Mains plug and charging system for a motor vehicle The invention relates to a mains plug according to Patent Claim 1 and a charging system according to Patent Claim 14.

A charging system, specifically for electric vehicles, having a charging device-side plug-in connector part and at least one sensor, is known from DE 20 2009 013 675 U1 , wherein the sensor emits a signal if a human body part approaches the plug-in charging system and/or if a human body part touches the plug-in charging system.

The object of the invention is the disclosure of an improved mains plug and an improved charging system.

This object is fulfilled by means of a mains plug according to Patent Claim 1 , and by means of a charging system according to Patent Claim 14. Advantageous forms of embodiment are disclosed in the dependent claims. It has been established that an improved mains plug and an improved charging system can be provided, wherein the mains plug comprises a contact housing and a sensor unit. The contact housing comprises at least one first gripping area. The sensor unit comprises at least one first sensor electrode, wherein the first sensor electrode is embedded in the contact housing. A first section of the contact housing is arranged between a first surface of the first gripping area and the first sensor electrode. In this manner, electrical contact between a human body part and the sensor electrode is prevented. A mains plug with long-term stability can be provided accordingly.

In a further form of embodiment, the first gripping area is at least partially delimited by a projection, wherein the sensor electrode is arranged at least partially adjacently to the projection. Particularly effective detection of contact between a human body part and the gripping area is ensured accordingly.

In a further form of embodiment, the projection has a projection outline, wherein the sensor electrode is arranged at least partially in parallel with the projection outline.

In a further form of embodiment, the mains plug incorporates a contact element, at least one protective contact, a protective conductor and at least one electrical conductor. The contact element is electrically connected to the electrical conductor. A contact element section of the contact element is embedded in the contact housing. A pin section of the contact element projects from the contact housing and extends in the plug-in direction of the mains plug. The arrangement of the first gripping area is at least partially offset in relation to the contact element, wherein the protective contact is electrically connected to the protective conductor, and is mechanically connected to the contact housing.

Preferably, the first gripping area is oriented in parallel with the plug-in direction. In a further form of embodiment, the contact housing comprises a second gripping area, wherein the first gripping area and the second gripping area are arranged with a mutual clearance, wherein the sensor unit comprises a second sensor electrode, and wherein a second section of the contact housing is arranged between a second surface of the second gripping area and the second sensor electrode. By this arrangement, a gripping movement on the part of a user of the charging system for the unplugging of the mains plug can be detected in a particularly reliable manner.

In a further form of embodiment, a third section of the contact housing is arranged between the first sensor electrode and the second sensor electrode, wherein the third section electrically isolates the first sensor electrode from the second sensor electrode.

In a further form of embodiment, the first sensor electrode is electrically connected to the second sensor electrode. In a further form of embodiment, the first sensor electrode is arranged in an area, specifically a plane, wherein said area is arranged in parallel with the first surface.

Additionally or alternatively, the sensor electrode at least partially comprises an electrically-conductive plastic and/or a wire and/or a leadframe. In a further form of embodiment, the contact housing incorporates an electrically- insulating material, specifically a plastic.

In a further form of embodiment, the sensor unit comprises a sensor circuit. The sensor circuit is at least electrically connected to the first sensor electrode. The sensor circuit is embedded in the contact housing. By this arrangement, damage to the sensor circuit, specifically by moisture, is reliably prevented. In a further form of embodiment, the sensor circuit incorporates a measuring capacitor and a capacitive proximity sensor, wherein the first sensor electrode is electrically connected to a first side of the measuring capacitor, and wherein a second side of the measuring capacitor is connected to a supply terminal of the proximity sensor.

In a further form of embodiment, the mains plug incorporates a signal line, wherein the sensor circuit comprises a bipolar transistor, preferably a NPN-doped bipolar transistor, having a base, an emitter and a collector, wherein the signal line is connectable to a monitoring circuit, and wherein the base is electrically connected to a signal output of the proximity sensor. The emitter is electrically connected to the protective conductor. The collector is connected to the signal line.

