JP6928909B2 - How to connect the battery pack and lead plate - Google Patents

Description

The present invention relates to a method for connecting a battery pack and a lead plate, and relates to a technique for welding a lead plate to a base battery electrode.

Conventionally, battery packs used in electrically power assisted bicycles and the like consist of a plurality of elementary batteries. This battery pack is, for example, as shown in FIGS. 4 to 6. The battery pack 1 is formed by arranging a group of a plurality of elementary batteries 2 vertically and horizontally, and a positive electrode row in which the positive electrodes 3 of the plurality of elementary batteries 2 are arranged in a row and a negative electrode 4 of the plurality of elementary electrodes 2 are arranged in a row. The negative electrode rows are arranged alternately. The arrangement of the positive electrode row and the negative electrode row is opposite on the VB side (plus side) and the VG side (minus side) of the battery pack 1. Then, the lead plates 5 and 6 connect the electrodes of the positive electrodes 3 and the negative electrodes 4 of the battery pack 1 to each other.

As shown in FIG. 5, on the VB side (plus side) of the battery pack 1, the first VB side lead plate 51 connects the positive electrodes 3 of the elementary batteries 2 in the first row 11 forming the positive electrode row to each other.
Next, the negative electrode 4 of the elementary battery 2 in the second row 12 in which the second VB side lead plate 52 forms the negative electrode row is connected to each other, and the same second VB side lead plate 52 forms the adjacent positive electrode row. The positive electrode 3 of the elementary battery 2 in the third row 13 is connected to each other, and the same second VB side lead plate 52 further connects the negative electrode 3 in the second row 12 and the positive electrode 4 in the third row 13 to each other. Hereinafter, in the same manner, the third VB side lead plate 53 connects the negative electrode 3 of the fourth row 14 and the positive electrode 4 of the fifth row 15 to each other, and the fourth VB side lead plate 54 is the sixth row 16. The negative electrode 3 and the positive electrode 4 in the 7th row 15 are connected to each other.

As shown in FIG. 6, on the VG side (minus side) of the battery pack 1, the negative electrode 4 of the elementary battery 2 in the first row 11 in which the first VG side lead plate 61 forms the negative electrode row is connected to each other and is the same. The positive electrode 3 of the elementary battery 2 in the second row 12 in which the first VG side lead plate 61 forms the positive electrode row is connected to each other. Further, the same first VG side lead plate 61 connects the negative electrode 4 of the first row 11 and the positive electrode 3 of the second row 12 to each other. Hereinafter, in the same manner, the second VG side lead plate 62 connects the negative electrode 3 of the third row 13 and the positive electrode 4 of the fourth row 14 to each other, and the third VG side lead plate 63 is the fifth row 16. The negative electrode 3 and the positive electrode 4 in the sixth row 16 are connected to each other. Then, the negative electrode 4 of the elementary battery 2 in the 7th row 17 in which the 4th VG side lead plate 64 forms the negative electrode row is connected to each other.

Further, Patent Document 1 describes a lead terminal for a battery. This is a battery lead terminal connected to an external terminal of a battery element, and holds a pair of long lead plates made of strip-shaped conductive metal and the pair of lead plates arranged side by side at predetermined intervals. It consists of a holding member. The holding member has an electric resistance larger than the electric resistance of the lead plate and the external terminal of the elementary battery.
When connecting the battery lead terminals to the battery, a pair of lead plates held at predetermined intervals by the holding member are placed in contact with the external terminals of the battery, and one lead is placed in this state. A current is passed from one plate to the other lead plate via the external terminal of the elementary battery, and the external terminal of the elementary battery and each lead plate are spot welded.

Japanese Patent No. 4524987

In the battery pack 1 described above, a method of welding the lead plate 5 or 6 to the positive electrode 3 or the negative electrode 4 of the elementary battery 2 will be described. In the following, the case where the lead plate 5 is welded to the positive electrode 3 will be described as an example, but the same applies to the case where the lead plate 6 is welded to the negative electrode 4.

