JP7010007B2 - How to manufacture assembled batteries - Google Patents

Description

The present invention relates to a method for manufacturing an assembled battery in which a plurality of batteries are combined. More specifically, the present invention relates to a method for manufacturing an assembled battery, in which a cooling process is performed on the battery before it is incorporated into the assembled battery, and a cooling member for cooling each battery at the stage of its use is incorporated in the assembled battery.

Conventionally, in the manufacturing process of lithium ion secondary batteries and other batteries, an activation process for activating the assembled battery has been performed. The activation treatment involves a high-temperature aging step in which the battery that has been charged up to the initial charge is held in a high temperature range (for example, about 55 to 70 ° C.) for a certain period of time, and then the battery is returned to the normal temperature range (for example, about 15 to 25 ° C.). It includes an inspection step of performing a self-discharge inspection (for example, Patent Document 1). Here, the temperature of the battery is lowered after the high temperature aging step. In order to do this in a shorter time, forced cooling in contact with the heat-removing member is more advantageous than relying on natural cooling.

As the heat-removing member for that purpose, it is conceivable to use the one described in FIG. 10 of Patent Document 2. The figure shows a "heat conduction sheet 10a" installed on the "cooling plate 11" ("(a)" in the figure). Then, the state of cooling the "battery module 9" by pressing the "battery module 9" against the "cooling plate 11" via the "heat conduction sheet 10a" is drawn ("(b)" in the figure). .. Since the "heat conductive sheet 10a" has elasticity such as a silicon resin sheet, the joint surfaces can be brought into close contact with each other ([0032] in the same document). Therefore, high cooling efficiency can be expected. In particular, since the "battery module 9" is an aggregate of a plurality of "battery cells 9a" ([0030] in the same document, FIG. 3), the elasticity of the "heat conductive sheet 10a" ensures that the joint surface is firmly adhered. Beneficial for. This is because the height of the joint surface of each "battery cell 9a" inevitably varies to some extent.

JP-A-2015-090806 JP-A-2015-153743

However, the above-mentioned conventional technique has the following problems. When the heat-removing member of FIG. 10 of Patent Document 2 described above is used for the activation process after assembling the battery, the "cooling plate 11" with the "heat conduction sheet 10a" is used repeatedly. Then, the "heat conductive sheet 10a" is creep-deformed and loses its elasticity. In a situation where the "heat conductive sheet 10a" is exhausted in this way, the joint surfaces can no longer be reliably adhered to each other, and high cooling efficiency cannot be expected. In particular, when the "battery module 9", which is an aggregate of a plurality of "battery cells 9a", is targeted for cooling, the degree of cooling varies from "battery cell 9a" to each other. However, it would be wasteful if the "heat conductive sheet 10a" was replaced every time.

The present invention has been made to solve the problems of the above-mentioned conventional techniques. That is, the problem is to provide a method for manufacturing an assembled battery, which can surely cool each battery in the cooling process during the manufacturing process of the assembled battery formed by combining a plurality of batteries.

The method for manufacturing an assembled battery according to one aspect of the present invention is a method for manufacturing an assembled battery in which a plurality of batteries and a cooling member for cooling each battery are combined, and the each battery is subjected to high temperature aging. Before, the heat conductive material placement process in which the elastic heat conductive material is placed on the cooling surface that is a part of the surface, and the heat conductive material of the battery in the stage after high temperature aging and before the self-discharge inspection are cooled. A cooling process in which the battery is cooled while in contact with a heat-removing member other than the member, an inspection process in which the battery after the cooling process is subjected to a self-discharge inspection, and a battery after the inspection process are left with the heat conductive material. It has a built-in process of incorporating the heat conductive material into the assembled battery so that it comes into contact with the cooling member, and the cooling process is performed in an assembled state in which a plurality of batteries are restrained by a restraint, and the heat-removing member is incorporated into the assembled battery. It is supposed to be something that cannot be done.

In the method for manufacturing an assembled battery in the above aspect, good heat exhaustability from the battery to the heat-removing member can be obtained by the elasticity of the heat conductive material in the cooling step. Therefore, the cooling process can be completed in a short time. Since the heat conductive material is incorporated into the assembled battery while being arranged on the cooling surface of the battery, it is not used repeatedly many times. Therefore, the heat conductive material is not creep-deformed and the heat exhaust property is not impaired.

According to this configuration, there is provided a method for manufacturing an assembled battery capable of reliably cooling each battery in a cooling step during the manufacturing process of the assembled battery composed of a combination of a plurality of batteries.

It is a perspective view which shows an example of an assembled battery. It is a perspective view which shows the appearance of a cell. It is a schematic diagram which shows the assembly at the time of an activation process. It is a schematic diagram which shows the situation at the time of a cooling process.

