BATTERY WITH TEMPERATURE MEASURING DEVICE

Description

[0001] The present invention relates to a battery with a temperature measuring device for measuring the temperature of the battery at a plurality of measuring positions.

[0002] German patent application DE 10 2016 207 334 A1 discloses a measuring device for determining a temperature, comprising a multilayer printed circuit board and a sensor device mounted on it. The conductor layers are partially overlapping and nested.

[0003] A temperature measuring device for a battery system is known from European patent EP 2 736 100 B1. Several infrared temperature sensors for measuring the temperature of battery cells are arranged on a printed circuit board. The sensors are mechanically decoupled from the battery cells.

[0004] The international patent application WO 2016 / 153 267 A1 describes a battery pack comprising at least one battery cell, a heat sink for dissipating heat generated by the battery cell, a printed circuit board with a section that touches the heat sink, and a temperature sensor mounted on the printed circuit board to measure the heat conducted from the heat sink to the printed circuit board.

[0005] Another device for measuring the temperature of a battery pack is described in Korean patent application KR 10 2018 0 043 875 A. Furthermore, WO 2015 / 019 511 A1 discloses a battery with a plurality of battery cells and a circuit board with a temperature sensor for measuring the battery's temperature. Other relevant documents are US 2010 / 203368 A1, EP 1 450 422 A1, and CN 100 472 877 C.

[0006] A battery of this type serves in particular as an energy storage device for supplying power to a building. Such a battery comprises a multitude of individual cells, which can be connected in series or in parallel. Especially in batteries with a multitude of individual cells, it is important to monitor the temperature of the cells. One problem to be solved by the invention is to provide a battery with a temperature measuring device that can monitor the temperature of as many cells as possible in the battery.

[0007] According to one aspect of the invention, the problem is solved by an electric battery according to claim 1. An electric battery according to the invention comprises at least one temperature measuring device. Further aspects of the invention are the subject of the dependent claims, the drawings, and the following description of exemplary embodiments.

[0008] A temperature measuring device of the battery according to the invention comprises a multilayer printed circuit board as a carrier element with an upper conductor layer and a lower conductor layer. In particular, the printed circuit board is made of a heat-insulating material, so that it has a low heat capacity. The temperature measuring device itself therefore absorbs only a small amount of heat from the battery being measured. This improves the accuracy and response time of the temperature measurement.

[0009] The temperature measuring device comprises a multitude of temperature sensors, each configured to generate a temperature-dependent measurement signal. By providing a large number of sensors, the temperature of a battery with numerous individual cells can be monitored at a multitude of measuring points. This ensures particularly reliable temperature monitoring. The temperature sensors are primarily temperature-dependent resistors, such as NTC thermistors (Negative Temperature Coefficient Thermistors). These resistors conduct electrical current better at higher temperatures than at lower temperatures. NTC thermistors can be particularly cost-effective, offer high measurement accuracy, and are very reliable. However, their use is not limited to NTC thermistors; PTC thermistors or other chip solutions can also be used as measuring devices.

[0010] The numerous temperature sensors are preferably arranged at uniform intervals along a longitudinal axis of the circuit board. The positions of the sensors can be determined, in particular, by the arrangement of the individual cells in the battery being measured. A uniform arrangement of the sensors on the circuit board allows, in particular, the measurement and monitoring of a uniform temperature distribution of the individual cells.

[0011] The circuit board of the temperature measuring device includes a variety of mounting means for attaching the circuit board to a battery. In particular, the mounting means are arranged at the level of the sensors, so that direct contact with the point on the battery to be measured can be established.

[0012] The temperature measuring device includes a multi-pole connector for reading the measurement signals. The multi-pole connector has, in particular, a plurality of signal poles, each of which is electrically connected to one of the plurality of temperature sensors via separate conductor tracks in the upper conductor layer. Furthermore, the multi-pole connector preferably has at least one grounding pole (GND) which is electrically connected to each of the plurality of temperature sensors via at least one conductor track. The conductor tracks in the upper conductor layer can thus be configured such that a first contact of each temperature sensor is connected to a ground conductor track and a second contact of each temperature sensor is connected to a separate signal conductor track, so that a separate temperature measurement or resistance value can be read for each temperature sensor.

[0013] Each of the numerous temperature sensors is positioned on a first insulated area of ​​the upper conductor layer. This first insulated area serves primarily as a thermal contact surface with the respective temperature sensor. The first insulated area is electrically isolated from the conductor tracks.

