JP6988776B2 - Terminal welding equipment - Google Patents

Description

In the present invention, among the external terminal members having an external terminal connecting portion including a protruding portion and a peripheral portion, the top surface of the protruding portion is brought into contact with one of the electrode terminal portions of the battery, and the external terminal connecting portion is connected to the electrode terminal. The present invention relates to a terminal welding device that performs resistance welding to a portion.

A battery module in which an external terminal connection portion of an external terminal member is welded to a positive or negative electrode terminal portion of a battery is known. For example, Patent Document 1 describes such a battery module. In Patent Document 1, the disk-shaped welded portion (external terminal connection portion) of the bus bar (external terminal member) and one connection terminal portion (electrode terminal portion) of the cylindrical battery are welded by the following method. ing.

That is, the disk-shaped welded portion (external terminal connecting portion) of the bus bar (external terminal member) is formed in a shape in which the central protruding portion protrudes from the peripheral portion surrounding the periphery thereof in an annular shape. Then, of the pair of electrode rods of the terminal welding device, one electrode rod is brought into contact with the connection terminal portion (electrode terminal portion) of the cylindrical battery, and the other electrode rod is brought into contact with the welded portion of the bus bar (external terminal member). It is pressed against (external terminal connection portion), and the top surface of the protruding portion of the welded portion (external terminal connection portion) is brought into contact with the connection terminal portion (electrode terminal portion) of the cylindrical battery (see FIG. 10 of Patent Document 1 and the like). ). Then, a welding current is passed between one electrode rod and the other electrode rod, and the welded portion (external terminal connection portion) of the bus bar (external terminal member) is used as the connection terminal portion (electrode terminal portion) of the cylindrical battery. It is resistance welded.

JP-A-2017-174521

However, due to variations in the shape of the protruding portion of the welded portion (external terminal connection portion) and variations in the pressing force that presses this protruding portion against the connection terminal portion (electrode terminal portion) of the cylindrical battery, the top surface of the protruding portion and the cylinder The contact resistance with the connection terminal (electrode terminal) of the mold battery will be different. Therefore, if resistance welding is performed without considering the magnitude of this contact resistance, welding variation will occur. That is, if this contact resistance is too small, the amount of heat generated at the contact portion between the top surface of the protruding portion and the connection terminal portion (electrode terminal portion) during resistance welding is too small to perform sufficient welding. On the other hand, if this contact resistance is too large, the amount of heat generated at the contact portion during resistance welding is too large, and problems such as melting and breaking of the welded portion may occur.

The present invention has been made in view of the present situation, and prior to resistance welding the external terminal connection portion of the external terminal member to one electrode terminal portion of the battery, the top surface of the protruding portion of the external terminal connection portion. It is an object of the present invention to provide a terminal welding apparatus capable of acquiring a value close to the contact resistance Ra between the battery and the electrode terminal portion of the battery.

One aspect of the present invention for solving the above-mentioned problems is to provide a top surface of the protruding portion of an external terminal member having an external terminal connecting portion in which a central protruding portion protrudes from a peripheral portion that surrounds the periphery thereof in an annular shape. , A terminal welding device that abuts on one of the electrode terminals of a battery and resistance welds the external terminal connection to the electrode terminal, and a first electrode rod that abuts on the electrode terminal and conducts conduction. Second, the peripheral portion of the external terminal connection portion is brought into contact with the peripheral portion to conduct conduction, and the peripheral portion is pressed toward the electrode terminal portion so that the top surface of the protruding portion is brought into contact with the electrode terminal portion. The electrode rod, the first resistance measuring probe that abuts on the electrode terminal portion and conducts, and the protruding portion of the external terminal connection portion that abuts and conducts on the proximal end surface opposite to the top surface. It is a terminal welding apparatus including a two-resistance measuring probe and a resistance detecting unit for detecting an inter-probe resistance value Rk between the first resistance measuring probe and the second resistance measuring probe.

