Method for charging an ev battery and ev power supply device

Abstract

The embodiment of the invention relates to a method for charging an EV battery and EV power supply equipment. A method for charging or discharging an electric vehicle power supply equipment (EVSE) battery of an electric vehicle (EV) using the EVSE. The method includes electrically coupling an EVSE charging interface conductor of the EVSE to an EV charging interface conductor of the EV and determining, by the EVSE, a current EV voltage provided by an EV battery at an entrance; and at least one of charging or discharging the EV battery by the EVSE. The charging comprises applying a charging voltage V to the connector and limiting the charging voltage V by a voltage upper limit VLimEVPresent, and wherein the discharging comprises applying the charging voltage V to the connector and limiting the charging voltage V by a voltage lower limit VLimEVPresent. And the voltage upper limit VLimEVPresent is determined according to the current voltage of the EV.

Description

Technical Field

[0001] The present disclosure belongs to the field of electric mobility and, in particular, relates to a method for charging or discharging an EV battery of an electric vehicle (EV), and an electric vehicle supply equipment (EVSE) for this purpose. The method preferably involves direct current charging or discharging of an EV battery. Background Art

[0002] A sufficiently developed charging infrastructure is crucial for the transition to electromobility. This includes a sufficient number of electric vehicle (EV) charging stations, also known as “electric vehicle supply equipment” (EVSE).

[0003] In order to charge the battery as quickly as possible, today's fast charging stations typically use direct current (DC) charging. Since vehicle batteries are charged using high voltage and high current (800V and 500A in some cases) to enable rapid charging and thus continue to drive the vehicle even when using high-capacity vehicle batteries, the EVSE and the components involved in charging must be able to withstand high loads.

[0004] In particular, the connection between the EVSE and the vehicle, including the EVSE connector and the EV inlet, is subject to high loads. To protect these devices, current flow to the vehicle battery is only enabled when the vehicle and EVSE have communicated that the charging cable connector is correctly connected and mechanically locked.

[0005] However, it has been observed in practice that arcs may occur in the event of a malfunction and / or user error. For example, an arc may occur if the connection fails to lock correctly and / or the charging cable connector is unlocked and disconnected too quickly. Although vehicles should generally lock the connection, some vehicles do not do so correctly, so the operator may be able to separate the connector from the inlet during charging. Another possible situation is wear and deterioration of the electrical contacts of the inlet and / or connector, for example due to dirt, moisture or corrosion, foreign matter and / or welding effects due to hot spots. Arcs may also occur due to other circumstances. Although modern charging stations are generally designed to minimize the risk of arcs, there may still be some abnormal situations that may lead to arcs. Arcs can be harmful and (further) damage the electrical contacts of the connector and / or inlet.

[0006] For example, even a brief arc can cause connector damage or premature wear of high-current connector contacts at high voltages and currents. Such damage can shorten the life of the EVSE connector and potentially render the charging station unusable.

[0007] It would be desirable to address these issues and reduce, at least to some extent, the risk of arcing and its adverse consequences. Summary of the Invention

[0008] To address the above-mentioned problems and other potential problems, embodiments of the present disclosure provide, in a first aspect, a method for charging an electric vehicle (EV) battery using electric vehicle supply equipment (EVSE). The method includes electrically connecting a connector of the EVSE to an inlet of the EV; determining, by the EVSE, the EV current voltage provided by the EV battery at the inlet; and charging the EV battery by the EVSE, wherein charging includes applying a charging voltage V to the connector. The method also includes determining, by the voltage upper limit V Lim_EVPresent To limit the charging voltage V, where the upper voltage limit V Lim_EVPresent Determined by the current voltage of the EV.

[0009] In a second aspect, electric vehicle supply equipment (EVSE) is configured to perform the method according to the first aspect.

[0010] In this article, the present invention is described by taking charging as an example. It is understood that a similar process can also be performed to discharge and / or cycle a battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following will introduce embodiments of the present disclosure in the form of examples and explain its advantages in more detail with reference to the accompanying drawings, in which:

[0012] Figure 1 A schematic diagram illustrating situations in which an arc may occur during the charging process;

[0013] Figure 2 A block diagram illustrating a method according to the present application is shown; DETAILED DESCRIPTION

[0014] The principles and spirit of the present invention will be described below in conjunction with exemplary embodiments. All of these embodiments are only provided for those skilled in the art to better understand and further practice the present invention and are not intended to limit the scope of the invention. In addition, the features shown or described as part of one aspect or embodiment may be used together with another aspect or embodiment.

