Method for producing a battery sensor and battery sensor

Abstract

The invention relates to a method for producing a battery sensor (10), in particular for a vehicle battery, and to such a battery sensor (10). The battery sensor (10) comprises an electrical conductor (16) with a measuring resistor (18) and a printed circuit board (26). A measuring circuit (24) contacted with the electrical conductor (16) and a temperature sensor (28) contacted with the measuring circuit (24) are provided on the printed circuit board (26). The electrical conductor (16) and the printed circuit board (26) are flat and overlap at least in sections. The temperature sensor (28) is provided in a region of the printed circuit board (26) that overlaps the electrical conductor (16), in particular in the region that overlaps the measuring resistor (18). The battery sensor is produced using the following steps: - Providing the electrical conductor (16) and the printed circuit board (26), - introducing a filling opening (34) extending through the electrical conductor (16) into the electrical conductor (16), - mounting the printed circuit board (26) on the electrical conductor (16), wherein the temperature sensor (28) is covered by the electrical conductor (16), in particular by the measuring resistor (18), - Introducing the thermally conductive material (32) through the filling opening (34) between the temperature sensor (28) and the electrical conductor (16).

Description

[0001] The invention relates to a method for producing a battery sensor, in particular for a vehicle battery, wherein the battery sensor comprises an electrical conductor with a measuring resistor and a printed circuit board on which a measuring circuit and at least one temperature sensor are arranged. The invention further relates to a battery sensor produced using such a method.

[0002] Battery sensors for detecting the currents of a battery, in particular a vehicle battery of a vehicle, are known from the prior art. The battery sensor has the task of determining or measuring the currents occurring very precisely, for example in order to make statements about the state of charge of the vehicle battery. In particular, such a battery sensor has an electrical conductor arranged between a first current connection and a second current connection with a measuring resistor with a known electrical resistance, through which the entire charging and discharging current of the battery flows. The voltage drop across this measuring resistor can be determined using a measuring circuit. From the measured voltage drop and the known electrical resistance of the measuring resistor, the current flowing through the measuring resistor, i.e. the current flowing through the electrical conductor, can be calculated using Ohm's law.For example, the measuring section consists of a copper-nickel-manganese alloy whose electrical resistance is known very precisely and which shows both a small change in electrical resistance over time and a small change in electrical resistance with temperature changes.

[0003] To improve measurement accuracy, it is necessary to additionally determine the temperature of the measuring resistor in order to take temperature-related changes in the electrical resistance of the measuring resistor into account when determining or measuring the current. Typically, a temperature sensor is placed on the circuit board to determine the temperature of the measuring section. The temperature sensor is positioned in the area of ​​the measuring resistor so that it can detect the temperature of the measuring resistor.

[0004] The object of the invention is to provide a battery sensor and a method for producing such a battery sensor, wherein the battery sensor has improved heat transfer between the measuring resistor and the temperature sensor and is easy to produce.

[0005] To achieve this objective, a method for producing a battery sensor, in particular for a vehicle battery, is provided. The battery sensor comprises an electrical conductor with a measuring resistor and a printed circuit board. A measuring circuit contacted with the electrical conductor and a temperature sensor contacted with the measuring circuit are provided on the printed circuit board. The electrical conductor and the printed circuit board are flat and overlap at least in sections, with the temperature sensor being provided in an area of ​​the printed circuit board that overlaps the electrical conductor, in particular in the area that overlaps the measuring resistor. The method comprises the following steps: - Providing the electrical conductor and the circuit board, - Inserting a filling opening extending through the electrical conductor into the electrical conductor, - Mounting the circuit board on the electrical conductor, whereby the temperature sensor is covered by the electrical conductor, in particular by the measuring resistor, - Introducing a thermally conductive material, in particular a thermally conductive fluid, through the filling opening into the filling opening.

