Manufacturing method for battery pack

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 technology]

[0002] 2. Description of the Related Art Battery packs are known in which a plurality of unit cells are housed in a battery case and fixed to the battery case with an adhesive, and methods for manufacturing such battery packs are also known.

[0003] For example, Patent Document 1 discloses a battery pack in which the inner surface of a case and the outer surface of a unit cell are bonded with a reactive hot melt to fix the unit cell. Patent Document 2 discloses a battery pack including a battery stack in which a plurality of batteries are arranged, a case for housing the battery stack, and a thermally conductive layer made of a thermally conductive thermosetting adhesive that fills the gap between the battery stack and the case. Although not directly related to the manufacturing method of a battery pack, Patent Document 3 discloses a resin filling method in which a coil that constitutes a motor is molded with resin and integrally sealed. In Patent Document 3, resin is filled while a current is applied to the coil to heat the coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-243364 A [Patent Document 2] JP 2021-140914 A [Patent Document 3] JP 2020-092521 A Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing a battery pack, it is assumed that an adhesive is filled into a battery case containing a single cell, and the single cell is fixed to the battery case by the hardened adhesive. Here, when the adhesive is a so-called two-component hardening type adhesive containing a base agent and a hardener, it is assumed that the adhesive is heated to promote hardening. On the other hand, if the electrode layer of the single cell is heated by heating the adhesive, there is a risk of the battery performance being deteriorated.

[0006] The present disclosure has been made in consideration of the above-described circumstances, and has as its main object to provide a manufacturing method for a battery pack that can efficiently harden an adhesive while suppressing heating of the unit cells. [Means for solving the problem]

[0007] [1] A method for manufacturing a battery pack, the method having a preparation step, an accommodation step, and a filling step, the preparation step being a step of preparing a stacked battery having a plurality of single cells stacked in the thickness direction, the accommodation step being a step of accommodating the stacked battery in a battery case, the filling step being a step of filling the battery case with an adhesive to fix the stacked battery to the battery case, the adhesive containing a base agent, a curing agent, and a filler, the filling step having a discharge process of discharging the adhesive from a nozzle and a heating process of heating the adhesive discharged from the nozzle by irradiating it with infrared rays, the infrared rays being irradiated onto the adhesive during the discharge process.

[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 manufacturing method according to [1] or [2], wherein the heat treatment is a treatment for heating the adhesive from room temperature to 40°C or higher.

[0010] [4] A battery pack having a stacked battery and a battery case, the stacked battery being housed in the battery case, the stacked battery having a plurality of unit cells stacked in a thickness direction, the stacked battery being fixed to the battery case by an adhesive, the adhesive containing a base agent, a curing agent, 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. Effect of the Invention

[0012] The present disclosure provides an advantage in that the adhesive can be cured efficiently while suppressing heating of the unit cells. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram illustrating a method for manufacturing a battery pack in the present disclosure. [Diagram 2] FIG. 2 is a schematic cross-sectional view illustrating a unit cell according to the present disclosure. [Diagram 3] FIG. 3 is a schematic cross-sectional view illustrating an example of a battery case in the present disclosure. [Figure 4] FIG. 4 is a schematic perspective view illustrating an example of the shape of a nozzle in the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The manufacturing method and the battery pack according to the present disclosure will be described in detail below. The figures shown below are merely examples, and the size and shape of each part may be exaggerated to make them easier to understand.

[0015] A. How to manufacture a battery pack FIG. 1 is a schematic diagram illustrating a manufacturing method in the present disclosure. Specifically, FIG. 1(a) is a schematic side view illustrating a stacked battery prepared in a preparation step. FIG. 1(b) is a schematic plan view illustrating a housing step. FIG. 1(c) is a cross-sectional view taken along line AA in FIG. 1(b). FIG. 1(d) is a schematic plan view illustrating a filling step. FIG. 1(e) is a cross-sectional view taken along line AA in FIG. 1(d).

[0016] As shown in FIG. 1(a), in the manufacturing method according to the present disclosure, first, T A stacked battery 100 having a plurality of unit cells 10 stacked on top of each other is prepared (preparation step). Next, as shown in Figs. 1(b) and (c), the stacked body 100 is housed in a battery case 200 (housing step). Then, as shown in Figs. 1(d) and (e), the battery case 200 is filled with adhesive F to fix the stacked battery 100 to the battery case 200 (filling step). The adhesive F contains a base agent, a curing agent, and a filler. The filling step includes a predetermined discharge process and a predetermined heating process. As shown in Figs. 1(d) and (e), the discharge process is a process of discharging the adhesive F from a nozzle 400. Furthermore, the heating process is a process of heating the adhesive F discharged from the nozzle 400 by irradiating it with infrared rays IR. Furthermore, 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 it with infrared rays during dispensing, which makes it possible to effectively cure the adhesive while preventing the unit cells from being heated.