In a further form of embodiment, the sensor circuit has a first predefined electrical resistance and a second predefined electrical resistance. The first electrical resistance is arranged between the base and the signal terminal of the proximity sensor. The second electrical resistance is arranged between the emitter and the protective conductor.

In a further form of embodiment, the charging system is designed for the charging of the electrical energy accumulator of the motor vehicle, wherein the charging system incorporates the above-mentioned mains plug.

In a further form of embodiment, the charging system incorporates at least one vehicle terminal, a monitoring circuit and a signal line, wherein the electrical conductor connects the contact element to the monitoring circuit, and wherein the signal line electrically connects the monitoring circuit to the sensor unit. The monitoring circuit has a first circuit state and a second circuit state wherein, in the first circuit state, the monitoring circuit electrically connects the electrical conductor to the vehicle terminal and wherein, in the second circuit state, the monitoring circuit electrically isolates the electrical conductor from the vehicle terminal. The sensor unit is designed to reduce a voltage in the event of contact between the first gripping area and a body part, wherein the monitoring circuit is designed to detect the reduced voltage and to switch from the first circuit state to the second circuit state.

In a further form of embodiment, the charging system incorporates at least one charging device and a monitoring circuit, wherein the charging device has a first operating state and a second operating state wherein, in the first operating state, the charging device is designed to charge the electrical energy accumulator and wherein, in the second operating state, the charging of the electrical energy accumulator by the charging device is interrupted. The monitoring circuit is connected to the sensor unit, wherein the monitoring circuit is designed, upon the detection of contact, to switch the charging device from the first operating state to the second operating state, by means of a control signal.

The invention is described in greater detail hereinafter, with reference to the figures. Herein: Figure 1 shows a schematic representation of a charging system, according to a first form of embodiment;

Figure 2 shows a perspective representation of a mains plug of the charging system represented in Figure 1 ;

Figure 3 shows a sectional view of the mains plug represented in Figure 2, at the sectional plane A-A shown in Figure 2;

Figure 4 shows a circuit diagram of the charging system represented in Figure 1 ; Figure 5 shows a flow diagram of a method for the operation of the charging system represented in Figure 1 ;

Figure 6 shows a schematic representation of a charging system, according to a second form of embodiment; and

Figure 7 shows a circuit diagram of the charging system represented in Figure 6.

In the following figures, reference is made to a coordinate system 5. For exemplary purposes, the coordinate system 5 is configured as a right-handed coordinate system, and has a x-axis, a y-axis and a z-axis.

Figure 1 shows a schematic representation of a charging system 10 for the charging of an electrical energy accumulator 15 of a motor vehicle 20. The motor vehicle 20 can be configured as a hybrid vehicle or as an electric vehicle, wherein at least part of the propulsion energy is stored in the electrical energy accumulator 15 of the motor vehicle 20. The electrical energy accumulator 15 can be, for example, a lithium-air accumulator. It is also conceivable that the electrical energy accumulator 15 is configured in a different form.

The charging system 10 comprises a charging device 25. For exemplary purposes, the charging device 25 is installed in the motor vehicle 20, and executes the control and/or regulation of a process for the charging of the electrical energy accumulator 15 with electrical energy from a permanent electrical network, preferably a permanent alternating current network. The charging system 10 further comprises a first vehicle terminal 30, which is arranged in the motor vehicle 20. The charging device 25 is electrically connected to the electrical energy accumulator 15 of the motor vehicle 20 by means of a first connection 35. The charging device 25 is also electrically connected to the first vehicle terminal 30 by means of a second connection 40.

The charging system 10 further comprises a mains plug 45, a monitoring circuit 55 and a second vehicle terminal 65. The mains plug 45, the monitoring circuit 55 and the second vehicle terminal 65 are configured in a stationary arrangement and, in this form of embodiment, are not installed in the motor vehicle 15.

The mains plug 45 comprises a first cable 50, and the monitoring circuit 55 comprises a second cable 60. The first cable 50 comprises a first electrical conductor 70, an exemplary second electrical conductor 75, a first protective conductor 80 and a signal line 85. The first electrical conductor 70, the second electrical conductor 75, the first protective conductor 80 and the signal line 85 are configured in the first cable 50 in a mutually electrically insulated arrangement.