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, for example, the present invention is applied to the manufacturing process of the assembled battery 1 as shown in FIG. In the assembled battery 1 of FIG. 1, a large number of cell cells 2 are arranged in one direction, and end plates 12 are arranged at both ends. Each cell 2 of the assembled battery 1 has a square flat plate-shaped outer shape. In the assembled battery 1, the thickness direction of each cell 2 is parallel to the arrangement direction of the assembled battery 1. Further, the end plates 12 at both ends are fastened to each other by the fastening rod 15. As a result, the assembled battery 1 is integrated. Further, each cell 2 is pressed in the thickness direction.

In the assembled battery 1 of FIG. 1, each cell 2 is arranged in a row on the cooling board 3. A heat conductive material 4 is arranged between the cooling board 3 and each cell 2. FIG. 2 shows a perspective view of the cell 2 as a cell. Although omitted in FIG. 1, positive and negative terminals 5 and 6 are provided on the upper surface of the cell 2 so as to project. The above-mentioned heat conductive material 4 is arranged on the bottom surface which is a part of the surface of the cell 2. The battery type of the cell 2 is mainly assumed to be a lithium ion secondary battery, but the present invention is not limited thereto.

In the manufacturing method of this embodiment, the assembled battery 1 as shown in FIG. 1 is manufactured by the following procedure. Of these, "3." and "4." are the activation treatments for the cell 2 after assembly. However, for the sake of description of the present specification, the subsequent "5." and "6." are also included in the activation process.
1. 1. Assembly of cell 2 2. 2. Arrangement of the heat conductive material 4 on the cell 2. First charge 4. High temperature aging 5. Cooling 6. Inspection 7. Incorporation into assembled battery 1

First, the assembly of "1." is to enclose the power generation element and the electrolytic solution in the outer case of the cell 2. This step is known (for example, [0010] to [0014] of Patent Document 1), and there are no particular features of the present invention. The heat conductive material 4 is not arranged on the cell 2 in the assembled state.

Next, the heat conductive material 4 of "2." is arranged. The heat conductive material 4 is a member having both elasticity and good heat conductivity. It is provided to satisfactorily exhaust heat from the cell 2 to the outside. As such a material, what is called a "heat dissipation sheet" is supplied by each manufacturer and can be used. As such, for example, "Hypersoft heat dissipation sheet" manufactured by 3M can be mentioned. According to the company's website, it is mainly composed of low-hardness acrylic resin, has a thermal conductivity of 2.0 to 3.5 [W / m · K], and has an Asker C hardness of 15 to 38. In this step, the heat dissipation sheet as described above is cut and attached according to the size of the bottom surface of the cell 2. Alternatively, a paste-like material having the above-mentioned properties by solidification may be applied to the bottom surface of the cell 2 and solidified. The cell 2 whose appearance is shown in FIG. 2 is at a stage after this step.

Subsequently, the initial charge of "3." and the subsequent high-temperature aging of "4." are performed. These steps may be performed by a known method (for example, [0015] and [0016] in Patent Document 1). Of these, high temperature aging is carried out in the state of the assembly 8 in which a plurality of cell cells 2 are restrained by an appropriate restraint 7 as shown in FIG. 3 for the convenience of processing handling. The initial charge before high temperature aging may also be performed in the state of the assembly 8.

After high temperature aging, the cooling of "5." is performed. This is to carry out the inspection of "6." at room temperature. Cooling is performed while keeping the state of the assembly 8 while pressing the heat conductive material 4 on the bottom surface of each cell 2 against the heat absorbing member 13 as shown in FIG. That is, in the cell 2, the bottom surface thereof is the cooling surface. A refrigerant liquid F (water or the like) is passed through the heat-removing member 13. Therefore, the temperature of the cell 2 after high temperature aging can be lowered to room temperature in a short time. The heat-removing member 13 is used in the production process and is not incorporated in the assembled battery 1. That is, it is different from the cooling board 3 described above. Further, it is not necessary to arrange a member similar to the heat conductive material 4 on the surface of the heat absorbing member 13.

Here, the heat conductive material 4 plays an important role. This is because the height of the bottom surface of each cell 2 is not exactly uniform in the state of the assembly 8. Therefore, when cooling is performed without the heat conductive material 4, depending on the cell 2, the cooling may be insufficient because it does not make much contact with the heat absorbing member 13. By having the heat conductive material 4 having elasticity and good heat conductivity, all the cells 2 are sufficiently cooled.

After that, the inspection of "6." is performed. That is, the cell 2 is self-discharged, and the quality of the cell 2 is determined according to the situation. As for this, the specific method may be a known one (for example, [0017] to [0023] of Patent Document 1). This inspection may be performed in the state of the assembly 8 or may be performed in the state of the individual cells 2 by disassembling the assembly 8.

