JP2018029021A - Power storage module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage module that has a protection circuit board mounted thereon without increasing the number of components.SOLUTION: A power storage module 10 has a plurality of power storage elements 1 including electrode leads 3 electrically connected in series and/or in parallel via the electrode leads 3. The power storage module includes a protection circuit board 4 that monitors and controls at least the voltage of the power storage elements 1; the protection circuit board 4 includes a TH connection part 5; the electrode leads 3 and TH connection part 5 are directly joined to each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage module.

  In power storage systems such as load leveling devices such as solar power generation and wind power generation, instantaneous voltage drop countermeasure devices, energy recovery devices for electric vehicles or hybrid cars, etc., they have a large energy capacity and can be charged and discharged quickly. A device is needed.

  In recent years, power storage modules using power storage elements such as lithium ion secondary batteries, nickel metal hydride batteries, electric double layer capacitors, and lithium ion capacitors have been developed. The power storage module includes a power storage unit in which a plurality of power storage elements are connected in series or in parallel, and can be charged and discharged in a high voltage or large capacity state. Therefore, the power storage module is used in various applications as a power supply device.

  The power storage module is configured by stacking storage batteries in the thickness direction, electrically connecting the storage batteries, and being fastened and held by an exterior component or the like. Among the flat-plate storage batteries, the storage battery manufactured with a pouch-type exterior body using a laminate film is easy to manufacture and has the advantage that it is easy to reduce the thickness and weight, and because it is thin, it dissipates heat. It has the advantage that it is excellent in property.

The power storage module has a built-in protection circuit board for monitoring and controlling the voltage or temperature of the power storage element in order to prevent overcharge, overdischarge, temperature abnormality and the like of the power storage element. Generally, the protection circuit board and the storage element built in the storage module are connected using an electric wire harness. Further, the electric wire harness and the storage element are connected by screw fastening or welding, and the electric wire harness and the protection circuit board are connected via a connector terminal or the like (Patent Document 1).
On the other hand, as a structure that can provide a smaller power storage module, an electrode terminal component is attached to the power storage element, and a through hole provided in the protection circuit board is disposed so that the electrode terminal component penetrates. A power storage module has been proposed in which a voltage detection portion and electrode terminal parts are connected by soldering (Patent Document 2).

JP 2014-127229 A JP 2001-93494 A

  Patent Document 1 describes that a weighted wiring module can be provided by providing a voltage detection electric wire formed by coating an aluminum or aluminum alloy core wire with an insulating coating. However, the power storage module described in Patent Document 1 has a problem that the wiring module itself has a large number of parts and is complicated to mount.

According to Patent Document 2, an isolation plate or the like is disposed between a printed circuit board and a secondary battery, the printed circuit board is isolated from the secondary battery, and the printed circuit board and the secondary battery are easily electrically connected. Is provided. However, it is necessary to connect an electrode terminal component for electrically connecting the printed circuit board and the secondary battery to the electrode portion of the secondary battery by a method such as spot welding, and the electrode terminal component is a printed circuit board. It is necessary to solder and fix to. Since the electrode terminal parts are used, there is a problem that the assembly process of the power storage module described in Patent Document 2 becomes complicated and the manufacturing cost increases. Also, soldering connection is required to connect the electrode terminal parts to the protection circuit board. However, since the electrode terminal parts are larger than general electronic circuit mounting parts, a large amount of solder is put on them. There is a reliability problem such that solder cracks are likely to occur. Furthermore, it is necessary to provide holes for the electrode terminal parts to pass through on the printed circuit board, and the circuit pattern on the printed circuit board must be designed to avoid the holes, resulting in a larger printed circuit board, resulting in storage of electricity. Module becomes large.
Therefore, an object of the present invention is to provide a power storage module on which a protection circuit board is mounted without increasing the number of components.

