Patent Description:
The present disclosure relates to an evaluation method.

A connecting portion of a charging connector on the side of facilities and a charging inlet on the side of a vehicle generates heat due to contact resistance when a current passes therethrough. This is particularly remarkable when rapid charging is performed with a large current (for example of <NUM> A). Accordingly, a liquid-cooled type charging connector coolable with liquid such as water is known. For example, <CIT> discloses a liquid-cooled type charging connector comprising a connector connectable to a vehicular inlet and a cooling mechanism capable of cooling the connector with a coolant (or cooling water).

When such a charging connector as disclosed in <CIT> varies in coolability, it affects a period of time taken to charge power. For example, a charging connector with relatively low coolability requires a longer charging time. Therefore, there is a need for appropriately evaluating a charging connector in coolability.

<CIT> discloses a method for evaluating a battery connection to the vehicle by measuring a contact resistance.

<CIT> discloses a method for evaluating a connection state of an electric vehicle through measuring a power loss at the contact portion.

An object of the present disclosure is to provide an evaluation method capable of appropriately evaluating a charging connector in coolability.

In order to address the above issue, an evaluation jig comprising a pair of female terminals connectable to a pair of male terminals of a charging connector may be used to evaluate the charging connector in coolability (or a degree at which temperature increases at a connecting portion of the male terminal and the female terminal).

If the contact resistance between the male terminal and the female terminal when an evaluation is made varies whenever the evaluation is made, the evaluation provides an unreliable result. Therefore, it is desirable that coolability be evaluated while the contact resistance falls within a prescribed range.

Meanwhile, the contact resistance varies depending on the male terminal's measurement point and the female terminal's measurement point. Accordingly, it is preferable to appropriately determine each terminal's measurement point. The present disclosure has been made based on the above point of view.

According to one aspect of the present disclosure, an evaluation method is provided according to Claim <NUM>.

In the present evaluation method, a measurement point for contact resistance between the male terminal and the female terminal is determined, and an appropriate evaluation result of the coolability can be obtained. Specifically, a measurement point on the side of the male terminal is a point of <NUM> from the surface of the bottom wall. At this point, the male terminal has a sufficiently large cross-sectional area, and an effect on the contact resistance is reduced. A measurement point on the side of the female terminal is a point of <NUM> from the surface of the bottom wall. This point is in a vicinity of a boundary of a region affected by a standard applied in designing the charging connector including the male terminal and a region unaffected by the standard. Therefore, designing the female terminal of the charging inlet to achieve contact resistance equal to or less than that measured at this point suppresses the male and female terminals' temperature to be a reference value or smaller when a charging connector that satisfies the standard is used to charge power.

Furthermore, the present evaluation method preferably further comprises, after the step of adjusting, evaluating the coolability based on whether the male terminal and the female terminal have a temperature equal to or lower than <NUM> when a charging current of <NUM> A is supplied to the male terminal and the female terminal for <NUM> minutes.

An Embodiment of the present disclosure will be described with reference to the drawings. In the drawings referred to below, identical or equivalent members are identically denoted.

<FIG> is a diagram schematically showing a vehicle charged. More specifically, <FIG> shows a state in which a charging connector <NUM> connected to a facility <NUM> such as a charging stand via a facility-side electric wire <NUM> is connected to a charging inlet <NUM> of a vehicle <NUM>. Vehicle <NUM> is, for example, an electric vehicle.

Charging connector <NUM> includes a handle (not shown) held by a user, and a male connector <NUM> (see <FIG>) connected to the handle. Charging connector <NUM> is cooled by a coolant. That is, charging connector <NUM> is a so-called liquid-cooled charging connector. An example of the coolant includes cooling water. The coolant flows between facility <NUM> and charging connector <NUM> via facility-side electric wire <NUM>.

Male connector <NUM> is a portion connected to charging inlet <NUM> of vehicle <NUM>. In the present embodiment, male connector <NUM> is based on the ChaoJi standard. As shown in <FIG>, male connector <NUM> includes a pair of male terminals <NUM>, a protective grounding terminal <NUM>, a pair of charging connection confirmation terminals <NUM>, a pair of charging communication terminals <NUM>, and a male casing <NUM>.