As shown in FIG. 7, the lead plate 5 is arranged in contact with the cap 7 forming the positive electrode 3 of the elementary battery 2. Then, the positive electrode rod 8 and the negative electrode rod 9 of the welding electrode are placed in contact with the lead plate 5.
Next, as shown in FIG. 8, the output current of the welding machine is applied from the positive electrode rod 8 of the welding electrode to the lead plate 5. The applied current I1 is divided into a welding current I2 that flows as a current that contributes to welding and an invalid current I3 that flows as a current that does not contribute to welding, and reaches the negative electrode rod 9.
The welding current I2 flows from the positive electrode rod 8 to the negative electrode rod 9 through the lead plate 5 and the cap 7. Then, as shown in FIG. 9, the welded portion (nugget) 10 is formed by the resistance heat generated at the welding interface between the lead plate 5 and the cap 7.

The invalid diversion I3 flows from the positive electrode rod 8 to the negative electrode rod 9 through the lead plate 5 forming a parallel circuit. This ineffective diversion I3 is 5 to 10 times as large as the welding current I2. Therefore, as the output current (applied current I1) of the welding machine, a total current of the welding current I2 and the invalid shunt current I3 is required, and the presence of the invalid shunt current I3 significantly increases the output current of the welding machine, resulting in cost. It is the cause of the up.
Further, there is a problem that the applied current I1 flowing through the positive electrode rod 8 and the negative electrode rod 9 increases due to the increase in the output current of the welding machine, and the life of the welded electrode rod is shortened due to the increase in the current thermal stress.
As a method of suppressing the generation of this invalid diversion I3, for example, there are those shown in FIGS. 10 and 11. In this method, a slit 101 is formed in the lead plate 100, the positive electrode rod 8 is brought into contact with one of the pair of welded portions 102 and 103 via the slit 101, and the negative electrode rod 9 is brought into contact with the other, and spot welding is performed. (Series welding).

However, although this method can suppress the occurrence of ineffective diversion I3 and reduce its value, it is not possible to eliminate the occurrence of ineffective diversion I3. Further, if the contact positions (spot welding positions) of the positive electrode rods 8 and the negative electrode rods 9 in the welded portions 102 and 103 of the lead plate 100 are displaced, the welding results will be different. That is, the closer the contact positions of the positive electrode rod 8 and the negative electrode rod 9 are to the inner end side of the slit 101, the more likely the invalid diversion I3 is to occur, and the closer to the opening side of the slit 101, the less the invalid diversion I3.
The increase / decrease in the welding current I2 due to the deviation of the spot welding position causes the following problems. That is, if the welding current I2 is excessive, welding spatter occurs and scatters around, and if the welding current I2 is too small, the amount of welded portion (nugget) generated is not stabilized, and welding defects (nugget generation defects) occur. In some cases, the variation in the contact positions of the positive electrode rod 8 and the negative electrode rod 9 has a great influence on the welding result.

Further, the above-mentioned conventional lead plate needs to have a complicated shape by press molding or the like, requires a mold cost and a large number of production man-hours, and has a structural factor of increasing the cost.
Next, the battery lead terminal of Patent Document 1 holds a pair of long lead plates at predetermined intervals by holding members, and is formed in advance in a specific shape according to the number of elementary batteries and the arrangement form. Need to keep. Further, the battery lead terminal of Patent Document 1 connects the positive electrodes of a plurality of elementary batteries arranged in a row to each other or the negative electrodes to each other in parallel.

Therefore, when a group of elementary batteries are arranged vertically and horizontally, it is difficult to connect each electrode with the battery lead terminal of Patent Document 1, for example, in the battery pack shown in FIGS. 4 to 6.
That is, in order to connect the rows of positive electrodes of a group of elementary batteries in parallel, connect the rows of negative electrodes in parallel, and connect the rows of positive electrodes and the rows of negative electrodes in series, the battery of Patent Document 1 is used. At the lead terminals, it is necessary to arrange the lead plates in a grid pattern. However, it is difficult to fix a plurality of leads arranged in a grid pattern with a holding member in a state in which each lead is independent and a predetermined distance is maintained between them.

Further, the battery lead terminal of Patent Document 1 needs to have a different shape according to the number of connected elementary batteries, and for each battery pack having a different number of elementary batteries, the battery lead terminal is provided according to the shape. It is necessary to prepare, which causes an increase in the number of parts in stock.
The present invention provides a method for connecting a battery pack and a lead plate, which can prevent the occurrence of invalid diversion with a lead plate having a simple shape and can realize a welding result that is not affected by the contact position of the electrode rods on the lead plate. The purpose is to provide.

