CN106981680B

CN106981680B - Conductive measurement layer for measuring potential differences

Info

Publication number: CN106981680B
Application number: CN201611196983.6A
Authority: CN
Inventors: A.格莱特; M.施泰尔
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-12-23
Filing date: 2016-12-22
Publication date: 2021-12-31
Anticipated expiration: 2036-12-22
Also published as: DE102015226665A1; CN106981680A

Abstract

The invention relates to an electrically conductive measuring layer for measuring a potential difference between a first electrical tap and at least one second electrical tap of the measuring layer, wherein the measuring layer has at least one first material layer having a substantially temperature-independent electrical resistance.

Description

Conductive measurement layer for measuring potential differences

Technical Field

The invention proceeds from an electrically conductive measuring layer for measuring a potential difference between a first tap and at least one second tap of the measuring layer according to the preamble of the independent claim.

Background

In battery systems, in particular lithium ion battery systems, current measuring devices are implemented which operate, for example, according to the shunt, hall or flux principle. The battery current is the most important measurement variable for observing and regulating the battery system, in addition to the battery temperature and the battery voltage.

The current sensor is constructed separately from the battery in the battery system as a current measuring device according to the prior art and is read by a control device (battery management system BMS). The communication between the sensors and the control unit is effected, for example, via a bus system (CAN, LIN bus), only in special cases by direct reading of the physical electrical signals.

For controlling and/or regulating the battery system, the current and the voltage are used in relation to each other for calculating, for example, for calculating the electrical power (P = U × I). For this purpose, it is important to simultaneously use continuously detected values which are summed up with one another (synchronicity of the current and voltage measurements). For example, if the current value at a first time is summed (verrechen) with the voltage value at a second time different from the first time, the calculated power value is wrong. However, and in particular when the current measurement in the current sensor is processed and the value is subsequently transmitted via the bus system to the control device, a time offset is formed, which converts the bus signal and can then use the values of the current measurement and the voltage measurement for the calculation. The voltage measurement itself can also be decoupled in time if, for example, a battery monitoring unit (CSC) is used for the voltage measurement, which communicates with the battery pack control unit via a bus system.

These problems which occur in the prior art are encountered, for example, in the complicated software-based filtering or smoothing of current and/or voltage values. This causes inaccuracies with respect to the measured values and only conditionally enables remediation in the problem of synchronicity. This is followed by a complex cable harness which connects the mechanisms to one another and also by a multi-part and partially complex busbar or cable in a high-voltage circuit in order to be able to connect the sensors in the middle. These measures lead to high complexity and therefore also to high costs. Furthermore, each sensor is at the expense of the required environment, for example cable harnesses and/or interfaces, structural space and weight in the battery pack and therefore reduces the efficiency in terms of volume and weight.

Furthermore, according to the prior art, the temperature is measured by the module controller by means of a temperature sensor in the vicinity of the battery, for example on the battery connector, and is transmitted to the battery pack control device via the bus system. Some disadvantages arise as already described above.

The invention strongly simplifies the determination of the flowing current and eliminates the mentioned disadvantages. In one embodiment, the present invention may also be used to determine temperature. At a certain location, e.g. the current, voltage and temperature on the module controller, are measured synchronously and sent to the battery pack control device. The quality of the measurement value detection and measurement value processing and the regulation of the battery pack are thereby greatly improved, and the complexity is thereby simplified, which leads to weight and installation space savings in addition to the associated cost savings. The eliminated cable harness improves the safety of the battery pack, since the risks associated with wiring, such as insulation failure or short circuit risk, are reduced.

Document DE 112010003272T 5 discloses a battery cell with an integrated sensor platform. The battery cell having a sensor platform with sensor elements is configured to provide information on the primary characteristics and parameters of the battery cell. Embodiments of the battery cell may have the sensor platform integrated into the structure of the battery cell, as a separate structure included in the battery cell, or as a combination of these. In the embodiment shown, the battery cell has a sensor platform with a sensor element in the vicinity of the located measuring region, wherein the sensor platform has a substrate with a material layer applied thereon. The material layer has at least one sensor layer that constitutes a sensor element such that the sensor element is responsive to a characteristic of the battery cell.

Disclosure of Invention

THE ADVANTAGES OF THE PRESENT INVENTION

The measure layer according to the invention, which has the characterizing features of the independent claim, has the advantage, however, that it has a substantially temperature-independent resistance. The current determination can thus be carried out essentially independently of the ambient temperature by means of the voltage drop across the measurement layer and the known resistance.

