JP2019125426A - Method of manufacturing battery pack - Google Patents

Abstract

To provide a method of manufacturing a battery pack in which each battery can be surely cooled in a cooling step in a manufacturing process of the battery pack formed by combining a plurality of batteries.SOLUTION: Disclosed is a method of manufacturing a battery pack formed by combining a plurality of single batteries 2 and a cooling member for cooling each single battery 2. This method includes: a cooling step of cooling a battery 2, while bringing a heat conduction material 4 arranged on the cooling surface which is a part of the battery 2 surface at a stage after high temperature aging and before self-discharge inspection into a heat removal member 13 different from the cooling member; an inspection step of subjecting the battery 2 after the cooling step to the self-discharge inspection; and an assembling step of incorporating the battery 2 after the inspection step into the battery pack so that the heat conduction material 4 comes into close contact with the cooling member while leaving the heat conduction material 4.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of manufacturing an assembled battery formed by combining a plurality of batteries. More specifically, the present invention relates to a method of manufacturing a battery assembly in which a cooling step is performed on the battery before being incorporated into the battery assembly, and a cooling member for cooling each battery at its use stage is incorporated into the battery assembly.

  Conventionally, in the manufacturing process of lithium ion secondary batteries and other batteries, an activation process is performed to activate the assembled battery. In the activation process, a high temperature aging step is performed to hold the battery, which has been subjected to initial charge, in a high temperature range (for example, about 55 to 70 ° C.) for a certain period of time, And an inspection step of performing a self-discharge inspection (e.g., Patent Document 1). Here, after the high temperature aging process, the temperature of the battery is lowered. In order to do this in a shorter time, forced cooling in which the heat removal member is in contact is more advantageous than relying on natural cooling.

  As the heat removal member for that purpose, it is conceivable to use the one described in FIG. 10 of Patent Document 2. In the same figure, what installed "the heat conductive sheet 10a" on the "cooling plate 11" is drawn ("(a)" of the same figure). Then, a state is shown in which the "battery module 9" is cooled by pressing the "battery module 9" against the "cooling plate 11" via the "heat conductive sheet 10a" ("(b)" in the figure). . Since the “heat conductive sheet 10 a” has stretchability such as a silicon resin sheet, the bonding surface is closely adhered ([0032] in the same document). Therefore, high cooling efficiency can be expected. In particular, since the "battery module 9" is an assembly of a plurality of "battery cells 9a" (FIG. 3, [0030] in the same document), the stretchability of the "heat conductive sheet 10a" Is beneficial for This is because a certain degree of variation is inevitable in the height of the bonding surface of each "battery cell 9a".

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

  However, the above-described conventional techniques have the following problems. When the heat removal member shown in FIG. 10 of Patent Document 2 described above is used for activation processing after assembly of the battery, the “cooling plate 11” with the “heat conductive sheet 10a” is repeatedly used many times. Then, the “heat conductive sheet 10 a” is creep-deformed and its stretchability is lost. In the situation where the "heat conductive sheet 10a" is thus exhausted, the bonding surface can no longer be firmly adhered and high cooling efficiency can not be expected. In particular, when the "battery module 9" which is an assembly of a plurality of "battery cells 9a" is to be cooled, the degree of cooling varies among the "battery cells 9a". However, it is wasteful to replace the “heat conductive sheet 10 a” once each time.

  The present invention has been made to solve the problems of the above-described conventional techniques. That is, it is an object of the present invention to provide a method of manufacturing an assembled battery capable of reliably cooling each battery in the cooling step in the process of manufacturing the assembled battery formed by combining a plurality of batteries.