In the terminal welding apparatus described above, in addition to the pair of electrode rods (first electrode rod and second electrode rod) for performing resistance welding, the above-mentioned pair of resistance measuring probes (first resistance measuring probe and second resistance measuring probe) are used. It is equipped with a resistance detection unit. As a result, the resistance value Rk between the probes between the resistance measurement probes can be detected prior to resistance welding the external terminal connection portion of the external terminal member to the electrode terminal portion of the battery, so that the top surface of the protruding portion of the external terminal connection portion can be detected. A value close to the contact resistance Ra between the battery and the electrode terminal portion of the battery can be obtained. In particular, in the terminal welding apparatus described above, the second resistance measuring probe is placed in the immediate vicinity of the contact portion between the top surface of the protrusion of the external terminal connection portion and the electrode terminal portion of the battery, specifically, the top of the protrusion. It is brought into contact with the base end surface on the opposite side of the surface. As a result, the distance from the second resistance measuring probe to the contact portion between the top surface of the protruding portion and the electrode terminal portion can be shortened to reduce the conductor resistance, and the second resistance measuring probe can be stably contacted. As the inter-probe resistance value Rk, a value closer to the contact resistance Ra can be stably obtained.

It is a partial top view of the battery module which concerns on embodiment. FIG. 3 is a partial cross-sectional view taken along the line AA in FIG. 1 of the battery module according to the embodiment. It is explanatory drawing which shows the terminal welding apparatus which concerns on embodiment. It is a flowchart of the resistance welding process using the terminal welding apparatus which concerns on embodiment. It is explanatory drawing which shows the state of detecting the resistance value Rk between probes between a pair of resistance measurement probes which concerns on embodiment. It is explanatory drawing which shows the state that the external terminal connection part of the external terminal member is resistance welded to the negative electrode terminal part of a battery according to an embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a partial top view and a partial cross-sectional view of the battery module 1 according to the present embodiment. In addition, in FIG. 2 and the cylindrical battery 10 of FIGS. 5 and 6 described later, the inside of the battery is not shown, and only the cross section of the battery case 11 is shown. Further, in the following, the vertical direction BH, the horizontal direction CH and the height direction DH of the battery module 1 will be described as the directions shown in FIGS. 1 and 2.

The battery module 1 is an in-vehicle battery module mounted on a vehicle such as a hybrid car, a plug-in hybrid car, or an electric vehicle. The battery module 1 is formed by connecting a plurality of cylindrical batteries (hereinafter, also simply referred to as “batteries”) 10 in parallel to each other, and in addition to the battery 10, a battery holding member (not shown) for holding the battery 10 and a battery. The external terminal member 20 on the negative electrode side that connects the negative electrode terminal portions (electrode terminal portions) 15 of the 10 and the external terminal member on the positive electrode side that connects the positive electrode terminal portions (electrode terminal portion, not shown) of the battery 10 (not shown). ) Etc.

Of these, the battery 10 is a cylindrical (cylindrical) and sealed lithium ion secondary battery (specifically, a 18650 type lithium ion secondary battery). The battery 10 has a cylindrical shape in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are stacked on each other via a pair of band-shaped separators inside a battery case 11 which is cylindrical and made of metal (carbon steel in this embodiment). An electrode body (not shown) wound around the surface is housed together with a non-aqueous electrolyte solution (not shown).
At one end (lower in FIG. 2) of the battery 10 in the axial direction (direction orthogonal to the paper surface in FIG. 1, direction perpendicular to the paper surface, vertical direction in FIG. 2), the battery is connected to the positive electrode plate of the electrode body and conducts. A convex positive electrode terminal portion (not shown) is provided. On the other hand, the bottom surface portion of the battery case 11 located at the other end (upper side in FIG. 2) of the battery 10 in the axial direction is a disk-shaped negative electrode terminal portion 15 connected to the negative electrode plate of the electrode body and conducts inside the battery. Is.

In each of the batteries 10 constituting the battery module 1, the negative electrode terminal portion 15 is directed toward the upper DS in the height direction DH, and the positive electrode terminal portion (not shown) is directed toward the lower DK in the height direction DH, so that they are parallel to each other. Moreover, they are arranged in the same height. The negative electrode terminal portion 15 of each battery 10 is connected (welded) to an external terminal member 20 on the negative electrode side, which will be described later, whereby the negative electrode terminal portions 15 are electrically connected to each other. On the other hand, the positive electrode terminal portion of each battery 10 is connected (welded) to an external terminal member (not shown) on the positive electrode side having substantially the same shape as the external terminal member 20 on the negative electrode side, whereby the positive electrode terminal portions are connected to each other. They are conducting with each other.

Next, the external terminal member 20 on the negative electrode side will be described. The external terminal member 20 is formed by performing a press punching process on a metal plate material (copper plate material in this embodiment), and has a plate shape as a whole. Specifically, the external terminal member 20 has a plate-shaped external terminal main body 21 in which a through hole 21h of a circular hole is provided at a position corresponding to each battery 10. In each through hole 21h of the external terminal main body 21, a disk-shaped external terminal connecting portion 23 and a band-shaped connecting portion 25 connecting the external terminal connecting portion 23 and the external terminal main body 21 are respectively. It is provided.