The second cable 60 incorporates a third electrical conductor 90, a fourth electrical conductor 95 and a second protective conductor 100.

The function of the mains plug 45 is the connection of the charging system 10 to a socket outlet 1 10 of the permanent electrical network. The first vehicle terminal 30 is connected to the second vehicle terminal 65, and thus constitutes an electrical coupling between the first vehicle terminal 30 and the second vehicle terminal 65.

Figure 2 shows a perspective representation of the mains plug 45 of the charging system 10 represented in Figure 1 .

The mains plug 45 incorporates a contact housing 1 15, a first contact element 120, a second contact element 125, a protective contact 130 and a sensor unit 135.

The first contact element 120 and the second contact element 125 are of pin-shaped design, and extend in the x-direction. The first contact element 120 is arranged in the z- direction, offset in relation to the second contact element 125. The first contact element 120 is thus electrically connected to the first electrical conductor 70, and the second contact element 125 is electrically connected to the second electrical conductor 75. The first contact element 120 and the second contact element 125 are arranged on a side of the contact housing 1 15 which faces the socket outlet 1 10.

The first contact element 120 incorporates a first pin section 141 and a first contact element section 142. The second contact element 125 incorporates a second pin section 143 and a second contact element section 144. The first contact element section 142 and the second contact element section 144 are embedded in the contact housing 1 15. The first pin section 141 of the first contact element 120 and the second pin section 143 of the second contact element 125 project from the contact housing 1 15, on an end face of the contact housing 1 15 which faces the socket outlet 1 10, outwardly from said contact housing 1 15. The respective pin section 141 , 143 extends in a plug-in direction (x- direction) of the contact element 120, 125, such that the pin section 141 , 143 is inserted in a jack socket of the socket outlet 1 10 which is respectively assigned to the pin section 141 , 143. By means of the contact element section 142, 144, the contact element 120, 125 is mechanically attached to the contact housing 1 15. Moreover, the first electrical conductor 70 can be connected to the first contact element section 142, and the second electrical conductor 75 can be connected to the second contact element section 144.

On the circumferential side, the first pin section 141 has a first contact surface 136 and, on the circumferential side, the second pin section 143 has a second contact surface 137. If the mains plug 45 is inserted in the socket outlet 1 10, by means of the first contact surface 136, a first electrical contact is provided with a first jack socket (not represented in Figure 2) of the socket outlet 1 10. With the mains plug 45 in the plugged-in state in the socket outlet 1 10, the second contact surface 141 provides a second electrical contact with a second jack socket (not represented in Figure 2) of the socket outlet 1 1 0.

The contact housing 1 15 incorporates a first housing region 145, a second housing region 150, and a third housing region 146. The third housing region 146 is arranged in the x-direction between the first housing region 145 and the second housing region 150. On the second housing region 150, the contact housing 1 15 incorporates a first gripping area 155 and a first projection 160 on a first lateral surface 157, and a second gripping area 165 and a second projection 170 on a second lateral surface 158, arranged opposite the first lateral surface 157. In the x-direction, the first gripping area 155 and the second gripping area 165 are arranged at the same height. In the z-direction, the first gripping area 155 and the second gripping area 165 are arranged with a mutual clearance. The gripping area 155, 165 is delimited on a side facing the contact element 120, 125 by the third housing region 146.

The third housing region 146 has an exemplary cup-shaped design, and tapers from the first housing region 145 in the direction of the second housing region 150. In the z- direction, the second housing region 150 is configured to a narrower dimension than the first housing region 145. On a side which is averted from the contact element 120, 125, the first gripping area 155 is delimited by the first projection 160 and the second gripping area 165 is delimited by the second projection 170. The projection 160, 170 is arranged with a clearance of approximately one finger's width from an upper end of the third housing region 146 in the x-direction. The projection 160, 170 extends in the z-direction. The function of the projection 160, 170 is to permit the particularly effective gripping of the body component, thereby facilitating the withdrawal of the first housing region 145 and the contact element 120, 125 from the socket outlet 1 10.