  A method of manufacturing a battery pack according to an aspect of the present invention is a method of manufacturing a battery pack comprising a plurality of batteries and a cooling member for cooling each battery, the method comprising the steps of: The heat conducting material in the battery in the stage where the heat conducting material having stretchability is disposed on the cooling surface which is a part of the surface is brought into contact with the heat removal member separate from the cooling member. Cooling step of cooling the battery, inspection step of subjecting the battery after the cooling step to self-discharge inspection, and battery after the inspection step, the assembled battery so that the heat conducting material contacts the cooling member while leaving the heat conducting material. And a built-in process to be incorporated into the

  In the method of manufacturing a battery assembly in the above aspect, good heat removal from the battery to the heat removal member can be obtained due to the stretchability of the heat conductive material in the cooling step. Therefore, the cooling process can be completed in a short time. Since the heat transfer material is incorporated into the assembled battery while being disposed on the cooling surface of the battery, it is not repeatedly used many times. For this reason, creep deformation does not occur in the heat conductive material, and the heat discharging property is not impaired.

  According to this configuration, there is provided a method of manufacturing a battery assembly, which can reliably cool each battery in the cooling step in the process of manufacturing the battery assembly in which a plurality of batteries are combined.

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

  Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In this embodiment, for example, the present invention is applied to the manufacturing process of a battery assembly 1 as shown in FIG. The battery assembly 1 of FIG. 1 has a large number of unit cells 2 arranged in one direction, and end plates 12 arranged at both ends. Each unit cell 2 of the battery pack 1 has a rectangular flat outer shape. In the assembled battery 1, the thickness direction of each unit cell 2 and the arrangement direction of the assembled battery 1 are parallel. Further, the end plates 12 of the both ends are fastened by a fastening rod 15. Thus, the battery pack 1 is integrated. Further, each unit cell 2 is compressed in the thickness direction.

  In the battery assembly 1 of FIG. 1, the cells 2 are arranged in a row on the cooling plate 3. A heat conducting material 4 is disposed between the cooling plate 3 and each unit cell 2. FIG. 2 shows a perspective view of the unit cell 2. Although omitted in FIG. 1, positive and negative terminals 5 and 6 are provided on the upper surface of the unit cell 2 so as to protrude. The heat conductive material 4 described above is disposed on the bottom surface which is a part of the surface of the unit cell 2. In addition, although a lithium ion secondary battery is mainly assumed as a battery type of the unit cell 2, the present invention is not limited thereto.

In the manufacturing method of this embodiment, the battery assembly 1 as shown in FIG. 1 is manufactured in the following procedure. Among these, “3.” and “4.” are the activation processing of the unit cell 2 after assembly. However, for the explanation of this specification, the following "5." and "6." are also included in the activation process.
1. Assembly of unit cell 2 Arrangement of heat conductive material 4 to unit cell 2 First charge 4. High temperature aging 5. Cooling 6. Inspection 7. Built-in battery 1

  First, the assembly of “1.” is to enclose the power generation element and the electrolyte in the outer case of the unit cell 2. This process is known (for example, from [0010] to [0014] in Patent Document 1), and the feature point of the present invention is not particularly limited. The heat conductive material 4 is not disposed in the unit cell 2 in a state of being just assembled.

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

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

  After high temperature aging, cool down "5." This is to carry out the inspection of “6.” at normal temperature. Cooling is performed while pressing the heat conduction member 4 on the bottom of each unit cell 2 against the heat removal member 13 as shown in FIG. That is, in the unit cell 2, the bottom surface is a cooling surface. A coolant liquid F (water or the like) is passed through the heat removal member 13. For this reason, the single battery 2 after high temperature aging can be cooled to normal temperature in a short time. The heat removal member 13 is used in the production process, and is not incorporated in the assembled battery 1. That is, the cooling plate 3 is different from the cooling plate 3 described above. Further, it is not necessary to arrange the same member as the heat conductive material 4 on the surface of the heat removal member 13.

  Here, the heat conductive material 4 plays an important role. In the state of the assembly 8, the height of the bottom of each unit cell 2 is not necessarily strictly uniform. For this reason, when cooling is performed without the heat conducting material 4, some cells 2 do not contact the heat removal member 13 so much that the cooling may be insufficient. The presence of the heat conductive material 4 which is stretchable and has a good heat conductivity sufficiently cools all the unit cells 2.