[0015] For the sake of clarity, this specification does not describe all features of an actual implementation. It will, of course, be understood that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which will vary from implementation to implementation. Furthermore, it will be understood that such development work can be complex and time-consuming, but will nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

[0016] According to one aspect, the present disclosure may be applied to charging stations for electric vehicles, in particular DC charging stations for charging vehicle traction batteries having high voltage and high capacity.

[0017] In these situations, measures are typically taken to prevent arcing. For example, the connection between the connector and the inlet is typically locked after an additional delay before the EVSE enables charging. Furthermore, the lock is not released until charging stops, also after a delay. However, there may still be situations where an arc could occur, as described above.

[0018] Figure 1 Figure 1 shows a possible arcing situation when the EVSE is charging the EV battery. The pins and sockets can be switched between EVSE and EV, or mixed (e.g., at least one pin and at least one socket for each). When the EVSE is charging the EV battery, the charging voltage V EVSE Applied to the connector 100b of the EVSE and applied to the battery of the EV via the inlet 100a of the EV. When the connector 100b of the EVSE and the inlet 100a of the EV are separated during charging for some reason, such as Figure 1 As shown, since the EVSE connector 100b (which is in the EVSE voltage defined by the EV) and the EV inlet 100a (which is at a voltage determined by the EV's battery voltage V Batt Given the voltage difference between the EV and the current voltage, an arc may occur and last for a long time. There may be some control procedures in place to limit the arc by stopping the charging process, but these control procedures are effective only for a certain time interval in some cases, after which the arc may have already caused some damage.

[0019] Therefore, according to one aspect of the present invention, Figure 1 As shown, the voltage limit V Lim_EVPresent To limit the charging voltage V to further reduce the arc risk, where the voltage upper limit V Lim_EVPresent The voltage V is determined based on the EV current voltage provided by the EV battery (also referred to as battery) at the inlet. By limiting the charging voltage V in this way, the risk and / or extent of arcing can be significantly reduced. That is, an arc can occur when the connection between the connector and the inlet is separated during charging (while the charging current is flowing). In this case, the voltage at the inlet will be limited by the EV current voltage provided by the EV battery at the inlet (will be at least approximately equal to the EV current voltage). By limiting the charging voltage V by Lim_EVPresentBy limiting the charging voltage V to a function of the EV's current voltage, the voltage difference between the connector and the inlet can be controlled by this upper limit. Thus, even if the connection between the connector and the inlet becomes disconnected during charging, the initiation and extent of arcing can be limited or even suppressed.

[0020] Figure 2 A block diagram illustrating an example of a method for charging an EV battery of an electric vehicle (EV) using electric vehicle supply equipment (EVSE) according to the present invention is shown. The method includes a step S1 of electrically connecting an EVSE connector to an EV inlet; a step S2 of determining, by the EVSE, the EV's current voltage provided by the EV battery at the inlet; and a step S3 of charging the EV battery by the EVSE. In step S3, a charging voltage V is applied to the connector (step 3.1). Therefore, the charging voltage V is subject to an upper voltage limit V. Lim_EVPresent The upper voltage limit V Lim_EVPresent Determined based on the current voltage of the EV. Steps 3.1 and 3.2 are performed together as part of step S3 and are not necessarily performed sequentially. Similarly, step S2 can be performed not only once at the start of charging, but also continuously (e.g., continuously or at least intermittently) during charging (step S3).

[0021] Next, some further aspects of the present invention are described.

[0022] According to one aspect, the method may include electrically coupling a connector of an EVSE to an inlet of an EV. The EVSE may typically be connected to the EV to be charged using a high current cable having a connector, and the vehicle may be connected to the EVSE using an inlet, these components being adapted for the high charging currents and voltages present.

[0023] The connector and inlet may typically have other contacts that enable the EVSE to communicate with the EV and / or vice versa. These contacts may be used, for example, to initiate locking of the charging plug on the vehicle or to transmit corresponding electrical data of the vehicle battery so that the EVSE can set appropriate charging parameters.