[0018] For example, when the adhesive filled in the battery case is heated, it is assumed that the entire battery case is heated. In this respect, the stacked battery housed in the battery case is also heated, and there is a risk that the electrode layer of the battery may deteriorate. Furthermore, such a heating method is not efficient in terms of heat capacity.

[0019] On the other hand, in the method of the present disclosure, only the adhesive can be heated by infrared rays. Therefore, the adhesive can be efficiently heated and cured. In addition, the adhesive in the present disclosure contains a filler. The filler absorbs infrared rays, and can promote heating of the adhesive. Furthermore, in the method of the present disclosure, infrared rays are irradiated onto the adhesive during discharging. Therefore, infrared rays are not directly irradiated onto the unit cells, and heating of the unit cells can be suppressed. Furthermore, even if a battery case that does not transmit infrared rays is used, the adhesive can be efficiently heated. Furthermore, since infrared rays are used, there is no risk of the adhesive scattering.

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

[0021] Fig. 2 is a schematic cross-sectional view illustrating a unit cell according to the present disclosure. As shown in Fig. 2, a unit cell 10 generally has an electrode E. The electrode E has a current collector 1 and an electrode layer (a positive electrode active material layer 2 or a negative electrode active material layer 3). The electrode layer is oriented in a thickness direction D T In the present disclosure, the single battery 10 is disposed on at least one surface of the current collector 1. As shown in FIG. 2, the single battery 10 may have a bipolar electrode BP as the electrode E. The bipolar electrode BP has a positive electrode active material layer 2 disposed on one surface of the current collector 1. The bipolar electrode BP also has a negative electrode active material layer 3 disposed on the other surface of the current collector 1 in the thickness direction. Note that the single battery in the present disclosure does not necessarily have a bipolar electrode.

[0022] The single cell 10 shown in FIG. 2 has, as electrodes E, bipolar electrodes (BP1 and BP2), a positive electrode end electrode CA, and a negative electrode end electrode AN. 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 shown in the figure, the single cell is usually sealed with an exterior body such as a laminate film.

[0023] As shown in FIG. 2, the single cell 10 usually includes a power generation unit U (U1, U2, U3). The 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 disposed between the positive electrode active material layer 2 and the negative electrode active material layer 3. The power generation unit U shown in FIG. 2 is sealed with a seal member 5 and a cover member 6. The inside of the power generation unit U is filled with an 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. The single cell may have one power generation unit, or may have two or more power generation units.

[0024] The current collectors (positive electrode current collector and negative electrode current collector) may be conventionally known members. The electrode layers (positive electrode active material layer and negative electrode active material layer) may be conventionally known members. The separator may be conventionally known members.

[0025] The unit cell may be an all-solid-state battery containing a solid electrolyte as an electrolyte. The unit cell may be a liquid-based battery containing a liquid electrolyte (electrolytic solution) as an electrolyte. The unit cell is typically a lithium-ion battery.

[0026] The planar shape of the unit 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 unit cell is, for example, 30 cm or more. The length of the side may be 60 cm or more, or may be 100 cm or more. On the other hand, the length of the side is, for example, 200 cm or less.

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

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

[0029] 2. Storage process The accommodation step in the present disclosure is a step of accommodating the laminate in a battery case.

[0030] 1(b) and (c), in the accommodation step, the stacked battery 100 is usually accommodated with a gap between it and the inner surface of the battery case 200 (the wall of the battery case described below). Also, as shown in FIG. 1(b), in the accommodation step, a control device 300 may be accommodated in the battery case 200 together with the stacked battery 100. The control device performs various controls of the battery.

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

[0032] 3.Filling process The filling step in the present disclosure is a step of filling the battery case with an adhesive to fix the laminated battery to the battery case. In particular, the filling step in the present disclosure includes a predetermined discharge process and a heat process.

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

[0034] The adhesive in the filling process contains a base agent and a hardener. That is, the adhesive is a so-called two-liquid curing adhesive. The adhesive also contains a filler. Examples of the filler include black pigments and black ceramics. Black pigments and black ceramics have better infrared absorption, so that the adhesive can be heated more quickly. The adhesive may contain only one of black pigments and black ceramics. The adhesive may contain both black pigments and black ceramics. Examples of the black pigments include conventionally known black pigments. Examples of the black ceramics include conventionally known black ceramics. The proportion of the filler in the adhesive is, for example, 5% by weight or more and 50% by weight or less.