[0006] Using a thermally conductive material, particularly a thermally conductive paste, the temperature of the measuring resistor can be measured much more accurately because of better heat transfer from the measuring resistor to the temperature sensor. The thermally conductive material is usually applied to the circuit board before it is mounted. However, it is difficult to ensure that the thermally conductive material is in the desired position between the measuring resistor and the temperature sensor after the circuit board has been mounted to the electrical conductor. In particular, it can happen that the thermally conductive material becomes liquid during assembly, especially during heat input during assembly and when the electrical conductor is contacted with the circuit board, and / or gets onto unwanted areas of the circuit board or the electrical conductor.

[0007] According to the invention, the thermally conductive material is only applied to the electrical conductor after the circuit board has been mounted, thus enabling very precise positioning and dosing of the thermally conductive material. In order to be able to insert the thermally conductive material as precisely as possible between the temperature sensor and the electrical conductor, even with the smallest possible gap between the electrical conductor and the circuit board, a filling opening, for example in the form of a bore, is made in the electrical conductor through which the thermally conductive material can be positioned precisely on the temperature sensor. In particular, this ensures that the thermally conductive material is positioned exclusively in the area of ​​the temperature sensor, in particular between the temperature sensor and the measuring resistor, and does not reach undesired areas of the circuit board.

[0008] To achieve a battery sensor with the smallest possible height, a recess into which the temperature sensor protrudes can be provided on the side of the electrical conductor facing the circuit board, particularly in the area of ​​the measuring resistor. This allows the circuit board and the electrical conductor to be positioned closer together. In this embodiment, the filling opening preferably extends into the recess. The thermally conductive material is poured into the recess and essentially fills it completely.

[0009] Preferably, the filling opening and / or the recess are introduced simultaneously, in particular during the production of the electrical conductor.

[0010] In particular, the filling opening and the recess can be individually introduced into the electrical conductor, preferably depending on the position of the temperature sensor.

[0011] For example, the filling opening and / or the recess are drilled or punched into the electrical conductor.

[0012] Preferably, mounting the circuit board on the electrical conductor comprises electrically connecting the circuit board to the electrical conductor, in particular by means of a soldering process. In particular, the circuit board can be connected to the electrical conductor upstream and downstream of the measuring resistor, for example, to detect a voltage drop across the measuring resistor. From this voltage drop and the known electrical resistance of the measuring resistor, the current flowing through the electrical conductor can be calculated using Ohm's law. For this purpose, the circuit board and / or the electrical conductor preferably has contact pins that protrude in the direction of the electrical conductor and / or the circuit board.

[0013] To achieve the object, a battery sensor, in particular for a vehicle battery, is further provided, wherein the battery sensor has an electrical conductor with a measuring resistor and a printed circuit board. A measuring circuit contacted with the electrical conductor and a temperature sensor contacted with the measuring circuit are provided on the printed circuit board. The electrical conductor and the printed circuit board are flat and overlap at least in sections, wherein the temperature sensor is provided in a region of the printed circuit board overlapping with the electrical conductor, in particular in the region overlapping with the measuring resistor. The battery sensor is produced using a method described above.

[0014] On the surface of the electrical conductor facing the circuit board, in particular in the area of ​​the measuring resistor, a recess can be provided into which the temperature sensor projects, the recess being completely filled with the thermally conductive material.

[0015] The measuring circuit can be provided on the side of the circuit board facing away from the electrical conductor and / or in an area of ​​the circuit board that does not overlap with the electrical conductor.

[0016] The measuring circuit is preferably connected to the electrical conductor upstream and downstream of the measuring resistor and can detect a voltage drop across the measuring resistor. The current flowing through the electrical conductor can be determined from the measured voltage drop and the known electrical resistance of the measuring resistor. The temperature of the electrical conductor, in particular of the measuring resistor, measured with the temperature sensor can be used to account for temperature-related changes in the electrical resistance of the measuring resistor when calculating the current flowing through the electrical conductor. Furthermore, the measuring circuit can have additional sensors or measuring devices to detect further parameters, for example a battery voltage or a battery temperature.

[0017] Further advantages and features can be found in the following description in conjunction with the attached drawings. These show: Fig. 1 a plan view of a battery sensor produced by a method according to the invention; Fig. 2 a sectional view through the battery sensor Fig. 1 Fig. 3 a detailed view of the battery sensor Fig. 2; Fig. 4 a top view of the battery sensor Fig. 1 during an assembly step; Fig. 5 a sectional view through the battery sensor Fig. 4; and Fig. 6 a detailed view of the battery sensor Fig. 5.

