JP2014002925A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent short-circuiting caused by tearing of an insulating tube covering a unit cell, when a battery pack formed by adjacently combining a plurality pieces of cylindrical battery cells is dropped.SOLUTION: A unit cell in which a lid is fitted by caulking to the top of a bottomed cylindrical can is covered with a paper cylinder only at its upper portion. Thereafter, the unit cell is covered with a normal insulating tube. Then, a battery pack is formed by adjacently combining a plurality pieces of the unit cell. As a result, short-circuiting can be prevented by preventing the insulating tube from being torn at a caulked portion of the unit cell. Moreover, external dimensions as the battery pack can be reduced as much as possible by forming the battery pack with the upper and lower portions alternately reversed when the plurality pieces of the unit cells are adjacently combined.

Description

  The present invention relates to an assembled battery in which a plurality of single cells covered with an insulating tube are adjacently assembled.

  Conventionally, for example, a cylindrical battery contains a group of positive and negative electrode plates separated by a separator in a cylindrical can, injects an electrolytic solution, and a lid having a protrusion is caulked and sealed, and the cylindrical can is used as a negative electrode terminal. The lid with the protrusion is used as the positive terminal. In addition, when the lid which is the positive electrode terminal is caulked to the cylindrical can which is the negative electrode terminal, the cylindrical can and the lid are insulated from each other by interposing an insulator. Such a unit cell is covered with a heat-shrinkable insulating tube, and a plurality of adjacent assembled batteries are arranged side by side, for example, as shown in FIG. If an assembled battery that covers the entire assembled battery in a row and consists of a total of 10 single cells in a row and covered with a heat-shrinkable insulating tube is accidentally dropped, etc. It may break down.

In order to solve this problem, it has been proposed that after the cells are assembled adjacent to each other, the entire periphery thereof is integrally fixed with an adhesive tape. (Patent Document 1)

JP 07-249400 A

  However, even with this configuration, the failure of the assembled battery has not been eliminated. As a result of investigating the cause, it may depend on the way of dropping, but it was found that when a plurality of batteries are adjacently assembled as described above, the insulating tube is broken and short-circuited at the portion where the lid is crimped. . This invention invents the structure which can prevent a short circuit by this fact.

In order to achieve the above object, the present invention is characterized in that only the upper part including the crimped portion of the unit cell is covered with an insulator in multiple layers.

  As a result, the insulator covering the caulking portion of the unit cell is reinforced, and it is possible to withstand an impact caused by dropping without breaking the insulator.

Furthermore, it is preferable to dispose the unit cells in this manner alternately at the top and bottom, so that the outer dimensions of the assembled battery can be reduced as much as possible.

  According to the present invention, even if an impact is applied to the assembled battery due to dropping or the like, it is possible to prevent a short circuit, and when forming the assembled battery, the outer dimensions of the assembled battery are arranged by alternately arranging the cells up and down. Can be made as small as possible and can be stored in a limited storage space.

It is a description perspective view of the assembled battery which concerns on embodiment of this invention. It is a partial cross section front view of the cell which comprises an assembled battery.

  FIG. 1 is an explanatory perspective view showing an embodiment of the assembled battery of the present invention. Reference numeral 1 denotes a single battery, in which a plate group in which positive and negative electrode plates are wound through a separator in a bottomed cylindrical can 11 is stored together with an electrolytic solution impregnated therein, and a lid 12 having a convex portion is formed of the cylindrical can 11. The bottomed cylindrical can is sealed with an insulating member in the opening, and the cylindrical can 11 serves as a negative electrode terminal and the lid 12 serves as a positive electrode terminal.