[0035] The adhesive may be a conventionally known two-component curing adhesive, except that it contains the above-mentioned filler. Examples of the adhesive include epoxy adhesives and urethane adhesives.

[0036] (1) Discharge process The discharge process is a process of discharging the adhesive from a nozzle, and is continued until a predetermined amount of adhesive is filled inside the battery case.

[0037] As shown in Fig. 1(e), the nozzle 400 is usually disposed above the battery case 200 (above the flange portion 203). Then, the adhesive F is discharged toward the gap between the battery case 200 and the laminate 100. Also, as shown in Fig. 1(d), it is preferable to discharge the adhesive F while scanning the nozzle 400 along the gap.

[0038] 4, the nozzle 400 is preferably shaped to eject the adhesive F in a curtain shape. In other words, the nozzle is preferably a curtain-type nozzle, because this allows the area irradiated with infrared rays to be increased.

[0039] The adhesive is preferably discharged from the nozzle in a state where the base agent, the curing agent, and the filler are mixed. The temperature of the discharged adhesive is preferably room temperature. Here, "room temperature" refers to a temperature of 15°C or more and 25°C or less. The speed at which the adhesive is discharged is, for example, 5cc / sec or more and 20cc / sec or less. The discharge direction (discharge angle) of the nozzle is preferably parallel to the thickness direction. Note that "parallel" does not mean only 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 that the angle between the two directions is 0° or more and 30° or less.

[0040] (2) Heat treatment The heating process is a process of heating the adhesive discharged from the nozzle by irradiating it with infrared rays. In the heating process, the adhesive is irradiated with infrared rays while it is being discharged. The "adhesive while it is being discharged" can be understood as adhesive that is not disposed in the battery case. For example, as shown in FIG. 1(e) and FIG. 4, T In this step, infrared rays IR are 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 Fig. 1(e), infrared rays are typically irradiated from a heat source 500. The heat source may be a focused lamp or a laser. As shown in Fig. 1(d), the heat source 500 may irradiate infrared rays while following the scanning of the nozzle 400.

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

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

[0044] B. Battery pack The battery pack in the present disclosure includes a stacked battery and a battery case. The stacked battery is housed in the battery case. The stacked battery includes a plurality of unit cells stacked in a thickness direction. The stacked battery is fixed to the battery case by an adhesive. The adhesive contains a base agent, a curing agent, and a filler. The battery pack may also include a lid that seals the battery case filled with the adhesive.

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

[0046] The use of the battery pack is not particularly limited. The battery pack can be used as a power source for a vehicle. Examples of the vehicle include a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), a gasoline-powered vehicle, and a diesel-powered vehicle. It is particularly preferable that the battery pack is used as a driving power source for a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or an electric vehicle (BEV). The battery pack may be used as a power source for a moving body other than a vehicle (for example, a train, a ship, or an aircraft). The battery pack may be used as a power source for an electric product such as an information processing device.

[0047] The present disclosure is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any configuration that is substantially the same as the technical idea described in the claims of the present disclosure and that exhibits similar effects is included in the technical scope of the present disclosure. [Explanation of symbols]

[0048] 1...Current collector 2...Cathode active material layer 3...Negative electrode active material layer 4...Separator E...Electrode 10...Double 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 having a preparation step, an accommodation step, and a filling step, the preparation step being a step of preparing a stacked battery having a plurality of single cells stacked in the thickness direction, the accommodation step being a step of accommodating the stacked battery in a battery case, the filling step being a step of filling the battery case with an adhesive to fix the stacked battery to the battery case, the adhesive containing a base agent, a curing agent, and a filler, the filling step having a discharge process of discharging the adhesive from a nozzle and a heating process of heating the adhesive discharged from the nozzle by irradiating it with infrared rays, the infrared rays being irradiated onto the adhesive during the discharge process.

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

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

4. A battery pack having a stacked battery and a battery case, the stacked battery being housed in the battery case, the stacked battery having a plurality of unit cells stacked in a thickness direction, the stacked battery being fixed to the battery case by an adhesive, the adhesive containing a base agent, a curing agent, and a filler.

5. The battery pack according to claim 4 , wherein the filler is at least one of a black pigment and a black ceramic.

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