[0014] The lower conductor layer has a second insulated area for each temperature sensor, serving as a thermal contact surface with the object being measured. These thermal contact surfaces in the lower conductor layer are arranged so that they can be positioned directly on the surface of a battery to be measured, where they are in thermal contact with the surface.

[0015] Each first insulated area is thermally connected to a corresponding second insulated area via at least one via. These vias through the insulating circuit board establish a thermally conductive connection between the heat sink, which is in direct contact with the battery, and the respective temperature sensor. Specifically, each first insulated area is thermally connected to a corresponding second insulated area via multiple vias, for example, three or more. This improves the thermal conductivity between the temperature sensors and their respective heat sinks, enabling accurate temperature measurement on the underside of the circuit board.

[0016] The temperature sensors are preferably each surrounded by a thermally conductive sheath that is thermally connected to the respective first insulated area. The thermally conductive sheath improves heat transfer from the first insulated area to the temperature sensor. In particular, the heat is distributed evenly over the entire circumference of the temperature sensor, thus enabling more accurate temperature measurement.

[0017] A preferred printed circuit board (PCB) has a multitude of cutouts. These cutouts reduce the overall surface area and mass of the temperature measuring device. This reduces the overall heat capacity of the device, which can lead to improved measurement accuracy because the device absorbs less heat from the battery being measured. Furthermore, the cutouts allow the individual cells to be cooled by air, as they do not need to be covered. Preferably, the cutouts also serve to secure the temperature measuring device to the battery. Even more preferably, the cutouts are arranged such that the cell holders of the individual cells can protrude through them, allowing the PCB to be positioned directly on the cells for direct thermal contact.

[0018] In the electric battery according to the invention, the second insulated areas are each in thermally conductive contact with at least one cell connector of the battery.

[0019] An electric battery according to the invention preferably has a plurality of adjacent rows of individual cells. For example, the individual cells can be arranged in a matrix of N individual cells in M ​​rows in the battery, where N and M are natural numbers greater than or equal to two.

[0020] A preferred battery has a plurality of temperature measuring devices, with one temperature measuring device being provided for each pair of rows of individual cells. In particular, each of the plurality of temperature sensors monitors the temperature of two to four individual cells.

[0021] A preferred electric battery includes electronics for evaluating the measurement signals from the temperature sensors. For this purpose, the electronics can be connected via a multi-pole cable to the multi-pole terminal of the at least one temperature measuring device. Preferably, the individual temperatures measured by the temperature sensors are determined ratiometrically. This means that, in particular, the ratios of the measured signals are determined, whereby, for example, a deviation from a setpoint or an average value, or the exceeding of a limit value, can be determined. Brief description of the characters

[0022] Further advantageous embodiments are described in more detail below with reference to an exemplary embodiment shown in the drawings, to which, however, the invention is not limited.

[0023] They show schematically: Figure 1 Fig. 1shows a sectional view of an embodiment of a battery with a temperature measuring device according to the invention. Figure 2 Fig. 2a shows a top view of a temperature measuring device according to the invention and Fig. 2b shows a corresponding view from below. Figure 3 Fig. 3 shows an exemplary circuit diagram of a temperature measuring device according to the invention. Figure 4 Figs. 4a and 4b Two different embodiments of the temperature measuring device according to the invention are shown. Figure 5 Fig. 5 shows a sectional view of another embodiment of a battery with a temperature measuring device according to the invention with compression tape. Detailed description of the invention using exemplary embodiments

[0024] In the following description of a preferred embodiment of the present invention, the same reference numerals denote identical or comparable components.

[0025] Fig. 1Figure 1 shows a sectional view of an embodiment of a battery 20 with a temperature measuring device 10 according to the invention. The battery 20 has a plurality of individual cells 21 arranged in a row. The individual cells 21 are connected in pairs via soldered or welded joints 24 to a cell connector 22 and connected in series. Cell holders 23 are arranged between the individual cells 21, which mechanically support the individual cells 21. A battery 20 according to the invention can have a plurality of rows of individual cells 21. In particular, a battery 20 can be constructed as a matrix of M rows, each with N individual cells 21, where M and N are, of course, numbers that are, for example, between ten and twenty, and in particular sixteen.

