tab formed of a material is extended. An electrochemical cell unit manufacturing method for manufacturing the electrochemical cell unit according to claim 10,
Including a positive electrode side resistance welding step for joining the positive electrode tab to the land by resistance welding,
In the positive electrode side resistance welding step, one of the pair of welding electrode rods is brought into contact with the positive electrode tab and the other welding electrode rod is brought into contact with the land. Electrochemical cell unit manufacturing method. An electrochemical cell unit manufacturing method for manufacturing the electrochemical cell unit according to claim 10,
Including a negative electrode side resistance welding step for bonding the negative electrode tab to the land by resistance welding,
In the negative electrode side resistance welding step, a pair of welding electrode bars are respectively brought into contact with the negative electrode tab, and the electrochemical cell unit manufacturing method is characterized.

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