DE102011111081A1 - Battery sensor for battery installed in motor vehicle, has several tongue structures that are arranged at specific distance away from terminal clamp, for providing mechanical support of current measuring resistor at terminal clamp - Google Patents

Abstract

The battery sensor has a terminal clamp (2) that is made of an electrically conductive material, for holding an electrical terminal particularly ground contact terminal of the battery. A low impedance current measuring resistor (4) is arranged for measuring the battery power which is charged or discharged through the battery. Several tongue structures (8-10) are arranged at a distance away from the terminal clamp, for providing mechanical support of the current measuring resistor at the terminal clamp. An independent claim is included for a battery.

Description

The invention relates to a battery sensor for a battery, in particular for a motor vehicle battery.

In modern motor vehicle electrical systems, the battery current (charging current or discharge current) can be measured by a battery sensor, which is integrated in the pole terminal, which is connected to the ground terminal of the motor vehicle battery. The actual measurement of the battery current is usually carried out by a low-impedance current measuring resistor ("shunt"), which is traversed by the battery current, so that the voltage drop across the low-impedance current measuring resistor according to the Ohm's law forms a measure of the battery current. For example, a current measuring resistor can be used as it is made EP 0 605 800 A1 is known. In addition, in the battery sensor, an electronic measuring circuit can be integrated, as for example EP 1 363 131 A1 and EP 1 030 185 A2 is known.

A problem with these known battery sensors is the mechanical stress that can result from improper use, for example, if an installer wants to lift the vehicle battery on the ground cable from the mounting space, since then the entire weight of the vehicle battery must be absorbed by the battery sensor.

Out DE 10 2004 051 489 A1 and DE 10 2004 055 848 A1 Various possible designs of battery sensors are known in which the low-impedance current measuring resistor forms an integral part of the pole terminal or is welded to the pole terminal. However, these known constructions of a battery sensor are relatively expensive or mechanically not sufficiently resilient.

The invention is therefore based on the object to provide a correspondingly improved battery sensor.

This object is achieved by a battery sensor according to the invention according to the main claim.

The battery sensor according to the invention is preferably designed for a motor vehicle battery, but the battery sensor according to the invention is also suitable for other types of batteries. It should also be noted that the invention in terms of the battery is not limited to specific battery capacities and battery voltages and is basically suitable for both rechargeable batteries and non-rechargeable batteries.

In accordance with the prior art, the battery sensor according to the invention also comprises a pole terminal made of an electrically conductive material, wherein the pole terminal can be mounted on a battery pole of the battery in order to establish an electrical and mechanical connection between the pole terminal and the battery pole. Preferably, the pole terminal is mounted in operation at the ground pole of the battery, but in principle it is also possible to attach the pole terminal to the voltage pole of the battery.

In addition, the battery sensor according to the invention also has a low-impedance current measuring resistor for measuring the battery current, the current measuring resistor flowing through the battery current during operation, so that the voltage drop across the low-impedance current measuring resistor forms a measure of the battery current in accordance with Ohm's law. For example, in the context of the invention, a current measuring resistor can be used, as in EP 605 800 A1 is described. However, the invention is basically also feasible with other types of current measuring resistors.

The invention now provides that the pole terminal has a plurality of tongues protruding from the pole terminal for mechanically holding the current measuring resistor. This type of mechanical support of the current sense resistor can provide greater mechanical resilience over the conventional designs described above.

The term tongue used in the context of the invention preferably comprises an elongated holder, which is preferably attached or integrally formed on the pole terminal. In the preferred embodiment of the invention, the tongues each have a rectangular cross-section, but tongues with other cross-sections are possible within the scope of the invention.

Preferably, the tongues are integrally formed on the pole terminal and consist in the core of the same material as the pole terminal, which allows a simple and cost-effective production of the pole terminal with the tongues.