Each male terminal <NUM> is formed in a round column. Each male terminal <NUM> is a direct-current power supply terminal. One male terminal <NUM> is a positive electrode and the other male terminal <NUM> is a negative electrode. In the present embodiment, male terminal <NUM> has an outer diameter of <NUM>.

Protective grounding terminal <NUM> is disposed at a position spaced from a center portion between the paired male terminals <NUM> on one side in a direction orthogonal to both an imaginary line connecting the paired male terminals <NUM> (i.e., a lateral direction in <FIG>) and an axis of each male terminals <NUM>, that is, in a vertical direction in <FIG>.

Each charging connection confirmation terminal <NUM> is disposed at a position spaced from one male terminal <NUM> on one side in the orthogonal direction.

Each charging communication terminal <NUM> is disposed at a position spaced from the other male terminal <NUM> on one side in the orthogonal direction and also spaced from each charging connection confirmation terminal <NUM> in a direction parallel to the imaginary line connecting the paired male terminals <NUM>.

Male casing <NUM> holds terminals <NUM> to <NUM>. Male casing <NUM> is made of resin. Male casing <NUM> has a bottom wall <NUM> and a tubular wall <NUM>.

As shown in <FIG>, bottom wall <NUM> holds terminals <NUM> to <NUM> in a state in which terminals <NUM> to <NUM> are inserted therethrough. Bottom wall <NUM> is formed in a flat plate. <FIG> shows a part of female connector <NUM> of charging inlet <NUM>.

Tubular wall <NUM> surrounds male terminal <NUM>. Tubular wall <NUM> erects from a portion of bottom wall <NUM> around male terminal <NUM>. Tubular wall <NUM> has a cylindrical inner peripheral surface. Female connector <NUM> of charging inlet <NUM> is inserted into a space between the inner peripheral surface and an outer peripheral surface of male terminal <NUM>. As shown in <FIG>, tubular wall <NUM> has an inner diameter set to <NUM>.

Charging inlet <NUM> is provided on an external surface of vehicle <NUM>. Charging inlet <NUM> includes female connector <NUM>. Female connector <NUM> has a pair of female terminals <NUM> and a female casing <NUM>.

Each female terminal <NUM> is connectable to male terminal <NUM>. As shown in <FIG>, each female terminal <NUM> has a shape capable of receiving male terminal <NUM>.

Female casing <NUM> holds female terminals <NUM>. Female casing <NUM> is made of resin. As shown in <FIG>, female casing <NUM> has a facing portion <NUM> and a tubular portion <NUM>.

Facing portion <NUM> is a portion facing tubular wall <NUM> in a direction parallel to the axial direction of male terminal <NUM> (i.e., a vertical direction in <FIG>). Facing portion <NUM> has a surface <NUM> formed flat. As shown in <FIG>, a distance between surface <NUM> of facing portion <NUM> and a surface <NUM> of bottom wall <NUM> in the direction parallel to the axial direction of male terminal <NUM> is set to <NUM>.

Tubular portion <NUM> is formed to have a cylindrical shape surrounding female terminal <NUM>. Tubular portion <NUM> is connected to facing portion <NUM> in a posture such that tubular portion <NUM> has its center axis orthogonal to facing portion <NUM>. Tubular portion <NUM> has an outer diameter smaller than the inner diameter of tubular wall <NUM>. In a state with charging connector <NUM> connected to charging inlet <NUM>, tubular portion <NUM> has a distal end portion 27a in contact with surface <NUM> of bottom wall <NUM>. As shown in <FIG>, distal end portion 27a has a length set to <NUM> in a direction parallel to the axial direction of tubular portion <NUM>.

Hereinafter, evaluation jig <NUM> will be described with reference to <FIG>. Evaluation jig <NUM> is a jig capable of evaluating charging connector <NUM> in coolability (or amount of heat generated at a connecting portion of male terminal <NUM> and the female terminal). As shown in <FIG>, evaluation jig <NUM> includes a pair of female terminals <NUM>, an electric wire <NUM>, a pair of crimp terminals <NUM>, and a pair of adjustment members <NUM>.