[0024] In addition, the charging method may also include the step of determining the EV current voltage provided by the EV battery at the inlet. The EV current voltage may be the difference between the positive and negative inlet contacts, or the difference between the ground and inlet contacts. Due to the charging / discharging process or other reasons, the EV current voltage may change slowly over time. Therefore, the algorithm may be adapted to adjust V over time. Lim_EVPresent The EV current voltage can be determined in various ways.

[0025] In one example, the current EV voltage can be determined by measuring the EV battery voltage. The current EV voltage can be determined by measuring the EV battery voltage applied to the inlet (the inlet voltage generated by the EV battery). The measurement can be performed by the EVSE, for example, by measuring the voltage applied to the inlet by the EV battery. For example, the measurement can be performed by at least one controller present in the EVSE, which also controls the voltage and current values ​​of a power converter or buck / boost converter present in the EVSE, and evaluates sensor inputs, for example, for fault detection.

[0026] In another example, a measurement can be performed by the EV and then transmitted to the EVSE. For example, after the EV has entered a communication state with the EVSE, the EV battery voltage (the EV battery voltage applied to the inlet, the inlet voltage due to the EV battery) is measured by the EV and the result or a value derived therefrom is transmitted to the EVSE. This example illustrates one aspect in which the current EV voltage can be determined by receiving charging parameters of the EV battery from the EV by the EVSE. According to one aspect, the charging parameters of the battery in the vehicle can be transmitted to the charging station via communication contacts in the charging plug. According to one aspect, the current EV voltage can be received by the EVSE from the EV.

[0027] When an EV battery is charged by an EVSE, charging includes applying a charging voltage V to the connector. Charging can be DC charging. Charging can be high-voltage charging. The charging voltage can be at least 50V, preferably at least 400V-800V. The charging current can be at least 1A, preferably at least 500A. According to one aspect, charging can be intermittently interrupted to determine the current EV voltage.

[0028] Furthermore, the method includes the following steps: Lim_EVPresent To limit the charging voltage V, the voltage upper limit V Lim_EVPresent Determined by the current voltage of EV. Therefore, V Lim_EVPresent is imposed as the maximum allowed voltage, and conditions are actively implemented to ensure that the charging voltage V (e.g., a set point for the charging voltage V) is limited to be lower than or at most equal to V Lim_EVPresent .

[0029] According to one aspect, V Lim_EVPresent (thereby limiting the charging voltage) so that the potential difference between the charging voltage and the battery vehicle voltage is below the arc generation condition.

[0030] According to one aspect, the upper voltage limit V Lim_EVPresent is determined as a function of the current voltage of the EV that imposes arc limiting conditions. For example, the function can define an upper voltage limit V Lim_EVPresent The maximum voltage difference between the EV and the current voltage is set so that the upper voltage limit never exceeds VLim_EVPresent is greater than the predetermined maximum offset voltage. Therefore, the upper voltage limit V Lim_EVPresent It can be determined based on the current voltage of EV, so that V Lim_EVPresent The EV current voltage plus a predetermined maximum offset voltage is never exceeded. The predetermined offset voltage may be at most 50 V, preferably at most 30 V, and more preferably at most 20 V. The predetermined offset voltage may also be applied at least during discharge.

[0031] According to one aspect, the upper voltage limit V Lim_EVPresent By setting the positive offset voltage (or negative offset voltage during discharge) V offset The offset voltage is determined by adding it to the current EV voltage, and is at most 50 V, preferably at most 30 V, and more preferably at most (or equal to) 20 V. The offset voltage can be a fixed voltage, but it can also be variable, for example depending on additional conditions such as the current EV voltage, charging current or state of charge, or depending on external conditions such as temperature and / or humidity.

[0032] Therefore, the voltage difference between the battery’s current voltage and the charging voltage provided by the EVSE is limited by V offset The effect of this limitation is that the arc is strongly suppressed. For example, for these voltage differences, the arc may not occur at all, or at least be less likely to occur and / or at least remain short-lived.

[0033] Therefore, according to one aspect, V is selected Lim_EVPresent The potential difference between the load voltage and the EV current voltage is made lower than or equal to a predetermined offset voltage (e.g., 20 V). This limitation of the potential difference may have a limiting effect on any arcing that may occur despite taking other precautions.