Further advantageous embodiments are the subject of the dependent claims.

The first material layer of the measuring layer is at least partially made of constantan, a doped semiconductor, a metal alloy, a metal and/or a conductive plastic. Good electrical conductivity and little temperature dependence are thereby achieved.

The first electrical tap and the second electrical tap of the conductive measurement layer are arranged on opposite sides of the measurement layer. This makes it possible to obtain a voltage measurement diagonal to the electrically conductive measuring layer, which enables a more accurate current determination, in particular in the case of electrically conductive measuring layers, with only one material layer.

The conductive measurement layer includes a second material layer having a temperature dependent resistance and a third electrical tap. Other properties, for example the temperature determination, can thus be determined by means of the electrically conductive measurement layer, provided that the second material layer has a greater temperature dependency than the first material layer.

The first material layer of the conductive measurement layer is preferably arranged between two second material layers. The first material layer can thus be adjusted precisely both on its base surface and also on its material thickness. The ohmic resistance of the first material layer is thereby adapted to the respective application. A smaller ohmic resistance is advantageous in terms of less heat generation.

The method according to the invention for determining the current flowing through an electrical energy store by means of an electrically conductive measuring layer according to the invention comprises the following steps: a first potential difference between the first electrical tap and the second electrical tap is measured by the measuring unit, and the current flowing through the electrical energy store is calculated from the quotient of the measured potential difference and the known temperature-independent resistance. The current flowing through the electrical energy store can thus be calculated in a simple manner with high accuracy.

The method according to the invention for determining the current flowing through an electrical energy store also comprises the following steps: the potential difference between the second electrical tap and the third electrical tap of the measurement layer is measured, and the present resistance of the second material layer is determined by means of the determined current and the measured second potential difference.

The temperature within the measurement layer or the ambient temperature of the measurement layer is determined by means of a model-based estimator and/or a temperature resistance characteristic. The temperature is thereby determined from the flowing current determined by means of the first material layer of the measuring layer and the measured second potential difference. Advantageously, both the current determination and the temperature determination can be achieved with the measuring layer and the associated method according to the invention.

The measuring layer according to the invention is advantageously used in a battery module having a plurality of battery cells, wherein the measuring layer is electrically conductively connected to a pole of the battery module, to at least one of the battery cells and/or to at least one electrically conductive plate for measuring a voltage drop across the measuring layer. This advantageously enables current determination and/or temperature determination to be integrated into the battery module.

The measuring layer is advantageously used in a battery module having a plurality of battery cells, wherein the battery cells comprise lithium ion cells, lithium sulfur cells, lithium air cells. This advantageously enables accurate current and/or temperature measurements for battery modules having a high energy density.

Drawings

Embodiments of the invention are illustrated in the drawings and are explained in detail in the description that follows.

Wherein:

fig. 1 shows a nut shell battery module according to the prior art; and is

Fig. 2 shows an example of a method of manufacturing a battery module by means of nut shell battery cells according to the prior art; and is

Fig. 3 shows an example of a series circuit and a parallel circuit of nut shell battery cells by means of metal contacts according to the prior art; and is

FIG. 4 shows a first application of a first embodiment of a measurement layer according to the invention; and is

FIG. 5 shows a second application of the first embodiment of the measuring layer according to the invention; and is

FIG. 6 shows a first embodiment of a measurement layer with one material layer; and is

FIG. 7 shows a second embodiment of a measurement layer with two material layers; and is

FIG. 8 shows a second embodiment of a measurement layer according to the invention; and is

FIG. 9 shows a third embodiment of a measurement layer according to the invention; and is

FIG. 10 shows a fourth embodiment of a measurement layer according to the invention; and is

FIG. 11 shows a fifth embodiment of a measurement layer according to the invention; and is

FIG. 12 shows a sixth embodiment of a measurement layer according to the invention; and is

Fig. 13 shows an example of a series circuit and a parallel circuit of a nut shell type battery cell to which the seventh embodiment of the measuring layer according to the present invention is applied.

Detailed Description

Like reference numerals refer to like apparatus components throughout the several views.

Fig. 1 shows a nut shell battery module 10 according to the prior art. The basic principle of a nut shell battery cell is: one geometric side (or portion of a face) of the nut shell battery cell is at a positive cell potential and the opposite side of the battery cell is at a negative cell potential. Nut shell battery cells, for example, comprise coated or repeatedly stacked (of contacts, anodes, electrolyte, cathodes and contacts) layers (pole groups) that are in contact with the battery cell casing in the interior of the nut shell battery cell. The upper and lower sides of the battery cell case are electrically insulated from each other.

