JP2006261083A - Connecting device between batteries - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting device between batteries, which connects between terminals of two batteries, reduces an electrical resistance, and is excellent in welding properties. <P>SOLUTION: The connecting device between batteries comprises a connecting plate between batteries 11, which connects between a battery case bottom 2 and a sealing plate 3 of two batteries 1a and 1b, where welding sections 4 welded to the case bottom 2 and the sealing plate 3 respectively are arranged on the both ends of a substrate 6 of the connecting plate between batteries 11, and a middle section 5 larger in thickness than the welding section 4 is formed by taking a means and the like for bonding a middle metal plate 7 to the middle portion between the welding sections 4 and 4 of the substrate 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inter-battery connection device that connects terminals of batteries arranged in parallel.

  In recent years, portable and cordless electronic devices such as AV devices or personal computers and portable communication devices have been rapidly promoted, and the power source for driving these electronic devices is highly reliable and easy to maintain. Therefore, nickel cadmium storage batteries, nickel hydride storage batteries, lithium secondary batteries, and the like are typically used. In addition, these batteries are widely used in various other applications, and in particular, they are used as drive power sources that require large load characteristics such as electric assist bicycles, lawn mowers, and electric vehicles. . In this type of battery for driving power supply, charge / discharge characteristics with a larger current are required, and development of a battery suitable for it is demanded.

  A battery as a driving power source is generally assembled as a battery pack or a battery module by connecting different polarities of a plurality of batteries to each other. Conventionally, the connection between the batteries is shown in FIG. As described above, the inter-battery connection plate 34 made of a metal plate obtained by cutting a hoop-like metal into a predetermined length is used, and the connection portions at both ends thereof are connected to the case bottom surface 32 of the battery 31a and the sealing plate of the battery 31b. 33 are connected to each other by welding at welding points 35.

Also, a second connection formed of a single plate-like body and formed by a first connecting portion that contacts the bottom of one unit cell and an annular recess or stepped portion that contacts the sealing plate of the other unit cell. A battery connection member provided with a portion is also known (for example, see Patent Document 1).
JP 2002-246003 A

  By the way, in a battery pack or battery module used for large current discharge, in order to obtain a structure suitable for large current discharge, in the structure of FIG. It needs to be wide. However, since it is difficult to increase the width of the inter-battery connection plate 34 beyond the diameter of the sealing plate 33, it is conceivable to increase the thickness of the inter-battery connection plate 34. However, if the plate thickness is increased, the battery case and the sealing plate The weldability to the plate is poor. In addition, when connecting two battery modules connected in a straight line between each one end, the end face position is adjusted to be on the same plane. The greater the thickness of the plate 34, the more difficult it is to follow.

  For this reason, there is a problem that peeling of the welded portion occurs, resulting in an increase in electrical resistance, deformation of the battery case or sealing plate, and perforation in the battery case due to welding with excessive energy. There are problems such as.

  In addition, there is a known method of reducing the thickness by changing the material of the battery connection plate to a metal having a low specific resistance such as copper, but if the specific resistance of the battery connection plate is lowered, the weldability may be inferior. There is a problem that the strength cannot be secured.

  In addition, the battery connection member disclosed in Patent Document 1 also needs to be thicker in order to cope with a large current discharge. If thicker, the weldability to the bottom surface of the battery case is inferior. There is a problem that the strength may be reduced, a hole may be formed in the welded portion on the bottom surface of the case, and the positional deviation between the end surfaces to be connected cannot be followed.

  In view of the above-described conventional problems, an object of the present invention is to provide an inter-battery connection device having excellent weldability while reducing electrical resistance.

  The inter-battery connection device of the present invention is an inter-battery connection device that connects two battery terminals arranged so that the axial directions thereof are parallel to each other. It consists of an intermediate part which connects between a part and the welding part of both ends, and the intermediate part is formed thicker than the welding part, It is characterized by the above-mentioned.