The unit cell 1 constructed in this manner is covered with a paper tube having a thickness of 0.3 mm with the surface having the lid 12 as the top, and the upper part is covered with a paper tube having a thickness of 0.3 mm. A single cell covered with a heat-shrinkable insulating tube and only the upper part covered with a multiple (double) insulator is formed, and 10 unit cells are arranged while the adjacent unit cells 1 are turned upside down. After being connected in series with each other, as shown by the alternate long and short dash line, the whole was similarly covered with a heat-shrinkable insulating tube 2 made of vinyl chloride and having a thickness of 0.2 mm to produce a battery assembly in a single row.

  As in the prior art, the single cells are connected by a strip-shaped connection body, and the lead cells connected to the outside such as a load are connected to the single cells located at both ends, but they are omitted in the drawing.

  FIG. 2 is a partial cross-sectional front view for explaining a state in which the unit cell 1 is covered with a paper tube 13 and a heat-shrinkable insulating tube 14. As shown in FIG. 2, the unit cell 1 includes a lid 12 having a convex portion that is caulked and attached to an upper opening portion of a bottomed cylindrical can 11 in which a wound electrode plate group and an electrolytic solution are stored. In the figure, a portion indicated by reference numeral 13 is a caulking portion.

  The unit cell 1 was covered with a paper tube 14 at the top where the lid 12 was caulked. As shown in the figure, the paper tube 14 also covered the periphery of the upper surface to which the lid 12 was attached, and covered the upper part shorter than half the full length of the unit cell 1. The entire height of the unit cell 1 was covered with a heat-shrinkable insulating tube 15 from above the paper tube 14. The insulating tube 15 also covers the peripheral edges of the upper and lower surfaces of the unit cell 1.

The 10 single cells shown in FIG. 1 were subjected to a drop test for one row and one stage assembled battery. The drop test was performed by dropping from a height of 750 mm onto a 100 mm thick plate.

As shown in FIG. 1, the battery packs are dropped so that the lids and can bottoms of the battery packs arranged side by side land as shown in FIG. The batteries were dropped so that the left and right end faces of the assembled batteries lined up side by side. The total fall was 30 times, changing the landing area. And after dropping, the heat-shrinkable tube 2 covering the whole was peeled off, and it was confirmed whether or not there was a crack or the like in the paper tube covering the unit cell 1 or the heat-shrinkable insulating tube.

As a result, some of the battery packs constituted by conventional single cells not using a paper tube had cracks in the insulating tube covering the single cells, but none of the products of the present invention.

Furthermore, according to the present invention, since only the upper part is covered with the paper tube, the material can be saved, and when the unit cell is alternately turned upside down, the length is one unit cell. The length of the battery pack can be shortened as much as possible by only increasing the thickness of the paper tube per cell, rather than twice the thickness of the paper tube. There are also effects such as being usable without problems. In addition, when the assembled battery in one row and one stage is configured with the top and bottom being the same, since the outer diameter is different between the top and bottom of the unit cell, the whole shape of the assembled battery is curved as it is. When it is desired to avoid bending, a spacer is interposed between the lower portions of each unit cell.

In the above embodiment, an example in which a paper tube is used as an insulator covering only the upper part is shown. It is also possible to cover only the upper part of the unit cell and then further cover the entire length. However, when a paper tube is used, it is preferable in terms of workability and moisture retention during assembly.

As described above, according to the present invention, it is possible to prevent a short circuit due to the fall of the assembled battery, further reduce the outer dimension of the assembled battery as much as possible, and enable storage in a limited storage space. It produces the effects such as.

DESCRIPTION OF SYMBOLS 1 Cell 11 Cylindrical can 12 Lid 13 Caulking part 14 Paper cylinder 15 Heat-shrinkable insulation tube

Claims (2)

  An assembled battery in which a plurality of single cells covered with an insulating tube and covered with a lid are crimped on a cylindrical can, and the plurality of assembled single cells are covered with an insulating tube. Only the battery pack is covered with multiple insulators. 2. The assembled battery according to claim 1, wherein the assembled battery is configured by alternately inverting the upper and lower unit cells covered with multiple insulators only in the upper part.

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