In a preferred embodiment of the invention, at least one of the tabs of the pole terminal is electrically conductive to electrically contact a terminal portion of the current sense resistor, in particular by welding or soldering the respective tab to the terminal portion of the current sense resistor. So this tongue has a mechanical and electrical double function by the tongue for a mechanical support of the Current sense resistor serves and on the other hand causes an electrical contacting of the current measuring resistor.

Furthermore, in the preferred embodiment of the invention, at least one of the tabs of the pole terminal is electrically insulated outwardly to avoid electrical contact of that tab with the current sense resistor, otherwise this would result in an electrical short across the current sense resistor. This electrically insulated tongue of the pole terminal thus serves only for mechanical support of the current measuring resistor and otherwise has no electrical contacting function.

In the preferred embodiment of the invention, the pole terminal has at least two such electrically isolated tongues which surround the current measuring resistor at the top and at the bottom. This is advantageous because a power supply cable is usually connected to the terminal part of the current measuring resistor which is not contacted by the pole terminal, so that considerable forces can act on this connection part of the current measuring resistor. If the forces acting on the free connection part are directed upwards, these forces are absorbed by the tongue of the pole terminal arranged on the upper side of the current measuring resistor and are mechanically discharged. On the other hand, if the mechanical forces acting on the free connection part of the current measuring resistor are directed downwards, these forces are absorbed and discharged by the tongue arranged on the underside of the current measuring resistor.

In addition, the battery sensor according to the invention preferably also has an integrated electronic measuring circuit, which measures the voltage drop across the current measuring resistor as a measure of the battery current. For example, for this purpose, a measuring circuit can be used, as in EP 1 030 185 A2 or EP 1 363 131 A1 is described. However, the invention is not limited in the construction of the measuring circuit to the measuring circuits described in the above-mentioned references.

In the preferred exemplary embodiment of the invention, the battery sensor for accommodating the electronic measuring circuit has a printed circuit board, wherein the printed circuit board is preferably arranged directly on the current measuring resistor.

On the one hand, this direct arrangement of the printed circuit board with the measuring circuit on the current measuring resistor is advantageous because it allows a stable design and a very low inductance to be achieved.

On the other hand, a good thermal contact between the printed circuit board and the current measuring resistor can be achieved in this way, whereby the disturbing influence of thermal voltages can be minimized.

In the preferred embodiment of the invention, the printed circuit board on its underside on voltage taps to measure the electrical voltage across the current measuring resistor, wherein the two voltage taps of the circuit board with two connection parts of the current sense resistor are electrically connected, in particular by a soldering. The measuring circuit (eg ASIC: Application Specific Integrated Circuit) is hereby preferably arranged on the upper side of the printed circuit board, but alternatively it is also possible to arrange the measuring circuit on the underside of the printed circuit board.

The power supply of the battery sensor and in particular of the measuring circuit integrated in the battery sensor preferably takes place via an electrical voltage input, via which a supply voltage is fed in, which is usually the battery voltage. In addition, the battery sensor can then also measure the supply voltage by means of the measuring circuit. The battery sensor according to the invention thus allows not only a measurement of the battery current in the preferred embodiment, but also a measurement of the battery voltage.

In addition, the battery sensor according to the invention preferably has a data output in order to be able to output measured values (eg battery current, battery voltage, etc.) via the data output.

In the preferred embodiment, the data output and the voltage input are realized in the same plug contact, thereby simplifying the electrical contact of the battery sensor.

The data output preferably provides a digital data bus, such as a CAN bus (CAN: Controller Area Network) or a LIN bus (LIN: Local Interconnect Network). However, the invention is not limited to these types of buses in terms of the data structure at the data output, but can be realized with other parallel or serial bus types.

Furthermore, the battery sensor according to the invention preferably also has a temperature measuring device which can measure different temperatures or temperature differences.

First, the temperature measuring device, the temperature of the current sense resistor to account for temperature variations in the resistance of the current sense resistor when measuring the battery current. This is advantageous because, in the calculation of the battery current according to Ohm's law, the resistance value of the current measuring resistor is assumed to be known.