The external terminal main body 21 is arranged in the upper DS of the negative electrode terminal portion 15 of each battery 10 so as to cover each battery 10 constituting the battery module 1 from the upper DS, and the external terminal member 20 is provided from the upper DS. When viewed in a plan view (see FIG. 1), the negative electrode terminal portion 15 of each battery 10 is located inside the radial direction of each through hole 21h.
The connecting portion 25 extends radially inward from the peripheral edge of the through hole 21h of the external terminal main body portion 21 and diagonally downward to the DK in a band shape, and the external terminal connecting portion 23 is provided at the tip of the connecting portion 25.
The external terminal connection portion 23 has a disk shape, and has a shape in which a central protruding portion 23c projects downward from the peripheral portion 23d that surrounds the periphery thereof in an annular shape. The protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10 are resistance welded as described later, and a welded portion (welding nugget) 30 between the protruding portion 23c and the negative electrode terminal portion 15 is formed. ing.

Next, a method of manufacturing the battery module 1 will be described (see FIGS. 3 to 6). First, a plurality of batteries 10 are prepared, and the negative electrode terminal portion 15 of each battery 10 is directed toward the upper DS and the positive electrode terminal portion is directed toward the lower DK. It is held by a holding member (not shown).

Next, the external terminal member 20 on the negative electrode side is prepared, and the protruding portion 23c of each external terminal connection portion 23 of the external terminal member 20 is resistance welded to the negative electrode terminal portion 15 of each held battery 10. This welding is performed using the terminal welding apparatus 100, which is outlined in FIG. In this terminal welding apparatus 100, a pair of electrode rods (first electrode rod 110 and a second tubular electrode rod 115) and a pair of resistance measuring probes (first resistance measuring probe 120 and second resistance measuring probe) for passing a welding current YA are provided. 125), variable current source 130, constant current source 140, voltmeter 145, personal computer (PC) 150 and the like. In this embodiment, the above-mentioned resistance detection unit 160 is configured by the constant current source 140, the voltmeter 145, and the PC 150.

Of these, the first electrode rod 110 is a solid round rod extending in the height direction DH. The first electrode rod 110 is configured to be movable in the height direction DH by a movement mechanism (not shown), is inserted into the through hole 21h of the external terminal member 20 from the upper DS, and is the tip of the first electrode rod 110. The portion 110s abuts on the negative electrode terminal portion 15 of the battery 10 and conducts conduction.

On the other hand, the second tubular electrode rod 115 is a hollow round rod (cylindrical shape) extending in the height direction DH. The second tubular electrode rod 115 is configured to be movable in the height direction DH by a moving mechanism (not shown), and is inserted into the through hole 21h of the external terminal member 20 from the upper DS to form the second tubular electrode rod 115. The tip end portion 115s of the rod 115 abuts on the peripheral portion 23d of the external terminal connection portion 23 of the external terminal member 20 and forms an annular shape over the entire circumference to conduct conduction. Further, the tip portion 115s of the second tubular electrode rod 115 presses the peripheral portion 23d toward the negative electrode terminal portion 15 side (lower DK) of the battery 10, and the top surface 23cn of the protruding portion 23c of the external terminal connection portion 23. Is in contact with the negative electrode terminal portion 15.

The first electrode rod 110 and the second tubular electrode rod 115 are connected to a variable current source 130 whose current value Ia can be changed. On the other hand, the variable current source 130 is connected to the PC 150, and the current value Ia described later is set in the welding current path EA between the first electrode rod 110 and the second tubular electrode rod 115 according to the instruction from the PC 150. It is configured so that the welding current YA of the above can be passed.

The first resistance measuring probe 120 has a needle shape extending in the height direction DH. The first resistance measuring probe 120 is arranged between the first electrode rod 110 arranged in the lateral CH and the second tubular electrode rod 115 (almost in the middle), and is arranged in the height direction DH by a moving mechanism (not shown). It is configured to be movable. The first resistance measuring probe 120 is inserted into the through hole 21h of the external terminal member 20 from the upper DS, and the tip portion 120s abuts on the negative electrode terminal portion 15 of the battery 10 to conduct conduction.