[0018] In the Fig. 1 to 3 show a battery sensor 10 having a first power connection 12 and a second power connection 14. The battery sensor 10 can be connected to the electrical circuit of a vehicle using the first power connection 12 and the second power connection 14. In particular, the battery sensor 10 is connected to the electrical circuit of the vehicle in such a way that the current of a vehicle battery flows completely through the battery sensor 10, so that all charging and discharging currents of the vehicle battery can be detected by the battery sensor 10.

[0019] An electrical conductor 16 with a measuring section 17 is provided between the first power terminal 12 and the second power terminal 14. The measuring section 17 consists, at least in part, of a measuring resistor 18 made of a material with a low dependence of the electrical resistance on temperature and a low aging drift of the electrical resistance. For example, the measuring resistor 18 is made of a copper-manganese-nickel alloy.

[0020] A first measuring contact 20 and a second measuring contact 22 are provided on the measuring section 17, with the measuring contacts being provided on both sides of the measuring resistor 18. The measuring contacts 20, 22 are connected to a current measuring device 24 (see Fig. 4) are electrically connected on a circuit board 26. The current measuring device 24 can detect the voltage potentials at the measuring contacts 20, 22. From the difference in the voltage potentials, i.e., the voltage drop between the measuring contacts 20, 22 and the known electrical resistance of the measuring section 16, the current flowing through the measuring section 16 can be calculated using Ohm's law.

[0021] The battery sensor 10 further comprises at least one temperature sensor 28 for detecting the temperature of the measuring resistor 18. The temperature detected by the temperature sensor 28 can be used to account for a temperature dependence of the electrical resistance of the measuring section 17, in particular of the measuring resistor 18, when determining or calculating the current flowing through the measuring section 16. In particular, a correction factor can be determined to correct the electrical resistance of the measuring section 16 or the determined current.

[0022] As in the Fig. 2 and Fig.As can be seen in Figure 3, the temperature sensor 28 is provided on the upper side of the circuit board 26 facing the measuring resistor 18. The temperature sensor 28 is further provided in an area of ​​the circuit board 26 that overlaps with the electrical conductor 16, so that it is positioned directly adjacent to the electrical conductor, whereby the temperature sensor 28 does not directly touch the electrical conductor 16.

[0023] A recess 30 is provided in the electrical conductor 16, particularly in the measuring resistor 18, into which the temperature sensor 28 projects. This recess 30 allows the printed circuit board 26 to be positioned closer to the electrical conductor 16.

[0024] A thermally conductive material 32 is provided between the electrical conductor 16 and the temperature sensor 28, which improves heat transfer from the electrical conductor 16 to the temperature sensor. The thermally conductive material 32 is merely thermally conductive and electrically insulating, so that although temperature transfer from the electrical conductor 16 to the temperature sensor 18 can occur, voltage flashover is prevented.

[0025] The thermally conductive material 32 is applied only in the area of ​​the temperature sensor 28 on the circuit board 26 or between the circuit board 26 and the electrical conductor 16. As a result, heat is transferred to the circuit board 26 only in the area of ​​the temperature sensor 28.

[0026] Typically, the thermally conductive material 32 is applied to the circuit board 26 before it is positioned on the electrical conductor 16. In order to apply the thermally conductive material 32 very precisely and exclusively in a point-like manner in the area of ​​the temperature sensor 28, a filling opening 34 is formed in the electrical conductor. In a plan view, the filling opening 34 is arranged perpendicular to the surface of the electrical conductor 167 and the circuit board 26 above the temperature sensor.

[0027] The filling opening was already introduced into the electrical conductor before the printed circuit board 26 was mounted on the electrical conductor 16. After the printed circuit board 26 has been positioned and mounted on the electrical conductor 16, the thermally conductive material 32 is introduced through the filling opening 34 between the electrical conductor 16 and the printed circuit board 26. This allows for a significantly better, and in particular more precise, application of the thermally conductive material 32. Furthermore, the thermally conductive material 32 can be introduced after the electrical conductor 16 has been contacted with the printed circuit board 26, in particular after the electrical contacts 20, 22 of the current measuring device 24 have been contacted with the electrical conductor 16. This prevents the thermally conductive material 32 from running, in particular due to the heat generated during electrical contact, for example during a soldering process.