Two nut

shell battery cells

100, 101 are shown in fig. 1. By stacking S1 the nut

shell battery cells

100, 101, the negative battery potential 110 of the nut shell battery cell 100 is brought into contact with the positive battery potential 111 of the nut shell battery cell 101. For clarity reasons, the frame, contacts and voltage measurements have been omitted from illustration.

Fig. 2 shows an example of a method of manufacturing a battery module by means of nut shell battery cells according to the prior art. The nut-shell battery module 20 (shown in the right-hand portion of fig. 2) is manufactured by stacking S2 a plurality of nut-shell battery cells 200 (1), 200 (2), 200 (3), 200 (n). To simplify the contacting,

electrical connection contacts

220, 230 are provided, wherein electrical contact 230 is electrically connected, for example, to the negative cell potential of nut shell battery cell 200 (1), and electrical contact 220 is electrically connected, for example, to the positive cell potential of nut shell battery cell 200 (n).

Fig. 3 shows an example of a series circuit and a parallel circuit of nut shell battery cells by means of metal contacts according to the prior art. The nut-shell battery module 30 is formed by stacking S3 a plurality of nut-shell battery cells 300 (1), 300 (2), 300 (3), 300 (5), 300 (n) and inserting electrical contacts 320 (1), 320 (m), such as metal conductor plates and/or conductive films. The nut-and-shell battery cells 300 (1), (300), (2), (300), (3), (300), (5), (300 (n) are connected in series and/or in parallel according to the electrical contacts 320 (1), (320 (m).

Fig. 4 shows a first application of a first embodiment of the measuring layer according to the invention. The nut-shell battery module 40 shown in the right-hand part of fig. 4 is formed by stacking S4 nut-shell battery cells 400 (1), 400 (2), 400 (3), 400 (n) and a first embodiment of a measurement layer 440 according to the invention. By stacking S4, the nut-shell battery cells 400 (1), (400) (2), (400) (3), 400 (n) are in electrical contact with one another, wherein electrical contact is made between two nut-shell battery cells by means of the measuring layer 440. The current path between the

electrical contacts

420, 430 is closed. The measuring layer 440 according to the invention is implemented as a single layer and therefore has only one material layer. The mounting position at the middle of the nut-shell battery module 40 shown in fig. 4 is exemplary, and an arrangement between two other nut-shell battery cells 400 (1), (400), (2), (400), (3), and 400 (n) is likewise possible.

Fig. 5 shows a second application of the first embodiment of the measuring layer according to the invention. The nut-shell battery module 50 shown in fig. 5 includes a plurality of nut-shell battery cells 500 (1), 500 (2), 500 (3), 500 (n) in electrical contact with each other. A measurement layer 540 according to the present invention is disposed between the nut shell battery cell 500 (n) and the electrical contact 520. The current path between electrical contact 530 and electrical contact 520 is closed. In the second illustrated embodiment, a voltage measurement is carried out between the nut shell battery cell 500 (n) and the electrical contact 520 by means of the measuring layer 540. This embodiment of the measurement layer 540 is single-layered and therefore has only one material layer.

Fig. 6 shows a first embodiment of a measuring layer with one material layer. The measurement layer 640 includes a material layer 641. The current, for example, shown by the current flow direction 650, is distributed substantially uniformly over the entire surface of the measurement layer 640 when flowing through the measurement layer 640. The material layer 641 of the measurement layer 640 has a specific resistance that substantially depends on the selected material of the material layer 641.

Fig. 7 shows a second embodiment of a measuring layer according to the invention with two material layers. The measuring layer 740 according to the invention comprises in the second embodiment shown three

material layers

741, 742, 743. The conductive material layer 742 preferably comprises a material such as constantan, a doped semiconductor, a metal alloy, a metal, and/or a conductive plastic. The resistance of material layer 742 is known and the materials are selected such that the operating temperature does not significantly affect the resistance over the entire operating range. The material layers 741, 743 include a conductive material having a temperature dependent resistance.

The current determination using the measurement layer 740 operates by measuring the voltage drop across the material layer 742 (the voltage measurement tap on the measurement layer 742 is omitted from illustration for clarity reasons) and this voltage drop is detected by electronics, such as a nut shell module controller. The current is calculated from the measured voltage drop and the known resistance by means of the formula I = U/R.

