JP5700008B2 - Electrode contact for laminate type secondary battery - Google Patents

Description

  The present invention relates to an electrode part contactor used for inspection of a laminate type secondary battery.

As a small and lightweight secondary battery, a laminate type secondary battery such as a laminate type lithium ion battery is widely used.
In the manufacturing process and the performance inspection process of the laminate type secondary battery, the initial charging process, the charge and discharge inspection, the OCV inspection, the DC-IR inspection, etc. are generally performed. The electrode tab of the laminate type secondary battery In connection with the circuit for each process, a laminate-type secondary battery electrode contact (which may be simply referred to as “contact” in the following) that can be used repeatedly is used.
Many of the laminated type secondary batteries use aluminum for the positive electrode tab and nickel-plated copper plate for the negative electrode tab. Therefore, there is a problem that poor contact with the contact tends to occur.

As a contactor, the electrode tab is clamped by a pressure contact terminal attached to a pair of movable pieces (clips) pivotally supported by a pedestal for the purpose of contacting the electrode tab with a stable contact force. (For example, refer to Patent Document 1).
In the contact of Patent Document 1, when the pair of movable pieces are rotated and the electrode tab is sandwiched between the press contact terminals, the contact angle between the press contact surface of the press contact terminal and the electrode tab is displaced and rubbed. Although wiping operation is performed to remove dirt, this wiping operation is not sufficient particularly for electrode tabs that form an insulating oxide film such as aluminum, and the pressure contact terminals are brought into contact with the electrode tabs with a stable contact force. Even so, the contact between the press contact terminal and the electrode tab cannot be sufficiently stabilized.

For this reason, the contact 11 as shown in the perspective view of FIG.
The contactor 11 holds the contact portions 12 and 12 that are a pair of conductors by holding portions 13 and 13 that are a pair of insulators that can rotate around a rotation center axis 14. , 12 are bent inwardly, and the opposing surfaces, which are the edges of the tips of the contact portions 12, 12, are cut into a cut shape (triangular wave-shaped irregularities) 12A, 12A.
According to such a contact 11, as shown in the enlarged cross-sectional view of the main part in FIG. 7B, the acute angle of the mountain cut shapes 12A and 12A with the electrode tab 9 held between the contact parts 12 and 12 The insulating oxide films 10 and 10 can be efficiently broken by the protrusions protruding to the top.

JP 2002-298929 A

However, as in the conventional contactor 11 shown in FIG. 7A, it is effective to break the insulating oxide films 10 and 10 by making the tips of the contact parts 12 and 12 into the cut-off shapes 12A and 12A. However, as shown in FIG. 7 (b), the contact width A between the tip of the chopped cut shape 12A and the electrode tab 9 is small, that is, the contact area is reduced. As shown in FIG. The contact mark (area) becomes smaller.
Therefore, there is a disadvantage that the contact resistance becomes high, and there is a problem that the electrode tab 9 generates abnormal heat due to Joule heat at a high current.
Here, as shown in the schematic configuration diagram of FIG. 9, the contact resistance, the contact temperature, and the like are measured by a DC constant current power source, a voltmeter V, a thermometer T1 for measuring ambient temperature, and a contact portion 12 (electrode tab 9). ) And the like, and a measurement result of 4 to 10 mΩ was obtained as the contact resistance.
For example, when the contact resistance is 4 mΩ and a current of 30 A is passed, the power P is P = R · I ² = 3.6 W, and as shown in the actual measurement result of FIG. Temperature) rose nearly 50 ° C.

  Therefore, in view of the above-described situation, the present invention intends to solve the problem of contact failure by providing a contact portion that can stably contact even an electrode tab that forms an insulating oxide film such as aluminum. An object of the present invention is to provide an electrode part contact for a laminate type secondary battery that can suppress the contact resistance and reduce the heat generation (temperature rise) of the electrode tab while preventing it.

  The inventors of the present application can efficiently break the insulating oxide film when the contact is brought into contact with the electrode tab of a laminate type secondary battery that makes an insulating oxide film such as aluminum in particular. (1) In order to solve both of the trade-off problems that the contact resistance does not increase, the contact parts are examined by examining various structures of the contactor and forming a pair of contact parts in a leaf spring shape. The idea was to break the insulating oxide film efficiently without cutting the tip of the ridge into a cut shape. And based on such an idea, simulation, trial manufacture evaluation, etc. were performed, and the present invention was completed by advancing the embodiment.