[0034] The battery voltage changes dynamically during the charging process: for example, the final discharge voltage of the battery may be much lower than the final charge voltage of the battery. Therefore, according to one aspect, the current voltage of the EV is determined throughout the charging process, for example continuously or at least intermittently. Therefore, the voltage upper limit V can be adjusted dynamically. Lim_EVPresent (and optional voltage offset V offset ) to adapt to the changing vehicle battery voltage. In addition, there may be V Lim_EVPresent The lower limit of the arc voltage that may occur during thermal disconnection

[0035] On the other hand, during the charging process, the battery voltage changes only dynamically, but usually relatively slowly. Therefore, it is not always necessary to continuously monitor the battery voltage. A time delay can also be applied to the battery voltage limit V Lim_EVPresentTo limit the charging voltage V. The time delay can be at least 10 ms in an example, preferably at least 30 or 50 ms, or even 100 ms. The time delay can also be 100 ms, 200 ms, 500 ms, 1 s in an example, depending on the expected voltage rise that is considered normal.

[0036] This delay is particularly useful when determining the current voltage of an EV by measuring the voltage at the EV inlet. In this case, when an arc forms, the voltage measured at the EV inlet may rise to V Lim_EVPresent By applying a delay, it is possible to ensure that V Lim_EVPresent It does not increase too quickly due to a perceived rise in the EV's current voltage in the event of an arc (in this example, due to a rise in voltage measured at the EV inlet), so that any arcing remains limited.

[0037] According to one aspect, the voltage V EVSE_Target You can use V Lim_EVPresent and the EV target voltage V received from the EV EV_Target There may be other upper limits, such as V EVSE_MAX , which is the upper voltage limit of EVSE.

[0038] According to one aspect, the EVSE target voltage V EVSE_Target The charging voltage V is applied to the connector as a set point for the charging voltage V, and the EVSE target voltage is limited by the voltage upper limit V Lim_EVPresent In an illustrative example that is not part of the present invention, the set point of the charging voltage V is set in a manner independent of the current voltage of the EV, e.g.

[0039] V EVSE_Target =min(V EV_Target ,V EVSE_MAX ),

[0040] Where V EV_Target (sometimes also called V EV_Req ) is the voltage requested by the electric vehicle, and V EVSE_MAX is the upper voltage limit of the EVSE. According to one embodiment of the present invention, the set point can be set to

[0041] V EVSE_Target =min(V EV_Target ,V EVSE_MAX ,V Lim_EVPresent ),

[0042] Where V Lim_EVPresent It is the voltage upper limit determined by the current voltage of the EV.

[0043] This set point may be used, for example, for constant current or constant voltage control, or for some other control scheme.

[0044] According to one aspect, a charging method for a BEV battery may use at least one of constant current control and constant voltage control (which may be according to a CC method and / or a CV method), or constant power control.

[0045] According to one aspect, the EVSE can be configured to determine arcing conditions based on a determined current EV voltage (e.g., determined as the measured voltage at the inlet). Thus, the EVSE can identify the presence (or potential presence) of dielectric breakdown caused by an arc. Various conditions can be used for this purpose, such as a sharp increase or decrease in the current EV voltage within a short period of time, or some other pattern. Machine learning can also be used to determine suitable patterns and characteristics of an arc. These conditions can be stored in the memory of the EVSE's controller. When an arc or potential arc is determined in this or other ways, the EVSE can stop the charging process.

[0046] According to one aspect, an electric vehicle supply equipment (EVSE) is configured to perform a method according to any of the previous embodiments. Thus, the EVSE may have a controller with a processor and a memory, and the memory may contain instructions for the EVSE to perform the method.

[0047] According to one aspect, in the previously disclosed charging method, the upper voltage limit V Lim_EVPresent It can be determined to depend on the charge or discharge current. For example, fixed offset + R*I, where R can be the expected resistance and I is the charge / discharge current.

[0048] According to one aspect, the EVSE charging interface conductor and the EV charging interface conductor are or include at least one of the following: (a) a connector and an inlet; (b) a pantograph and a pantograph receiving conductor, such as a wire or a track. The vehicle can be a truck, a car, or a rail vehicle, such as a train or a subway.

