Battery pack manufacturing method

Abstract

To provide a manufacturing method for a battery pack, in which an adhesive can be efficiently cured while the heating of a unit cell is suppressed.SOLUTION: In the present disclosure, the problem is solved by providing a method for manufacturing a battery pack as follows. The method for manufacturing the battery pack includes a preparing step, an accommodating step, and a filling step. In the preparing step, a multilayer battery including a plurality of unit cells stacked in a thickness direction is prepared. In the accommodating step, the multilayer battery is accommodated in a battery case. In the filling step, the battery case is filled with an adhesive and the multilayer battery is fixed to the battery case. The adhesive contains a main agent, a curing agent, and a filler. The filling step includes a discharging process of discharging the adhesive from a nozzle, and a heating process of heating the adhesive discharged from the nozzle by irradiation with infrared rays. The infrared rays are delivered to the adhesive in the middle of discharging.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a battery pack.

Background Art

[0002] There is known a battery pack in which a plurality of single cells are housed in a battery case and the single cells are fixed to the battery case with an adhesive. Also, a method for manufacturing such a battery pack is known.

[0003] For example, Patent Document 1 discloses a battery pack in which the inner surface of the case and the outer surface of the elementary cell are adhered with a reactive hot melt to fix the elementary cell. Also, Patent Document 2 discloses a battery pack including a battery laminate in which a plurality of batteries are arranged, a case that houses the battery laminate, and a heat conduction layer composed of a thermally conductive thermosetting adhesive filled in the gap between the battery laminate and the case. Although not directly related to the method for manufacturing a battery pack, Patent Document 3 discloses a method for filling a resin for molding and integrally sealing a coil constituting a motor with the resin. In Patent Document 3, the resin is filled while applying a current to the coil to generate heat in the coil.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] When manufacturing a battery pack, it is assumed that adhesive is filled into a battery case containing individual cells, and the cells are fixed to the battery case by the cured adhesive. If the adhesive is a so-called two-part curing adhesive containing a main component and a hardener, it is assumed that the adhesive will be heated to accelerate curing. On the other hand, if the electrode layer of the individual cell is heated by the heating of the adhesive, there is a risk that the battery performance will deteriorate.

[0006] This disclosure is made in view of the above circumstances, and its main purpose is to provide a method for manufacturing a battery pack that can efficiently cure the adhesive while suppressing the heating of the individual cells. [Means for solving the problem]

[0007] [1] A method for manufacturing a battery pack, comprising a preparation step, a housing step, and a filling step, wherein the preparation step is a step of preparing a stacked battery having a plurality of single cells stacked in the thickness direction, the housing step is a step of housing the stacked battery in a battery case, and the filling step is a step of filling the battery case with adhesive to fix the stacked battery in the battery case, wherein the adhesive contains a main agent, a hardener, and a filler, and the filling step comprises a discharge process of discharging the adhesive from a nozzle and a heat process of heating the adhesive discharged from the nozzle by irradiation with infrared light, wherein the infrared light is irradiated onto the adhesive in the process of being discharged.

[0008] [2] The manufacturing method according to [1], wherein the filler is at least one of a black pigment and a black ceramic.

[0009] [3] The above heat treatment is a process of heating the temperature of the adhesive from room temperature to 40°C or higher, as described in [1] or [2].

[0010] [4] A battery pack having a stacked battery and a battery case, wherein the stacked battery is housed in the battery case, the stacked battery has a plurality of single cells stacked in the thickness direction, the stacked battery is fixed to the battery case with an adhesive, and the adhesive contains a main agent, a hardener, and a filler.

[0011] [5] The battery pack according to [4], wherein the filler is at least one of a black pigment and a black ceramic. [Effects of the Invention]

[0012] This disclosure provides the effect of efficiently curing the adhesive while suppressing the heating of the single cell. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram illustrating the method for manufacturing a battery pack in this disclosure. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating a single cell in this disclosure. [Figure 3] Figure 3 is a schematic cross-sectional view illustrating a battery case in this disclosure. [Figure 4] Figure 4 is a schematic perspective view illustrating the shape of the nozzle in this disclosure. [Modes for carrying out the invention]

[0014] The manufacturing method and battery pack described herein will be explained in detail below. The figures shown below are illustrative and may be exaggerated in size and shape for ease of understanding.

