Battery Sensor

Abstract

The invention relates to a battery sensor (10), in particular a battery sensor for a vehicle battery, comprising two line sections (12, 16), a measuring resistor (20) arranged between the line sections (12, 16), and a voltage detection device for detecting a voltage drop across the measuring resistor (20), wherein the measuring resistor (20) is electrically conductively connected to the line sections (12, 16) at contact surfaces (24a, 24b). The longitudinal axes (32, 36) of the line sections (12, 16) are at an angle relative to the longitudinal axis (34) of the measuring resistor (20).

Description

Technical Field

[0001] The invention relates to a battery sensor, in particular a battery sensor for a vehicle battery, which has two line sections, a measuring resistor arranged between the line sections, and a voltage detection device for detecting a voltage drop across the measuring resistor, wherein the measuring resistor is electrically conductively connected to the line sections at a contact surface. Background Art

[0002] Battery sensors are used in vehicles to detect battery parameters of the vehicle battery in order to be able to draw conclusions about the state of charge and / or state of health of the battery. Battery parameters to be detected are, for example, the battery voltage, the battery current and the temperature of the battery. In particular, the battery voltage and the battery current must ideally be detected continuously in order, for example, to be able to draw precise conclusions about the state of charge of the battery.

[0003] The battery sensor is usually arranged on one of the battery electrodes and has, for example, a battery clamp for contacting the vehicle battery. In addition, the battery sensor has a connection end for a cable (for example, a ground cable).

[0004] In order to detect the battery current, for example, a measuring resistor is provided which is arranged in the current path of the load current and electrically connects two wire sections (these wire sections may be sections of the battery clamp and the connection terminal) to each other. In addition, a voltage detection device is provided for detecting the voltage drop across the measuring resistor. If the resistance of the measuring resistor is known, the current flowing through the measuring resistor (i.e., the battery sensor) can be calculated based on the detected voltage drop across the measuring resistor.

[0005] Due to the installation situation in the vehicle, in particular in the electrode recess of the vehicle battery, the battery sensor must be designed to be very compact. The electrode recess is usually formed by a substantially rectangular recess at the corner of the vehicle battery. In this case, the battery electrode projects from the substantially rectangular base surface of the recess perpendicularly to the base surface into the recess.

[0006] In addition, high requirements are placed on the battery sensor in terms of stability. In particular, due to the cables connected to the connection terminals of the battery sensor, large forces (in particular large pulling forces or vibrations) act on the battery sensor. Summary of the invention

[0007] The object of the present invention is to provide a battery sensor which has a very compact design and is sufficiently stable with respect to the loads occurring during vehicle operation.

[0008] To achieve this object, in a battery sensor, in particular a battery sensor for a vehicle battery, which has two line segments, a measuring resistor arranged between the line segments, and a voltage detection device for detecting a voltage drop across the measuring resistor, wherein the measuring resistor is conductively connected to the measuring resistor at a contact surface, it is proposed that the longitudinal axes of the line segments are at an angle relative to the longitudinal axis of the measuring resistor.

[0009] Due to the small space available in the electrode recess, the conductor section provided with the connection for the grounding cable is usually at an angle of 90° to the conductor section provided with the electrode clamp. However, due to the 90° angle, higher load peaks are obtained in the area of ​​the corners, which lead to the need to reinforce the battery sensor or to arrange additional supporting elements.

[0010] At the same time, the current flow is concentrated in this corner, since the shortest path between the electrode clamp and the ground cable, ie the path with the smallest possible resistance, leads through this corner.

[0011] In order to reduce the load and at the same time provide a compact battery sensor, the two conductor sections are angled relative to the longitudinal axis of the measuring resistor. The angle between the conductor section and the measuring resistor is therefore significantly smaller. The angle is selected so that there are no sharp corners between the measuring resistor and the corresponding conductor section, so that no load peaks of mechanical loads or only smaller load peaks of mechanical loads can be generated in this area. Therefore, the use of additional reinforcing elements can be substantially omitted, because the assembly consisting of the conductor section and the measuring resistor can absorb the generated loads.

[0012] Another advantage is that, due to the straighter current path, the current is distributed more evenly over the conductor section and the cross section of the measuring resistor. Local heating or temperature maldistribution due to maldistribution of the current can thus be prevented. A maldistribution of temperature can make it difficult to determine the temperature of the measuring resistor and thus of the battery sensor. The battery sensor described above can thus achieve a more accurate determination of the temperature.