  According to this configuration, since the thickness of the intermediate part between the welded parts is thick, the inter-battery connection resistance can be reduced, which is suitable for large current charge / discharge characteristics, and the surface area increases in proportion to the increase in thickness. Therefore, the heat dissipation is improved and the thermal influence is alleviated, so that the electrical resistance can be remarkably reduced as compared with the conventional case, and a high output battery pack and battery module can be configured. In addition, since the welded portions at both ends are thin, the battery can flexibly follow the displacement of the terminal end face of the battery to be welded, and the shunt current in resistance welding can be reduced, resulting in a strong weld and a battery with excellent weldability. An inter-connection device can be realized.

  Further, this inter-battery connecting device is formed by joining one or more metal plates made of the same material or different materials, and having a substrate portion having welds at both ends and one or more metal plates made of the same material or different materials. It can be set as the structure formed by joining the intermediate part joined. In that case, one or more metal plates in the intermediate part are crimped by crimping with a claw-like part extending from both sides of the binding band or the intermediate part of the substrate part, or resistance welding, ultrasonic welding, laser welding or friction It is preferable to employ a configuration in which the members are joined by one means selected from welding by stirring joining.

  In addition, this inter-battery connection device may be configured such that a welded portion is formed thinner than the intermediate portion by forging or cutting a metal plate having a predetermined thickness.

  Further, the inter-battery connection device includes a connection plate having a welded portion with respect to the sealing plate of one battery at one end and a connection piece extending from the intermediate portion toward the other end with substantially the same thickness, and the other A connection ring that forms a welded portion of the battery case to the bottom of the battery case, the connection piece is abutted on the connection ring, and is held from above by a holding wing piece provided on the connection ring, and the holding wing piece It can be set as the structure which joined to the connection piece part. The holding blade piece and the connecting piece portion may be joined by caulking, welding, or other means.

  According to this configuration, since the thin connecting ring is joined from the holding blade side to the connecting piece of the thick connecting plate, it can be easily joined by caulking or stably and reliably welded. The battery case can be at least free of perforation, and the deformation of the holding blade can flexibly follow the displacement of the end face of the battery to be welded, and the connection between the upper surface of the connection ring and the holding blade The degree of freedom of the distance between the center axes of the battery is also increased by adjusting the insertion amount of the one part.

  Further, it is preferable that the connecting ring is configured to be fitted to the outer periphery of the bottom of the battery case and welded to the outer peripheral side surface. Then, the side surface of the battery case is less likely to be deformed than the bottom surface, the welding quality is stable, and highly reliable welding can be performed without fear of making a hole in the battery case.

  Further, the material is preferably made of nickel, iron, copper, or any one or more selected from nickel or iron or copper surface-treated with nickel.

  Further, in the welded portion, a central opening, a plurality of cutout grooves around the opening, and a projection for resistance welding with the battery terminal disposed between the cutout grooves, The notch groove is flexible so that it fits easily and reliably to the battery terminal, and the reactive current during welding can be suppressed by the notch groove, and the notch groove is securely contacted and welded. Therefore, it is preferable that a highly reliable welding can be realized.

  In addition, the projection may be a dot in the shape of a circle in plan view. However, if the projection is formed in a linear shape or a curved line shape such as an arc shape, the welding area can be increased and the connection resistance can be reduced and the welding strength can be increased. Can be secured.

  According to the inter-battery connection device of the present invention, since the thickness of the intermediate portion is thick, the inter-battery connection resistance can be reduced, and it is suitable for charge / discharge characteristics of a large current, and the thickness of the welded portions at both ends is thin Therefore, it is possible to flexibly follow the positional deviation of the terminal end face of the battery to be welded, and since the shunt current in resistance welding is small, it provides excellent weldability and strong welding, and is applied to high-power battery packs and battery modules. In this way, a great effect is exhibited.

  Hereinafter, each embodiment of the inter-battery connection device of the present invention will be described with reference to FIGS.