The above problem is solved by the following technical means.
[1]
A plurality of power storage elements having electrode leads are power storage modules electrically connected in series and / or in parallel via the electrode leads,
The power storage module has a protection circuit board that monitors and controls at least the voltage of the power storage element,
The protective circuit board has a TH connection portion, and the electrode lead and the TH connection portion are directly bonded.
The power storage module.
[2]
The electrical storage module according to [1], wherein a state of direct bonding between the electrode lead and the TH connection portion is a welded state.
[3]
The TH connection section is the power storage module according to [1] or [2], which is a conductor layer disposed on one surface of the protection circuit board.
[4]
The TH connection portion is the power storage module according to [1] or [2], which is a conductor layer that penetrates the protection circuit board in a thickness direction.
[5]
The electrical storage module according to [3] or [4], wherein the conductor layer is a metal material containing copper or silver.
[6]
Aligning the positions of the electrode leads and the TH connection provided on the protection circuit board;
Irradiating a laser beam from the upper surface side of the TH connection portion to bond the TH connection portion and the electrode lead;
The manufacturing method of the electrical storage module of any one of [1]-[5] containing.

  According to the present invention, the TH connecting portion provided on the circuit board and the electrode lead provided on the power storage element are directly joined, so that the power storage equipped with the protection circuit board without increasing the number of components. Modules can be provided.

FIG. 1 is a perspective view showing an internal structure of a power storage module 10 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the internal structure of the power storage module 10 taken along the line A-A ′ of FIG. 1. FIG. 3A is an enlarged schematic view of a portion where the TH connection portion 5 and the electrode lead 3 are directly joined in the power storage module 10 according to the first embodiment of the present invention, and FIG. b) is a schematic diagram illustrating a method of directly joining the TH connection portion 5 and the electrode lead 3. FIG. 4 is a perspective view showing the internal structure of the power storage module 10 according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view of the internal structure of the power storage module 10 taken along the line B-B ′ of FIG. 4. FIG. 6A is an enlarged schematic view of a portion where the TH connection portion 5 and the electrode lead 3 are directly joined in the power storage module 10 according to the second embodiment of the present invention, and FIG. b) is a schematic diagram illustrating a method of directly joining the TH connection portion 5 and the electrode lead 3.

  Hereinafter, an embodiment of a power storage module and a method for manufacturing the power storage module of the present application will be described in detail based on the drawings. In addition, this invention is not limited by this embodiment.

<Embodiment 1>
FIG. 1 is a perspective view showing an internal structure of a power storage module 10 according to the first embodiment of the present invention.
The power storage module 10 has a structure in which a plurality of power storage elements 1 having electrode leads 3 are stacked in the thickness direction of the power storage elements 1 and the electrode leads 3 of the respective power storage elements 1 are electrically connected in series and / or in parallel. have. As an example, FIG. 1 shows the internal structure of a power storage module 10 in which eight power storage elements 1 are stacked, but the number of stacked power storage elements 1 is not limited.
One of the electrode leads 3 of the storage element 1 located at both ends is connected to the electrode lead 3 of the adjacent storage element 1, while the other is connected to an external terminal of the storage module 10 (not shown).

  The power storage module 10 includes an end plate (not shown) for fixing the stacked power storage elements 1 from both ends, a restraining member (not shown) connected to the end plates and pressed in the direction in which the power storage elements 1 are stacked, An exterior case (not shown) or the like is attached.

  The power storage element 1 includes a power generation element (not shown), electrode leads 3 (a positive electrode lead and a negative electrode lead) electrically connected to the power generation element, and an exterior body made of a metal laminate resin film. Furthermore, the power storage element 1 has a power collection unit in which a power generation element is accommodated. In FIG. 1, the power storage module 10 is stacked so that the power collection units of the power storage elements 1 overlap each other.

  The power storage element 1 has an exterior made of an airtight flexible packaging material such as a laminated film material in which an organic electrolyte containing lithium ions and an electrode laminate are sealed, for example, an aluminum foil laminated with a resin film. The outermost surface of the exterior body is generally composed of a nylon material, a PET material (polyethylene terephthalate), or the like.

  In the present embodiment, the power generation element (not shown) is a member that generates electricity or converts energy other than electric power into electric power in the element. The power generation element may be a pair of electrodes facing each other or a stacked body thereof, a stacked body in which a separator is interposed between the two electrodes, or a rolled body thereof, other batteries or capacitors, and the like.