That is, the electrode member contact for a laminate type secondary battery according to the present invention includes a contact portion that is a pair of conductors that are in contact with the electrode tab of the laminate type secondary battery, in order to solve the above problem. An electrode part contact for a laminate type secondary battery that is held by a holding part that is a pair of insulators that can be rotated about an axis, and the pair of the contact parts are at least the tips of the holding parts A portion protruding from the plate spring is formed in a rectangular plate shape, a corner portion of the contact portion away from the rotation center axis is a straight line that is one side of the rectangle, and a pair of the corners When the holding portions are rotated about the rotation center axis and the tip of the contact portion is closed, the linear corner portion is in line contact with the surface of the electrode tab, and the pair When the electrode tab is clamped by the contact portion, the contact portion Becomes elastically deformed state, the linear corner with rubbing the surface in line contact, characterized in that said corner portion bites into the surface.

According to such a configuration, the tip of the contact portion that comes into contact with the surface of the electrode tab is not a chopped cut shape (triangular wave-shaped uneven shape), but a linear corner portion that is one side of a rectangle. Since the contact area is not reduced as in the configuration in which the tip of the electrode is cut into a cut shape, the contact resistance does not increase, so that the electrode tab does not generate abnormal heat even at a high current.
In addition, the pair of contact portions is a leaf spring in which at least a portion protruding from the tip of the holding portion is a rectangular plate shape, and in a state where the electrode tab is sandwiched between the pair of contact portions, the contact is a leaf spring. The surface of the electrode tab is rubbed against the surface of the electrode tab, which is elastically deformed, and the linear corner at the tip of the contact portion is in line contact, and the corner of the contact portion bites into the surface of the electrode tab. Since the oxide film can be efficiently broken and the insulating oxide film can be removed to obtain reliable contact, the contact portion of the contactor stably contacts the electrode tab, thereby preventing contact failure. it can.

As described above, according to the electrode member contact for a laminate type secondary battery according to the present invention, the pair of contact portions is a leaf spring in which at least a portion protruding from the tip of the holding portion is formed in a rectangular plate shape, The corner of the tip is a straight line that is one side of the rectangle, and when the straight corner is brought into line contact with the surface of the electrode tab and further pressed from this state, the contact part that is a leaf spring is elastic. The deformation causes the corners to rub against the surface and bite into the surface, so that both (1) the insulating oxide film can be efficiently broken and (2) the contact resistance does not increase, It is possible to solve the above problem, and it is possible to obtain a highly reliable and reusable laminate type secondary battery electrode contactor.

The external appearance of the electrode part contactor for laminate type secondary batteries which concerns on embodiment of this invention is shown, (a) is the perspective view seen from the contact part side diagonally upper direction, (b) is with respect to a rotation center axis | shaft It is the perspective view seen from the diagonally upper side opposite the contact part. It is the top view of a contactor, and the principal part enlarged plan view of a contact part. (A) is explanatory drawing of the force and deflection angle which act around the corner | angular part of a contact part, (b) is explanatory drawing of the deflection | deviation of a contact part. It is a figure which shows the contact trace of the electrode tab surface by a contactor. It is a figure which shows the measurement results, such as contact resistance and contact temperature. It is a perspective view which shows an example of the apparatus using the electrode part contactor for laminate type secondary batteries which concerns on embodiment of this invention, and description of one part contactor is abbreviate | omitted for convenience of description. (A) is a perspective view of the electrode part contactor for the conventional laminated type secondary batteries, (b) is a principal part expanded sectional view which shows the contact state of an electrode tab and a contact part. It is a figure which shows the contact trace of the electrode tab surface by a contactor. It is a schematic block diagram of the evaluation circuit for measuring contact resistance. It is a figure which shows the measurement results, such as contact resistance and contact temperature.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. It is a waste.

As shown in the perspective view of FIG. 1 and the plan view of FIG. 2, the electrode part contact 1 for a laminate type secondary battery according to the embodiment of the present invention is in contact with the electrode tab 9 of the laminate type secondary battery. The contact portions 2 and 2 that are a pair of conductors are held by holding portions 3 and 3 that are a pair of insulators that can rotate around the rotation center axis 4, and the pair of contact portions 2 and 2. Is a leaf spring, and at least the portions of the contact portions 2 and 2 protruding from the tips (free ends) of the holding portions 3 and 3 have a rectangular plate shape, and the corner portions 2B and 2B of the tips (free ends) 2A and 2A, 2B is a straight line that is one side of a rectangle, and the base ends of the contact portions 2 and 2 are fixed to the holding portions 3 and 3.
Further, since the holding portions 3 and 3 are rotatable around the rotation center axis 4, the contact portions 2 and 2 are also rotated as the holding portions 3 and 3 are rotated, and the tips of the holding portions 3 and 3 are rotated. The front ends 2A and 2A of the contact portions 2 and 2 away from the rotation center shaft 4 projecting from the front and rear are opened and closed, and the inner corner portions 2B and 2B of the front ends 2A and 2A are opposed to each other.