Further, the second resistance measuring probe 125 has a needle shape extending in the height direction DH similar to the first resistance measuring probe 120. The second resistance measuring probe 125 is coaxially inserted inside the cylindrical second tubular electrode rod 115, and is configured to be movable in the height direction DH by a moving mechanism (not shown). The tip portion 125s of the second resistance measuring probe 125 abuts on the center of the base end surface 23 cm (the surface opposite to the top surface 23cn) of the protruding portion 23c of the external terminal connecting portion 23 and conducts conduction.

The first resistance measuring probe 120 and the second resistance measuring probe 125 are connected to the constant current source 140 and the voltmeter 145. On the other hand, the constant current source 140 and the voltmeter 145 are connected to the PC 150, and the inspection current between the first resistance measuring probe 120 and the second resistance measuring probe 125 from the constant current source 140 according to the instruction from the PC 150. An inspection current YK of a certain magnitude (current value Ik) can be passed through the path EK, and a voltage value Vk between the first resistance measurement probe 120 and the second resistance measurement probe 125 detected by the voltmeter 145. Is configured to be output to the PC 150.

Further, the PC 150 obtains the inter-probe resistance value Rk between the pair of resistance measurement probes 120 and 125 from the current value Ik and the voltage value Vk of the above-mentioned inspection current YK, and the inter-probe resistance value Rk = (voltage value Vk) / (. Calculated by the current value Ik). Since the circuit resistance of the terminal welding apparatus 100 including the first resistance measuring probe 120 and the second resistance measuring probe 125 is extremely small, it is ignored in this embodiment.

Further, in the PC 150, the contact resistance Ra between the top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10 is obtained from the inter-probe resistance value Rk. In the present embodiment, since the conductor resistance Rb of the protruding portion 23c of the external terminal connecting portion 23 forming the inspection current path EK and the negative electrode terminal portion 15 of the battery 10 are substantially constant, predetermined values obtained in advance by experiments are used. The contact resistance Ra is calculated from the contact resistance Ra = the inter-probe resistance value Rk (acquired value) − the conductor resistance Rb (predetermined value).
In this embodiment, since the magnitude of the conductor resistance Rb is only about 1/100 of the average value of the contact resistance Ra, the conductor resistance Rb is ignored and the contact resistance Ra = the resistance value between probes Rk is set between the probes. The resistance value Rk can be used as it is as the contact resistance Ra.

Further, in the PC 150, the contact resistance Ra is set so that the calorific value Q generated at the contact portion between the top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10 in resistance welding becomes a predetermined calorific value. Based on the above, the current value Ia of the welding current YA flowing through the welding current path EA between the pair of electrode rods 110 and 115 is determined. The calorific value Q can be expressed by the following equation, where t is the energization time.
Calorific value Q = (contact resistance Ra) × (current value Ia) ² × (energization time t)
Using predetermined values for the calorific value Q and the energization time t, the current value Ia of the welding current YA is calculated by this equation. Further, the PC 150 controls the variable current source 130 so that the welding current YA having the current value Ia flows in the welding current path EA between the pair of electrode rods 110 and 115.

Next, a resistance welding process of resistance welding the external terminal connection portion 23 of the external terminal member 20 and the negative electrode terminal portion 15 of the battery 10 using this terminal welding device 100 will be described (see FIGS. 3 to 6). First, the external terminal member 20 is aligned and arranged on the upper DS of each battery 10 held by the battery holding member (not shown).

Then, in step S1 (see FIG. 4), the pair of electrode rods 110 and 115 and the pair of resistance measurement probes 120 and 125 of the terminal welding apparatus 100 are moved to the lower DK and brought into contact with each other at predetermined positions. Specifically, the pair of electrode rods 110, 115 and the pair of resistance measuring probes 120, 125 are moved to the lower DK and inserted into the through hole 21h of the external terminal member 20. Of these, the tip portion 110s of the first electrode rod 110 is brought into contact with the negative electrode terminal portion 15 of the battery 10. Further, the tip portion 115s of the second tubular electrode rod 115 is brought into contact with the peripheral portion 23d of the external terminal connection portion 23 of the external terminal member 20 over the entire circumference, and further, the peripheral portion 23d is pressed downward by the DK. , The top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 is brought into contact with the negative electrode terminal portion 15.

Further, the tip portion 120s of the first resistance measuring probe 120 is brought into contact with the negative electrode terminal portion 15 of the battery 10 approximately in the middle of the pair of electrode rods 110 and 115. Further, the tip portion 125s of the second resistance measuring probe 125 inserted into the second tubular electrode rod 115 is brought into contact with the center of the base end surface 23 cm of the protruding portion 23c of the external terminal connecting portion 23.
The above-mentioned contact state of the pair of electrode rods 110 and 115 and the pair of resistance measuring probes 120 and 125 is maintained until the resistance welding is completed.

