Diagnosis of battery cells during fabrication by current measurement

Abstract

The invention relates to diagnosis of a battery cell by current measurement during manufacturing. A method for determining a current in a battery cell during fabrication of the battery cell is provided. The method comprises: arranging a non-contact current sensor relative to the battery cell, wherein the non-contact current sensor comprises at least one current sensing element; performing at least one of filling the battery cell with an electrolyte, charging the battery cell, and discharging the battery cell; and determining, by the non-contact current sensor, a current within the battery cell during or after the at least one of filling the battery cell with the electrolyte, charging the battery cell, and discharging the battery cell. Further, a non-contact current sensor and corresponding manufacturing equipment are provided.

Description

Technical Field

[0001] The invention of the present application relates to diagnosing a battery cell by current measurement during the manufacture of the battery cell. In this regard, the manufacture of the battery cell may include the steps of filling the battery cell with an electrolyte or forming the battery cell. The present application provides a method for determining the current in a battery cell during manufacture, a current sensor configured to determine the current during the manufacture of the battery cell, a manufacturing equipment including a corresponding current sensor, and a battery cell produced by a method involving determining the current during manufacture. Background Art

[0002] Batteries such as lithium-ion batteries are widely used in various technical fields. Typically, a battery includes a plurality of battery cells. Such battery cells are typically produced in a manufacturing facility. The manufacturing facility for manufacturing a battery cell may perform one or more steps of a manufacturing process. These steps may include steps of filling a battery cell with an electrolyte or forming a battery cell. An example of a manufacturing facility may be an electrolyte filling facility, in which a battery cell is filled with an electrolyte. Other examples of manufacturing facilities may be forming facilities, in which battery cells are then cycled and discharged until they reach a desired capacity. Similarly, in the sense of the current application, the manufacturing facility may also be configured to perform a plurality of steps of manufacturing a battery cell. For example, the manufacturing facility may perform electrolyte filling and forming.

[0003] The production of battery cells is often prone to high yield losses, especially when a new production line is started up. Unfortunately, detection of faulty cells conventionally occurs only at the end of a formation cycle (e.g., by electrochemical reading) or even only when the battery cell is in use. A faulty battery cell can adversely affect the capacity of the battery and can even shorten the life of the battery.

[0004] Therefore, there is a need in the art to detect defective cells already during battery cell production. Summary of the invention

[0005] The above needs are solved by a method for determining the current in a battery cell during the manufacture of the battery cell according to the attached independent claim. The method can be applied during or after the battery cell manufacturing steps (e.g. when filling the battery with electrolyte or when the battery cell is formed using forming equipment).

[0006] According to the present invention, the method includes arranging a contactless current sensor relative to the battery cell, wherein the contactless current sensor includes at least one current sensing element. In the sense of the current application, the (contactless) current sensor can be used to determine the current in the circuit or the electronic component of the circuit without the need for the (contactless) current sensor to be electrically connected to the circuit. This can be achieved by measuring the physical quantities affected by the current in the circuit or the electronic component of the circuit, respectively. Examples of such physical quantities may include a magnetic field (including any of the characteristics of the magnetic field, such as one or more spatial components of the magnetic field, the orientation of the magnetic field lines, one or more gradients of the magnetic field, a differential magnetic field, a magnetic flux density (i.e., one or more spatial components of the B field or its spatial components), a magnetic field intensity (i.e., one or more spatial components of the H field or its spatial components), etc.) or a temperature (including a temperature gradient), etc. Those skilled in the art will appreciate that any of these measurements may include measurements indicating any of the above examples, such as measuring a magnetic field by the Hall effect or any magnetoresistance effect.

[0007] Further, at least one of the following is performed: filling the battery cell with electrolyte, charging the battery cell, and discharging the battery cell. These steps may represent the steps of manufacturing a battery cell, wherein the battery cell is usually first filled with electrolyte, and then the battery cell is usually formed by alternately charging and discharging the battery cell. According to the present invention, during or after the at least one step of battery manufacturing, the current in the battery cell is determined by a contactless current sensor. All combinations (including combinations of multiple steps) of performing current determination during or after any manufacturing step in the above-mentioned manufacturing steps are covered in the present disclosure. In some preferred examples, the current can be determined during charging the battery cell, during discharging the battery cell, or during both charging and discharging. In some other preferred examples, the current can be determined after the electrolyte is filled. In some examples, determining the current after the electrolyte is filled may require applying a potential to the battery cell in order to promote current flow.