On the other hand, the temperature measuring device can measure the temperature difference between the connection parts of the current measuring resistor. This is advantageous because at such a temperature difference, a slight thermal voltage can occur, which distorts the voltage measurement and thus the measurement of the battery current. By measuring this temperature difference, the thermoelectric voltage can then be calculated and taken into account compensatorily in the measurement of the battery current.

In the preferred exemplary embodiment of the invention, the battery sensor has an electrically insulating plastic casing which completely or partially encloses the current measuring resistor, the printed circuit board, the measuring circuit, the plug contact, the temperature measuring device and / or the tongues of the pole terminal.

In the preferred embodiment of the invention, the plastic coating together with the tongues for mechanical support of the current sense resistor. The tongues then fulfill their mechanical stabilization function only in conjunction with the plastic casing. The tongues themselves therefore do not have to be directly adjacent to the current measuring resistor in order to be able to hold the current measuring resistor. However, there is also the possibility within the scope of the invention that the tongues bear directly against the current measuring resistor and therefore mechanically hold the current measuring resistor independently of the plastic casing.

This plastic sheath is preferably made of a thermoset, which is advantageous for various reasons. First, Duroplast adheres well to metal, which simplifies manufacturing. On the other hand Duroplast is also moisture-proof at transition points between the thermoset and the metal of the current measuring resistor. A further advantage of thermosetting plastic as a material for the plastic coating is that the thermal expansion coefficient of thermosetting plastic is adapted to the thermal expansion coefficient of metal, so that no thermal problems arise with temperature changes. In addition, thermoset is also mechanically stronger than other plastics, whereby the mechanical strength of the battery sensor according to the invention is further improved. Furthermore, thermoset is extremely thin during encapsulation and does not damage electronic components, which is not the case for example with thermoplastics. Finally, thermoset allows easy production by the plastic coating is simply overmolded.

However, the invention is not limited to thermoset material in terms of the material of the plastic, but in principle also with other plastics feasible, which are preferably thermally conductive and preferably have the same thermal expansion behavior as the circuit board, the current measuring resistor and / or the measuring circuit.

It should also be mentioned that, in the preferred exemplary embodiment, the current measuring resistor partially protrudes from the plastic casing with one of its two plate-shaped connection parts and forms a power connection with the protruding part in order to initiate or discharge the battery current.

It should also be mentioned that the invention is not limited to the battery sensor according to the invention described above as a single component, but also includes a battery on which a battery sensor according to the invention is mounted.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:

1 an exploded view of a battery sensor according to the invention,

2A a perspective view of a pole terminal of the battery sensor according to the invention,

2 B a perspective view of the pole terminal according to 2 with the current measuring resistor already mounted therein,

2C 3 is a perspective view of a further assembly step with the printed circuit board already arranged on the current measuring resistor with a measuring circuit;

2D a further assembly step with a plug contact connected to the circuit board, as well

2E a perspective view of a fully assembled battery sensor according to the invention.

The drawings show a battery sensor according to the invention 1 (see. 2E ), which can be used to measure the battery current (charging current or discharge current) in a conventional motor vehicle battery.

For this purpose, the battery sensor 1 a pole clamp 2 on, which plugged for measuring the battery current to the ground terminal of the motor vehicle battery and then by means of a Schraubflanschs 3 is attached to the ground terminal, whereby an electrical and mechanical connection between the terminal post 2 and the ground pole of the motor vehicle battery is manufactured.

The measurement of the battery current is carried out according to the known four-wire technology by means of a low-impedance current measuring resistor 4 , where the current measuring resistor 4 may be formed in a conventional manner, such as in EP 0 605 800 A1 is described. So has the current measuring resistor 4 two plate-shaped connecting parts 5 . 6 of a conductor material (eg copper or a copper alloy) and also a plate-shaped resistance element 7 of a low resistance alloy (z. B. Manganin ^®), wherein the resistance element 7 in the current path between the two connection parts 5 . 6 is arranged, so that the battery power over the two connecting parts 5 . 6 introduced into the current measuring resistor or derived therefrom and by the low-resistance resistor element 7 flows. The voltage drop across the low resistance element 7 Thus, according to Ohm's law, it corresponds to the battery current generated by the current measuring resistor 4 flows.