[0015] A. Method for manufacturing battery packs FIG. 1 is a schematic diagram illustrating the manufacturing method in the present disclosure. Specifically, FIG. 1(a) is a schematic side view illustrating the laminated battery prepared in the preparation step. FIG. 1(b) is a schematic plan view illustrating the accommodation step. FIG. 1(c) is a cross-sectional view taken along line A-A of FIG. 1(b). FIG. 1(d) is a schematic plan view illustrating the filling step. FIG. 1(e) is a cross-sectional view taken along line A-A of FIG. 1(d).

[0016] As shown in FIG. 1(a), in the manufacturing method in the present disclosure, first, a laminated battery 100 having a plurality of single cells 10 laminated in the thickness direction D is prepared (preparation step). Next, as shown in FIGS. 1(b) and (c), the laminate 100 is accommodated in the battery case 200 (accommodation step). Then, as shown in FIGS. 1(d) and (e), the adhesive F is filled into the battery case 200 to fix the laminated battery 100 to the battery case 200 (filling step). The adhesive F contains a main agent, a curing agent, and a filler. Further, the filling step has a predetermined discharging process and a predetermined heat treatment. As shown in FIGS. 1(d) and (e), the discharging process is a process of discharging the adhesive F from the nozzle 400. Further, the heat treatment is a process of heating the adhesive F discharged from the nozzle 400 by irradiation with infrared rays IR. Further, as shown in FIG. 1(e), the infrared rays IR are irradiated onto the adhesive F during discharging.

[0017] According to the present disclosure, the adhesive is heated by irradiating infrared rays onto the adhesive during discharging. Therefore, the adhesive can be efficiently cured while suppressing the heating of the single cell.

[0018] For example, when heating the adhesive filled in the battery case, it is assumed that the entire battery case is heated. In this regard, the laminated battery accommodated in the battery case is also heated, and there is a risk of deterioration of the electrode layer in the battery. Further, such a heating method is not efficient in terms of heat capacity.

[0019] ​​On the other hand, the method of this disclosure allows only the adhesive to be heated by infrared radiation. Therefore, the adhesive can be heated and cured efficiently. Furthermore, the adhesive in this disclosure contains a filler. Since the filler absorbs infrared radiation, it can accelerate the heating of the adhesive. In addition, in the method of this disclosure, infrared radiation is irradiated onto the adhesive while it is being dispensed. Therefore, the infrared radiation is not directly irradiated onto the cell, and heating of the cell can be suppressed. Furthermore, even when using a battery case that does not transmit infrared radiation, the adhesive can be heated efficiently. Moreover, because infrared radiation is used, there is no risk of the adhesive scattering.

[0020] 1. Preparation process The preparation step in this disclosure is a step of preparing a stacked battery having a plurality of single cells stacked in the thickness direction.

[0021] Figure 2 is a schematic cross-sectional view illustrating a single cell in this disclosure. As shown in Figure 2, a single cell 10 typically has electrodes E. Electrodes E have a current collector 1 and an electrode layer (positive electrode active material layer 2 or negative electrode active material layer 3). The electrode layer has a thickness direction D T In this case, it is arranged on at least one surface of the current collector 1. As shown in Figure 2, the single cell 10 may have a bipolar electrode BP as electrode E. The bipolar electrode BP has a positive electrode active material layer 2 arranged on one surface of the current collector 1. The bipolar electrode BP also has a negative electrode active material layer 3 arranged on the other surface of the current collector 1 in the thickness direction. Note that the single cell in this disclosure does not have to have a bipolar electrode.

[0022] The single cell 10 shown in Figure 2 has bipolar electrodes (BP1 and BP2), a positive electrode end electrode CA, and a negative electrode end electrode AN as electrodes E. The bipolar electrodes are as described above. The positive electrode end electrode CA has a current collector 1 and a positive electrode active material layer 2 disposed on one surface of the current collector 1. The negative electrode end electrode AN has a current collector 1 and a negative electrode active material layer 3 disposed on one surface of the current collector 1. Although not specifically shown, single cells are usually sealed with an outer casing such as a laminate film.