[0008] The current within a battery cell may indicate one or more characteristics associated with the battery cell. These characteristics include the capacity of the cell, the voltage of the cell, the internal impedance of the cell, the impedance of one or more of the electrodes of the cell, the impedance of the electrolyte of the cell, the self-discharge rate of the cell, or the wetting of the battery by the electrolyte. Each of these characteristics or the deviation of these characteristics from the specification value and / or the deviation from the characteristics of other cells may provide an early indication of a faulty cell. For example, determining the current during the formation of the battery cell may detect a faulty battery cell by comparing the current with the expected current or comparing the currents of several battery cells formed and sensed at the same time. In some embodiments, a spatially resolved map of the spatial distribution of the current during or after the manufacturing step may be obtained, which may be analyzed to identify anomalies that may indicate a faulty cell. More details on the determination of the current will be presented below when discussing the preferred embodiments of the present invention. The above-mentioned deviations of the characteristics may also be referred to as anomalies.

[0009] The above needs are overcome by the above detection of faulty battery cells during the manufacture of the battery cells (eg, during or after electrolyte filling or during battery cell formation), and the efficiency and quality of battery cell manufacturing will be significantly improved.

[0010] In the sense of the invention, a battery cell can be, for example, a pouch cell, a prismatic cell, a coin / button cell, etc. Depending on the geometry and structure of the battery, the method can be applied to a single cell, a pair of cells, a plurality of cells or to the entire battery.

[0011] In some preferred embodiments, at least one current sensing element may be any one of the following: a Hall element, a magnetoresistive element, a magnetoresistive sensing element (e.g., a giant magnetoresistive (GMI)), a fluxgate magnetometer, a microelectromechanical system (MEMS) magnetometer, or an inductive sensing element. A magnetoresistive element is an element sensitive to a magnetoresistive effect, including a colossal magnetoresistive (CMR) effect, a giant magnetoresistive (GMR) effect, and a tunneling magnetoresistive (TMR) effect.

[0012] These current sensing elements may be made at least in part of a semiconductor, such as silicon. For example, they may include an integrated complementary metal oxide semiconductor (CMOS) circuit, or they may be made of a semiconductor compound, such as a compound containing a substance of chemical groups III and V, such as gallium arsenide (GaAs). Such a configuration may increase the sensitivity of the current sensing element.

[0013] In some preferred embodiments, the contactless current sensor can be configured to measure the spatial components of the magnetic field. To achieve this, the contactless current sensor can include a sensing component that is sensitive to one spatial magnetic field component, two spatial magnetic field components, or even three spatial magnetic field components. Depending on the number of spatial magnetic field components that the contactless current sensor can measure, the contactless current sensor can be called a 1D, 2D, or 3D sensor.

[0014] In some preferred embodiments, determining the current in the battery cell can be based on the measurement of the magnetic field gradient. The measurement of the magnetic field gradient can be performed by measuring the change of one or more spatial magnetic field components along one or more spatial directions. In this way, one to nine gradients can be measured simultaneously or subsequently depending on the current sensor used. For example, in a three-dimensional Euclidean (x, y, z) space, the change of the spatial x component can be determined along the y direction, which represents a single gradient. An example of two gradients is to measure the change of two spatial magnetic field components (e.g., x component and y component) along a spatial direction (e.g., y direction). Alternatively, a single spatial magnetic field component can be measured along two spatial directions (e.g., y and z directions). For six gradients, three spatial components can be measured along two spatial directions, or two spatial components can be measured along three spatial directions, and for nine gradients, three spatial components can be measured along three spatial directions. It is worth noting that the spatial direction along which the change of one or more magnetic field components is determined does not need to correspond to the three main axes of the three-dimensional space. Instead, the change of one or more magnetic field components can be determined in any arbitrary spatial direction, including but not limited to the (x, y) direction, the (y, z) direction, and the (x, z) direction. In the above description, although only some examples are explicitly mentioned, all combinations of three spatial magnetic field components measured along any spatial direction are included in the scope of the present disclosure.