The protective contact 130 is arranged laterally on the first housing region 145 of the contact housing 1 15 which is configured to match the socket outlet 1 10. In the fitted state of the mains plug 45 in the socket outlet 1 10, the first housing region 145 is

circumferentially enclosed by the socket outlet 1 10. The protective contact 130 is electrically connected to the first protective conductor 80.

Figure 3 shows a sectional view of the mains plug 45 represented in Figure 2, at the sectional plane A-A shown in Figure 2.

The second projection 170 extends in the z-direction, in the opposite direction to the first projection 160. It is particularly advantageous, moreover, if the first gripping area 155 and/or the first projection 160, and the second gripping area 165 and/or the second projection 170, are arranged with mirror-image symmetry to a plane of symmetry 175, which is arranged between the first gripping area 155 and the second gripping area 165 and is, for example, an xy-plane. The plane of symmetry 175 is centrally arranged between the first contact element 120 and the second contact element 125. By means of the opposing arrangement, a reliable gripping of the mains plug 45 is ensured. It is particularly advantageous if the projection 160, 170, at least in part, is configured transversely to the plug-in direction (x-direction) of the contact element 120, 125. It is further advantageous if the gripping area 155, 165 is essentially arranged in parallel to the plug-in direction of the contact element 120, 125. The first projection 160 incorporates a first projection outline 195, and the second projection 170 incorporates a second projection outline 200. The first projection outline 195 and/or the second projection outline 200 can be configured, for example, with a L-shaped or U-shaped design.

The sensor unit 135 incorporates a sensor circuit 180, a first sensor electrode 185 and preferably a second sensor electrode 190. The sensor electrode 185, 190 can comprise, for example, a wire and/or a leadf rame and/or an electrically-conductive plastic. The first sensor electrode 185 and the second sensor electrode 190 can be arranged on a common leadframe, or on a leadframe which is respectively assigned to each of the sensor electrodes 185, 190. It is particularly advantageous if the sensor circuit 180, the first sensor electrode 185 and the second sensor electrode 190 are arranged on a common leadframe. The sensor unit 135 is preferably completely embedded in a material of the contact housing 1 15. The material is, for example, electrically insulating, and preferably comprises a plastic. It is particularly advantageous here if, during the manufacture of the mains plug 45, the sensor electrode 185, 190 and the sensor circuit 180 are moulded with the material of the contact housing 1 15, in an injection mould. The first sensor electrode 185 is arranged adjacently to the first projection 160, preferably at an equal height in the x-direction. The second sensor electrode 190 is arranged adjacently to the second projection 170, preferably at an equal height in the x-direction.

The sensor electrode 185, 190 can be configured with a meander-shaped design. It is particularly advantageous if the first sensor electrode 185 is at least partially arranged in parallel with the first projection outline 195, and the second sensor electrode 190 is at least partially arranged in parallel with the second projection outline 200.

The contact housing 1 15 comprises a first section 210, between a first surface 205 of the first gripping area 155 and the first sensor electrode. The first section 21 0 electrically insulates the first sensor electrode 185 from the first gripping area 155.

The contact housing 1 15 comprises a second section 220, between a second surface 215 of the second gripping area 165 and the second sensor electrode 190. The second section 220 electrically insulates the second sensor electrode 190 from the second surface 215.

The contact housing 1 15 comprises a third section 225, between the first sensor electrode 185 and the second sensor electrode 190. The third section 225 electrically insulates the first sensor electrode 185 from the second sensor electrode 190.

The first sensor electrode 185 is arranged in a first area 226, preferably in a first plane. The first area 226 is arranged in parallel with the first surface 205. The second sensor electrode 190 is preferably arranged in a second area 227, specifically in a second plane. The second area 227 can be arranged in parallel with the first area 226 of the first sensor electrode 185. Moreover, the second area 227 is arranged in parallel with the second surface 215. Figure 4 shows a circuit diagram of the charging system 10 represented in Figure 1 .