Each female terminal <NUM> is a terminal connected to male terminal <NUM>. Each female terminal <NUM> includes a plurality of (eight in the present embodiment) contact pieces <NUM>, a support portion <NUM>, and a female-side flange <NUM>.

Each contact piece <NUM> is a portion that can contact male terminal <NUM>. The plurality of contact pieces <NUM> are disposed about and spaced from a center axis A (see <FIG>). Specifically, the plurality of contact pieces <NUM> are disposed about and equally spaced from center axis A. Contact pieces <NUM> are preferably set in number to <NUM> or more and <NUM> or less, particularly preferably <NUM>. Each contact piece <NUM> has a flexible piece <NUM> and a contact portion <NUM>.

Flexible piece <NUM> has a shape extending in a direction parallel to center axis A. Flexible piece <NUM> forms a portion of a cylinder having center axis A. In other words, in the cross sections shown in <FIG> and <FIG>, flexible piece <NUM> has an outer peripheral surface in the form of an arc. A slit <NUM> is provided between any pair of flexible pieces <NUM> adjacent in the circumferential direction of the cylinder.

In the direction parallel to center axis A, flexible piece <NUM> has a length L1 (see <FIG>) set to be equal to or larger than twice the outer diameter of the cylinder. In the present embodiment, the cylinder has an outer diameter ϕ2 (see <FIG>) of <NUM>, and flexible piece <NUM> has length L1 of <NUM>. The cylinder has an inner diameter cp1 (see <FIG>) of <NUM>. That is, flexible piece <NUM> has a thickness of <NUM>.

Flexible piece <NUM> is elastically deformable such that flexible piece <NUM> has a distal end portion 112a displaced in the radial direction of the cylinder relative to a proximal end portion of flexible piece <NUM>, which is a connecting portion of flexible piece <NUM> and support portion <NUM>. That is, the plurality of contact pieces <NUM> (the cylinder) can be reduced in diameter.

As shown in <FIG> and <FIG>, flexible piece <NUM> has a facing surface 112b facing flexible piece <NUM> adjacent to flexible piece <NUM> of interest in the circumferential direction of the cylinder. Any pair of facing surfaces 112b facing each other in the circumferential direction are parallel to each other. The paired facing surfaces 112b are spaced by <NUM>.

Contact portion <NUM> has a shape protruding from the inner surface of flexible piece <NUM> toward center axis A. Contact portion <NUM> is connected to the inner surface of flexible piece <NUM> at a portion away from distal end portion 112a in the direction parallel to center axis A. That is, distal end portion 112a of flexible piece <NUM> configures a protruding portion protruding from contact portion <NUM> in the direction parallel to center axis A away from support portion <NUM> (or downward in <FIG>).

Contact portion <NUM> has a shape curved so as to protrude inward in the radial direction. As shown in <FIG>, flexible piece <NUM> and contact portion <NUM> have a boundary portion <NUM> therebetween in a curve. Contact portion <NUM> has an apex 114c with a curvature smaller than that of boundary portion <NUM>. In the present embodiment, apex 114c has a radius of curvature of <NUM>. Boundary portion <NUM> has a radius of curvature for example of <NUM>.

As shown in <FIG>, a straight line connecting a specific apex 114c and center axis A and a straight line connecting an apex 114c adjacent to the specific apex 114c and center axis A form an angle of <NUM> degrees. A tangent to an end on one side of contact portion <NUM> in the circumferential direction and a tangent to an end on the other side of contact portion <NUM> in the circumferential direction form an angle of <NUM> degrees.

Contact portion <NUM> has a shape extending in the direction parallel to center axis A. As shown in <FIG> and <FIG>, contact portion <NUM> has a contact edge portion 114a and a connecting portion 114b.

Contact portion <NUM> has a shape extending in the direction parallel to center axis A. Contact edge portion 114a has a length L3 of <NUM>.