[0026] In Fig. 1Two individual cells 21 are shown in the center, with the left one having its positive terminal facing upwards and the right one having its positive terminal facing downwards. The two individual cells 21 are connected to the upper cell connector 22 by soldered or welded joints 24 and are thus connected in series. To the right and left of the centrally shown individual cells 21, further individual cells 21 are shown with dashed lines to indicate that only a section of a larger number of individual cells 21 is depicted.

[0027] A temperature measuring device 10 is arranged on the battery 20. The temperature measuring device 10 has a multilayer printed circuit board 1 as a carrier element with an upper conductor layer 1a and a lower conductor layer 1b. The printed circuit board 1 is made of a heat-insulating material, for example, plastic or fiber-reinforced plastic or commercially available FR4 (class of flame-retardant composite materials consisting of epoxy resin and glass fiber fabric, "Flame Retardant 4") and has a thickness of one to several millimeters. The conductor layers 1a, 1b typically have a thickness of several tens to several hundred micrometers, for example, 35 µm, and are made of a conductive material, such as copper.

[0028] A multitude of temperature sensors 2 are arranged on the circuit board 1, each generating a temperature-dependent measurement signal. The one in the middle of the Fig. 1The temperature sensor 2 shown is arranged on a first insulated area 5a of the upper conductor layer 1a. This insulated area 5a is separated from the rest of the upper conductor layer 1a by an electrical insulation 6. The temperature sensor 2 is arranged directly on the first insulated area 5a, so that the temperature sensor 2 measures the temperature of the first insulated area 5a.

[0029] Beneath the first insulated area 5a on the underside of the circuit board 1 is a second insulated area 5b, which serves as a thermal contact surface. The thermal contact surface rests directly on a cell connector 22 of the battery 20. The distance shown in the drawing is for illustrative purposes only. Thermal paste can be used to improve heat transfer between the cell connector 22 and the thermal contact surface.

[0030] The first insulated area 5a is thermally connected to the underlying second insulated area 5b via three vias 4, so that the heat dissipated from the individual cells 21 to the cell connector 22 is transferred directly to the first insulated area 5a and thus to the temperature sensor 2 via the thermal contact surface 5b and the vias 4. Therefore, the temperature sensor 2, located on the top side of the circuit board 1, enables a very precise measurement of the temperature of the underlying individual cells 21.

[0031] The vias 4, like the conductor layers 1a and 1b, can be made of copper. Depending on its purity, copper has a relatively high thermal conductivity of approximately 240 to 400 W / (m K). In contrast, plastics have a very low thermal conductivity of less than 1 W / (m K). Therefore, direct heat transfer from the thermal contact surface 5b (measuring point) to the temperature sensor 2 is possible without heat loss in the circuit board 1. Furthermore, copper has a relatively low specific heat capacity of approximately 0.382 kJ / (kg K), so that high thermal conductivity results in a correspondingly high thermal diffusivity a. The thermal diffusivity a is calculated as the quotient of thermal conductivity λ and specific heat capacity c multiplied by density ρ: a = λ ρ ⋅ c

[0032] The thermal diffusivity α quantifies the temporal change in the spatial distribution of temperature due to heat conduction as a result of a temperature gradient. This means that, due to the high thermal diffusivity of the material between temperature sensor 2 and thermal contact surface 5b, temperature measurement can be performed quickly and with minimal loss.

[0033] It goes without saying that any other suitable material can be used instead of copper.

[0034] As in Fig. 1 The temperature sensor 2 is shown attached to the circuit board 1 by solder points 7. The solder points 7 also establish the electrical contact to the conductor tracks 3a and 3b, which are connected to a multi-pin connector 11 for reading the measurement signals (see Fig. 2 ).

[0035] In an embodiment not shown, the temperature sensors 2 can each be surrounded by a thermally conductive sheath that is thermally connected to the respective first insulated area 5a. Such a thermally conductive sheath can improve the heat transfer from the first insulated area 5a to the temperature sensor 2. In particular, the heat is distributed evenly over the entire circumference of the temperature sensor 2, thus enabling a more accurate temperature measurement.

[0036] Fig. 2a shows a top view of a temperature measuring device 10 according to the invention and Fig. 2b Figure 1 shows a corresponding view from below. Only a central section of the temperature measuring device 10 is shown, revealing four temperature sensors 2. The temperature measuring device 10 extends further to the left and right than shown in the illustration. In total, the exemplary temperature measuring device 10 has eight temperature sensors 2.