Furthermore, a pair of hooking portions 5 and 5 for opening and closing operations are provided on the opposite sides of the holding portions 3 and 3 to the contact portions 2 and 2 with respect to the rotation center shaft 4.
In the apparatus (opening / closing mechanism) using the laminated type secondary battery electrode contacts 1, 1,... Shown in the perspective view of FIG. 6, the upper plate 6 and the lower plate 7 driven by the actuator 8 are in opposite directions. The one hooking part 5 of the pair of hooking parts 5 and 5 of the contact 1 (see FIG. 1B) is engaged with the upper plate 6 and the other hooking part 5 is engaged. Is engaged with the lower plate 7, the actuator 8 is operated to drive the upper plate 6 and the lower plate 7, so that the upper plate 6 and the lower plate 7 are moved in the opposite directions, and a pair of contacts 1. Since the space | interval of the hook parts 5 and 5 spreads, the front-end | tips 2A and 2A of the contact parts 2 and 2 can be closed like the arrows B and B of Fig.2 (a).

  Here, the material of the contact portion 2, which is a flat conductor as a leaf spring, is preferably a metal having a low volume resistivity and a high yield strength (proportional limit) (for example, phosphor bronze for a spring). Further, the material of the holding part 3 which is an insulator for holding the contact part 2 is not only insulative but also a synthetic material having relatively high rigidity and strength in order to securely hold the base end of the contact part 2 which is a leaf spring. A resin (for example, polyphenylene oxide (PPO) or polyphenylene sulfide (PPS)) is desirable.

  2 and 3B, the deflection of the contact portion 2 which is a leaf spring (deflection at the position of X from the tip 2A) δ uses a general elastic curve equation. Thus, it can be obtained by the following equation (1).

δ = (F / (EI) ) · (X 3/6-XL 2/2 + L 3/3) (1)

  Here, E is a longitudinal elastic modulus of the contact portion 2, I is a cross-sectional secondary moment of the contact portion 2, and F is a load applied to the tip 2A of the contact portion 2 (restoring force due to elastic deformation of the contact portion 2). .

  Further, the deflection angle θ of the tip 2A of the contact portion 2 shown in the explanatory diagram of FIG. 3A can be obtained by the following equation (2) using a general elastic curve equation.

θ = (F / (2EI)) · (X ² −L ² ) (2)

  Furthermore, since the contact part 2 which is a leaf | plate spring must be used in the range which does not raise | generate a plastic deformation, the maximum value (sigma) max of bending stress needs to satisfy following Formula (3).

                       σmax = (Mmax / Z) <σb (3)

  Here, Mmax is the maximum value of the bending moment applied to the contact portion 2, Z is the section modulus of the contact portion 2, and σb is the yield strength (proportional limit) of the material used.

The pair of hooks 5 and 5 of the contact 1 are operated by the opening / closing mechanism, the holding parts 3 and 3 are rotated around the rotation center axis 4 and the tips 2A and 2A of the contact parts 2 and 2 are moved in the closing direction. Then, the linear corners 2B and 2B of the contact portions 2 and 2 are in line contact with the surface of the electrode tab 9, as indicated by a two-dot chain line in the enlarged plan view of the main part in FIG.
When the holding parts 3 and 3 are further rotated from this state, the contact parts 2 and 2 which are leaf springs are elastically deformed as shown by the solid lines in the enlarged plan view of the main part in FIG. 2B rubs the surface of the electrode tab 9 in line contact , and the corners 2B and 2B bite into the surface of the electrode tab 9.
Here, the length (movement distance) C in which the corner portions 2B and 2B of the contact portions 2 and 2 of the contact 1 according to the embodiment of the present invention rub against the surface of the electrode tab 9 is about 0.2 mm.