The sensor circuit 180 incorporates a measuring capacitor 230, a capacitive proximity sensor 235, a bipolar transistor 240, a first predefined electrical resistance 245, and a second predefined electrical resistance 250.

The first sensor electrode 185 is electrically connected to a first side 260 of the measuring capacitor 230, by means of a third connection 255. Moreover, the second sensor electrode 190 is electrically connected to the first side 260 of the measuring capacitor 230, by means of a fourth connection 265.

The capacitive proximity sensor 235 comprises a first supply terminal 280, a second supply terminal 285, a signal terminal 290 and a ground terminal 295. The capacitive proximity sensor 235 can, for example, be of the AT42QT1010 type. A fifth connection 275 electrically connects the first supply terminal 280 to a second side 270 of the measuring capacitor 230. The signal terminal 290 is electrically connected to a first side of the first electrical resistor 245 by means of a sixth connection 300. The second supply terminal 285 is electrically connected to a first junction 310 by means of a seventh connection 305. The ground terminal 295 is electrically connected to the first protective conductor 80 by means of an eighth connection 315.

The bipolar transistor 240 is preferably configured as a NPN-doped bipolar transistor. The bipolar transistor 240 comprises a base 320, an emitter 325 and a collector 330. The first junction 310 is electrically connected to the signal line 85. Moreover, the first junction 310 is electrically connected to the collector 330 by means of a ninth connection 340. The base 320 is connected to a second side of the first electrical resistance 245 by means of a tenth connection 345. The emitter 325 is electrically connected to a first side of the second electrical resistance 250 by means of an eleventh connection 350. A second side of the second electrical resistance 250 is electrically connected to the first protective conductor 80 by means of a twelfth connection 355. The exemplary monitoring circuit 55 comprises a switching means 360, a comparator circuit 365 and an energy supply 370. The switching means 360 can be configured, for example, as a relay. The energy supply 370 delivers a further electrical energy input in relation to ground at a second junction 375 of the monitoring circuit 55, at a supply voltage U. The supply voltage U has a predefined value, for example of 5 V. The second junction 375 is electrically connected to the comparator circuit 365 by means of a thirteenth connection 380. The comparator circuit 365 is electrically connected to the switching means 360.

The switching means 360 has a first circuit state and a second circuit state, wherein the second circuit state is represented in Figure 4, for exemplary purposes. The switching means 360 is connected to the first electrical conductor 70 on a first terminal 385. On a second terminal 390, the switching means 360 is connected to the second electrical conductor 75. A third terminal 395 of the switching means 360 is connected to the second vehicle terminal 65 by means of the third electrical conductor 90. The fourth terminal 400 is electrically connected to the second vehicle terminal 65 by means of the fourth electrical conductor 95.

In the second circuit state of the switching means 360, the terminals 385, 390, 395, 400 are mutually electrically isolated. In the first circuit state, the switching means 360 is closed, and the first terminal 385 is electrically connected to the third terminal 295.

Moreover, in the first circuit state, the second terminal 390 is electrically connected to the fourth terminal 400.

Figure 5 shows a flow diagram of a method of the charging system 10 represented in Figures 1 to 4.

In a first process step 500, the mains plug 45 is inserted in the socket outlet 1 10, and the contact element 120, 125 is electrically connected to the socket outlet 1 10. Moreover, the charging device 25 can be activated. The switching means 360 is in the first circuit state. Electrical energy supplied by the AC voltage network is thus transmitted via the mains plug 45, the first cable 50, the switching means 360, the second cable 60, the vehicle terminals 30, 65, and the second connection 40 to the charging device 25. The charging device 25 controls and/or regulates an electric current and/or an electric voltage of the electrical energy for the charging of the electrical energy accumulator 15 of the motor vehicle 20. The further electrical energy is transmitted via the signal line 85 of the first cable 50 to the first junction 310. Moreover, the further electrical energy is transmitted via the seventh connection 305 to the second supply terminal 285 of the proximity sensor 235. The proximity sensor 235 delivers further electrical energy to the first supply terminal 280. The further electrical energy is further transmitted via the fifth connection 275 to the second side 270 of the measuring capacitor 230. The measuring capacitor 230 is electrically charged by the further electrical energy. By the charging of the measuring capacitor, a first electric field 425 is generated around the first sensor electrode 185, and a second electric field 430 is generated around the second sensor electrode. In a second process step 505, a user of the charging system 10 touches the first gripping area 155 and the second gripping area 165 with a part of their body, for example the fingers, in order to withdraw the mains plug 45 from the socket outlet 1 10. As a result, the first electric field 425 and the second electric field 430 are altered by the drain of charge from the electric fields 425, 430 to the human body part. As a result, the charging of the measuring capacitor 230 by the sensor electrode 185 is also altered.