[0037] As in Fig. 2 As can be seen, the temperature measuring device 10 has a plurality of fastening means 12 for attaching the circuit board 1 to a battery (20). The fastening means 12 are, for example, designed as holes in the circuit board 1 located directly next to the temperature sensors 2, so that the temperature measuring device 10 can be screwed onto the battery 20, ensuring a firm and direct contact between the thermal contact surfaces 5b and the cell connectors 22 of the battery 20.

[0038] In Fig. 2aThe multi-pole connector 11 for reading the measurement signals is shown in the center. In the illustrated embodiment, this is a 10-pole connector 11 with eight signal poles and two grounding poles. The signal poles are each connected to a first terminal of the temperature sensors 2 via separate first conductor tracks 3a in the upper conductor layer 1a. The grounding poles are each connected to a second terminal of the temperature sensors 2 via common second conductor tracks 3b.

[0039] The temperature measuring device 10 can be connected to electronics for evaluating the measurement signals from the temperature sensors 2 via the multi-pole connector 11 and a corresponding multi-pole cable. According to one embodiment, the individual temperatures measured by the temperature sensors 2 are determined ratiometrically by electronics. This means that, in particular, the ratios of the measured signals to each other are determined, whereby, for example, a deviation from a setpoint or an average value, or the exceeding of a limit value, can be detected.

[0040] The circuit board 1 also has a plurality of rectangular cutouts 14. The cutouts 14 reduce the total surface area and the total mass of the temperature measuring device 10. This reduces the overall heat capacity of the temperature measuring device 10, which leads to improved measurement accuracy, since the temperature measuring device 10 absorbs less heat from the battery 20 being measured.

[0041] Furthermore, the milled recesses 14 allow air to flow in and thus cool the individual cells 21. The milled recesses 14 also serve to secure the temperature measuring device 10 to the battery 20. In addition, the milled recesses are arranged such that the cell holders 23 of the individual cells can protrude through the milled recesses 14, allowing the circuit board 1 to be positioned directly on the cell connectors 22 of the individual cells 21 to achieve direct thermal contact. The circuit board 1 also has locking holes 13 for attaching the temperature measuring device 10 to the battery 20.

[0042] Fig. 3Figure 1 shows an exemplary circuit diagram of the temperature measuring device 10. Eight signal lines 3a run from the 10-pin connector 11 to the eight temperature sensors 2. Two grounding lines 3b are also provided for grounding the temperature sensors 2. The temperature sensors 2 are designed as NTC thermistors, whose resistance can be determined as a measured value of the temperature.

[0043] Figs. 4a and 4b Each shows a section of the temperature measuring device 10 in a top view similar to Fig. 2a , where a section around a temperature sensor 2 is shown. In Fig. 2a Details such as conductor tracks 3a and 3b were shown in Fig. 4 Omitted for the sake of clarity.

[0044] Figs. 4a and 4b Two different embodiments with different arrangements of the vias are shown. 4. In Fig. 4aThree vias 4 are arranged directly below the temperature sensor 2. This design essentially corresponds to the one in Fig. 1 The example shown. The vias 4 can be, for example, copper-filled vias. However, the vias 4 can also be designed as holes where only the walls are covered with a conductive layer, e.g., copper, leaving a through-hole in each case through which air can flow. The first insulated area 5a is in Figs. 4a and 4b Each is represented as a dashed area.

[0045] Fig. 4b Figure 1 shows an alternative exemplary embodiment in which the vias 4 are not arranged below the temperature sensor 2 but next to it. Furthermore, a third insulated area 5c is arranged next to the temperature sensor 2, the surface of which is essentially identical to the second insulated area 5b on the underside of the temperature measuring device 10 (see Figure 1). Fig. 2b ) corresponds. The third insulated area 5c can, for example, be provided as a copper area. In this design, the vias 4 can have a larger diameter. In Fig. 4b Four vias 4 are shown as an example. Due to the larger available area, more than four vias 4 can also be provided.

[0046] Similar to the example of Fig. 4a The vias of the alternative exemplary embodiment can be copper-filled or designed as holes where only the walls are covered with a conductive layer, e.g., copper, leaving a through-hole in each case through which air can flow. Due to the larger diameter compared to Fig. 4aThe through-holes can be larger, allowing for improved air exchange. Furthermore, improved thermal conductivity can be achieved through the vias 4. Additionally, capillary effects can be reduced, thus preventing condensation in the through-holes.

