Battery sensor for detecting charging and discharging currents

Abstract

The invention relates to a battery sensor for detecting a charging current and a discharging current of a battery, in particular of a vehicle battery, wherein the battery sensor has a first current path for the charging current of the battery, in addition to which the battery sensor has a second current path for the discharging current and at least one current measuring device for detecting the charging current and the discharging current, characterized in that the first current path and the second current path have a shared line section.

Description

Technical Field

[0001] This invention relates to a battery sensor for detecting the charging and discharging currents of batteries, particularly vehicle batteries. Background Technology

[0002] High-voltage batteries are used in vehicles, especially electric or hybrid vehicles. During vehicle operation, it is necessary to continuously monitor the battery current to accurately determine the battery's charge level. This involves both the battery's charging and discharging currents, i.e., the vehicle's current consumption.

[0003] To significantly shorten charging time, the charging current is considerably greater than the discharging current generated during normal vehicle operation. The problem here is measuring the higher charging current during charging versus the discharging current generated during normal vehicle operation with the same accuracy. Current sensors designed for charging current are, for example, unsuitable for detecting with sufficient accuracy the significantly smaller current generated during normal vehicle operation compared to the charging current. Summary of the Invention

[0004] The purpose of this invention is to provide a battery sensor that is suitable for detecting both charging current and discharging current.

[0005] To achieve this objective, a battery sensor is proposed for detecting the charging and discharging currents of a battery, particularly a vehicle battery. The battery sensor has a first current path for the charging current, a second current path for the discharging current, and at least one current measuring device for detecting the charging and discharging currents. The first and second current paths share a common circuit section.

[0006] This invention is based on the consideration of providing multiple current paths within the battery sensor, these current paths being designed for the corresponding generated charging and discharging currents. To keep manufacturing costs as low as possible, a shared circuit section is provided for use by two of the current paths.

[0007] In addition to the shared line section, at least one of these current paths has an additional line section. This line section can, for example, be used to reduce the voltage by series resistors to a level where the current measuring devices arranged in the shared line section can detect the current in both current paths with the same accuracy. Alternatively, independent current measuring devices can be provided in the separate line sections of the two current paths, with their measuring ranges designed for the respective currents to be detected. Additional current measuring devices can be provided in the shared line section for reliability testing of the detected currents.

[0008] Placing the current measuring device outside the shared circuit section has the following advantages: it allows the measurement accuracy of the current measuring device to be matched with the corresponding measurement range. Thus, a high-precision current measuring device for discharge current is not affected by very high charging currents. This can, for example, slow down the aging process or extend the calibration interval. However, independently, additional components, such as an evaluation unit, can be used within the battery sensor for both current measuring devices. For example, it can also be implemented where the current measuring device only detects the measured values, and these values ​​are processed in a shared evaluation unit.

[0009] Preferably, the resistance of the first current path is less than the resistance of the second current path. The charging current is typically significantly greater than the discharging current. Importantly, the charging current is conducted to the battery with low power loss. Therefore, the first current path, which requires the charging current, has a smaller resistance.

[0010] For example, the battery sensor has a charging current contact for a first current path and a discharging current contact for a second current path, as well as a battery contact for contacting the vehicle battery, wherein a common wiring section is connected to the battery contact.

[0011] In the above embodiment, the battery sensor can have an electrical conductor extending from the discharge current contact to the battery contact, wherein the charging current contact is disposed on the electrical conductor between the charging current contact and the battery contact. Therefore, the battery sensor has only one electrical conductor, wherein the discharge current flows through the entire electrical conductor, and the charging current flows only through a portion of the electrical conductor, i.e., a shared circuit segment. Thus, the above structure can be implemented at a very low construction cost. In particular, the electrical conductor can be prefabricated, allowing different resistors to be integrated into it.

[0012] For example, current measurement can be performed in a shared line section, wherein at least one first measurement section is provided in the shared line section, wherein the measurement section has at least one first current measuring device for detecting the current flowing through the measurement section.