For mechanical mounting of the current measuring resistor 4 at the pole terminal 2 has the pole terminal 2 three tongues 8th . 9 . 10 on, in one piece to the pole terminal 2 are formed and parallel to each other laterally from the pole terminal 2 protrude.

The tongue 10 not only serves to mechanically hold the current measuring resistor 4 , but also for electrical contacting of the connection part 6 of the current sense resistor 4 , in particular from 2 B is apparent. That's the connection part 6 of the current sense resistor 4 in the assembled state by a soldered connection with the tongue 10 the pole terminal 2 connected. To enable this electrical contact is the pole terminal 2 and with it the tongue too 10 made of an electrically conductive material (eg brass), the tongue 10 is not isolated to the outside to the electrical contact of the connection part 6 to enable. The tongue 10 So in this embodiment has a dual function. For one thing, the tongue supports 10 the current measuring resistor 4 below the connection part 6 and thus serves for mechanical support of the current sense resistor 4 , The other is the tongue 10 but also for electrical contacting of the current measuring resistor 4 ,

The other two tongues 8th . 9 the pole terminal 2 On the other hand, they serve exclusively for the mechanical holding of the current measuring resistor 4 , That's how the tongue supports 9 the current measuring resistor 4 on the underside while the other tongue 8th at the top of the current sense resistor 4 rests so that the two tongues 8th . 9 the current measuring resistor 4 embrace at the top or at the bottom.

From the 2C and 2D It can also be seen that at the top of the current sense resistor, a printed circuit board 11 with a measuring circuit (not shown) is arranged, wherein the circuit board 11 has on its underside two voltage taps, which by a solder joint with the two connecting parts 5 . 6 of the current sense resistor 4 are connected, so that the voltage taps the circuit board 11 the voltage drop across the resistor element 7 measure up. The on top of the circuit board 11 arranged measuring circuit is connected via corresponding tracks with these two voltage taps and thus measures the voltage drop across the resistor element 7 of the current sense resistor 4 , In addition, the circuit board points 11 Also, a ground contact, not shown.

Furthermore, the battery sensor according to the invention 1 a plug contact 12 up, which has two functions.

On the one hand, via the plug contact 12 the battery voltage supplied to the motor vehicle battery, that of the on the circuit board 11 arranged measuring circuit is also measured and also to the power supply of the battery sensor 1 serves.

On the other hand contains the plug contact 12 but also a data output in the form of a CAN bus (CAN: Controller Area Network) or a LIN bus (LIN: Local Interconnect Network) in order to output the data measured by the measuring circuit.

Of particular importance is still a plastic casing 13 made of thermoset, which is the current measuring resistor 4 , the tongues 8th - 10 , the circuit board 11 and the interior of the plug contact 12 jacketed.

On the one hand, the plastic sheath serves for electrical insulation and hermetic sealing of the battery sensor 1 outward.

On the other hand serves the plastic coating 13 but also for the mechanical stabilization of the battery sensor 1 , So the connection part protrudes 5 of the current sense resistor 4 from the plastic casing 13 out so that the at the connector part 5 attacking mechanical forces not only from the two tongues 8th . 9 be absorbed, but also from the plastic coating 13 , which thus also contributes to the mechanical stabilization. In addition, the plastic casing fills 13 the space between the tongues 8th . 9 on the one hand and the current measuring resistor 4 on the other hand, so that the tongues 8th . 9 the current measuring resistor 4 can stabilize mechanically.

It should also be mentioned that on the circuit board 11 arranged measuring circuit and the temperature difference between the two connecting parts 5 . 6 of the current sense resistor 4 measures. This is advantageous because in this way thermoelectric voltages can be compensated, due to a temperature difference between the two connecting parts 5 . 6 of the current sense resistor arise.