Connecting portion 114b connects contact edge portion 114a and an inner surface of flexible piece <NUM>. Connecting portion 114b has a shape inclined so as to gradually approach the inner surface of flexible piece <NUM> as connecting portion 114b is farther away from contact edge portion 114a in the direction parallel to center axis A. Connecting portion 114b and the inner surface of flexible piece <NUM> have a boundary portion therebetween with a radius of curvature of <NUM>. Connecting portion 114b and contact edge portion 114a have a boundary portion therebetween with a radius of curvature of <NUM>.

Support portion <NUM> supports the plurality of contact pieces <NUM>. In the present embodiment, support portion <NUM> is formed to have a cylindrical shape having center axis A as a center. Support portion <NUM> has an outer peripheral surface contiguous to that of each flexible piece <NUM>. That is, support portion <NUM> has an outer diameter equal to that of the cylinder composed of the plurality of flexible pieces <NUM>.

As shown in <FIG>, support portion <NUM> is equal in thickness to each flexible piece <NUM>. As shown in <FIG>, in a direction along center axis A, support portion <NUM> has a length L2 set to be smaller than length L1 of each flexible piece <NUM>. Specifically, support portion <NUM> has length L2 of <NUM>. Support portion <NUM> may be formed in a round columnar shape, a rectangular columnar shape, or the like.

Female-side flange <NUM> has a shape projecting from an outer peripheral surface of support portion <NUM> outward in the radial direction of support portion <NUM>. Female-side flange <NUM> is formed flat. In the direction parallel to center axis A, female-side flange <NUM> has a length equal to that of support portion <NUM> (<NUM> in the present embodiment).

Female-side flange <NUM> is provided with an insertion hole <NUM>. Insertion hole <NUM> has a diameter of <NUM>. A distance between center axis A and the center of insertion hole <NUM> is <NUM>.

Electric wire <NUM> is provided to connect the paired female terminals <NUM> to each other. Electric wire <NUM> is made of copper or silver. Electric wire <NUM> preferably has a cross-sectional area set to <NUM><NUM> or more and <NUM><NUM> or less. In the present embodiment, electric wire <NUM> has a cross-sectional area set to <NUM><NUM>. Electric wire <NUM> has a length set to <NUM> or more. The reason for this will be described with reference to <FIG>.

<FIG> represents each terminal and each electric wire in temperature when male terminal <NUM> is connected to female terminal <NUM> and a current of <NUM> A is supplied for <NUM> minutes. In <FIG>, a region R of a connecting portion of male terminal <NUM> and female terminal <NUM> is a region which attains highest temperature.

As shown in <FIG>, when a vehicle-side electric wire <NUM> has a cross-sectional area of <NUM><NUM>, and whether a portion up to <NUM> from male terminal <NUM> may or may not be cooled with water, it has been confirmed that a portion of vehicle-side electric wire <NUM> away from female terminal <NUM> by <NUM> is stable in temperature (or an effect of heat generated at the connecting portion of male terminal <NUM> and female terminal <NUM> is substantially negligible).

Furthermore, when the portion is water-cooled, and whether vehicle-side electric wire <NUM> may have a cross-sectional area of <NUM><NUM> or <NUM><NUM>, it has been confirmed that the portion of vehicle-side electric wire <NUM> away from female terminal <NUM> by <NUM> is stable in temperature (or an effect of heat generated at the connecting portion of male terminal <NUM> and female terminal <NUM> is substantially negligible).

From the above results, it can be seen that, by setting electric wire <NUM> to have a length of <NUM> or more, an effect of heat generated at a connecting portion of one male terminal <NUM> and one female terminal <NUM> on a connecting portion of the other male terminal <NUM> and the other female terminal <NUM> via the electric wire is negligible. Thus, in the present embodiment, electric wire <NUM> is set to have a length of <NUM> or more.

Each crimp terminal <NUM> is connected to an end <NUM> of electric wire <NUM>. Each crimp terminal <NUM> has a crimp portion <NUM> and a crimp-side flange <NUM>.

Crimp portion <NUM> crimps end <NUM> of electric wire <NUM>.

Crimp-side flange <NUM> is connected to crimp portion <NUM>. Crimp-side flange <NUM> is formed flat. Crimp-side flange <NUM> is provided with an insertion hole (not shown). Crimp-side flange <NUM> is fixed to female-side flange <NUM> by a bolt B and a nut (not shown). Bolt B is inserted into insertion hole <NUM> of female-side flange <NUM> and the insertion hole of crimp-side flange <NUM>.