[0013] The measuring resistor is made, for example, of a material with low temperature dependence, for example of a copper-nickel-manganese alloy. Alternatively, however, the measuring resistor can be made of any material suitable for such a measuring resistor, for example of copper or a copper alloy.

[0014] The conductor sections and the measuring resistor can be designed to be planar and extend in a plane. This plane can, for example, extend perpendicularly to the longitudinal axis of the electrode receptacle formed on the conductor section, so that in the assembled state the conductor sections and the measuring resistor extend at the battery electrode of the vehicle battery in a plane perpendicular to the longitudinal axis of the battery electrode.

[0015] The longitudinal axes of the conductor sections preferably form an angle of 28° to 60°, in particular 45°, relative to the longitudinal axis of the measuring resistor. At these angles, load peaks in the corners between the conductor section and the measuring resistor can be reliably reduced or prevented.

[0016] In particular, the longitudinal axis of the conductor section encloses different angles with the longitudinal axis of the measuring resistor. These angles can be adapted to the installation conditions, for example.

[0017] Preferably, the conductor section and the contact surface of the measuring resistor extend in planes which are substantially parallel to one another. As a result, the current paths are substantially the same length over the cross section of the measuring resistor, so that the resistance is constant or approximately constant over the entire cross section of the measuring resistor. Preferably, the measuring resistor has a substantially uniform cross section and / or a numerically constant cross-sectional area over the entire length.

[0018] Preferably, the cross-sectional area of ​​at least one wire segment in the region of the joint surface of the wire segment that abuts the contact surface corresponds at least to the cross-sectional area of ​​the measuring resistor at the contact surface. Therefore, the cross-sectional area of ​​the wire segment in the region adjacent to the contact surface corresponds at least to the cross-sectional area of ​​the contact surface or is larger than the cross-sectional area. The wire segment is thus connected to the contact surface of the measuring resistor in a planar manner. This improves the stability of the connection between the measuring resistor and the corresponding wire segment. In addition, the current flow in the battery sensor is thereby improved.

[0019] The line sections can be connected to the measuring resistor in any desired manner in order, for example, to provide a battery sensor that is as compact as possible.

[0020] The contact surface of the conductor section that bears against the contact surface can be inclined, for example, relative to the longitudinal axis of the conductor section, in particular at an angle of 28° to 60°, in particular at an angle of approximately 45°. The contact surfaces can each be inclined at different angles relative to the longitudinal axis of the respective conductor section.

[0021] In order to reduce the installation space of the battery sensor, the longitudinal axes of the line sections can be at an angle to one another, in particular at an angle of 90°.

[0022] The battery sensor can additionally have a housing which surrounds the measuring resistor, the voltage detection device and at least partially surrounds the line segments. The housing has the function of protecting the measuring resistor and the voltage detection device. In addition, the housing can also absorb mechanical loads acting on the battery sensor, in particular on the line segments, to a certain extent.

[0023] The housing is produced, for example, from plastic and is, in particular, injection-molded at least onto the conductor section in order to produce a stable connection between the housing and the conductor section.

[0024] The housing can additionally be connected at least to the line section in a materially and / or form-fitting manner in order to produce a stable connection between the housing and the line section, in particular for absorbing tensile loads.

[0025] For example, the holding section can be formed by a depression, an embossing and / or a recess, into which a projection of the housing projects. For example, the projection is produced during the production of the housing, in particular by an injection molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further advantages and features will be apparent from the following description in conjunction with the accompanying drawings. In the drawings:

[0027] Figure 1 A battery sensor from the prior art is shown;

[0028] Figure 2 Shown from Figure 1 A detailed view of the battery sensor, and

[0029] Figure 3 A battery sensor according to the present invention is shown. DETAILED DESCRIPTION

[0030] exist Figure 1 and Figure 2 1 shows a battery sensor 10' for detecting battery characteristic values. The battery sensor 10' has a first wire section 12' connected to an electrode clamp 14' and a second wire section 16' connected to a connection end 18' for a cable (e.g., a ground cable). The wire sections 12', 16' are electrically connected to each other via a measuring resistor 20'. In addition, a housing 22' is provided, which surrounds the measuring resistor 20' and at least partially surrounds the wire sections 12', 16'.

[0031] The measuring resistor 20 ′ is connected in an electrically conductive manner with a contact surface 24 a ′, 24 b ′ to a connection surface 26 a ′, 26 b ′ of the conductor sections 12 ′, 16 ′, respectively.