The proximity sensor 235 detects the drain of charge of the measuring capacitor 230 by a change in a capacitor voltage of the measuring capacitor 230 on the first supply terminal 280. On the signal terminal 290, the proximity sensor 235 delivers a signal which is constituted in accordance with the measured capacitor voltage. The signal is transmitted to the base 320 via the first electrical resistance 245, the sixth connection 300 and the tenth connection 345.

In a third process step 510, the bipolar transistor 240 switches through in response to the signal such that, from the energy supply 370, a further current of the further electrical energy flows via the signal line 85, the first junction 310 and the ninth connection 340 through the bipolar transistor 240 to the eleventh connection 350. The further electrical energy is converted into heat in the second electrical resistance 250.

It is particularly advantageous if the energy supply 370 is designed to deliver the further electrical energy at a specific and predefined electric power rating. If the bipolar transistor 240 is switched through, the (supply) voltage on the second junction 375 dips in relation to ground. The voltage dip thus correlates to a corresponding through-switching of the bipolar transistor 240. If, for example, only one of the two gripping areas 155, 165 is touched, the voltage dip on the second junction 375 in relation to ground is smaller than in the event that both the gripping areas 155, 165 are touched, and a stronger drain of charge occurs on the measuring capacitor 230 than in the event that only one of the two gripping areas 155, 165 is touched.

In a fourth process step 515, the comparator circuit 365 detects a voltage on the second junction 375, in relation to ground. In the non-switched-through state of the bipolar transistor 240, the measured voltage corresponds to the supply voltage U. The comparator circuit 365 compares the voltage in relation to ground on the second junction 375 with a predefined threshold value. If the voltage detected on the second junction 375 undershoots the predefined threshold value, the comparator circuit 365 proceeds to the execution of a fifth process step 520. If the voltage detected on the second junction 375 exceeds the predefined threshold value, the comparator circuit 365 proceeds to the execution of a sixth process step 525.

In the fifth process step 520, the comparator circuit 365 switches the switching means 360 from a first circuit state to a second circuit state, such that the switching means 360 interrupts the electrical connection between the first terminal 385 and the third terminal 395, and between the second terminal 390 and the fourth terminal 400, and no electrical energy flows via the first and second electrical conductors 70, 75 to the charging device 25. Accordingly, the charging process for the charging of the electrical energy

accumulator 15 of the motor vehicle 20 is interrupted. Switching of the switching means 360 from the first circuit state to the second circuit state proceeds more rapidly than a typical process for the withdrawal of the mains plug 45 from the socket outlet 1 10. The generation of an arc between the contact elements 120, 125 to the socket outlet 1 10 can be prevented accordingly. If the measured electric voltage between the second junction 375 and ground exceeds the predefined threshold value, the comparator circuit 365 allows the switching means 360 to remain in the first circuit state, such that electrical energy continues to be transmitted from the first and second electrical conductors 70, 75 to the charging device 25, and the charging process for the charging of the electrical energy accumulator 15 is maintained. It is particularly advantageous if the predefined threshold value is selected such that the predefined threshold value exclusively correlates to a touching of both gripping areas 155, 165, such that the proximity of the user to the mains plug 45, for example by inadvertent contact with only one of the two gripping areas 155, 165, by means of which no withdrawal of the mains plug 45 from the socket outlet 1 10 is executed, can be distinguished from a withdrawal process in which a human body part touches both of the gripping areas 155, 165.