Adjustment member <NUM> can adjust contact resistance of female terminal <NUM> and male terminal <NUM>. Specifically, adjustment member <NUM> can apply an external force to each female terminal <NUM> to reduce each female terminal <NUM> in diameter. Adjustment member <NUM> includes an annular band <NUM>, a metal band <NUM>, and an adjustment unit <NUM>.

Annular band <NUM> is attached around the plurality of contact pieces <NUM>. Annular band <NUM> surrounds the entire circumference of the plurality of contact pieces <NUM>. Annular band <NUM> is made of an electrically and thermally insulating material (resin or the like). In the direction parallel to center axis A, annular band <NUM> is smaller in length than slit <NUM>.

Metal band <NUM> is wrapped around annular band <NUM>. Metal band <NUM> can apply an external force to the plurality of contact pieces <NUM> of female terminal <NUM> to reduce the plurality of contact pieces <NUM> in diameter.

Adjustment unit <NUM> can adjust a force applied by metal band <NUM> to clamp the plurality of contact pieces <NUM> (or reduce the plurality of contact pieces <NUM> in diameter). Specifically, adjustment unit <NUM> adjusts metal band <NUM> in diameter to adjust the clamping force. Adjustment unit <NUM> has a screw capable of adjusting metal band <NUM> in diameter.

A method for evaluating charging connector <NUM> in coolability by using evaluation jig <NUM> will now be described. Specifically, charging connector <NUM> is evaluated in coolability by connecting the pair of female terminals <NUM> of evaluation jig <NUM> to the pair of male terminals <NUM> of male connector <NUM>. This evaluation method includes a removing step, a connecting step, an adjusting step, and an evaluating step.

The removing step is a step of removing a portion of each tubular wall <NUM> of male casing <NUM>. Specifically, as shown in <FIG>, in the removing step, each tubular wall <NUM> is partially removed to form around male terminal <NUM> an operating space <NUM> allowing an operation to be performed therein via adjustment unit <NUM> to adjust the external force. This partially exposes each male terminal <NUM>. Thus, the removing step removes a portion other than a portion capable of suppressing a short circuit of male terminals <NUM> or male terminal <NUM> and other terminals <NUM> to <NUM>, that is, a portion of tubular wall <NUM> where paired tubular walls <NUM> face each other. In the present embodiment, a portion of tubular wall <NUM> outside male terminal <NUM> in a direction of an imaginary line connecting male terminal <NUM> and protective grounding terminal <NUM> is removed.

The connecting step is a step of connecting the pair of female terminals <NUM> of evaluation jig <NUM> to the pair of male terminals <NUM>. In the connecting step, in a state in which each female terminal <NUM> has the plurality of contact pieces <NUM> with annular band <NUM> and metal band <NUM> attached thereto, female terminal <NUM> is connected to male terminal <NUM>. As shown in <FIG>, in the connecting step, female terminal <NUM> is inserted until distal end portion 112a of each flexible piece <NUM> contacts surface <NUM> of bottom wall <NUM> of male casing <NUM>. <FIG> shows one female terminal <NUM> alone receiving male terminal <NUM>.

The adjusting step is a step of adjusting a connection state of male terminal <NUM> and female terminal <NUM>. Specifically, in the adjusting step, the external force (the clamping force by metal band <NUM>) is adjusted by adjustment unit <NUM>. More specifically, in the adjusting step, the external force is adjusted by operating adjustment unit <NUM> with an operating tool (not shown) in operating space <NUM> so that contact resistance between male terminal <NUM> and female terminal <NUM> falls within a prescribed range. In this step, for example, from above in <FIG>, the clamping force of adjustment unit <NUM> is adjusted with the operating tool.

In the adjusting step, the external force is preferably adjusted so that the contact resistance is <NUM> mΩ or more and <NUM> mΩ or less, more preferably <NUM> mΩ or more and <NUM> mΩ or less.