Furthermore, the measures on the circuit board 11 arranged temperature measuring device and the temperature of the current sense resistor 4 , This is useful because of the resistance of the resistive element 7 of the current sense resistor 4 varies slightly with temperature. By measuring the temperature of the resistive element 7 These temperature-related variations of the resistance value during the measurement of the battery current can also be taken into account and compensated.

The invention is not limited to the preferred embodiment described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope. Moreover, the invention also claims protection for the subject matter and the features of the subclaims independently of the features of the claims referred to. For example, the idea of a plastic casing in the context of the invention enjoys its own worthy worth protection.

LIST OF REFERENCE NUMBERS

1

battery sensor

2

Polklemme

3

screw flange

4

Current sense resistor

5

connector

6

connector

7

resistive element

8th

tongue

9

tongue

10

tongue

11

circuit board

12

plug contact

13

Plastic sheathing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0605800 A1 [0002, 0043]
• EP 1363131 A1 [0002, 0016]
• EP 1030185 A2 [0002, 0016]
• DE 102004051489 A1 [0004]
• DE 102004055848 A1 [0004]
• EP 605800 A1 [0009]

Claims (15)

Battery sensor ( 1 ) for a battery, in particular for a motor vehicle battery, with a) a pole terminal ( 2 ) made of an electrically conductive material for the electrical connection of the battery sensor ( 1 ) to a terminal contact of a battery, in particular to a ground contact of the battery, b) a low-impedance current measuring resistor ( 4 ) for measuring a battery current with which the battery is discharged or charged, characterized by c) several of the pole terminal ( 2 ) protruding tongues ( 8th - 10 ) for mechanically holding the current measuring resistor ( 4 ) at the pole terminal ( 2 ). Battery sensor ( 1 ) according to claim 1, characterized in that the tongues ( 8th - 10 ) in one piece to the pole terminal ( 2 ) are formed. Battery sensor ( 1 ) according to one of the preceding claims, characterized in that at least one of the tongues ( 10 ) of the pole terminal ( 2 ) is electrically conductive to the outside to a connection part ( 6 ) of the current measuring resistor ( 4 ) electrically contact, in particular by a welding or soldering of the tongue to the terminal part of the current sense resistor ( 4 ). Battery sensor ( 1 ) according to one of the preceding claims, characterized in that a) that at least one of the tongues ( 8th - 10 ) of the pole terminal ( 2 ) is electrically insulated to the outside in order to make electrical contact with the current measuring resistor ( 4 ) and / or b) that two tongues ( 8th . 9 ) of the pole terminal ( 2 ) are electrically insulated to the outside and the current measuring resistor ( 4 ) engage around on its top and on its underside. Battery sensor ( 1 ) according to one of the preceding claims, characterized by an electronic measuring circuit for measuring an over the current measuring resistor ( 4 ) falling voltage as a measure of the battery current. Battery sensor ( 1 ) according to claim 5, characterized in that a) that for receiving the electronic measuring circuit, a printed circuit board ( 11 ) is provided, and / or b) that the circuit board ( 11 ) directly on the current measuring resistor ( 4 ), and / or c) that the printed circuit board ( 11 ) has at its bottom voltage taps to the electrical voltage across the current measuring resistor ( 4 ), the two voltage taps of the printed circuit board ( 11 ) with two connection parts of the current measuring resistor ( 4 ) are electrically connected, in particular by a soldering, and / or d) that the measuring circuit on top of the printed circuit board ( 11 ) is arranged. Battery sensor ( 1 ) according to one of claims 5 or 6, characterized by a) that the battery sensor ( 1 ) has an electrical voltage input for feeding a supply voltage, and / or b) that the measuring circuit is supplied with electrical energy from the supplied via the voltage input supply voltage, and / or c) that the measuring circuit in addition to the battery current and the supply voltage supplied via the voltage input measures. Battery sensor ( 1 ) according to one of the preceding claims, characterized in that a) that the battery sensor ( 1 ) has a data output