(First embodiment)
First, a first embodiment will be described with reference to FIGS. FIG. 1 is a front view showing a battery pack connection step. The battery pack 10 is an inter-battery connection device that connects two batteries 1a and 1b and terminals of different polarities of these batteries 1a and 1b, specifically, between the battery case bottom 2 and the battery sealing plate 3. And the inter-battery connection plate 11. The inter-battery connection plate 11 includes a welded portion 4 and 4 at both ends and an intermediate portion 5 that connects between the welded portions 4 and 4 at both ends. The intermediate portion 5 is formed thicker than the welded portion 4. ing. In the example of FIG. 1, the inter-battery connection plate 11 is constituted by a substrate portion 6 extending between the welded portions 4 and 4 at both ends and an intermediate metal plate 7 joined to the intermediate portion 5.

  Projections 8 protrude from the welded portions 4 at both ends, and the welded portions 4 at both ends are resistance welded to the battery case bottom surface 2 and the battery sealing plate 3 through the projections 8, respectively.

  By increasing the thickness of the intermediate portion 5 of the inter-battery connection plate 11 in this way, the electrical resistance of the inter-battery connection plate 11 can be reduced without increasing the welded portion 4. As a result, the welded part 4 is less welded during resistance welding, and can flexibly follow deformation due to heat and pressure associated with welding, and thus has excellent weldability.

  2A to 2C show some specific examples of the inter-battery connection plate 11 in which the intermediate part 5 is configured by joining the intermediate metal plate 7 to the substrate part 6. In the inter-battery connection plate 11 a shown in FIG. 2A, a single intermediate metal plate 7 a is joined to the intermediate portion of the substrate portion 6 to constitute the intermediate portion 5. The inter-battery connection plate 11 b shown in FIG. 2B is configured by joining an intermediate metal plate 7 b formed by laminating and joining a plurality of thin metal plates to the intermediate portion of the substrate portion 6. In these inter-battery connection plates 11a and 11b, a method of joining the substrate portion 6 in the intermediate portion 5 and the thin metal plates forming the intermediate metal plates 7a and 7b or the intermediate metal plate 7b is resistance welding or ultrasonic welding. Laser welding or friction stir welding may be used.

  In these inter-battery connection plates 11a and 11b, the metal plates 7a and 7b are joined to the intermediate portion of the substrate portion 6, respectively, thereby reducing energization resistance without impairing the weldability at the welded portions 4 at both ends of the substrate portion 6. be able to. Further, in the inter-battery connection plate 11b, the intermediate metal plate 7b is formed by laminating thin metal plates, so that the surface area as a whole increases, and the effect of easily radiating heat and reducing electrical resistance is great. And since it has flexibility, it is easy to follow the position shift of the end surfaces of the two batteries 1a and 1b to be connected.

  The inter-battery connection plate 11 c shown in FIG. 2C is configured by disposing an intermediate metal plate 7 c at the intermediate portion of the substrate portion 6 and caulking and fixing the intermediate metal plate 7 c with the claw-like portions 9. The claw-like portion 9 is formed to extend from the side edge of the substrate portion 6 of the inter-battery connection plate 11c. Instead of caulking and fixing by the claw-like portion 9, the intermediate metal plate 7c may be fixed by a binding band to form an inter-battery connection plate (not shown).

  The material of the substrate portion 6 and the intermediate metal plate 7 (7a, 7b, 7c) of each inter-battery connection plate 11 shown in FIG. 2 may be the same material or different materials. In addition, these materials are preferably nickel, iron, copper, or a material in which the surface of iron or copper is coated with nickel. The surface coating on iron or copper can be formed by clad processing or plating.

  The inter-battery connection plate 11d shown in FIG. 3 is obtained by forming a welded portion 4 thinner than the intermediate portion 5 by forging or cutting a metal plate having a predetermined thickness. The inter-battery connection plate 11d has almost the same effect as each structural example shown in FIG. 2, and can be easily manufactured, so that the cost can be reduced.

  The material of the inter-battery connection plate 11d shown in FIG. 3 is preferably nickel, iron, or copper. When copper or iron is used, corrosion resistance and weldability can be improved by nickel plating after processing.