  Further, as shown in FIG. 3A, the force FT that the corners 2B and 2B try to rub the surface of the electrode tab 9 and the force FN that the corners 2B and 2B bite into the surface of the electrode tab 9 are From the state in contact with the electrode tab 9 to the final state, it changes from moment to moment depending on the load applied to the tip 2A of the contact portion 2 (restoring force due to elastic deformation of the contact portion 2) F and the deflection angle θ of equation (2). That is, FT = Fsinθ and FN = Fcosθ.

In the contact 1 according to the present invention, when the electrode tab 9 is sandwiched between the pair of contact portions 2 and 2, the contact portions 2 and 2 are elastically deformed, and the linear corner portions 2B and 2B are in line contact. While the surface of the electrode tab 9 is rubbed and the corners 2B and 2B are designed to bite into the surface of the electrode tab, the design of the contact 1 (the contact portions 2 and 2 and the holding portions 3 and 3 etc.) ) And the maximum bending stress σmax in equation (3) are taken into account and the parameters of the material of the contact portion 2 and the shapes and sizes of the contact portion 2 and the holding portion 3 are used as parameters. 1) Deflection δ, Deflection angle θ in Equation (2), Load applied to tip 2A of contact portion 2 (restoring force due to elastic deformation of contact portion 2) F, Corner portions 2B and 2B rub the surface of electrode tab 9 Do not seek the force FT to try and the force FN that the corners 2B, 2B bite into the surface of the electrode tab 9. Et al., Can be carried out on the basis of a comprehensive judgment.

According to the configuration of the electrode part contact 1 for a laminate type secondary battery according to the embodiment of the present invention as described above, the tips of the contact parts 2 and 2 that are in contact with the surface of the electrode tab 9 are cut into a cut shape. Since it is not the (triangular wave-shaped uneven shape) but the straight corners 2B, 2B, the contact area does not become small as in the configuration in which the tip of the contact part has a mountain cut shape, and the contact resistance does not increase. Therefore, the electrode tab does not generate abnormal heat even at a high current.
For example, compared with FIG. 8 which is the prior art, the contact mark (area) on the electrode tab surface is increased as shown in FIG. From this, the contact resistance can be reduced to about 0.6 mΩ. Therefore, as shown in the actual measurement result of FIG. 5 when a current of 30 A is passed, the contact temperature (temperature of the contact portion 2) also increases by 25. It could be suppressed to about ℃.

Further, the pair of contact portions 2 and 2 are leaf springs, and in a state where the electrode tab 9 is sandwiched between the pair of contact portions 2 and 2, the contact portions 2 and 2 which are leaf springs are elastically deformed, and FIG. ) Rubs the surface of the electrode tab 9 where the linear corners 2B and 2B at the tips of the contact portions 2 and 2 are in line contact , and the corners 2B and 2B are rubbed by the force FN of FIG. Since it cuts into the surface of the electrode tab 9, the insulating oxide film on the surface of the electrode tab 9 can be efficiently broken, and the insulating oxide film can be removed to obtain a reliable contact. Since contact with 9 is stable, contact failure can be prevented.

C Length of contact part corner electrode tab surface (moving distance)
F Restoring force due to elastic deformation of the contact portion FN Force applied perpendicularly to the electrode tab FT Force for rubbing the electrode tab surface 1 Contact portion 2A of the laminate type secondary battery of the present invention Contact portion 2A Tip 2B Corner portion 3 Holding Part 4 Rotation center shaft 5 Hook for opening / closing 6 Upper plate 7 Lower plate 8 Actuator 9 Electrode tab 10 Insulating oxide film 11 Conventional contact part for laminated secondary battery electrode 12 Contact part 12A Mountain cut shape (triangular wave shape) Uneven shape)
13 Holding part 14 Rotation center axis

Claims (1)

A laminate type in which a contact portion that is a pair of conductors that contacts an electrode tab of a laminate type secondary battery is held by a pair of insulators that can be rotated around a rotation center axis. An electrode part contact for a secondary battery,
The pair of contact portions is a leaf spring in which at least a portion protruding from the tip of the holding portion is formed in a rectangular plate shape, and a corner portion at the tip of the contact portion away from the rotation center axis is the rectangle. A pair of the corners facing each other,
When the holding portion rotates around the rotation center axis and the tip of the contact portion is closed, the linear corner portion makes a line contact with the surface of the electrode tab,
When the electrode tab is sandwiched between the pair of contact portions, the contact portion is in an elastically deformed state, the linear corner portions rub against the surface in line contact, and the corner portions are in contact with the surface. An electrode contact for a laminate type secondary battery, characterized by biting.

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