for the output of measured values, and / or b) that the data output and the voltage input in the same plug-in contact ( 12 ), and / or c) that the data output provides a digital data bus, in particular a CAN bus or a LIN bus. Battery sensor ( 1 ) according to one of the preceding claims, characterized by a temperature measuring device for measuring the temperature of the current measuring resistor ( 4 ) and / or for measuring a temperature difference between connection parts of the current measuring resistor ( 4 ). Battery sensor ( 1 ) according to claim 9, characterized in that a) that the measuring circuit as a function of the measured temperature difference across the current measuring resistor ( 4 ) one above the current sense resistor ( 4 ) and that the thermoelectric voltage is taken into account in the measurement of the battery current, and / or b) that the measuring circuit depends on the measured temperature of the current measuring resistor ( 4 ) calculates a thermally induced resistance change and takes into account the thermally induced change in resistance when measuring the battery current. Battery sensor ( 1 ) according to one of the preceding claims, characterized by an electrically insulating plastic casing ( 13 ), the current measuring resistor ( 4 ), the printed circuit board ( 11 ), the measuring circuit, the plug contact ( 12 ), the temperature measuring device and / or the tongues ( 8th - 10 ) of the pole terminal ( 2 ) sheathed. Battery sensor ( 1 ) according to claim 11, characterized in that a) that the plastic casing ( 13 ) consists of a thermoset, and / or b) that the current measuring resistor ( 4 ), the printed circuit board ( 11 ), the measuring circuit, the plug contact ( 12 ), the temperature measuring device and / or the tongues ( 8th - 10 ) of the pole terminal ( 2 ) are encapsulated with the thermoset, and / or c) that the plastic coating ( 13 ) consists of a plastic which has substantially the same thermal expansion behavior as the printed circuit board ( 11 ) and / or the measuring circuit, and / or d) that the plastic casing ( 13 ) consists of a plastic which is thermally conductive, and / or e) that the current measuring resistor ( 4 ) with one of its two connecting parts partly from the plastic casing ( 13 ) and forms a power outlet with the protruding part to initiate or dissipate the battery current. Battery sensor ( 1 ) according to one of the preceding claims, characterized in that a) the current measuring resistor ( 4 ) a first plate-shaped connection part ( 6 ) of a conductor material and a second plate-shaped connection part ( 5 ) of the conductor material, b) that the current measuring resistor ( 4 ) a plate-shaped resistance element ( 7 ) of a resistance alloy, c) that the resistance element ( 7 ) in the current path between the two connection parts ( 5 . 6 ), d) that the conductor material has a smaller electrical resistivity than the resistance alloy. Battery sensor ( 1 ) according to claim 13, characterized in that a) that a first tongue ( 10 ) of the pole terminal ( 2 ) the first connection part ( 6 ) of the current measuring resistor ( 4 ) mechanically supported from below, b) that the first tongue ( 10 ) of the pole terminal ( 2 ) the first connection part ( 6 ) of the current measuring resistor ( 4 ) electrically contacted, c) that the second connection part ( 5 ) of the current measuring resistor ( 4 ) forms a power connection to initiate or discharge the battery current, d) that a second tongue ( 9 ) of the pole terminal ( 2 ) the current measuring resistor ( 4 ) is supported from below, e) that a third tongue ( 8th ) of the pole terminal ( 2 ) the current measuring resistor ( 4 ) is supported from above, f) that the second tongue ( 9 ) and the third tongue ( 8th ) of the pole terminal ( 2 ) are electrically insulating to the outside to an electrical contacting of the current measuring resistor ( 4 ), g) that the second tongue ( 9 ) and the third tongue ( 8th ) the current measuring resistor ( 4 ) between the two connecting parts ( 5 . 6 ) to a mechanical load on the serving as a power connector second connector ( 5 ). Battery, in particular motor vehicle battery, with two connection contacts, characterized in that a battery sensor ( 1 ) is attached to one of the terminal contacts according to one of the preceding claims, in particular at a ground pole of the battery.

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