  FIG. 4 is a front view showing a process of connecting two batteries 1a and 1b arranged in parallel by resistance welding using the inter-battery connection plate 11a in the present embodiment. As shown by a virtual line, an insulating ring 20 is fitted in advance to the positive electrode terminal of the battery 1b to prevent the sealing plate 3 and the battery case from being short-circuited by the inter-battery connection plate 11a. Further, by forming the projection 8 on the welding surface of the welded portion 4, the strength and reliability of welding are improved. In resistance welding, a series of welding is performed by bringing a pair of welding electrodes 12 into contact with projections 8 on both sides of a notch groove 13 (see FIGS. 2 and 3) formed to suppress a welding reactive current. good. When welding the battery case bottom surface 2 of the battery 1 a and the welded portion 4, the battery is passed through an opening 14 (see FIGS. 2 and 3) formed on one side of the welding electrode 12 at the center of the welded portion 4. Welding may be performed by indirect welding in which the case bottom 2 is brought into contact and the other is brought into contact with the projection 8.

  FIG. 5 shows an example in which the connection by the inter-battery connection plate 11a shown in FIG. 4 is applied to the connection between the two battery modules 15a and 15b.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the example in which the inter-battery connection device is configured by the single-cell inter-battery connection plate 11 has been described. However, in the present embodiment, the connection plate 16 and the connection ring 18 are joined to each other. Is configured. In the description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 6 (a), 6 (b), and 6 (c), the inter-battery connection device of the present embodiment has a thin welded portion 4 for the sealing plate 3 of the battery 1b at one end and a plate thickness. A connecting plate 16 having a thick intermediate portion 5 and further having a connecting piece portion 17 extending from the intermediate portion 5 toward the other end with the same thickness, and a welded portion 4 to the battery case bottom 2a of the battery 1a. It is comprised by the thin connection ring 18 which comprises. The connection ring 18 is formed of a substantially circular dish-shaped member that fits on the outer periphery of the battery case bottom 2a of the battery 1a, and is resistance-welded to the outer peripheral surface of the battery case bottom 2a at a plurality of welding locations 19 arranged on the peripheral side wall. To be fixed. Reference numeral 23 denotes a notch groove that suppresses a welding reactive current formed between the welding locations 19 and 19. A pair of holding blade pieces 21 for holding the connection piece portion 17 are cut and raised on the end wall of the connection ring 18 in an L-shaped cross section, and the connection piece portion 17 is formed with the end wall of the connection ring 18 and the holding blade piece. It is comprised so that it may be hold | maintained by inserting between 21. Further, the holding blade piece 21 and the connecting piece portion 17 are welded at the welding point 22 from the holding blade piece 21 side and are integrally connected.

  As shown in FIG. 7, the connecting plate 16 is formed with a welded portion 4 that protrudes in a thin state so as to contact the sealing plate 3, and the welded portion 4 has strength and reliability of welding with the sealing plate 3. In order to improve performance, a plurality of arc-shaped projections 24 are formed around the opening 14 with a notch groove 13 interposed therebetween. By welding in a linear manner through such an arc-shaped projection 24, the welding area becomes larger than in the case of welding in a spot shape through a circular projection 8, so that the connection resistance can be reduced and the welding strength can be increased. Can be secured.

  In addition, a pair of connecting piece portions 17 of the connecting plate 16 are extended from both sides of the intermediate portion 5 so as to be spaced apart from each other. Correspondingly, the holding blade pieces 21 of the connecting ring 18 connect these connecting piece portions 17 to each other. In order to hold from the inside, it is cut and raised outward in a L-shaped cross section.

  In the connection process in the inter-battery connection apparatus having the above configuration, as shown in FIG. 8, a connection ring 18 is fixed in advance to the battery case bottom 2a of the battery 1b among the batteries 1a and 1b to be connected to each other by welding. At the time of connection, the welding portion 4 of the connection plate 16 is welded to the sealing plate 3 of the battery 1 a to fix the connection plate 16 to the battery 1 a, and then the connection plate 16 is connected to the holding blade piece 21 of the connection ring 18. By inserting the piece 17, the connection piece 17 is brought into contact with the connection ring 18 and is held from above by the holding blade piece 21, and the distance between the batteries 1 a and 1 b and the position in the axial direction. In this state, as shown in FIG. 6, resistance welding is performed on the welded portion 22, so that the batteries 1 a and 1 b are connected and fixed to each other, and the sealing plate 3 and the battery case bottom 2 a are small in electrical resistance. Electrically connected with That.