Then, in step S2, the resistance value Rk between the probes between the pair of resistance measurement probes 120 and 125 is detected. Specifically, an inspection current YK having a constant magnitude (current value Ik) is passed between the constant current source 140 and the pair of resistance measurement probes 120 and 125 (see FIG. 5). On the other hand, the voltage value Vk generated between the pair of resistance measuring probes 120 and 125 is measured by the voltmeter 145 and output to the PC 150. In the PC 150, the inter-probe resistance value Rk is calculated by the inter-probe resistance value Rk = (voltage value Vk) / (current value Ik).

After that, in step S3, the contact resistance Ra between the top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10 is calculated. Specifically, in the PC 150, the contact resistance Ra between the top surface 23cn of the protrusion 23c and the negative electrode terminal portion 15 is calculated from the contact resistance Ra = the inter-probe resistance value Rk-conductor resistance Rb (predetermined value).
Then, in step S4, the current value Ia of the welding current YA is determined. Specifically, in the PC 150, the calorific value Q = (contact resistance) so that the calorific value Q generated at the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 during resistance welding becomes a predetermined calorific value. The current value Ia of the welding current YA is calculated by Ra) × (current value Ia) ^{2 × (energization time t).}

Next, in step S5, resistance welding is performed with the determined current value Ia. Specifically, the PC 150 controls the variable current source 130 to control the welding current path EA between the pair of electrode rods 110 and 115 (the first of the negative electrode terminal portion 15 and the external terminal connection portion 23 in contact with the negative electrode terminal portion 15). A welding current YA having a determined current value Ia is passed through the current path from the portion where the electrode rod 110 abuts to the portion where the second tubular electrode rod 115 abuts, and the external terminal connection portion 23 The protruding portion 23c is resistance-welded to the negative electrode terminal portion 15 of the battery 10 to form a welded portion 30 between the protruding portion 23c and the negative electrode terminal portion 15. By performing resistance welding with the current value Ia of the welding current YA set to an appropriate size in this way, the calorific value Q generated at the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 during resistance welding. Therefore, even if there is a variation in the contact resistance Ra between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15, welding variation can be suppressed.

After the welding is completed, in step S6, the pair of electrode rods 110 and 115 and the pair of resistance measuring probes 120 and 125 are moved to the upper DS and returned to their original positions.
After that, the resistance welding process described above is repeated to resist the negative electrode terminal portions 15 of all the batteries 10 constituting the battery module 1 with the protruding portions 23c of the external terminal connection portions 23 of the external terminal member 20. Weld. As a result, the negative electrode terminal portions 15 of each battery 10 are electrically connected to each other via the external terminal member 20.

Next, an external terminal member (not shown) on the positive electrode side is prepared, and the external terminal member and the positive electrode terminal portion (not shown) of each battery 10 are connected (welded). Thus, the battery module 1 in which the batteries 10 are connected in parallel to each other is completed.

In the terminal welding apparatus 100 described above, in addition to the pair of electrode rods (first electrode rod 110 and the second tubular electrode rod 115) for performing resistance welding, a pair of resistance measuring probes (first resistance measuring probe 120 and second resistance). It includes a measurement probe 125) and a resistance detection unit 160. As a result, the resistance value Rk between the probes between the resistance measuring probes 120 and 125 can be detected prior to resistance welding the external terminal connection portion 23 of the external terminal member 20 to the negative electrode terminal portion 15 of the battery 10, so that the external terminal connection can be performed. It is possible to obtain a value close to the contact resistance Ra between the top surface 23cn of the protruding portion 23c of the portion 23 and the negative electrode terminal portion 15 of the battery 10.

In particular, in the terminal welding apparatus 100, the second resistance measuring probe 125 is placed in the immediate vicinity of the contact portion between the top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10, specifically. It is in contact with the base end surface 23 cm of the protruding portion 23c. As a result, the distance from the tip portion 125s of the second resistance measuring probe 125 to the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 can be shortened to reduce the conductor resistance, and the second resistance measuring probe 125 can be reduced. Since the tip portion 125s of the above can be stably contacted, a value closer to the contact resistance Ra can be stably obtained as the inter-probe resistance value Rk.