[0023] Furthermore, as shown in Figure 2, the single cell 10 typically includes power generation units U (U1, U2, U3). Each power generation unit U has a positive electrode active material layer 2, a negative electrode active material layer 3, and a separator (electrolyte layer) 4. The separator 4 is positioned between the positive electrode active material layer 2 and the negative electrode active material layer 3. The power generation unit U shown in Figure 2 is sealed by a sealing member 5 and a cover member 6. The inside of the power generation unit U is filled with electrolyte 7. As a result, the positive electrode active material layer 2, the negative electrode active material layer 3, and the separator 4 are each impregnated with the electrolyte. A single cell may have one power generation unit, or it may have two or more.

[0024] The current collectors (positive electrode current collector and negative electrode current collector) can be made of conventionally known materials. The electrode layers (positive electrode active material layer and negative electrode active material layer) can be made of conventionally known materials. The separator can be made of conventionally known materials.

[0025] A single cell may be an all-solid-state battery containing a solid electrolyte. Alternatively, a single cell may be a liquid-type battery containing a liquid electrolyte (electrolyte solution). A single cell is typically a lithium-ion battery.

[0026] The planar shape of a single cell (shape viewed from the thickness direction) is, for example, a square or a rectangle. The length of each side constituting the planar shape of the single cell is, for example, 30 cm or more. The side length may also be 60 cm or more, or 100 cm or more. On the other hand, the above side length is, for example, 200 cm or less.

[0027] In a stacked battery, the number of individual cells is 2 or more. The number of individual cells may be 3 or more, 5 or more, or 10 or more. On the other hand, the number of individual cells may be, for example, 50 or less.

[0028] As shown in Figure 1(a), the laminate 100 may have an intermediate member 20. The intermediate member is placed between a plurality of the single cells that are stacked in the thickness direction. In the battery pack, the intermediate member functions as a cooling member for cooling the single cells.

[0029] 2. Storage process The housing step in this disclosure is the step of housing the laminate in a battery case.

[0030] As shown in Figures 1(b) and (c), during the housing process, the stacked battery 100 is usually housed with a gap between it and the inner surface of the battery case 200 (the wall portion of the battery case, which will be described later). Also, as shown in Figure 1(b), during the housing process, the control equipment 300 may be housed in the battery case 200 together with the stacked battery 100. The control equipment performs various controls on the battery.

[0031] Figure 3 is a schematic cross-sectional view illustrating a battery case. As shown in Figure 3, the cross-sectional shape of the battery case 200 is typically a concave shape having a bottom portion 201, a wall portion 202, and a flange portion 203. Also, "inside the battery case" refers to the thickness direction D T In this context, the space can be considered to be the space on the bottom 201 side of the flange portion 203. The material of the battery case is not particularly limited and can be any conventionally known material.

[0032] 3.Filling process The filling step in this disclosure is a step of filling the battery case with adhesive to fix the stacked battery in the battery case. In particular, the filling step in this disclosure includes a predetermined dispensing process and a heat treatment.

[0033] As shown in Figure 1(d), in the filling process, it is preferable to fill the adhesive so as to surround the entire outer circumference of the stacked battery 100. The amount of adhesive to be filled is, for example, an amount that allows all the individual cells in the stacked battery to come into contact with the adhesive.

[0034] The adhesive used in the filling process contains a main component and a curing agent. In other words, the adhesive is a so-called two-component curing type adhesive. The adhesive also contains a filler. Examples of fillers include black pigments and black ceramics. Since black pigments and black ceramics have better infrared absorption, they can further promote the heating of the adhesive. The adhesive may contain only one of the black pigments or black ceramics. The adhesive may contain both the black pigments and black ceramics. Examples of black pigments include conventionally known black pigments. Examples of black ceramics include conventionally known black ceramics. The proportion of filler in the adhesive is, for example, 5% by weight or more and 50% by weight or less.

[0035] Examples of adhesives include conventionally known two-component curing adhesives, other than those containing the above-mentioned filler. Examples of adhesives include epoxy adhesives and urethane adhesives.

[0036] (1) Discharge process The dispensing process involves dispensing the adhesive from the nozzle. The dispensing process continues until a predetermined amount of adhesive is filled inside the battery case.