[0013] Optionally or additionally, current measurements can also be performed in sections outside the shared line section.

[0014] For this purpose, for example, a second measurement section is provided in the first current path, outside the shared line section, wherein the second measurement section has at least one second current measuring device.

[0015] In addition, a third measurement section may be provided in the second current path, outside the shared line section, wherein the third measurement section has at least one third current measuring device.

[0016] Therefore, current measuring devices outside the shared line section are designed to have their measurement range matched accordingly to the charging or discharging current. If a current measuring device is also provided within the shared line section, it can have a lower measurement accuracy, as it is only used to verify or test the reliability of measurements from other current measuring devices.

[0017] Optionally, the battery sensor may have a particularly wireless receiving device for receiving current measurements, particularly measurements of the charging current. Typically, charging stations for electric vehicles have their own current measuring devices, primarily for billing the current already charged. To test the reliability of the measured battery values, it is also conceivable to transmit the measurements from this current measuring device to the vehicle or the battery sensor and compare these measurements with those from the battery sensor. For example, a current measuring device, primarily for the discharge current, may be located within the battery sensor in a second current path, while a less accurate current measuring device may be located in a shared section of the line. The measurements from this current measuring device can be compared with and corrected for by the current measurements received from the charging station.

[0018] Different current measurement principles can be used for the first current measuring device, the second current measuring device, and the third current measuring device.

[0019] For example, the first measurement section, the second measurement section, and / or the third measurement section may have at least one measuring resistor, wherein the first current measuring device, the second current measuring device, and / or the third current measuring device have a voltage detection device capable of detecting the voltage drop across the measuring resistor. If the resistance of the corresponding measuring resistor is known, the current flowing through the measuring resistor (i.e., charging current or discharging current) can be calculated based on the voltage drop detected across the measuring resistor. Furthermore, the measuring resistor can also be used to correspondingly set the resistance of the first current path and the second current path.

[0020] Alternatively or additionally, at least one magnetic current sensor may be provided in each of the first, second, and / or third measurement sections. Attached Figure Description

[0021] Other advantages and features can be derived from the following description in conjunction with the accompanying drawings. In the accompanying drawings:

[0022] Figure 1 A schematic diagram showing a first embodiment of the battery sensor according to the present invention is shown;

[0023] Figure 2 A second embodiment of the battery sensor according to the present invention is shown;

[0024] Figure 3 A third embodiment of the battery sensor according to the present invention is shown;

[0025] Figure 4 A diagram showing an electrical conductor used in a battery sensor according to the present invention is provided. Detailed Implementation

[0026] exist Figure 1 The diagram illustrates a charging scheme 10 for vehicle 12. Vehicle 12 has a battery 14, a power consumer 16, and a battery sensor 18. The power consumer 16 may be, for example, vehicle electronics or the vehicle's electric motor. Additionally, a charging station 20 is shown, which can be connected to a charging plug 22 on vehicle 12 to charge the battery 14.

[0027] The battery sensor 18 has a charging current contact 24 that can be connected to the charging plug 22, a discharging contact 26 that can be connected to the power consumer 16, and a battery contact 28 that can be connected to the vehicle battery 14.

[0028] The first current path 30 extends from the charging current contact 24 to the battery contact 28. The second current path 32 extends from the discharging contact 26 to the battery contact 28. (As in...) Figure 1 As can be seen, the two current paths 30 and 32 have a shared line segment 34 extending from a common node 36 to the battery contact 28. The first current path 30 also has a first line segment 38 extending from node 36 to the charging current contact 24. The second current path 32 has a second line segment 40 extending from node 36 to the discharging contact 26.

[0029] A measuring resistor 42 is arranged in the first line section 38, which has a resistance of 10 microohms in the embodiment shown here. A measuring resistor 44 is provided in the second line section 40, which has a resistance (50 microohms in the embodiment shown here) greater than that of the resistor 42 in the first line section 38.