Figure 6 shows a schematic representation of a charging system 10 according to a second form of embodiment.

The charging system 10 is essentially of identical design to the charging system 10 represented in Figure 1 . It differs, in that the second cable 60 additionally incorporates a second signal line 105. The second signal line 105 connects the monitoring circuit 55 to the charging device 25, and is designed to transmit a control signal between the monitoring circuit 55 and the charging device 25.

Figure 7 shows a circuit diagram for the charging system 10 represented in Figure 6.

The charging system 10 is essentially of identical design to the charging system 10 represented in Figure 4. It differs in that the switching means 360 is omitted, wherein a transmitter 600 is provided in place of the switching means 360. The transmitter 600 is connected to the charging device 25 by means of the second signal line 105. The transmitter 600 can, for example, deliver a pulse-width-modulated signal to the charging device 25. Moreover, the first and second electrical conductor 70, 75 in the monitoring circuit is permanently connected to the third and fourth electrical conductor 90, 95.

The operation of the charging system 10 proceeds in a similar manner to that described in Figure 5. The first to fourth process steps 500 to 515 are identical to the first to fourth process steps 500 to 515 described in Figure 5. A difference is provided in that, in the fifth process step 520, the monitoring circuit 55, upon the undershoot of the threshold value by the voltage on the second junction 375, transmits a first control signal to the charging device 25 by means of the transmitter 600. The charging device 25 detects the first control signal, wherein the charging device 25, on the basis of the first control signal, interrupts the charging process of the electrical energy accumulator 15.

In the sixth process step 525, the monitoring circuit 55, via the transmitter 600, delivers a second control signal to the charging device 25 by means of the transmitter 600. The charging device 25 detects the second control signal wherein, on the basis of the second control signal, the charging device 25 maintains the execution of the charging process.

It is hereby indicated that the charging system 10 can naturally be configured with a different design. Specifically, it is conceivable that both the sensor unit 135 and the monitoring circuit 55 can be configured with a different design. It is specifically indicated that the representation of the monitoring circuit 55 in Figures 4 and 7 is exemplary. The monitoring circuit 55 can also be configured as a digital circuit, which evaluates a digital signal which is delivered by the proximity sensor 235.

List of reference numbers

5 Coordinate system

10 Charging system

15 Electrical energy accumulator

20 Motor vehicle

25 Charging device

30 First vehicle terminal

35 First connection

40 Second connection

45 Mains plug

50 First cable

55 Monitoring circuit

60 Second cable

65 Second vehicle terminal

70 First electrical conductor

75 Second electrical conductor

80 First protective conductor

85 First signal line

90 Third electrical conductor

95 Fourth electrical conductor

100 Second protective conductor

105 Second signal line

1 10 Socket outlet

1 15 Contact housing

120 First contact element

125 Second contact element

130 Protective contact

135 Sensor unit

136 First contact surface

137 First pin section

142 First contact element section

143 Second pin section

144 Second contact element section

145 First section

146 Transition section

150 Second section 155 First gripping area

157 First lateral surface

158 Second lateral surface

160 First projection

165 Second gripping area

170 Second projection

175 Plane of symmetry

180 Sensor circuit

185 First sensor electrode

190 Second sensor electrode

195 First projection outline

200 Second projection outline

205 First surface

210 First section

215 Second surface

220 Second section

225 Third section

226 First area

227 Second area

230 Measuring capacitor

235 Proximity sensor

240 Bipolar transistor

245 First resistance

250 Second resistance

255 Third connection

260 First side of measuring state sensor

265 Fourth connection

270 Second side of measuring state sensor

275 Fifth connection

280 First supply terminal

285 Second supply terminal

290 Signal terminal

295 Ground terminal

300 Sixth connection

305 Seventh connection

310 First junction

315 Eighth connection Base

Emitter

Collector

Ninth connection Tenth connection Eleventh connection Twelfth connection Relay

Comparator circuit Voltage supply Second junction Thirteenth connection First terminal Second terminal Third terminal Fourth terminal First input

Second input First electric field Second electric field First process step Second process step Third process step Fourth process step Fifth process step Sixth process step