The determination of the temperature of the measurement layer 740 is carried out by measuring the voltage drop across the material layers 741, 743 and determining the temperature of the material layers 741, 743 using the current calculated by means of this current determination. The ohmic resistance, which in one of the subsequent calculation steps results in the assigned temperature, is determined from the voltage drop and the calculated current of the material layer 742. The temperature determination may be supported by a model-based estimator in the analytical electronics. The temperature-resistance characteristic curve can be stored in a so-called look-up table in the software of the analysis electronics.

Fig. 8 shows a second embodiment of a measuring layer according to the invention. Measurement layer 840 includes a layer of material 841 and first and second

electrical taps

850, 860. Thereby enabling voltage measurement between the first electrical tap 850 and the second electrical tap 860. By arranging the first electrical tap 850 and the second electrical tap 860 on opposite sides of the material layer 841, a small structural space is required for the measurement layer 840.

Fig. 9 shows a third embodiment of a measuring layer according to the invention. The measurement layer 940 includes three layers of

material

941, 942, 943 and a first electrical tap 950 and a second electrical tap 960. Measurement layers 941 and 943 have, for example, a temperature-dependent resistance, so that a temperature determination can be carried out by means of measurement layer 940. The material layer 942 has a resistance that is substantially independent of temperature.

The current determination using the measurement layer 940 operates by measuring the voltage drop across the material layer 942 (the voltage measurement tap on the measurement layer 942 has been omitted from illustration for clarity reasons) and detecting this voltage drop by an electronic device, such as a nut shell module controller. The current is calculated from the measured voltage drop and the known resistance by means of the formula I = U/R.

The determination of the temperature using the measurement layer 940 is carried out by measuring the voltage drop across the material layers 941, 943 and determining the temperature of the material layers 941, 943 using the current calculated by means of this current determination. The ohmic resistance, which in a subsequent calculation step results in the assigned temperature, is determined from the voltage drop and the calculated current of the material layer 942.

Fig. 10 shows a fourth embodiment of the measuring layer according to the invention. Measurement layer 1040 includes a layer of material 1041 and first and second

electrical taps

1050 and 1060. The first electrical tap 1050 and the second electrical tap 1060 are diagonally arranged on opposite sides of the measurement layer. This makes it possible to achieve more accurate voltage measurements than in the case of an off-diagonal arrangement, in particular in the case of a single measurement layer.

Fig. 11 shows a fifth embodiment of a measuring layer according to the invention. The measurement layer 1140 includes a first material layer 1141, a second material layer 1142, and a third material layer 1143. First and second

electrical taps

1150, 1160 are diagonally arranged on opposite sides of the measurement layer. Thereby a more accurate current determination can be achieved. Due to the three-layer structure of the measurement layer 1140, both a current determination and a temperature determination can be realized by means of the measurement layer 1140.

The current determination using the measurement layer 1140 operates by measuring the voltage drop across the material layer 1142 (the voltage measurement tap on the measurement layer 1142 is omitted from illustration for clarity reasons) and detecting the voltage drop by an electronic device, such as a nut shell module controller. The current is calculated from the measured voltage drop and the known resistance by means of the formula I = U/R.

The determination of the temperature of measurement layer 1140 is used to determine the operation of measuring the voltage drop across

material layers

1141, 1143 and determining the temperature of

material layers

1141, 1143 using the current calculated from the current determination. The ohmic resistance, which in a subsequent calculation step results in the dispensed temperature, is determined from the voltage drop and the calculated current of the material layer 1142.

Fig. 12 shows a sixth embodiment of the measuring layer according to the invention. The measurement layer 1240 includes three

material layers

1241, 1242, 1243 and first and second

electrical taps

1250, 1260. The material layer 1242 includes three material regions. First region 1242 (1) comprises a first conductive material and is surrounded by non-conductive regions 1242 (2) and non-conductive regions 1242 (3). Measurement layer 1240 also includes a first electrical tap 1250 and a second electrical tap 1260. The material layers 1241 and 1243 are non-conductive. The ohmic resistance of material region 1242 (1) can be tuned for an application, since material region 1242 (1) can be adjusted in its size and in its thickness. The ohmic resistance should be in the region where the measurement voltage is sufficiently large, but the heating source is not formed by passing a current.