Further, in the present embodiment, the first resistance measuring probe 120 is also brought close to the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15. Specifically, the first resistance measuring probe 120 is arranged between the pair of electrode rods 110 and 115. As a result, the distance from the tip portion 120s of the first resistance measuring probe 120 to the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 is short, and the conductor resistance can be reduced. Further, a value close to the contact resistance Ra can be obtained.

Further, in the terminal welding apparatus 100, the calorific value Q generated at the contact portion between the top surface 23cn of the protruding portion 23c of the external terminal connecting portion 23 and the negative electrode terminal portion 15 of the battery 10 in resistance welding is set to a predetermined calorific value. The current value Ia of the welding current YA is changed based on the magnitude of the contact resistance Ra. By performing resistance welding with the current value Ia of the welding current YA set to an appropriate value in this way, the calorific value Q generated at the contact portion between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 during resistance welding can be obtained. Since it can be made constant, even if there is a variation in the contact resistance Ra between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15, welding variation can be suppressed.

Although the present invention has been described above in accordance with the embodiments, it is needless to say that the present invention is not limited to the embodiments and can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, it is exemplified that the terminal welding apparatus 100 of the present invention is used in the step of resistance welding the external terminal connecting portion 23 of the external terminal member 20 to the negative electrode terminal portion 15 of the battery 10, but the present invention is limited to this. No. The terminal welding apparatus 100 may be used in the step of resistance welding the external terminal connection portion of the external terminal member to the positive electrode terminal portion of the battery 10.

Further, in the method of using the terminal welding apparatus 100 of the embodiment, the current value Ia of the welding current YA is determined in step S4 based on the magnitude of the contact resistance Ra obtained in step S3, and this current value Ia is determined in step S5. Welding variation was suppressed by performing resistance welding in, but the present invention is not limited to this. As another method of using the terminal welding apparatus 100, for example, when the contact resistance Ra obtained in step S3 is larger or smaller than the predetermined range, the electrode rods 110 and 115 are once moved to the upper DS, and then the electrode rods 110 and 115 are moved upward DS. The electrode rods 110 and 115 are moved to the lower DK again to re-contact the negative electrode terminal portion 15 and the external terminal connection portion 23. After that, steps S2 and S3 are performed again to obtain the contact resistance Ra, and after confirming that the contact resistance Ra is within a predetermined range, resistance welding can be performed with a predetermined current value determined in advance. By aligning the contact resistance Ra between the top surface 23cn of the protruding portion 23c and the negative electrode terminal portion 15 to the same size in this way, welding variation can be suppressed.

1 Battery module 10 Cylindrical battery (battery)
15 Negative electrode terminal (electrode terminal)
20 External terminal member 23 External terminal connection part 23c Protruding part 23cn Top surface 23cm (protruding part) Base end surface 23d Peripheral part 25 Connecting part 30 Welding part (welding nugget)
100 Terminal welding device 110 1st electrode rod (electrode rod)
115 Second tubular electrode rod (electrode rod)
120 First resistance measurement probe (resistance measurement probe)
125 Second resistance measurement probe (resistance measurement probe)
130 Variable current source 140 Constant current source 145 Voltmeter 150 Personal computer (PC)
160 Resistance detector YK Inspection current YA Welding current Ik (Inspection current) Current value Ia (Welding current) Current value Vk (Between resistance measurement probes) Voltage value EK Inspection current path EA Welding current path Rk (Inspection current path) ) Inter-probe resistance value Ra (the top surface of the protruding part of the external terminal connection part and the negative side terminal part of the battery) Contact resistance Rb (inspection current path) Conductor resistance Q Calorific value t Energization time

Claims (1)

Among the external terminal members having an external terminal connection portion in which the central protruding portion protrudes from the peripheral portion that surrounds the periphery thereof in an annular shape, the top surface of the protruding portion is brought into contact with one of the electrode terminal portions of the battery. A terminal welding device that resistance welds the external terminal connection portion to the electrode terminal portion.
The first electrode rod that abuts on the electrode terminal and conducts conduction,
A second electrode that abuts on the peripheral portion of the external terminal connection portion to conduct conduction, and presses the peripheral portion toward the electrode terminal portion to bring the top surface of the protruding portion into contact with the electrode terminal portion. With a stick,
The first resistance measuring probe that abuts on the electrode terminal and conducts,
Among the protruding portions of the external terminal connecting portion, the second resistance measuring probe that abuts on the proximal end surface on the side opposite to the top surface and conducts conduction, and the
A terminal welding apparatus including a resistance detecting unit for detecting a resistance value Rk between probes between the first resistance measuring probe and the second resistance measuring probe.

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