[0030] Two current measuring devices 43 and 45, each equipped with a voltage detection device, are provided on the two measuring resistors. These voltage detection devices can detect the voltage drop across the corresponding measuring resistors 42 and 44 caused by the current flowing through the corresponding line section. Based on the detected voltage drop across the corresponding measuring resistors 42 and 44 and the known resistance, the current flowing through line sections 38 and 40 can be calculated using Ohm's law.

[0031] If a connection is established between the charging current contact 24 and the charging station 20, a first circuit 46 is formed, which extends from the charging station 20 to the battery 14 via a first current path 30. The first circuit from the battery 14 to the charging station 20 is closed, and the first circuit 46 can extend through the power consumer 16. The vehicle battery 14 can be charged via the first circuit 46.

[0032] As in Figure 1 As can be seen, the first circuit 46 extends only through the first current path 30 and therefore only through the first measuring resistor 42. Preferably, the second circuit 46 does not extend through the power consumer 16. In this embodiment, the second measuring resistor 44, the discharge contact 26, and therefore a portion of the second current path 32 are located outside the first circuit 46.

[0033] If the connection to the charging station 20 is disconnected, current flows through the second circuit 48, which includes the vehicle battery 14, the second current path 32, and the vehicle electronics 16. During normal vehicle operation, current is supplied to the power consumers 16 through the second circuit 48, wherein current consumption is measured by a measuring resistor 44 and a voltage detection device disposed thereon.

[0034] The two circuits 46 and 48 share a common line segment 34 that is directly connected to the battery contact 28. Therefore, only one contact is needed between the battery sensor 18 and the battery 14.

[0035] However, the connection terminals for the charging station 20 and the power consumer 16 are implemented independently, thus allowing the current paths 30 and 32 to be designed for the corresponding current intensities via line sections 38 and 40 located outside the shared line section 34. In particular, the resistance of the first measuring resistor 42 is very small, thus enabling charging of the vehicle battery with minimal loss. Especially, because the resistance of the first measuring resistor 42 is small, it prevents the measuring resistor from overheating due to the high charging current. Overheating would lead to significant power loss and potentially cause changes in the resistance of the measuring resistor 42.

[0036] The resistance of the second measuring resistor 44 is chosen to be relatively large, resulting in a larger voltage drop caused by the discharge current. This allows for the measurement of the discharge current with higher accuracy. The at least partial separation of the first current path 30 and the second current path 32 has the advantage that higher charging currents do not flow through the current measuring device of the second circuit 32. Higher currents could cause the current measuring device or measuring resistor 44 to be subjected to a larger load and / or become hotter, potentially causing it to age faster or require more frequent calibration.

[0037] Optionally, to more accurately determine the charging current, a receiving device may be provided, which can receive the measurement value from an external current measuring device. This receiving device may be designed to be wireless or connected to the battery sensor 18 via a cable, for example, through the charging current contact 24.

[0038] An external current measuring device could be, for example, part of the charging station 20, where very accurate current measurements are performed to bill the current already charged. The measured current value can be transmitted to the battery sensor 18 via a receiving device and taken into account by the battery sensor to improve measurement accuracy.

[0039] In the embodiment shown here, the current in the first current path 30 and the second current path 32 is measured by detecting the voltage drop across the measuring resistors 42 and 44. Alternatively, other measurement methods, such as magnetic measurement methods, can be used. In particular, measurement methods with lower accuracy can also be used to detect the charging current.

[0040] exist Figure 2 The embodiment shown here differs from the embodiment described above only in that a current measuring device 43 based on the magnetic principle is used instead of the first measuring resistor 42. Therefore, the resistance of the first current path 30 can be further reduced.

[0041] exist Figure 3 In the embodiment shown, the first segment 38 of the first current path 30 does not have a measuring resistor. Instead, a third measuring resistor 50 with a current measuring device 51 is provided in the shared line segment 34. This arrangement offers the advantage that the discharge current can be obtained using two current measuring devices 45, 51, thus allowing for reliability testing of the measured current values. Furthermore, the charging current can also be obtained using the current measuring device 51, wherein the second current measuring device 45 is located in the second segment 40 of the second current path 32, rather than in the first circuit, and is therefore unaffected by the charging current load.