Herein, as shown in <FIG>, the contact resistance is measured by a resistance value between a point P1 of <NUM> from surface <NUM> of bottom wall <NUM> and a point P2 of <NUM> from surface <NUM> of bottom wall <NUM>. The contact resistance may be measured with a milliohm tester or may be determined by a voltage drop caused when a current of <NUM> A is supplied. Point P2 is in a vicinity of a boundary between a region affected by a standard applied in designing male connector <NUM> including male terminal <NUM> and a region unaffected thereby.

In the evaluating step, in a state with male terminal <NUM> and female terminal <NUM> connected together, a charging current of <NUM> A is supplied for <NUM> minutes, and the charging connector is evaluated in coolability by whether male terminal <NUM> and female terminal <NUM> have a temperature of <NUM> or lower. Whether male terminal <NUM> and female terminal <NUM> have such a temperature may be detected with a temperature sensor (not shown) provided to male terminal <NUM> or female terminal <NUM>.

Thus, by using evaluation jig <NUM> of the present embodiment, an amount of heat generated when charging connector <NUM> has a current passing therethrough can appropriately be evaluated.

The exemplary embodiment described above is a specific example of the following aspect.

An evaluation jig of the above embodiment comprises a pair of female terminals connectable to a pair of male terminals of a charging connector, and an electric wire connecting the paired female terminals, the electric wire having a cross-sectional area of <NUM><NUM> or more and <NUM><NUM> or less and a length of <NUM> or more.

The evaluation jig that comprises the electric wire having a cross-sectional area of <NUM><NUM> or more and <NUM><NUM> or less and a length of <NUM> or more allows an appropriate evaluation of an amount of heat generated (or a degree at which temperature rise) at a connecting portion of a male terminal and a female terminal without being substantially affected by the electric wire's heat radiation characteristic when a current passes (or the evaluation is made). Each terminal can thus be designed based on a result of the evaluation.

Preferably, the electric wire is made of copper.

Furthermore, an evaluation jig comprises a pair of female terminals connectable to a pair of male terminals of a charging connector, and an adjustment member that can adjust contact resistance of the female terminal and the male terminal, wherein the female terminal can be reduced in diameter, the adjustment member includes an annular band attached to an outer peripheral surface of the female terminal and formed in an annular shape surrounding the female terminal, a metal band attached to an outer peripheral surface of the annular band and capable of applying an external force to the female terminal to reduce the female terminal in diameter, and an adjustment unit that can adjust the external force applied by the metal band to the female terminal, and the annular band is made of an electrically and thermally insulating material.

The evaluation jig that comprises the adjustment unit that can adjust the external (or clamping) force applied by the metal band to the female terminal can adjust contact resistance between the male terminal and the female terminal, and furthermore, the annular band disposed between the female terminal and the metal band that is made of an electrically and thermally insulating material can suppress heat radiation caused at the metal band or the adjustment unit, and hence reduction in accuracy in evaluating an amount of heat generated at a connecting portion of the male terminal and the female terminal.

An evaluation method of the above embodiment is an evaluation method performed by connecting to a charging connector including a pair of male terminals that can be cooled with a coolant an evaluation jig including a pair of female terminals connectable to the pair of male terminals, by connecting the pair of female terminals of the evaluation jig to the pair of male terminals of the charging connector, for evaluating the charging connector in coolability, the method comprising: connecting the pair of female terminals to the pair of male terminals; adjusting a connection state of the male terminal and the female terminal so that a contact resistance between the male terminal and the female terminal is <NUM> mΩ or more and <NUM> mΩ or less; and, after the step of adjusting, evaluating the coolability depending on whether the male terminal and the female terminal have a temperature of <NUM> or lower when a charging current of <NUM> A is supplied to the male terminal and the female terminal for <NUM> minutes.

In this evaluation method, contact resistance between the male terminal and the female terminal is defined to fall within a range of <NUM> mΩ or more and <NUM> mΩ or less, and variation in evaluation results is suppressed. Therefore, the charging connector's coolability can be appropriately evaluated. Further, designing the female terminal of the charging inlet such that the contact resistance is <NUM> mΩ or more and <NUM> mΩ or less allows the male terminal and the female terminal to have a temperature of <NUM> or lower when a charging connector which obtains a good evaluation result in the step of evaluating is used to charge power with a charging current of <NUM> A supplied for <NUM> minutes.