The current collector is a portion in which a power generating element (such as an organic electrolyte and an electrode laminate) is housed.
The electrode laminate is formed by laminating a plurality of negative electrode bodies, separators, and positive electrode bodies.
The negative electrode body has a negative electrode current collector made of copper foil or the like, and a negative electrode active material layer provided on one side or both sides of the negative electrode current collector.
The positive electrode body includes a positive electrode current collector made of an aluminum foil and the like, and a positive electrode active material layer provided on one side or both sides of the positive electrode current collector.
The stacking direction of the electrode stack is defined as the thickness direction.

  The material of the electrode lead 3 is made of a metal whose main material is aluminum or copper. In this specification, that a specific part or material contains a specific content as a main component means that the specific part or material contains 50% by mass or more of the specific content. Further, the surface of the electrode lead 3 may be plated, and for example, it may have a nickel plating surface with respect to a copper base material. Moreover, the thickness of the electrode lead 3 is in the range of 0.1 mm or more and 2 mm or less, for example.

  A protection circuit board 4 that monitors and controls at least the voltage of the power storage element 1 is connected to the electrode leads 3 that are electrically connected in series and / or in parallel between the plurality of adjacent power storage elements 1. The protection circuit board 4 has a TH (Through Hole) connection portion 5, and the electrode lead 3 and the TH connection portion 5 are directly bonded. In the protection circuit board 4, the TH connection portion 5 is provided at a position substantially overlapping with the position of the electrode lead 3. In FIG. 1, the TH connection portion 5 has a round shape, but is not particularly limited, and may be a square shape or the like.

For the sake of explanation, the protective circuit board 4 in the present embodiment has a side facing the power storage element 1 as a lower surface and the opposite surface as an upper surface.
The direct bonding in the present embodiment refers to a state in which the electrode lead 3 and the TH connection portion 5 are electrically connected without using an electrode terminal component, an electric wire harness, a connector terminal, or the like.

  The protection circuit board 4 is mounted with electronic components that constitute a protection circuit (not shown), and the TH connection portion 5 is electrically connected to the protection circuit. The protection circuit detects overcharge and / or overdischarge and outputs a warning signal according to the voltage value of each storage element 1.

FIG. 2 is a cross-sectional view of the internal structure of the power storage module 10 taken along the line AA ′ of FIG.
The electrode lead 3 is located on the lower surface side of the protection circuit board 4 and is directly joined to the TH connection portion 5. Although the method of direct joining is not specifically limited, For example, it can join by welding, such as laser welding. That is, the TH connection portion 5 and the electrode lead 3 can be welded by irradiating the TH connection portion 5 with laser light from the upper surface side of the protection circuit board 4. At this time, since the irradiation time of the laser light is an extremely short time of several milliseconds, it is possible to perform the welding without affecting other portions of the protection circuit board 4, such as a circuit pattern or an electronic component.
Further, as described above, since the electrode lead 3 connects the electrode leads 3 of the adjacent power storage elements 1, the two electrode leads 3 and the TH connection portion 5 may be welded by laser light.

  The state of direct bonding between the electrode lead 3 and the TH connection portion 5 may be a welded state. The welded state is a state in which the metals are mixed and joined, and whether or not it is in a welded state can be confirmed by observing the cross-sectional shape of the joint. Moreover, even if each metal is the same kind of metal, the state of change in grain boundaries of each metal and the mixed state of the surface layer (for example, natural oxide layer or plating layer) possessed by each metal It is possible to determine whether or not the welded state is obtained by observing.

  FIG. 3A is an enlarged schematic view of a portion where the TH connection portion 5 and the electrode lead 3 are directly joined. The protective circuit board 4 is a printed circuit board, and the material thereof is, for example, a phenol resin containing a paper material, an epoxy resin containing a paper material, an epoxy resin containing a glass fiber, or a composite material obtained by combining these. The protection circuit board 4 is a flexible printed circuit board, and the material thereof is made of, for example, polyimide resin or polyester resin.