The battery pack according to the present invention has a group of elementary batteries arranged vertically and horizontally, and is an uncoated independent battery manufactured by cutting the same hoop material on each electrode of the elementary battery without undergoing a molding process. It is characterized in that a plurality of lead plates forming a form are spot-welded in series.
The battery pack according to the present invention is characterized in that the lead plate has a strip shape.
In the battery pack according to the present invention, in the group of elementary batteries, the positive electrode row in which the positive electrodes of the plurality of elementary batteries form a row and the negative electrode row in which the negative electrodes of the plurality of elementary electrodes form a row are arranged next to each other, and are uncoated and independent. It is characterized in that a plurality of strip-shaped lead plates having the above-mentioned shape are arranged so as to be laid between the positive electrode row and the negative electrode row which are adjacent to each other between the positive electrode row and the negative electrode row which form a pair.
The battery pack according to the present invention is characterized in that strip-shaped lead plates having an uncoated independent form are arranged so as to extend between the positive electrodes in the positive electrode row and between the negative electrodes in the negative electrode row. do.
The battery device according to the present invention is characterized in that it powers an electrically assisted bicycle and is equipped with any of the above battery packs.

In the method of connecting the lead plates of the battery pack according to the present invention, a group of elementary batteries are arranged vertically and horizontally, and a positive electrode row in which the positive electrodes of the plurality of elementary batteries form a row and a negative electrode row in which the negative electrodes of the plurality of elementary electrodes form a row. And are placed next to each other, and the same hoop material is cut between the positive and negative electrodes that are adjacent to each other between the positive electrode row and the negative electrode row that form a pair, and the uncoated material is manufactured without a molding process. It is characterized by arranging a plurality of strip-shaped lead plates forming independent forms, and arranging the anode or cathode of the welding electrode on each of the plurality of lead plates on each electrode of the elementary battery to perform series spot welding. do.
In the method for connecting the lead plates of the battery pack according to the present invention, strip-shaped lead plates having an uncoated independent form are arranged so as to extend between the positive electrodes in the positive electrode row and between the negative electrodes in the negative electrode row. It is characterized in that series spot welding is performed by arranging the anode or cathode of the welding electrode on each of a plurality of lead plates on each electrode of the elementary battery.
In the method for connecting the lead plate of the battery pack according to the present invention, a lead holding portion is formed on a welding jig for holding the lead plate with a lead plate arrangement pattern corresponding to the element battery arrangement pattern of a group of elementary batteries, and welding is performed. The feature is that a plurality of lead plates arranged in each lead holding portion of the tool are collectively held by a welding jig and arranged so as to face a group of elementary batteries, and each lead plate is spot-welded to each positive electrode or negative electrode. do.

According to the present invention, a plurality of uncoated independent lead plates are arranged on one electrode of the elementary battery, and the plurality of lead plates are welded to the electrodes by series spot welding to perform invalid flow separation. Can be prevented. Therefore, even if the spot welding position shifts, the welding current does not increase or decrease, and the amount of welded portion (nugget) generated is stabilized. In addition, the applied current applied to the welding electrode does not need to be set in anticipation of the occurrence of ineffective diversion, so that it corresponds to the welding current, power consumption can be reduced, and the length of the welding electrode is reduced by reducing the current thermal stress. Life can be extended.
In addition, since the lead plate has an independent strip shape to be covered, when connecting the electrodes with the lead plate in a battery pack consisting of a group of elementary batteries, the arrangement pattern of the lead plates can be changed according to the arrangement form of the elementary batteries. It can be changed flexibly, and even if a group of elementary batteries are arranged in any form, they can be connected by a small number of types of lead plates having a similar strip-like simple shape with different lengths.

