MEASUREMENT SYSTEM AND METHOD FOR MEASURING ENERGY CELLS - Patent application

Abstract

The present invention relates to a measurement system 10 for measuring an energy cell 20, preferably a battery cell, in particular a single cell without added electrolyte, whereby said measurement system 10 comprises an AC voltage bridge or an auto-balancing bridge 11 and is configured to measure the capacitance C and / or the ohmic resistance R of the energy cell 20 by means of high-frequency measurements. Furthermore, the present invention relates to a corresponding method.

Description

[Technical field]

[0001] The present invention relates to a measurement system for measuring an energy cell according to the preamble of claim 1 and to a measurement method according to the preamble of claim 5. [Background technology]

[0002] During the manufacture of energy cells or accumulators, especially battery cells, foreign bodies can accumulate between the individual layers (anode, separator and cathode) of which the energy cells are composed. This can destroy the separator layer, for example, during compression. This can short-circuit the individual cells and therefore render them unusable.

[0003] In general, energy cells, especially battery cells, are constructed by stacking a number of single cells. It is very important to recognize such short circuits before stacking a number of single cells, because a single defective single cell can make the whole stack or battery cell unusable. For example, a short circuit may exist when the resistance value is significantly different from the typical insulation resistance value of the single cells, for example, when the resistance value is below a preset limit resistance value.

[0004] In order to further reduce the production costs of battery manufacturing, in particular the production rates must be further increased. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide a measuring system and a measuring method with higher process reliability and process speed. [Means for solving the problem]

[0006] This problem of the invention is solved by the features of the independent claims. Further preferred embodiments of the invention are described in the dependent claims, the corresponding description and the drawings.

[0007] To achieve this goal, a measuring system for measuring energy cells, preferably battery cells, in particular single cells without added electrolyte, is therefore proposed, which comprises an AC voltage bridge or an automatic balancing bridge and is configured to measure the capacitance C and / or the ohmic resistance R of the energy cell by high-frequency measurements.

[0008] The term "radio frequency" basically means electromagnetic waves with a frequency below 100 MHZ, limited to the microwave region. Typically, the frequency is, for example, 0.5 kHz, further for example, 1 kHz or further for example, 100 kHz. Moreover, radio frequency measurements of energy cells, in particular battery cells, differ from direct current measurements, which in this case measure the resistance value by charging and / or discharging the battery.

[0009] AC voltage bridges or automatic balancing bridges allow fast measurements of energy cells, in particular of single cells without added electrolyte of battery cells. The measurements can be carried out with low currents and voltages. This allows for an implementation that is easily compliant with electromagnetic compatibility. Therefore, less power is required and the risk of electric shock for operators is significantly reduced. Furthermore, this allows a compact construction to be achieved, which further simplifies the integration into the production process.

[0010] The proposed measurement system allows the measurement of the capacity of the cells in addition to the measurement of the ohmic resistance, so that in addition to checking for short circuits, further information is provided regarding the quality of each energy cell, and in particular each cell.

[0011] An AC voltage bridge or an auto-balancing bridge refers to a measuring circuit. In this case, the current passing through a reference impedance is varied by comparing it with the current passing through the element or energy cell to be measured until the sum of the current passing through the reference impedance and the current passing through the element or energy cell to be measured is zero. In general, the adjustment is performed by appropriately changing the amplitude and phase of the current passing through the reference impedance. From the adjusted amplitude and phase of the current passing through the reference impedance, the complex impedance of the element or energy cell to be measured can finally be calculated. For example, the presence of a parasitic short circuit (small parallel resistance) significantly changes the angle or phase position and amplitude of the adjustment current to be adjusted. Thus, the detection of a short circuit, i.e. a small ohmic resistance, can be performed by comparing the angle of the adjustment current to be adjusted with a limit value.

[0012] The energy cell to be measured may in particular be a single cell of a lithium battery. The measuring system is particularly suitable for measuring a single cell of a battery without added electrolyte, i.e. a single cell that has not yet been filled with electrolyte. The single cell is capacitive, and therefore the reference impedance must also be capacitive. Preferably, the measuring electronics, in particular an AC voltage bridge or an automatic balancing bridge, are adapted to the relatively large possible capacity of the energy cell, in particular the single cell.