  According to the present embodiment, the connection ring 18 is fitted to the outer periphery of the battery case bottom 2a of the battery 1b and welded to the outer peripheral side surface, and the side surface of the battery case bottom 2a is deformed compared to the bottom surface. Therefore, welding quality is stable, and highly reliable welding can be performed without fear of making a hole in the battery case. Further, since welding is performed from the holding blade piece 21 side of the thin connecting ring 18 to the connecting piece portion 17 of the thick connecting plate 16, it can be stably and highly reliably welded, and at least the battery There is no possibility that the case will be perforated, and it is possible to flexibly follow the displacement of the end faces of the batteries 1a and 1b that are connected to each other by deformation of the holding blade piece 21, and between the upper surface of the connection ring 18 and the holding blade piece 21. Adjustment of the amount of insertion of the connecting piece 17 also increases the degree of freedom in the inter-axis distance between the batteries 1a and 1b.

  In the illustrated connection plate 16 shown in FIGS. 6 to 8, a pair of connection piece portions 17 are extended from both sides of the intermediate portion 5 toward the other end, and a pair of holding blade pieces 21 are provided on the connection ring 18 side. 9 and FIG. 10, as shown in FIGS. 9 and 10, a single connection piece 17a is extended from the intermediate portion 5 to the other end of the connection plate 16 to have the same width and connected. A pair of holding blade pieces 21a may be formed inward on the ring 18 side, and both side portions of the connection piece portion 17a may be held from the outside by the pair of holding blade pieces 21a. In this example, the circular projection 8 is formed in the welded portion 4 as in the first embodiment, but it is needless to say that the arc-shaped projection 24 may be formed.

(Example)
As an example of the present invention, batteries 1a and 1b were connected using an inter-battery connection plate 11a shown in FIG. The inter-battery connection plate 11a is joined to an intermediate portion of a substrate portion 6 made of a nickel plate having a thickness of 0.4 mm by an iron intermediate metal plate 7a having a nickel plating thickness of 2.6 mm (resistance welding, ultrasonic wave). Any of welding, friction stir welding, and laser welding may be used), and the intermediate portion 5 was formed to a total thickness of 3.0 mm.

  In the connection process using the inter-battery connection plate 11a, as shown in FIG. 4, two welding electrodes 8 are applied to the projection 8 of the welded portion 4 of the inter-battery connection plate 11a, and one of the batteries 1a has a diameter of 32 mm. It joined to the case bottom face 2, and the welding part 4 of the other end was welded similarly to the battery sealing board 3 of the other battery 1b, and the battery pack using the connection board 11a between batteries was produced.

(Conventional example)
For comparison with the above example, a battery pack (conventional example A) in which an inter-battery connection plate made of a nickel plate having a thickness of 0.4 mm without joining an intermediate metal plate and a nickel plating having a thickness of 0.6 mm are applied. A battery pack (conventional example B) was prepared by welding the iron plate inter-battery connection plate.

  For these three battery packs of Examples and Conventional Examples A and B, the connection plate resistance value and the welding current value when the inter-battery connection plate was welded to the battery case and the sealing plate were measured and compared. .

  As shown in Table 1, it can be seen that the connection plate resistance value of the embodiment which is a battery pack using the inter-battery connection plate 11a in which the iron plated with 2.6 mm nickel is joined to the intermediate portion 5 is the lowest. This is because the specific resistance of the intermediate metal plate 7a is low, and the path resistance between the two batteries decreases as the plate thickness of the inter-battery connection plate increases. As a result, the electrical resistance of the connection plate decreases. High rate discharge becomes possible.

  Moreover, even if the total thickness of the inter-battery connection plate 11a of the battery pack of the embodiment becomes thicker than the inter-battery connection plate 34 of the battery packs of the conventional examples A and B, the battery case bottom surface 2 and the sealing plate 3 are welded. The welding current value required for this is the same as or smaller than the conventional value.