The TH connection portion 5 is a conductor layer that penetrates in the thickness direction of the protective circuit board 4 and is made of, for example, a metal material mainly composed of copper or silver, such as a plating method or a conductive paste thermosetting method. Can be installed.
The thickness of the TH connecting portion 5 can be suitably selected, for example, within a range of 0.2 mm to 4.0 mm.

  As described above, the TH connection portion 5 and the electrode lead 3 are directly connected by forming a welded state. Thereby, the electrical storage element 1 and the protection circuit board can be electrically connected without using electrode terminal parts, and the reliability problem of solder cracks can be solved. Furthermore, since the welded state is joined so that the metals are mixed, cracks due to the difference in linear expansion coefficient hardly occur, and a more reliable connection state can be obtained.

Next, a method for manufacturing the power storage module according to this embodiment will be described.
First, an internal structure of a power storage module 10 is prepared in which a plurality of power storage elements 1 having electrode leads 3 are stacked in the thickness direction so that the electrode leads 3 can be electrically connected in series and / or in parallel. To do.

  Next, a step of aligning the positions of the TH connection portion 5 provided on the protection circuit board 4 and the electrode lead 3 is performed. That is, adjustment is made so that the electrode lead 3 is positioned immediately above / below the TH connection portion 5, and the TH connection portion 5 and the electrode lead 3 are brought into contact with each other. At this time, the TH connecting portion 5 and the electrode lead 3 may be pressed and brought into contact with each other using a jig or the like.

Next, a process of joining the TH connection portion 5 and the electrode lead 3 by irradiating laser light from the upper surface side of the TH connection portion 5 is performed. At this time, the laser beam is first irradiated to the TH connection portion 5 and a part of the conductor layer of the TH connection portion 5 is melted and penetrated. Thereafter, the laser beam is irradiated second to the electrode lead 3 and the electrode A part of the lead 3 is melted and mixed with the melted conductor layer, and upon completion of the laser light irradiation, the molten metal is cured and the direct connection between the TH connection portion 5 and the electrode lead 3 is completed.
In this embodiment, the laser beam is irradiated with a 1AG joule of energy of 13.0 joules collected at a diameter of φ0.4 mm for 5 milliseconds.

  FIG. 3B is a schematic diagram illustrating a method for directly joining the TH connection portion 5 and the electrode lead 3. Direct bonding can be performed by irradiating laser light as described above, and the dotted line in the figure indicates the irradiated portion 6 of the laser light. The laser light is preferably irradiated so as not to penetrate the electrode lead 3 irradiated second, and can be controlled by suitably setting the irradiation energy density, irradiation time, etc. of the laser light. Further, the number of points irradiated with laser light is not limited to one point, and may be plural. In addition to spot welding, seam welding may be used.

  Next, external terminals are connected to the electrode leads of the power storage elements located at both ends of the stacked power storage elements. Further, end plates are attached to both ends of the stacked power storage elements, and a restraining member is attached so as to connect and fix the end plates. Finally, the assembly of the power storage module is completed by attaching the exterior case.

  As described above, the TH connection portion 5 and the electrode lead 3 are directly joined by irradiating the laser beam so as to penetrate the TH connection portion 5. Accordingly, the power storage element 1 and the protection circuit board can be electrically connected without performing the soldering process using the electrode terminal parts, and the reliability problem of solder cracks can be solved. Furthermore, since the welded state is joined so that the metals are mixed, cracks due to the difference in linear expansion coefficient are unlikely to occur, and a more reliable connection state can be obtained.

<Embodiment 2>
FIG. 4 is a perspective view showing the internal structure of the power storage module 10 according to the second embodiment of the present invention, and FIG. 5 is the internal structure of the power storage module 10 along the line BB ′ in the second embodiment. FIG. The second embodiment is different from the first embodiment in that the electrode lead 3 is disposed on the upper surface side of the protection circuit board 4.

The protection circuit board 4 is installed so as to be accommodated in a notch provided in the electrode lead 3, and is fixed by a component (not shown).
The TH connection portion 5 (shaded portion) is a conductor layer provided on at least one surface of the protection circuit board 4, and is filled with a metal material mainly composed of copper or silver, for example.