[0013] According to a further developed embodiment, the measurement system is configured to measure the energy cells of a continuous production flow of energy cells, thus enabling an online quality check without slowing down the production rate.

[0014] It is further proposed that the measurement system comprises a drum, the measurement system being configured to measure the energy cells transported on the drum, whereby the energy cells, in particular the cells, can be measured on the drum during transport, so that an online process control can be carried out for each energy cell, in particular for each cell, during the manufacturing process, without any adverse effects on the process speed.

[0015] Instead, it is proposed that the measuring system comprises a belt conveyor, the measuring system being configured to measure the energy cells transported on the belt conveyor, whereby similar advantages in terms of process quality assurance are obtained, but at the same time at high process speeds.

[0016] Furthermore, in order to solve the above problems, a measurement method is proposed for measuring an energy cell, preferably a battery cell, in particular a single cell without added electrolyte, in which the capacitance C and / or the ohmic resistance R of the energy cell are measured by the automatic balancing bridge method.

[0017] Energy cells can be measured very quickly by the measurement method, so that during the manufacturing process each energy cell, in particular each cell, can be measured without the process speed being adversely affected by the measurement. The capacity measurement gives information about the quality of the cells and the product. Preferably, the energy cell measurements are performed during a continuous transfer of energy cells.

[0018] According to a further developed embodiment, it is proposed that the measurement of the energy cells is carried out on a moving conveyor belt or on a rotating drum, which allows a continuous production flow, which has an advantageous effect on the processing speed and the energy efficiency of the manufacturing process.

[0019] The energy cells, in particular the single cells, to be measured are preferably so-called energy cells without added electrolyte, that is, no liquid electrolyte has been added to them up until the time of measuring the energy cells.

[0020] It is further proposed that after measuring the ohmic resistance of an energy cell, this ohmic resistance R is compared with a limit value below which this energy cell is excluded from the production flow.

[0021] In this way, the manufacturing quality of the energy cells can be brought to a high level, whereby the use of cells in a stack can be avoided in constructing the stacked energy cells, particularly when measuring the cells during the production flow, which eliminates further rejects that may occur when using defective cells arranged in a stack.

[0022] According to a further developed embodiment, it is proposed that after measuring the capacitance C and / or the ohmic resistance R of an energy cell, in particular a single cell, said respective capacitance C and / or ohmic resistance R is stored in a data processing device.

[0023] Thereby, continuous quality monitoring of the production of energy cells can be achieved.

[0024] According to a further developed embodiment, after measuring the capacitance C of the energy cell, this capacitance C is compared with an upper and / or lower limit value, and it is proposed to exclude this energy cell from the production flow when it exceeds or falls below the respective limit value. Such deviations outside the range of configurable limits indicate poor quality, for example due to stacking faults, which may occur in particular due to temperature deviations.

[0025] According to a further developed embodiment, after measuring the electric capacity C of a plurality of energy cells, in particular a plurality of single cells, which may each have a different electric capacity, a total capacity C that is greater than a lower limit and smaller than an upper limit is determined. _ges It is proposed that the electrodes be assembled into a stack having

[0026] This allows energy cells, consisting of a stacked arrangement of multiple cells, to be manufactured with a consistent property profile.

[0027] The present invention will now be described based on preferred embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0028] [Figure 1] 1 shows a measurement system for measuring cells on a drum. [Diagram 2] 1 shows a measurement system for measuring cells on a belt conveyor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] 1 shows a schematic representation of an embodiment of a measurement system 10 for measuring an energy cell 20. The measurement system 10 comprises an automatic balancing bridge 11. An energy cell 20 (in this embodiment a single cell without added electrolyte for a lithium battery) is brought into contact with the automatic balancing bridge 11.

[0030] The capacitance C and the ohmic resistance of the energy cell 20 are measured by high-frequency measurements by means of an automatic balancing bridge 11. This automatic balancing bridge 11 allows said measurement of both values ​​during short-term measurements in a simple manner.

[0031] In the embodiment of Fig. 1, the energy cells 20 on the drum 12 are transported in a continuous production flow. Measurements of the energy cells 20 are performed during this continuous transport, as indicated by the arrows in Fig. 1. This, in addition to short measurement periods with the auto-balancing bridge 11, allows online measurements of the energy cells 20 without interrupting or slowing down the production flow.