Preferably, in the step of adjusting, the connection state is adjusted so that the contact resistance is <NUM> mΩ or more and <NUM> mΩ or less.

Further, an evaluation method of the above embodiment is an evaluation method performed by connecting to a charging connector including a pair of male terminals that can be cooled with a coolant and a bottom wall that holds the pair of male terminals in a state in which the pair of male terminals are inserted therethrough an evaluation jig including a pair of female terminals connectable to the pair of male terminals, by connecting the pair of female terminals of the evaluation jig to the pair of male terminals of the charging connector, for evaluating the charging connector in coolability, the method comprising: connecting the pair of female terminals to the pair of male terminals; and adjusting a connection state of the male terminal and the female terminal so that contact resistance between the male terminal and the female terminal falls within a prescribed range, wherein in the step of adjusting, a resistance between a point of <NUM> of the male terminal from a surface of the bottom wall and a point of <NUM> of the female terminal from the surface of the bottom wall is measured as the contact resistance.

In this evaluation method, a measurement point for contact resistance between the male terminal and the female terminal is determined, and an appropriate evaluation result of the coolability can be obtained. Specifically, a measurement point on the side of the male terminal is a point of <NUM> from the surface of the bottom wall. At this point, the male terminal has a sufficiently large cross-sectional area, and an effect on the contact resistance is reduced. A measurement point on the side of the female terminal is a point of <NUM> from the surface of the bottom wall. This point is in a vicinity of a boundary of a region affected by a standard applied in designing the charging connector including the male terminal and a region unaffected by the standard. Therefore, designing the female terminal of the charging inlet to achieve contact resistance equal to or less than that measured at this point suppresses the male and female terminals' temperature to be a reference value or smaller when a charging connector that satisfies the standard is used to charge power.

Preferably, the evaluation method further comprises, after the step of adjusting, evaluating the coolability based on whether the male terminal and the female terminal have a temperature equal to or lower than <NUM> when a charging current of <NUM> A is supplied to the male terminal and the female terminal for <NUM> minutes.

Furthermore, an evaluation jig of the above embodiment includes a pair of female terminals connectable to a pair of male terminals of a charging connector, and an adjustment member that can adjust contact resistance of the female terminal and the male terminal, wherein the female terminal can be reduced in diameter, and the adjustment member can apply an external force to the female terminal to reduce the female terminal in diameter.

In this evaluation jig, the female terminal can be reduced in diameter and the adjustment member can apply an external force to the female terminal to reduce the female terminal in diameter, and contact resistance of the male terminal and the female terminal can be adjusted to fall within a prescribed range. Thus, the charging connector's coolability can be appropriately evaluated.

Furthermore, an evaluation method of the above embodiment is a method performed by connecting to a charging connector including a pair of male terminals that can be cooled with a coolant and a pair of tubular walls surrounding each of the paired male terminals an evaluation jig including a pair of female terminals that can be connected to the pair of male terminals and reduced in diameter and an adjustment member that can apply an external force to each of the paired female terminals to reduce the female terminal in diameter, by connecting the pair of female terminals of the evaluation jig to the pair of male terminals of the charging connector, for evaluating the charging connector in coolability, the method comprising: partially removing each tubular wall of the paired tubular walls to form around the male terminal an operating space allowing an operation to be performed therein via the adjustment member to adjust the external force; connecting the pair of female terminals to the pair of male terminals; and adjusting the external force in the operating space by the adjustment member so that contact resistance between the male terminal and the female terminal falls within a prescribed range.

In this evaluation method, an operating space allowing an operation to be performed therein to adjust external force is formed around a male terminal, and contact resistance can be adjusted in a state with the evaluation jig having a female terminal connected to the male terminal.

In the step of removing, the tubular wall preferably has removed a portion other than a portion at which the paired tubular walls face each other.

This suppresses short circuit of the male terminals.