A perspective view showing a battery pack according to an embodiment of the present invention. Schematic diagram showing the welding procedure of the lead plate in the battery pack Schematic diagram showing series spot welding of lead plates in the same battery pack Schematic diagram showing a state in which the lead plate is removed in a conventional battery pack A perspective view showing the VB side (plus side) where the lead plate is arranged in the same battery pack. Perspective view showing the VG side (minus side) where the lead plate is arranged in the same battery pack. Schematic diagram showing conventional series spot welding of lead plates Schematic diagram showing current flow in series spot welding of the lead plate Schematic diagram showing nugget formation in series spot welding of the lead plate Schematic diagram showing series spot welding of other conventional lead plates Schematic diagram showing the flow of invalid diversion in series spot welding of the same lead plate

The battery pack according to the embodiment of the present invention will be described with reference to the drawings. This battery pack has the same basic structure as that shown in FIGS. 4 to 6 above, and the same elements will be described with the same reference numerals.
FIG. 1 shows the VB side (plus side) of the battery pack 200. Hereinafter, the VB side (plus side) of the battery pack 200 will be described, but the same applies to the VG side (minus side).
The battery pack 200 is mounted on, for example, a battery device that powers an electrically power assisted bicycle. In the battery pack 200, a group of a plurality of elementary batteries 2, 21 of which are arranged vertically and horizontally in 3 × 7, a plurality of elementary batteries 2, here, the positive electrodes 3 of the three elementary batteries 2 are arranged in a row. A row of positive electrodes arranged side by side and a row of negative electrodes in which a plurality of elementary electrodes 2 and negative electrodes 4 of three elementary batteries 2 are arranged in a row are alternately arranged next to each other to form seven rows of electrodes. ..

As shown in FIG. 1, on the VB side (plus side) of the battery pack 200, the first row 211 forms the positive electrode row of the positive electrode 3, the second row 212 forms the negative electrode row of the negative electrode 4, and thereafter the positive electrode row. The negative electrode rows alternate, and the final seventh row 217 forms the positive electrode row.
The arrangement of the positive electrode row and the negative electrode row is opposite on the VB side (plus side) and the VG side (minus side) of the battery pack 200.
This battery pack 200 uses two types of lead plates 201 and 202. On the other hand, the lead plate 201 is arranged so as to extend between the positive electrode 3 and the negative electrode 4 adjacent to each other between the positive electrode row and the negative electrode row forming the set, and has a short shape suitable for the two elementary batteries 2. The other lead plate 202 is arranged so as to span between the positive electrodes 3 in the positive electrode row and between the negative electrodes 4 in the negative electrode row, and has a long shape suitable for the three elementary batteries 2. These plurality of lead plates 201 and 202 are series spot welded on each electrode of the positive electrode 3 or the negative electrode 4 of the group of elementary batteries 2 arranged vertically and horizontally.

As shown in FIG. 2 (d), the lead plates 201 and 202 are in an uncoated state in which they are shapely independent of other objects and are not covered with an insulator or the like, and have a simple and simple strip-shaped elongated shape. It is made of a thin plate made of an inexpensive material such as Ni-Fe.
The lead plates 201 and 202 have a simple and simple strip-shaped shape, and can be manufactured by simply cutting a hoop material (thin plate coil) to a fixed length with a cutting machine. Is unnecessary. In addition, no treatment such as insulation coating is required. Therefore, the man-hours and costs involved in manufacturing the lead plates 201 and 202 can be reduced.
The connection of the lead plates 201 and 202 to the group of elementary batteries 2 in the battery pack 200 is as follows.
1. 1. When connecting the positive electrode row alone or the negative electrode row alone in parallel

As shown in FIG. 2A, on the VB side (plus side) of the battery pack 200, a pair of long lead plates 202 are arranged so as to extend between the positive electrodes 3 in the positive electrode row of the first row 211. Then, a pair of lead plates 202 are spot-welded to each positive electrode 3, and the positive electrodes 3 in the positive electrode row are connected in parallel.
That is, as shown in FIG. 3, the anode rod 8 or the cathode rod 9 of the weld electrode is attached to each of the plurality of lead plates 202 on the positive electrode cap 231 forming one positive electrode 3 of the elementary battery 2 in the first row 211. The lead plate 202 is sandwiched between the anode rod 8 or the cathode rod 9 and the positive electrode cap 231 to perform series spot welding.
At this time, the applied current I4 applied to the anode rod 8 flows as a welding current I5 to the positive electrode cap 231 via one lead plate 202, and flows from the positive electrode cap 231 to the cathode rod 9 via the other lead plate 202. Since both lead plates 202 are geometrically independent of each other, no current directly flows between both lead plates 202, and invalid diversion does not occur.
Therefore, regardless of the contact positions of the anode rod 8 and the cathode rod 9 with respect to the lead plate 202, resistance welding can be performed with a stable welding current I5 that is just right, and a sufficient nugget can be formed. Further, since the invalid current split does not occur, the applied current I4 can be suppressed, and the welding current I5 can be reduced to less than half of the welding current I2 in the conventional welding method involving the invalid split current I3, which is caused by the overcurrent. It is possible to suppress welding spatter and extend the life of the electrode rod.