[0032] Figure 2 shows a schematic representation of another embodiment of the measurement system 10. In this case, the energy cells 20 are continuously transported on a belt conveyor 13, in contrast to the embodiment of Figure 1, while they are measured by an automatic balancing bridge 11.

[0033] In the embodiments of figures 1 and 2, one data processing device 14 each is provided which is arranged to store the recorded measurement data, preferably the ohmic resistance R and the capacitance C.

[0034] Both measurement data of the respective energy cell 20 can be used to assess the quality. The stored measurement data of the respective energy cell 20 are then compared with limit values ​​preset in the data processing device 14. In this case, in particular energy cells 20 that have an ohmic resistance below a predefined limit value, generally due to a recognized short circuit in the energy cell 20, are unusable. Unusable energy cells 20 can thus be recognized during the ongoing production flow and can be rejected from the production flow by a rejection device 16 controlled by the data processing device. Possible short circuits in the cells can therefore be recognized early. As a result, these unusable energy cells 20, in particular the cells, are not stacked, for example, for the stack 15. The measurement can therefore avoid the production of unusable stacks 15 due to short circuits in individual cells.

[0035] In a preferred embodiment, the total capacity C of the stack 15 having a certain number of individual energy cells 20 or cells is _ges can be optimized by the data processing device 14. As a result, the measured energy cells 20 can be sorted by their respective capacitances C to obtain the total capacitance C of the individual energy cells 20 of the stack 15. _ges Or multiple stacks 15 may be assembled that are within a preset range of average capacity, thereby ensuring the same characteristics for multiple stacks.

Claims

1. A measuring system (10) for measuring an energy cell (20), preferably a battery cell, in particular a single cell without added electrolyte, The measurement system (10) comprises an AC voltage bridge or an auto-balancing bridge (11) and is configured to measure the capacitance C and / or the ohmic resistance R of an energy cell (20) by high-frequency measurement.

2. The measurement system (10) of claim 1, wherein the measurement system (10) is configured to measure energy cells (20) of a continuous production flow of energy cells (20).

3. The measuring system (10) comprises a drum (12), 3. The measurement system (10) according to claim 1 or 2, characterized in that the measurement system (10) is configured to measure energy cells transported on the drum.

4. The measuring system (10) comprises a belt conveyor (13), 3. The measuring system (10) according to claim 1 or 2, characterized in that the measuring system (10) is configured to measure energy cells (20) transported on the belt conveyor (13).

5. A measuring method for measuring an energy cell (20), preferably a battery cell, in particular a single cell without added electrolyte, comprising: A measuring method characterized in that the capacitance C and / or ohmic resistance R of the energy cell (20) is measured by an automatic balancing bridge method.

6. 6. The method according to claim 5, wherein the measurement of the energy cell (20) is carried out on a moving belt conveyor (13) or on a rotating drum (12).

7. 7. The method according to claim 5, wherein after measuring the ohmic resistance of an energy cell (20), this ohmic resistance R is compared with a limit value, below which the energy cell (20) is excluded from the production flow.

8. 7. The measuring method according to claim 5 or 6, characterized in that after measuring the ohmic resistance R of the energy cell (20), this ohmic resistance R is compared with a limit value, and when this limit value is exceeded, this energy cell (20), in particular a single cell, is stacked with other energy cells (20), in particular single cells.

9. 7. The method according to claim 5 or 6, characterized in that after measuring the capacitance C and / or the ohmic resistance R of the energy cell (20), in particular the single cell, the respective capacitance C and / or ohmic resistance R is stored in a data processing device (14).

10. 7. The method according to claim 5 or 6, characterized in that after measuring the capacitance C of the energy cell (20), this capacitance C is compared with an upper and / or lower limit value, and when the capacitance C exceeds or falls below the respective limit value, this energy cell (20) is excluded from the production flow.

11. After measuring the electrical capacities C of a plurality of energy cells (20), in particular a plurality of single cells, each of which may have a different electrical capacity C, a total capacity C that is greater than a lower limit value and less than an upper limit value is obtained. ＿ｇｅｓ 7. The measuring method according to claim 5 or 6, characterized in that the measuring device is assembled into a stack (15) having:

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