[0049] Voltage upper limit V Lim_EVPresent Can be determined based on (depending on) the charge or discharge current. Voltage upper limit V Lim_EVPresent It can be determined based on (depending on) the charge or discharge current. For example, the upper voltage limit V Lim_EVPresent can be determined to be linearly dependent on the charge or discharge current, including a possible fixed offset. Lim_EVPresent can be calculated at least in part according to formula V Lim_EVPresent =V0+R*I, where V0 is the fixed offset, R is the expected resistance, and I is the charge / discharge current.

[0050] The above method may describe one mode of operation of the EVSE, but the EVSE may also operate in other modes of operation in which the charging voltage V is not necessarily limited as described herein, or at least the limit is reduced, for example, by increasing a predetermined offset voltage. For example, the EVSE may operate in the mode described herein under normal circumstances, but for certain vehicles (e.g., vehicles that are known to be able to reliably avoid possible causes of arcing) or certain situations where predetermined conditions are met (e.g., ultra-fast charging conditions or low battery voltage conditions), another mode of operation may be selected in which the limit is reduced or omitted. On the other hand, in certain other modes of operation, the limit on the charging voltage V may be further increased or partially different than described herein. According to certain aspects, the EVSE may operate exclusively or in a mode in which the charging voltage V is limited by an upper voltage limit V Lim_EVPresent Operate under the restrictions described in this document.

Claims

1. A method for charging or discharging an EV battery of an electric vehicle (EV) using electric vehicle supply equipment (EVSE), the method comprising: electrically coupling an EVSE charging interface conductor of the EVSE to an EV charging interface conductor of the EV; determining, by the EVSE, a current EV voltage provided by the EV battery at an inlet; as well as The EVSE at least one of charges or discharges the EV battery, wherein The charging comprises applying a charging voltage V to the connector; and the voltage upper limit V Lim_EVPresent to limit the charging voltage V, and where The discharging comprises applying a charging voltage V to the connector; and the voltage lower limit V Lim_EVPresent to limit the charging voltage V, and where The upper voltage limit V Lim_EVPresent The current voltage of the EV is determined. 2 . The method of claim 1 , wherein the EV current voltage is determined at regular intervals.

3. The method according to any one of the preceding claims, wherein the upper voltage limit V Lim_EVPresent According to the EV current voltage is determined so that V Lim_EVPresent Greater than the current voltage of the EV and at most +50V of the current voltage of the EV.

4. The method according to any one of the preceding claims, wherein the upper voltage limit V Lim_EVPresent is achieved by applying a positive offset voltage V offset The positive offset voltage is determined by adding it to the current voltage of the EV, and is at most 50V, preferably at most 30V, and more preferably at most 20V.

5. The method according to any one of the preceding claims, wherein a time delay is applied to the upper voltage limit V Lim_EVPresent The charging voltage V is limited.

6. Method according to claim 5, wherein the time delay is at least 10 ms, preferably at least 30 ms or even 50 ms.

7. The method of any one of the preceding claims, wherein the EV current voltage is determined by measuring the EV battery voltage.

8. The method according to any one of the preceding claims, wherein the EV current voltage is determined by receiving charging parameters of the EV battery from the EV by the EVSE.

9. The method according to any one of the preceding claims, wherein V EVSE_Target Is to use V Lim_EVPresent The minimum value and the EV target voltage V received from the EV EV_Target To be determined.

10. The method according to any one of the preceding claims, wherein the upper voltage limit V Lim_EVPresent The predetermined offset voltage is determined to be at most higher than the current voltage of the EV, the predetermined offset voltage is preferably at most 50V, more preferably at most 30V, and more preferably at most 20V.

11. The method of any one of the preceding claims, wherein the charging method for the BEV battery uses at least one of constant current control and constant voltage control.

12. A method according to any one of the preceding claims, wherein load current is interrupted to determine the EV's current voltage.

13. The method of any one of the preceding claims, wherein the EVSE is configured to determine an arc generation condition based on the determined EV present voltage.

14. The method according to any one of the preceding claims, wherein the upper voltage limit V Lim_EVPresent It is determined based on the charging current or discharging current.

15. An electric vehicle supply equipment configured to perform the method according to any preceding claim.

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