Fig. 13 shows an example of a series circuit and a parallel circuit of a nut shell type battery cell to which the seventh embodiment of the measuring layer according to the present invention is applied. The nut-shell battery module 1330 includes a plurality of nut-shell battery cells 1300 (1), 1300 (2), 1300 (3), 1300 (5), 1300 (n-1), 1300 (n) electrically connected to each other by means of electrical contacts 1320 (1), 1320 (m). A seventh embodiment of the measuring layer 1340 according to the invention is arranged between the electrical contact 1320 (m) and the nut shell battery cells 1300 (n), 1300 (n-1) and is electrically connected to the electrical contact 1320 (m) and the nut shell battery cells 1300 (n), 1300 (n-1). The measurement layer 1340 includes three

material layers

1341, 1342, 1343. The material layers 1341, 1343 are configured as electrical contacts with little electrical resistance. The potential difference between the

electrical taps

1350, 1360 of the measurement layer 1340 is measured by means of the material layer 1342, the material layer 1342 having a temperature independent resistance. The current flowing through the measurement layer 1340 is determined by means of the measured potential difference.

In an alternative embodiment, the nut shell battery module 1330 comprises, in addition to the measuring layer 1340, a further measuring layer according to the invention having at least one material layer with a temperature-independent electrical resistance, wherein the current determined by means of the measuring layer 1340 is used for the temperature determination.

The implementation and application of the measuring layer according to the invention is not limited to the embodiments shown in the figures, but can be implemented in any combination. In particular, at least one current determination and/or at least one temperature determination is carried out in at least one nut-shell battery module.

The nut shell battery module is schematically shown in the drawing, and the wiring is omitted for reasons of clarity.

For reasons of clarity, detailed implementation of the design of the electrical tap is likewise dispensed with. The electrical taps can be realized in different ways, for example as welded connections, press contacts, bolted connections, welded connections to join and/or clamp. The measurement layer according to the invention can be embodied as a plate, a film, a thin layer, a flexible mat and/or a stamped semiconductor wafer.

Furthermore, the use of the measuring layer according to the invention within a nut-shell battery cell is possible.

Claims

1. A battery module having

A plurality of battery cells, and

an electrically conductive measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240) for measuring a potential difference between a first electrical tap (850, 950, 1050, 1150, 1250) and at least one second electrical tap (860, 960, 1060, 1160, 1260) of the measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240), wherein the measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240) has at least one layer (641, 742, 841, 942, 1041, 1142, 1242 (1)) of a first material having a substantially temperature-independent resistance,

wherein the measurement layer is in electrical contact with a pole of the battery module, with at least one of the plurality of battery cells, and/or with at least one conductive plate of the battery module.

2. The battery module according to claim 1, characterized in that the first material layer (641, 742, 841, 942, 1041, 1142, 1242 (1)) of the measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240) consists at least partially of a doped semiconductor, a metal alloy, a metal and/or a conductive plastic.

3. The battery module according to one of the preceding claims, characterized in that the first electrical tap (850, 950, 1050, 1150, 1250) and the second electrical tap (860, 960, 1060, 1160, 1260) are arranged on opposite sides of the measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240).

4. The battery module according to one of claims 1 to 2, characterized in that the measurement layers (440, 540, 640, 740, 840, 940, 1040, 1140, 1240) comprise at least one second material layer (741, 743, 941, 943, 1141, 1143, 1242 (2), 1242 (3)) having a temperature-dependent resistance and a third electrical tap.

5. The battery module according to one of claims 1 to 2, characterized in that the first material layer (641, 742, 841, 942, 1041, 1142, 1242 (1)) is arranged between at least two second material layers (741, 743, 941, 943, 1141, 1143, 1242 (2), 1242 (3)).

6. The battery module of claim 1, wherein the battery cells comprise lithium ion cells, lithium sulfur cells, lithium air cells.

7. Method for determining the current flowing through a battery module according to one of claims 1 to 6, characterized in that a first potential difference between a first electrical tap (850, 950, 1050, 1150, 1250) and a second electrical tap (860, 960, 1060, 1160, 1260) is measured by a measuring unit and the current flowing through the battery module is calculated from the quotient of the measured potential difference and the resistance by means of a temperature-independent resistance.

8. The method according to claim 7, wherein a second potential difference between a second electrical tap (860, 960, 1060, 1160, 1260) and a third electrical tap of the measurement layer (440, 540, 640, 740, 840, 940, 1040, 1140, 1240) is measured and a present resistance of the second material layer (741, 743, 941, 943, 1141, 1143, 1242 (2), 1242 (3)) is determined by means of the determined current and the measured second potential difference.

9. The method according to claim 8, wherein the temperature is determined by means of a model-based estimator and/or a temperature resistance characteristic.