[0032] Furthermore, an evaluation unit (not shown in detail here) is provided in the housing 22', which is used to evaluate the battery value detected by the battery sensor 10'. The evaluation unit comprises, for example, a voltage detection device for detecting the voltage drop across the measuring resistor 20'. The voltage detection device contacts the contact points 28a', 28b' in front of and behind the measuring resistor 20'. A plug connection 30' is provided on the housing for outputting the measurement signal, for example to a vehicle control device.

[0033] The resistance of the measuring resistor 20 ′ is known. Based on the known resistance of the measuring resistor 20 ′ and the detected voltage drop, the current flowing through the measuring resistor 20 ′, ie, through the battery sensor 10 ′, can be determined.

[0034] The measuring resistor 20' can be made of a material with low temperature dependence, for example a copper-nickel-manganese alloy. Alternatively or additionally, a correction value for the resistor can be determined accordingly by the evaluation unit in order to correct for resistance changes (for example due to aging phenomena or temperature changes).

[0035] As especially in Figure 2 As can be seen in FIG. 1 , the longitudinal axis 32 ′ of the first conductor section 12 ′ extends parallel to the longitudinal axis 34 ′ of the measuring resistor 20 ′. The longitudinal axis 36 ′ of the second conductor section 16 ′ extends at right angles to the longitudinal axis 34 ′ of the measuring resistor 20 ′. Since the battery sensor 10 ′ is very compact, it can be inserted, for example, into an electrode recess of a vehicle battery.

[0036] The arrangement of the measuring resistor 20' at right angles to the second conductor section 16' results in an inner angle 38' at the battery sensor. If a tensile force 40' acts on the cable connected to the second conductor section 16', this inner angle is highly loaded (especially due to notch stresses). Figure 1 and Figure 2 In the battery sensor 10 ′ shown in FIG. 1 , the transition region from the measuring resistor 20 ′ to the second conductor section 16 ′ needs to be reinforced in order to be able to absorb these stress peaks.

[0037] Furthermore, the arrangement of the measuring resistor 20' and the second conductor section 16' at right angles leads to an uneven current distribution in the measuring resistor 20' or the second conductor section 16'. The shortest path between the first conductor section 12' and the connection 18', i.e. the current path with the least resistance, leads directly through the region adjacent to the inner corner 38'. This leads to a higher current density in this region, which can, for example, lead to a local heating of the measuring resistor 20' and the second conductor section 16'.

[0038] exist Figure 3The battery sensor 10 according to the invention shown in FIG. 1 has substantially the same components as the battery sensor 10 ′ described above. In particular, the measuring resistor 20 has substantially the same dimensions as the measuring resistor 20 ′ described above. However, other measuring resistors 20 , in particular measuring resistors 20 having other dimensions, can also be used.

[0039] As especially in Figure 3 As can be seen in FIG. 2 , the contact surfaces 24a, 24b are arranged parallel to each other. In addition, the longitudinal axes 32, 36 of the conductor sections 12, 16 are arranged substantially at right angles to each other, so that the orientation of the second conductor section 16 is substantially the same as in FIG. Figure 1 and Figure 2 The orientation of second line section 16 ′ shown in , corresponding to that of battery sensor 10 ′ from the prior art.

[0040] However, battery sensor 10 differs from battery sensor 10' described above in that longitudinal axis 34 of measuring resistor 20 is angled with longitudinal axis 32 of first wire segment 12 and longitudinal axis 36 of second wire segment 16. In the embodiment shown here, angle 42 between longitudinal axis 32 of first wire segment 12 and longitudinal axis 34 of measuring resistor 20 is approximately 145°. In the embodiment shown here, angle 44 between longitudinal axis 36 of second wire segment 16 and longitudinal axis 34 of measuring resistor 20 is approximately 125°.

[0041] Due to the angle between the second conductor section 16 and the measuring resistor 20, the inner angle 38 is formed significantly less sharply, so that significantly less stress (especially notch stress) is generated at the inner angle 38 due to the pulling force 40 acting on the second conductor section 16. In addition, due to the smaller angle between the second conductor section 16 and the measuring resistor 20, the current distribution over the cross section of the measuring resistor 20 is substantially more uniform, so that local heating of the measuring resistor 20 and the second conductor section can be significantly lower or can even be completely avoided.

[0042] In order to achieve the highest possible stability of battery sensor 10 , longitudinal axis 34 of measuring resistor 20 forms an angle of between 30° and 60°, preferably approximately 45°, with longitudinal axes 32 , 36 of conductor sections 12 , 16 .