[0028] In particular, the filler opening 34 can be individually introduced into the electrical conductor 16, particularly depending on the position of the temperature sensor 28. Preferably, the filler opening 34 and the recess 30 can be introduced simultaneously. This can be done during the manufacture of the electrical conductor 16, but alternatively, it can also be done during the assembly of the battery sensor 10. Optionally, only the recess 30 can be introduced during the manufacture of the electrical conductor 16, and the filler opening can be introduced during the assembly of the battery sensor 10.

[0029] Preferably, the filling opening 34 and the recess 30 are completely filled with the thermally conductive material.

Claims

[1] A method for producing a battery sensor (10), in particular for a vehicle battery, wherein the battery sensor (10) has an electrical conductor (16) with a measuring resistor (18) and a printed circuit board (26), wherein a measuring circuit (24) contacted with the electrical conductor (16) and a temperature sensor (28) contacted with the measuring circuit (24) are provided on the printed circuit board (26), wherein the electrical conductor (16) and the printed circuit board (26) are flat and overlap at least in sections, wherein the temperature sensor (28) is provided in a region of the printed circuit board (26) overlapping with the electrical conductor (16), in particular in the region overlapping with the measuring resistor (18), comprising the following steps: - Providing the electrical conductor (16) and the printed circuit board (26), - introducing a filling opening (34) extending through the electrical conductor (16) into the electrical conductor (16), - mounting the printed circuit board (26) on the electrical conductor (16), wherein the temperature sensor (28) is covered by the electrical conductor (16), in particular by the measuring resistor (18), - Introducing the thermally conductive material (32) through the filling opening (34) between the temperature sensor (28) and the electrical conductor (16). [2] Method according to claim 1, characterized by that on the side of the electrical conductor (16) facing the printed circuit board (26), in particular in the region of the measuring resistor (18), a recess (30) is provided into which the temperature sensor (28) projects, wherein the filling opening (34) extends into the recess (30), and the thermally conductive material (32) is filled into the recess (30) and essentially completely fills it. [3] Method according to one of claims 1 and 2, characterized by that the filling opening (34) and / or the recess (30) are introduced simultaneously, in particular during the production of the electrical conductor (16). [4] Method according to one of the preceding claims, characterized by that the mounting of the printed circuit board (26) on the electrical conductor (16) comprises an electrical connection of the printed circuit board (26) to the electrical conductor (16), in particular by means of a soldering process. [5] Method according to one of the preceding claims, characterized by that the filling opening (34) and / or the recess (30) are drilled or punched into the electrical conductor (16). [6] Battery sensor (10), in particular for a vehicle battery, with an electrical conductor (16) having a measuring resistor (18), and with a printed circuit board (26) on which a measuring circuit (24) is provided, wherein the measuring circuit (24) is connected to the electrical conductor (16), wherein the electrical conductor (16) and the printed circuit board (26) are flat and overlap at least in sections, wherein at least one temperature sensor (28) connected to the measuring circuit (24) is provided on the printed circuit board (26), which temperature sensor is provided in the region of the measuring circuit (24) overlapping with the electrical conductor (16), in particular in the region overlapping with the measuring resistor (18), characterized by that the battery sensor (10) is manufactured using a method according to one of the preceding claims. [7] Battery sensor according to claim 6, characterized bythat on the surface of the electrical conductor (16) facing the printed circuit board (26), in particular in the region of the measuring resistor (18), a recess (30) is provided into which the temperature sensor (28) projects, the recess (30) being completely filled with the thermally conductive material (32). [8] Battery sensor according to one of claims 6 and 7, characterized by that the measuring circuit (24) is provided on the side of the printed circuit board (26) facing away from the electrical conductor (16) and / or in an area of ​​the printed circuit board (26) which does not overlap with the electrical conductor (16).

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