Then, "7." is incorporated. That is, only the cell cells 2 judged to be non-defective by the inspection of "6." are collected to form the assembled battery 1 as shown in FIG. At that time, the heat conductive material 4 is left as it is without being peeled off from the cell 2. Therefore, even in the process of using the assembled battery 1, the heat exhausted from the cell 2 to the cooling board 3 is efficiently exhausted via the heat conductive material 4. Further, in a state where the assembled battery 1 is mounted on a device such as a vehicle or a home electric appliance, the refrigerant liquid can be passed from the device to the cooling board 3.

This integration may be divided into stacking and packing. Stacking is to stack and restrain a large number of cells 2 and corresponds to obtaining a battery 1 in FIG. 1 in a state excluding the cooling board 3. Packing is to store the stacked items in a pack container to make a battery pack. A cooling board 3 or an equivalent is arranged on the bottom surface of the pack container.

As described in detail above, according to the present embodiment, the heat conductive material 4 is arranged in the assembled cell 2 before the cooling step is reached. The heat conductive material 4 is not only used for exhaust heat in the cooling process, but is also incorporated into the assembled battery 1 as it is and used for exhaust heat even in the use stage. This has the following advantages.

First, good heat exhaustability can be obtained in all the cells 2 regardless of the variation in the height direction position of the cells 2 in both the cooling step and the use stage. In particular, since good heat exhaustability is obtained in the cooling step, the treatment time required for the activation treatment can be shortened. The initial charging step can also be performed while cooling the cell 2, and even in that case, the effect of good heat exhaustion by the heat conductive material 4 can be obtained. On the other hand, the heat conductive material 4 itself is incorporated into the assembled battery 1 only by experiencing the activation process including the cooling step once. Therefore, the number of times that the heat conductive material 4 repeats compression and its release before being incorporated in the assembled battery 1 is at most several times. Therefore, creep deformation does not occur in the heat conductive material 4 at the time of incorporation into the assembled battery 1. Therefore, sufficient heat dissipation at the stage of use can be obtained.

It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Therefore, as a matter of course, the present invention can be improved and modified in various ways without departing from the gist of the present invention. For example, the shape and combination of the end plate 12 and the fastening rod 15 shown in FIG. 1 are arbitrary. Anything that can maintain the integrity of the assembled battery 1 may be used. Further, the specific material that can be used as the heat conductive material 4 is not limited to the illustrated material, and may be an equivalent product manufactured by another manufacturer. Further, the elasticity of the heat conductive material 4 is sufficient if it is at least in the thickness direction thereof. Further, the assembly 8 at the stage of the activation process is different from the assembled battery 1 after assembly, but is not limited to this. If the inspection results of the cell cells 2 included in the assembly 8 are all good, the cooling board 3 may be added as it is so that the assembled battery 1 can be used.

Further, in FIG. 1, it seems that the cells 2 are in close contact with each other, but the present invention is not limited to this. A ventilation path may exist between the cell 2 cells. Further, it is not essential to assemble the assembly 8 at the stage of the activation process. Even when the activation treatment is performed with the individual cells 2 as they are, the effect of the present invention can be obtained to some extent. Further, the time for arranging the heat conductive material 4 in the cell 2 may be any time before the cooling step. Further, it does not prevent the same member as the heat conductive material 4 from being arranged on the surface of the heat absorbing member 13. Further, the cooling board 3 and the heat-removing member 13 are not limited to those using the refrigerant liquid, and may be those that cool by the thermoelectric effect of the Peltier element or the like.

1 set battery 2 cell cell 3 cooling board 4 heat conductive material 13 heat absorbing member

Claims (1)

It is a method for manufacturing an assembled battery, which comprises a combination of a plurality of batteries and a cooling member for cooling each of the batteries.
For each battery, a heat conductive material placement step of placing a stretchable heat conductive material on a cooling surface that is a part of the surface of the battery before high temperature aging, and a process of arranging the heat conductive material.
A cooling step of cooling the battery while contacting the heat conductive material of the battery in a stage after high temperature aging and before the self-discharge inspection with a heat absorbing member different from the cooling member.
An inspection step of subjecting the battery to a self-discharge inspection after the cooling step, and
It has a built-in step of incorporating the battery after the inspection step into the assembled battery so that the heat conductive material comes into contact with the cooling member while leaving the heat conductive material.
The cooling step is performed in an assembled state in which a plurality of the batteries are restrained by a restraint.
A method for manufacturing an assembled battery, wherein the heat-removing member is not incorporated in the assembled battery.

Images