Further, the adjustment member may include an annular band that is attached to an outer peripheral surface of the female terminal and formed in an annular shape surrounding the female terminal, a metal band that is attached to an outer peripheral surface of the annular band and can apply a force to the female terminal to reduce the female terminal in diameter, and an adjustment unit that can adjust a force applied by the metal band to clamp the female terminal, and the annular band may be made of an electrically and thermally insulating material. In this case, preferably, in the step of connecting, the pair of female terminals is connected to the pair of male terminals in a state with the annular and metal bands attached to each female terminal, and in the step of adjusting, the force applied by the metal band to clamp the female terminal is adjusted in the operating space.

Furthermore, an evaluation jig of the above embodiment comprises a female terminal connectable to a male terminal of a charging connector, the female terminal including a plurality of contact pieces which can each contact the male terminal and are spaced about a center axis, and a support portion to support the plurality of contact pieces, the plurality of contact pieces each having a flexible piece having a shape extending from the support portion in a direction parallel to the center axis, and a contact portion protruding toward the center axis from an inner surface of the flexible piece, the flexible piece forming a portion of a cylinder having the center axis, the flexible piece having a length equal to or larger than twice an outer diameter of the cylinder in a direction parallel to the center axis, the flexible piece being elastically deformable so that the flexible piece has a distal end portion to be displaceable in a radial direction of the cylinder relative to a proximal end portion of the flexible piece serving as a connecting portion of the flexible piece and the support portion, the contact portion having a shape curved so as to protrude inward in the radial direction.

In this evaluation jig, the flexible piece that has a length equal to or greater than twice the outer diameter of the cylinder in the direction parallel to the center axis is each less plastically deformable when the female terminal is repeatedly connected to and pulled out of the male terminal, and furthermore, each contact portion having a shape curved so as to protrude inward in the radial direction reliably contacts the male terminal. This allows prescribed contact resistance to be reliably reproduced and the charging connector's coolability to be evaluated appropriately.

Preferably, the contact portion has a shape extending in a direction parallel to the center axis.

Thus, even when the female terminal is connected to the male terminal in a state with the female terminal's center axis inclined relative to the male terminal's center axis, the female terminal is guided to have a posture so that the center axes match each other.

Preferably, the flexible piece has a protruding portion protruding from the contact portion in a direction parallel to the center axis away from the support portion.

Preferably, the flexible piece and the contact portion have a boundary portion therebetween in a curved shape.

In this case, the contact portion preferably has an apex smaller in curvature than the boundary portion.

Furthermore, preferably, the flexible piece has a facing surface facing a flexible piece adjacent to the flexible piece of interest in the circumferential direction of the cylinder, and any pair of such facing surfaces facing each other in the circumferential direction are parallel to each other.

Claim 1:
An evaluation method for evaluating a charging connector (<NUM>) in coolability by connecting an evaluation jig (<NUM>) to the charging connector (<NUM>), the charging connector (<NUM>) including a pair of male terminals (<NUM>) coolable with a coolant and a bottom wall (<NUM>) holding the pair of male terminals (<NUM>) in a state with the pair of male terminals (<NUM>) inserted therethrough, the evaluation jig (<NUM>) including a pair of female terminals (<NUM>) connectable to the pair of male terminals (<NUM>), the pair of female terminals (<NUM>) being connected to the pair of male terminals (<NUM>) in evaluating the charging connector (<NUM>) in coolability, wherein the male connectors are based on the ChaoJi standard, the method comprising:
connecting the pair of female terminals (<NUM>) to the pair of male terminals (<NUM>);
adjusting a connection state of the male terminal (<NUM>) and the female terminal (<NUM>) so that contact resistance between the male terminal (<NUM>) and the female terminal (<NUM>) falls within a prescribed range,
in the step of adjusting, a resistance between a point of <NUM> of the male terminal (<NUM>) from a surface (<NUM>) of the bottom wall (<NUM>) and a point of <NUM> of the female terminal (<NUM>) from the surface (<NUM>) of the bottom wall (<NUM>) being measured as the contact resistance; and
after the step of adjusting, evaluating the coolability based on whether a temperature of the male terminal (<NUM>) and of the female terminal (<NUM>) is a reference value or smaller during power charging.