  The electrode lead 3 is located on the upper surface side of the protection circuit board 4 and is directly joined to the TH connection portion 5. Although the method of direct joining is not specifically limited, For example, it can join by welding, such as laser welding. That is, the electrode lead 3 and the TH connection portion 5 can be welded by irradiating the TH connection portion 5 with laser light from the surface of the electrode lead 3.

  FIG. 6A is an enlarged schematic view of a portion where the TH connection portion 5 and the electrode lead 3 are directly joined in the present embodiment, and the cross-sectional shape of the TH connection portion 5 is shown as an inverted trapezoid. However, it is not particularly limited, and may be a rectangle or an inverted triangle. Furthermore, a structure in which the width changes stepwise in the thickness direction of the protection circuit board 4 may be used.

  Further, the TH connection portion 5 may be a conductor layer penetrating the protection circuit board 4 as in the first embodiment shown in FIG. In this case, when carrying out welding joining with laser light, there is a possibility that the laser light may pass through the TH connection portion 5 and reach the electricity storage element 1, but by appropriately selecting the intensity and irradiation time of the laser light. This problem can be avoided by preventing the laser beam from penetrating or by installing a shielding object such as a jig at the point where the laser beam penetrates the conductor layer.

  In addition, it is conceivable that the electrode lead 3 is provided with a notch, so that the cross-sectional area of the electrode lead 3 with respect to the direction in which the current flows decreases and the resistance increases. However, this problem can be avoided by increasing the cross-sectional area of the electrode lead 3 in advance or by providing a portion in which the electrode lead 3 is extended without providing a notch.

Then, the manufacturing method of the electrical storage module which concerns on 2nd embodiment is demonstrated.
The order in which the laser light is irradiated is the same as in the first embodiment except that the electrode lead 3 is irradiated first and the TH connection portion 5 is irradiated second. Such a power storage module can be manufactured.
FIG. 6B is a schematic diagram illustrating a method for directly joining the TH connection portion 5 and the electrode lead 3. Direct bonding can be performed by irradiating laser light as described above, and the dotted line in the figure indicates the irradiated portion 6 of the laser light. The laser beam is preferably irradiated so as not to penetrate the TH connection portion 5 to be irradiated second, and can be controlled by suitably setting the irradiation energy density, irradiation time, etc. of the laser beam. Further, the number of points irradiated with laser light is not limited to one point, and may be plural. In addition to spot welding, seam welding may be used.

  From the above explanation, the TH connection portion provided on the circuit board and the electrode lead arranged on the power storage element are directly joined, so that the power storage module equipped with the protection circuit board can be mounted without increasing the number of parts. Can be provided.

  The power storage element and the power storage module of the present invention are suitable, for example, in the field of a hybrid drive system in which an internal combustion engine, a fuel cell, or a motor in a car and a power storage element are combined; Can be used.

DESCRIPTION OF SYMBOLS 1 Power storage element 2 Cell stack 3 Electrode lead 4 Protection circuit board 5 TH connection part 6 Laser light irradiation part 10 Power storage module

Claims (6)

A plurality of power storage elements having electrode leads are power storage modules electrically connected in series and / or in parallel via the electrode leads,
The power storage module has a protection circuit board that monitors and controls at least the voltage of the power storage element,
The protective circuit board has a TH connection portion, and the electrode lead and the TH connection portion are directly bonded.
The power storage module.   The power storage module according to claim 1, wherein a state of direct bonding between the electrode lead and the TH connection portion is a welded state.   The power storage module according to claim 1, wherein the TH connection portion is a conductor layer disposed on one surface of the protection circuit board.   The power storage module according to claim 1, wherein the TH connection portion is a conductor layer that penetrates the protection circuit board in a thickness direction.   The power storage module according to claim 3 or 4, wherein the conductor layer is a metal material containing copper or silver. Aligning the positions of the electrode leads and the TH connection provided on the protection circuit board;
Irradiating a laser beam from the upper surface side of the TH connection portion to bond the TH connection portion and the electrode lead;
The manufacturing method of the electrical storage module of any one of Claims 1-5 containing these.