Similarly, as shown in FIG. 2C, on the VG side (minus side) of the battery pack 200, a pair of long lead plates 202 are hung between the negative electrodes 4 on the negative electrode row of the 7th row 217. Deploy. Then, a pair of lead plates 202 are spot-welded on each electrode, and the negative electrodes 4 in the negative electrode row are connected in parallel.
2. When the positive electrode row and the negative electrode row are connected in series and the positive electrode row and the negative electrode row are connected in parallel As shown in FIG. 2B, the positive electrode 3 and the negative electrode 4 adjacent to each other between the positive electrode row and the negative electrode row forming a pair A pair of short lead plates 201 are arranged so as to span each other. Further, one long lead plate 202 is laid across the positive electrodes 3 in the positive electrode row, and one long lead plate 202 is hung between the negative electrodes 4 in the negative electrode row.
Then, a pair of lead plates 201 and 202 are spot-welded on each electrode as described above with reference to FIG.
Here, among the plurality of lead plates 201 and 202 on the negative electrode terminal 232 forming the negative electrode 4 of the anode battery 2 in the negative electrode row, the long lead plate 202 and one of the short lead plates 201 are welded to each other. The anode rod 8 or the cathode rod 9 of the electrode is arranged, and the lead plates 201 and 202 are sandwiched between the anode rod 8 or the cathode rod 9 and the negative electrode terminal 232 to perform series spot welding P1.

At this time, similarly to that shown in FIG. 3, the applied current I4 applied to the anode rod 8 flows as a welding current I5 to the negative electrode terminal 232 via the long lead plate 202, and one short lead plate 201 from the negative electrode terminal 232. It flows to the cathode rod 9 through. Since both lead plates 201 and 202 are geometrically independent of each other, no current directly flows between both lead plates 201 and 202, and invalid diversion does not occur. Therefore, resistance welding can be performed with a stable welding current I2 that is just right, and a sufficient welded portion (nugget) can be formed.
Further, since the invalid current split does not occur, the applied current I4 can be suppressed, and the welding current I5 can be reduced to less than half of the welding current I2 in the conventional welding method involving the invalid split current I3, which is caused by the overcurrent. It is possible to suppress welding spatter and extend the life of the electrode rod.

Next, the anode rod 8 or the cathode rod 9 of the welding electrode is arranged on the long lead plate 202 and the other short lead plate 201, respectively, and the lead plate 201, is placed between the anode rod 8 or the cathode rod 9 and the positive electrode cap 231. Series spot welding P2 is performed with 202 in between.
Similarly, the lead plates 201 and 202 are spot-welded in the other negative electrode terminals 232 and the positive electrode caps 231 in the positive electrode row.
As a result, the positive electrode 3 and the negative electrode 4 adjacent to each other between the positive electrode row and the negative electrode row forming the pair are connected in series by the lead plate 201, each positive electrode 3 in the positive electrode row is connected in parallel by the lead plate 202, and each negative electrode in the negative electrode row. 4 are connected in parallel by the lead plate 202.
Similarly, on the VG side (minus side) of the battery pack 200, the lead plates 201 and 202 are spot-welded at each negative electrode terminal 232 and each positive electrode cap 231.