[0042] exist Figure 4 The image shows the use of Figure 3 The battery sensor 18 shown has an electrical conductor. The electrical conductor is cut from a substrate 54 having a first segment 56, a second segment 58, and an elongated resistor segment 60. The first segment 56 and the second segment 58 are made of a conductive material, such as copper or a copper alloy. The elongated resistor segment 60 is made of a resistive material, such as a copper-nickel-manganese alloy whose resistance has a low temperature dependence.

[0043] Electrical conductors are cut from substrate 54, with the first measuring resistor 42 and the third measuring resistor 48 cut from resistor section 60, and the remaining circuit sections cut from these two sections 56 and 58. Battery contacts and discharge contacts are located on the second section 58, and charging current contacts are located on the first section 56.

[0044] The first current path 30 is formed between the charging current contact and the battery contact, so the charging current flows through only one resistor, namely the third measuring resistor 48. The second current path 32 is formed between the discharging current contact and the battery contact, so the discharging current flows through two measuring resistors 44 and 48.

[0045] As in Figure 4 As can be seen, the two measuring resistors 44 and 48 are the same length, but their widths differ. The third measuring resistor 48 is designed to be significantly wider, thus having a smaller resistance. Therefore, different resistances can be achieved in a simple way by measuring the widths of the resistors 44 and 48.

[0046] Independent of the embodiments shown herein, additional and / or multiple current measuring devices may be arranged in individual sections to improve measurement accuracy.

Claims

1. A battery sensor for detecting charging current and discharging current of a battery, wherein the battery sensor has a first current path for the charging current of the battery, and further has a second current path for the discharging current, and at least one current measuring device for detecting the charging current and the discharging current, characterized in that, The first current path and the second current path have a shared line section, wherein an additional current measuring device is provided in the shared line section, wherein the at least one current measuring device and the additional current measuring device only detect measured values, and these measured values ​​are processed in a shared evaluation unit.

2. The battery sensor according to claim 1, characterized in that, The battery sensor has a charging current contact for the first current path and a discharging current contact for the second current path, as well as a battery contact for contacting the battery, wherein the common line segment is connected to the battery contact.

3. The battery sensor according to claim 2, characterized in that, The resistance of the first current path is less than the resistance of the second current path.

4. The battery sensor according to claim 2 or 3, characterized in that, The battery sensor has an electrical conductor extending from the discharge current contact to the battery contact, wherein the charging current contact is disposed on the electrical conductor between the charging current contact and the battery contact.

5. The battery sensor according to claim 1 or 2, characterized in that, At least one first measurement section is provided in the shared line section, wherein the measurement section has at least one first current measuring device for detecting the current flowing through the measurement section.

6. The battery sensor according to claim 5, characterized in that, A second measurement section is provided in the first current path, outside the shared line section, wherein the second measurement section has at least one second current measuring device.

7. The battery sensor according to claim 6, characterized in that, A third measurement section is provided in the second current path, outside the shared line section, wherein the third measurement section has at least one third current measuring device.

8. The battery sensor according to claim 7, characterized in that, The first measurement section, the second measurement section, and / or the third measurement section have at least one measuring resistor, wherein the first current measuring device, the second current measuring device, and / or the third current measuring device have a voltage detection device, which is capable of detecting the voltage drop across the measuring resistor.

9. The battery sensor according to claim 7, characterized in that, At least one magnetic current sensor is provided in the first measurement section, the second measurement section and / or the third measurement section.

10. The battery sensor according to claim 1 or 2, characterized in that, The battery sensor has a wireless receiver for receiving current measurements.

11. The battery sensor according to claim 1, characterized in that, The battery in question is a vehicle battery.

12. The battery sensor according to claim 10, characterized in that, The current measurement value is the current measurement value of the charging current.

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