  After that, perform the test of "6." That is, the unit cell 2 is self-discharged, and the quality of the unit cell 2 is determined based on the situation. This specific method may be 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 disassembled and performed in the state of the individual single battery 2.

  Then, install "7." That is, only the unit cells 2 determined to be non-defective in 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 unit cell 2. For this reason, also in the process of use as the assembled battery 1, the exhaust heat from the unit cell 2 to the cooling plate 3 is efficiently performed via the heat conduction member 4. Further, in a state where the battery assembly 1 is mounted on a device such as a vehicle or a home appliance, the refrigerant liquid can be passed from the device to the cooling plate 3.

  This incorporation may be divided into stacking and packing. Stacking refers to stacking and restraining a large number of single cells 2 and corresponds to obtaining a state in which the cooling plate 3 is removed from the assembled battery 1 of FIG. 1. Packing means to store the stacked ones in a pack container to make a battery pack. A cooling plate 3 or the equivalent is disposed on the bottom of the pack container.

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

  First, regardless of the variation in the position in the height direction of the unit cell 2 in the cooling step or in the use stage, good heat removal can be obtained in all the unit cells 2. In particular, since good heat removal properties can be obtained in the cooling step, the time required for the activation process can be shortened. The initial charging step can also be performed while cooling the unit cell 2, and also in this case, a good effect of heat removal by the heat conductive material 4 can be obtained. On the other hand, the heat conductive material 4 itself is incorporated into the battery assembly 1 only by one activation process including a cooling step. Therefore, the number of times the heat conductive material 4 repeats compression and release thereof before being incorporated into the battery assembly 1 is about several times at most. Therefore, creep deformation does not occur in the heat conductive material 4 at the time of incorporation into the assembled battery 1. Therefore, the heat removal property at the use stage can be sufficiently obtained.

  The present embodiment is merely an example and does not limit the present invention. Therefore, the present invention is naturally capable of various improvements and modifications without departing from the scope of the invention. For example, the shape and combination of the end plate 12 and the fastening rod 15 shown in FIG. 1 are arbitrary. It may be anything that can maintain the integrity of the battery pack 1. Moreover, the concrete thing which can be used as the heat conductive material 4 is not limited to the exemplified ones, but may be equivalent products from other manufacturers. Also, the stretchability of the heat conductive material 4 is sufficient if it is at least in the thickness direction. Further, although the assembly 8 at the activation processing stage is different from the assembled battery 1 after assembly, it is not limited thereto. If all the inspection results of the unit cells 2 included in the assembly 8 are good, the cooling plate 3 may be added as it is to make the assembled battery 1 possible.

  Moreover, although it seems that single cells 2 are in close contact with each other in FIG. 1, the present invention is not limited thereto. A ventilation path may exist between the unit cells 2. Moreover, it is not essential to assemble the assembly 8 at the stage of the activation process. Even when the activation process is performed with the individual single cells 2 as they are, the effect of the present invention can be obtained to some extent. Further, the heat conductive material 4 may be disposed in the unit cell 2 at any time before the cooling step. In addition, the same member as the heat conduction member 4 is not disposed on the surface of the heat removal member 13. Further, the cooling plate 3 and the heat removal member 13 are not limited to those using the refrigerant liquid, but may be cooling by the thermoelectric effect of a Peltier element or the like.

1 battery pack 2 single battery 3 cooling board 4 heat conduction material 13 heat removal member

Claims (1)

A method of manufacturing an assembled battery comprising a plurality of batteries and a cooling member for cooling each of the batteries,
In the battery after the high temperature aging and before the self-discharge test, the heat conductive material in the heat conductive material disposed on the cooling surface which is a part of the surface is the heat conductive material, the cooling member Cooling the battery while in contact with another heat removal member,
An inspection step of subjecting the battery after the cooling step to a self-discharge inspection;
Incorporating the battery after the inspection step into the battery assembly so that the heat conductive material is in contact with the cooling member while leaving the heat conductive material. .

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