[0043] The contact surfaces 24a, 24b are parallel to one another, so that the current path on the measuring resistor 20 is substantially of equal length over the entire cross section of the measuring resistor 20. In contrast, the contact surfaces 26a, 26b are respectively inclined relative to the longitudinal axes 32, 36 of the conductor sections 12, 16. That is, the longitudinal axes 32, 36 of the conductor sections 12, 16 are angled by the inclined contact surfaces 26a, 26b. Preferably, the contact surfaces 26a, 26b are inclined at an angle 42, 44 of 30° to 60°, in particular at an angle of approximately 45°.

[0044] The angle between the longitudinal axes 32, 36 of the conductor sections 12, 16 is preferably 90°, so that instead of Figure 1 and Figure 2 The battery sensor 10 ′ described in illustrative embodiments uses the above-described battery sensor 10 without changing the installation conditions at the vehicle battery, in particular without changing the installation conditions in the vehicle.

[0045] Reference numerals list

[0046] 10,10' Battery Sensor

[0047] 12, 12' First conductor section

[0048] 14, 14' electrode clamp

[0049] 16, 16' Second conductor section

[0050] 18, 18' connection end

[0051] 20, 20' Measuring resistor

[0052] 22, 22' shell

[0053] 24a, 24a' first contact surface

[0054] 24b, 24b' Second contact surface

[0055] 26a, 26a' first joint surface

[0056] 26b, 26b' Second joint surface

[0057] 28a', 28b' contact position

[0058] 30' plug-in connector

[0059] 32, 32' Longitudinal axis of the first conductor section

[0060] 34, 34' longitudinal axis of the measuring resistor

[0061] 36, 36' Longitudinal axis of the second conductor section

[0062] 38 interior angle

[0063] 40 traction force

Claims

1. A battery sensor (10), comprising two conductor sections (12, 16), a measuring resistor (20) arranged between the conductor sections (12, 16), and a voltage detection device for detecting a voltage drop across the measuring resistor (20), wherein the measuring resistor (20) is electrically conductively connected to the conductor sections (12, 16) at contact surfaces (24a, 24b), It is characterized in that The longitudinal axes (32, 36) of the conductor sections (12, 16) are angled relative to the longitudinal axis (34) of the measuring resistor (20), wherein the cross-sectional area of ​​at least one conductor section (12, 16) in the region of a joining surface (26a, 26b) of the conductor section (12, 16) which abuts against a contact surface (24a, 24b) corresponds at least to the cross-sectional area of ​​the measuring resistor (20) at the corresponding contact surface (24a, 24b), and the joining surface (26a, 26b) of at least one conductor section (12, 16) extends at an angle of 30° to 60° relative to the longitudinal axis of the corresponding conductor section (12, 16), wherein the longitudinal axes (32, 36) of the conductor sections (12, 16) are each angled at 120° to 150° relative to the longitudinal axis (34) of the measuring resistor (20).

2. The battery sensor according to claim 1, characterized in that: The longitudinal axes (32, 36) of the conductor sections (12, 16) are each at an angle of at least 135° relative to the longitudinal axis (34) of the measuring resistor (20).

3. The battery sensor according to any one of claims 1 and 2, characterized in that: The contact surfaces (24a, 24b) of the measuring resistor (20) extend in planes parallel to one another.

4. The battery sensor according to claim 1 or 2, characterized in that: A joining surface (26a, 26b) of at least one conductor section (12, 16) extends at an angle of 45° relative to a longitudinal axis of the corresponding conductor section (12, 16).

5. The battery sensor according to claim 1 or 2, characterized in that: The longitudinal axes (32, 36) of the wire segments (12, 16) are angled with respect to each other.

6. The battery sensor according to claim 1 or 2, characterized in that: The measuring resistor (20) and the line sections (12, 16) are of planar design and extend in a common plane.

7. The battery sensor according to claim 6, characterized in that: The battery sensor (10) has a housing (22) which surrounds a measuring resistor (20), a voltage detection device and at least partially surrounds line sections (12, 16).

8. The battery sensor according to claim 7, characterized in that: The housing (22) is made of plastic.

9. The battery sensor according to claim 7, characterized in that: The housing (22) is connected at least to the conductor sections (12, 16) in a materially and / or form-fitting manner.

10. The battery sensor according to claim 1, characterized in that: The battery sensor (10) is designed for a vehicle battery.

11. The battery sensor according to claim 5, characterized in that: The longitudinal axes (32, 36) of the conductor sections (12, 16) are at an angle of 90° to one another.

12. The battery sensor according to claim 8, characterized in that: The housing (22) is injection-molded at least onto the conductor sections (12, 16).

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