[0037] As shown in Figure 1(e), the nozzle 400 is usually positioned above the battery case 200 (above the flange portion 203). The adhesive F is then dispensed towards the gap between the battery case 200 and the laminate 100. Alternatively, as shown in Figure 1(d), it is preferable to dispense the adhesive F while scanning the nozzle 400 along the gap.

[0038] As shown in Figure 4, the shape of the nozzle 400 is preferably such that it dispenses the adhesive F in a curtain-like manner. In other words, a curtain-type nozzle is preferable because it allows for a larger area to be irradiated with infrared light.

[0039] The adhesive is preferably dispensed from the nozzle in a state in which the main component, hardener, and filler are mixed. Furthermore, the temperature of the dispensed adhesive is preferably room temperature. Here, "room temperature" refers to a temperature between 15°C and 25°C. The dispensing speed of the adhesive is, for example, between 5cc / sec and 20cc / sec. The dispensing direction (dispensing angle) of the nozzle is preferably parallel to the thickness direction. Note that "parallel" does not mean strictly parallel. In other words, "parallel" in this disclosure does not mean only when the angle between the two directions is 0°. In this disclosure, "parallel" means when the angle between the two directions is between 0° and 30°.

[0040] (2) Heat treatment The heat treatment is a process in which the adhesive discharged from the nozzle is heated by irradiation with infrared light. In the heat treatment, the infrared light is irradiated onto the adhesive in the process of being discharged. "Adhesive in the process of being discharged" can be considered as adhesive that is not yet placed inside the battery case. For example, as shown in Figures 1(e) and 4, in the thickness direction D T In this process, infrared (IR) light is irradiated onto the adhesive F located between the nozzle 400 and the battery case 200 (the flange portion 203 of the battery case 200).

[0041] As shown in Figure 1(e), infrared radiation is typically emitted from a heat source 500. The heat source may be a focusing lamp or a laser. As shown in Figure 1(d), the heat source 500 may emit infrared radiation while following the scanning of the nozzle 400.

[0042] The heat treatment preferably involves heating the adhesive from room temperature to 40°C or higher. The heat treatment may also involve heating the adhesive to 50°C or higher. The heat treatment may also involve heating the adhesive to 60°C or higher.

[0043] The type of infrared radiation is not particularly limited. The infrared radiation may be near-infrared, mid-infrared, or far-infrared. Among these, near-infrared is preferred.

[0044] B. Battery pack The battery pack in this disclosure comprises a stacked battery and a battery case. The stacked battery is housed in the battery case. The stacked battery has a plurality of single cells stacked in the thickness direction. The stacked battery is fixed to the battery case by an adhesive. The adhesive contains a main component, a hardener, and a filler. The battery pack may also have a lid that seals the battery case filled with the adhesive.

[0045] The stacked battery, battery case, and adhesive are as described above. Furthermore, the lid can be made from a conventionally known material.

[0046] The applications of the battery pack are not particularly limited. The battery pack can be used as a power source for vehicles. Examples of vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline cars, and diesel cars. The battery pack is particularly preferably used as a power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). The battery pack may also be used as a power source for mobile devices other than vehicles (e.g., trains, ships, aircraft). The battery pack may also be used as a power source for electrical products such as information processing devices.

[0047] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Explanation of Symbols]

[0048] 1 ... Current collector 2...Cathode active material layer 3...Negative electrode active material layer 4 ... Separator E...Electrode 10... Single cell 100…Stacked battery 200... Battery case 300 ... control equipment 400…nozzle 500…Heat source

Claims

1. A method for manufacturing a battery pack, the method comprising a preparation step, a housing step, and a filling step, wherein the preparation step is a step of preparing a stacked battery having a plurality of single cells stacked in the thickness direction, the housing step is a step of housing the stacked battery in a battery case, and the filling step is a step of filling the battery case with adhesive to fix the stacked battery in the battery case, the adhesive containing a main agent, a hardener, and a filler, and the filling step comprises a discharge process of discharging the adhesive from a nozzle and a heat process of heating the adhesive discharged from the nozzle by irradiation with infrared light, the infrared light being irradiated onto the adhesive in the process of being discharged.

2. The manufacturing method according to claim 1, wherein the filler is at least one of a black pigment and a black ceramic.

3. The manufacturing method according to claim 1 or claim 2, wherein the heat treatment is a process of heating the temperature of the adhesive from room temperature to 40°C or higher.

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