The lead plates 201 and 202 can be arranged on a welding jig (not shown) and then collectively arranged on a group of elementary batteries 2. That is, a welding process for holding the lead plates 201 and 202. A lead holding portion is formed on the jig with a lead plate arrangement pattern corresponding to the element battery arrangement pattern of the group of elementary batteries 2.
Lead plates 201 and 202 are arranged on each lead holding portion of this welding jig. Then, a plurality of lead plates 201 and 202 are collectively held by a welding jig and arranged so as to face a group of elementary batteries 2, and the lead plates 201 and 202 are spot-welded to each positive electrode 3 or negative electrode 4. At that time, it is also possible to use a robot instead of manually.
As described above, according to the battery pack 200 according to the present embodiment, a plurality of strip-shaped lead plates 201 and 202 having an uncoated independent form are connected to the positive electrode 3 and the negative electrode 4 of the elementary battery 2. By using it, it is possible to prevent the occurrence of invalid diversion in series spot welding.
Therefore, even if the spot welding position shifts, the welding current does not increase or decrease, and the amount of welded portion (nugget) generated is stabilized. In addition, the applied current applied to the welding electrode does not need to be set in anticipation of the occurrence of ineffective diversion, so that it corresponds to the welding current, power consumption can be reduced, and the length of the welding electrode is reduced by reducing the current thermal stress. Life can be extended.

Further, since the lead plates 201 and 202 form independent strips without coating, when the positive electrode 3 and the negative electrode 4 are connected by the lead plates 201 and 202 in the battery pack 200 composed of a group of elementary batteries 2, the elementary batteries are connected. The lead arrangement pattern of the lead plates 201 and 202 can be flexibly changed according to the element battery arrangement pattern of 2, and no matter how the group of element batteries 2 is arranged in any form, a small number of types of lead plates 201 and 202 can be used. You can connect.
The present invention is not limited to the above-described embodiment, and can be applied to various types of battery packs.

The present invention is useful for a battery device or the like that forms a power source for an electrically power assisted bicycle.

2 Battery 3 Positive electrode 4 Negative electrode 8 Anode rod 9 Cathode rod 200 Battery pack 201, 202 Lead plate 231 Positive electrode cap

Claims (8)

It has a group of elementary batteries arranged vertically and horizontally, and on each electrode of the elementary battery, a plurality of uncoated independent lead plates manufactured by cutting the same hoop material and not undergoing a molding process are formed. Series Battery pack featuring spot welding. The battery pack according to claim 1, wherein the lead plate has a strip shape. In a group of elementary batteries, a plurality of lead plates in which a positive electrode row in which positive electrodes of a plurality of elementary batteries are arranged and a negative electrode row in which negative electrodes of a plurality of elementary electrodes are arranged are arranged next to each other and form an uncoated independent form. The battery pack according to claim 1 or 2, wherein the battery pack is arranged so as to extend between the positive electrode and the negative electrode which are adjacent to each other between the positive electrode row and the negative electrode row which form a pair. The battery pack according to claim 3, wherein uncoated lead plates having an independent form are arranged so as to extend between the positive electrodes in the positive electrode row and between the negative electrodes in the negative electrode row. A battery device that powers an electrically power assisted bicycle and is equipped with the battery pack according to any one of claims 1 to 4. A group of elementary batteries are arranged vertically and horizontally, and a positive electrode row in which the positive electrodes of a plurality of elementary batteries form a row and a negative electrode row in which the negative electrodes of a plurality of elementary electrodes form a row are arranged next to each other. A plurality of uncoated independent lead plates manufactured by cutting the same hoop material and forming an uncoated independent form are arranged so as to be hung between the positive electrode and the negative electrode adjacent to each other between the rows. A method of connecting the lead plates of a battery pack, which comprises arranging an anode or a cathode of the welding electrode on each of a plurality of lead plates on each electrode of the elementary battery to perform series spot welding. An uncoated independent lead plate is arranged between the positive electrodes in the positive electrode row and between the negative electrodes in the negative electrode row, and each of the plurality of lead plates on each electrode of the elementary battery is arranged. The method for connecting a lead plate of a battery pack according to claim 6, wherein an anode or a cathode of a welding electrode is arranged on the surface of the welding electrode to perform series spot welding. A lead holding portion is formed on the welding jig for holding the lead plate with a lead plate arrangement pattern corresponding to the elementary battery arrangement pattern of the group of elementary batteries, and a plurality of lead plates arranged on each lead holding portion of the welding jig are formed. The lead plate of the battery pack according to claim 6 or 7, wherein the lead plates are collectively held by a welding jig, arranged so as to face a group of elementary batteries, and each lead plate is spot-welded to each positive electrode or negative electrode. Connection method.

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