  Furthermore, the battery packs of the examples have less heat generated from the inter-battery connection plate 11a due to the improvement in heat dissipation due to the increase in the surface area of the inter-battery connection plate 11a, the weldability is excellent, and stable welding can be performed. Increase in connection resistance due to peeling of the portion 4, defective height dimensions of the batteries 1 a and 1 b due to deformation of the battery case bottom 2 and the sealing plate 3, and occurrence of defective hole formation in the case due to welding with excessive energy are suppressed. It is possible.

  The inter-battery connection device of the present invention exhibits a great effect in the connection between a battery case and a battery sealing plate in a battery pack and a battery module that require large load characteristics because charging and discharging are performed with a large current, and with an electric assist. The present invention can be suitably applied to battery packs and battery modules applied to driving power sources for bicycles, lawn mowers, and electric vehicles.

The front view which shows the connection process in 1st Embodiment of the connection apparatus between batteries of this invention. The perspective view which shows the various specific structural examples of the connection board between batteries in the same embodiment. The perspective view which shows another structural example of the connection board between batteries in the same embodiment. The front view which shows the welding process of the connection board between batteries in the same embodiment. The perspective view of the battery module connected by the embodiment. The 2nd Embodiment of the connection apparatus between batteries of this invention is shown, (a) is a perspective view which shows a connection state, (b) is a top view of the principal part, (c) is an end elevation. The perspective view of the connection board in the embodiment. The perspective view which shows the connection process of the connection board and connection ring in the embodiment. The perspective view which shows the connection state of the modification structural example in the embodiment. The perspective view which shows the connection process of the connection board and connection ring in the modification structural example. The perspective view which shows the connection state by the battery connection apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Battery 2 Battery case bottom 3 Sealing plate 4 Welding part 5 Intermediate part 6 Substrate part 7 (7a, 7b, 7c) Intermediate metal plate 8 Projection 9 Claw-like part 11 (11a, 11b, 11c, 11d) Connection between batteries Board (battery connection device)
16 Connection plate 17, 17a Connection piece 18 Connection ring 19 Welding location 21, 21a Connection blade 22 Welding location 24 Arc-shaped projection

Claims (9)

  An inter-battery connecting device for connecting two battery terminals arranged so that the axial directions thereof are parallel to each other, wherein the welded parts at both ends welded to the terminals of the battery are connected between the welded parts at both ends. An inter-battery connection device comprising an intermediate part to be connected, wherein the intermediate part is formed thicker than the welded part.   Join one or more metal plates of the same or different material, and join the substrate part with welds at both ends and the intermediate part of one or more metal plates of the same or different material. The inter-battery connection device according to claim 1, wherein   One or more metal plates in the middle part are crimped by crimping with a claw-like part extending from both sides of the middle part of the cable tie or the substrate part, or by resistance welding, ultrasonic welding, laser welding or friction stir welding 3. The inter-battery connection device according to claim 2, wherein the inter-battery connection device is joined by one means selected from welding.   2. The inter-battery connection device according to claim 1, wherein a welded portion is formed thinner than the intermediate portion by forging or cutting a metal plate having a predetermined thickness.   A connection plate having a connection piece at one end and a connection piece extending from the intermediate portion toward the other end with substantially the same thickness, and a weld portion to the battery case bottom of the other battery A connecting ring that constitutes the connecting ring, abutting the connecting piece on the connecting ring, holding the connecting wing piece from above with a holding wing piece provided on the connecting ring, and holding the holding wing piece on the connecting piece portion The inter-battery connection device according to claim 1, wherein the inter-battery connection device is bonded to the battery.   6. The inter-battery connection device according to claim 5, wherein the connection ring is fitted to the outer periphery of the bottom of the battery case and welded to the outer peripheral side surface.   7. It consists of any 1 type or multiple types of materials selected from nickel, iron, copper, or the surface which processed the surface of nickel on at least one side of iron or copper. Battery connection device.   The welded portion is formed with an opening at the center, a plurality of notched grooves around the opening, and a projection for resistance welding with the battery terminals disposed between the notched grooves. The inter-battery connection device according to any one of claims 1 to 7. 9. The inter-battery connection device according to claim 8, wherein the projection is formed in a linear shape.

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