[0047] The third insulated area 5c is particularly good at absorbing heat from the second insulated area 5b and transferring it to the temperature sensor 2 via the connection to the first insulated area 5a. This allows for improved heat transfer from the underside of the temperature measuring device 10 to the top side with the temperature sensors 2, thus improving the temperature measurement.

[0048] Fig. 5 shows a further embodiment of a battery 20 according to the invention, wherein, in contrast to the embodiment of the Fig. 1A compression band 30 is arranged on the temperature measuring device 10. In particular, the compression band 30 can be glued to the circuit board 1 of the temperature measuring device 10.

[0049] The compression tape 30 is electrically and thermally insulating and sealing. It can be, for example, a pre-compressed, impregnated foam sealing tape, e.g., polyurethane-based. Alternatively, it can be, for example, a rubber compression tape. It can be mechanically deformed so that it conforms to the surface of the temperature measuring device 10 and expands again on its own after compression. A housing cover of the battery 20 allows the compression tape 30 to be mechanically pressed against the circuit board 1 of the temperature measuring device 10, so that it rests firmly on the circuit board 1 even without adhesive.

[0050] The compression tape 30 can advantageously cover the temperature measuring device 10 in an airtight manner, thus preventing harmful condensation from forming on the temperature measuring device 10. Furthermore, the compression tape 10 serves as thermal insulation against the ambient air, which improves the accuracy of the temperature measurement, since the temperature of the circuit board 1 is no longer (or at least only minimally) affected by the ambient air.

Claims

1. An electric battery (20) with a plurality of individual cells (21), wherein the battery (20) has at least one temperature measuring device (10), wherein the at least one temperature measuring device (10) comprises: a multilayer printed circuit board (1) as a carrier element with an upper conductor layer (1a) and a lower conductor layer (1b); a plurality of temperature sensors (2), which are each configured to generate a temperature-dependent measurement signal; a multipolar connection (11) for reading out the measurement signals, wherein: each of the plurality of temperature sensors (2) is in each case arranged on a first insulated region (5a) of the upper conductor layer (1a); the lower conductor layer (1b) has a second insulated region (5b) as a thermal contact surface for each temperature sensor (2); each first insulated region (5a) is in each case thermally conductively connected to a corresponding second insulated region (5b) via at least one plated-through hole (4), wherein the second insulated regions (5b) are in each case thermally conductively in contact with at least one cell connector (22) of the battery (20).

2. The electric battery (20) according to Claim 1, wherein the multipolar connection (11): has a plurality of signal poles, which are in each case electrically connected to one of the plurality of temperature sensors (10) via separate conductor tracks (3a) in the upper conductor layer (1a); and has at least one ground pole, which is electrically connected to each of the plurality of temperature sensors (10) via at least one conductor track (3b).

3. The electric battery (20) according to Claim 1 or 2, wherein each first insulated region (5a) is in each case thermally conductively connected to a corresponding second insulated region (5b) via a plurality of plated-through holes (4).

4. The electric battery (20) according to at least one of the preceding claims, wherein: the printed circuit board (1) is manufactured from a plastic, a fiber-reinforced plastic or a flame-retardant and flame-retardant composite material consisting of epoxy resin and glass fiber fabric; and / or the temperature measuring device (10) furthermore has a plurality of fastening means (12) for fastening the printed circuit board (1) on a battery (20).

5. The electric battery (20) according to at least one of the preceding claims, wherein the temperature sensors (2) are in each case surrounded by a thermally conductive jacket, which is thermally conductively connected to the respective first insulated region (5a).

6. The electric battery (20) according to at least one of the preceding claims, wherein the printed circuit board (1) has a plurality of milled-out portions (14).

7. The electric battery (20) according to Claim 1, wherein: the battery (20) has a plurality of rows of individual cells (21) arranged next to one another; and each of the plurality of temperature sensors (2) is provided for measuring the temperature of a plurality of individual cells (21) from adjacent rows.

8. The electric battery (20) according to Claim 1 or 7, wherein the individual temperatures measured by the temperature sensors (2) are determined ratiometrically.

9. The electric battery (20) according to at least one of the preceding claims, wherein a composite tape (30) is arranged on an upper side of the temperature measuring device (10).

10. The electric battery (20) according to at least one of the preceding claims, wherein the plurality of plated-through holes (4) is arranged between a third insulated region (5c) on the upper conductor layer (1a) and the second insulated region (5b), wherein the third insulated region (5c) is in each case arranged offset next to a temperature sensor (2).