[0015] The gradient can be determined by using a single sensing element that is inherently sensitive to the magnetic field gradient (e.g., a MEMS gradiometer), or the gradient can be determined by determining the difference between two sensing elements arranged oppositely along the spatial direction in which the gradient is to be determined. The latter can be facilitated by arranging the current sensing elements in an array, as will be explained in the following paragraphs.

[0016] In some preferred embodiments, at least one contactless current sensor may include an array comprising a plurality of current sensing elements. Equipping the current sensor with a plurality of current sensing elements allows the spatial resolution of the current sensor to be improved, and may allow identification of areas where the current in the battery cell may be abnormal (e.g., the current is lower than expected). The current sensing elements in the plurality of current sensing elements may be distributed in a preferred manner. For example, a plurality of current sensing elements may be evenly distributed in a plane. Such a configuration has the benefit that the current can be determined with a substantially uniform spatial resolution.

[0017] Alternatively, the current sensing elements among the plurality of current sensing elements may be unevenly distributed. This may allow the spatial resolution of the current sensor to be adjusted according to the geometric characteristics of the battery cell. For example, for some battery cells, it may be known that anomalies in the current occur more often in the edge region of the battery cell than in the central region. In this case, when arranged relative to the battery cell, the plurality of current sensing elements may be more densely distributed in the edge region of the battery cell than in the central region of the battery cell. For example, the current sensor may have a spatial extent similar to that of the battery cell, such that a first group of current sensing elements among the plurality of current sensing elements located in the edge region of the current sensor may be more densely distributed than a second group of current sensing elements among the plurality of current sensing elements located in the central region of the current sensor.

[0018] In the case where the current sensor includes two or more current sensing elements, determining the current within the battery cell can be performed simultaneously for each current sensing element or can be performed sequentially for a subgroup of the current sensing elements. Each subgroup can be composed of one or more current sensing elements. In particular, when the multiple current sensing elements include a large number of current sensing elements, performing the determination sequentially can reduce the bandwidth of the measurement signal provided by the current sensing element. On the other hand, performing the determination simultaneously can provide the highest measurement accuracy and can improve the comparability of the results.

[0019] In some embodiments, determining the current within the battery cell can be performed at repeated time instances. For example, determining the current can be performed continuously, such as periodically repeated according to a predetermined time interval. The data can be stored in a memory (e.g., a working memory (such as a random access memory) or a main storage device). In the case where the data is stored, the data can be used to monitor the current over time, which allows the identification of anomalies that cause abnormal or unstable current rates. Depending on the frequency at which the current is determined, the amount of data may be large in the case where the data is stored. Therefore, it may be necessary to selectively store the data. For example, this can be achieved by not storing the data each time the data is acquired. For example, the data can be stored only at a specific time instance, at a specific time point during the formation cycle (e.g., once a certain percentage of the formation is performed), or only the latest data can be retained and replaced after the new data has been acquired and evaluated.

[0020] It may be known that some battery cells may have specific time characteristics of their formation cycle, which means that for some battery cells, anomalies in the current may occur more frequently at specific time instances after electrolyte filling or during the formation of the battery cell (for example, at the beginning or end of the formation cycle, or after 30% or 50% of the formation cycle). The time instances at which the determination of the current is performed can take these time characteristics of the formation of the battery cell into account, for example, by repeating the determination of the current more frequently at specific times (for example, at the beginning (i.e., during the first 20% of the formation of the battery cell), at times corresponding to 30%, 40% or 50% of the formation of the battery cell, or at the end of the formation of the battery cell). Determining the anomaly in the current at the beginning (i.e., during the first 20% of the formation of the battery cell) may be preferred because the chemical / physical change rate within the battery cell is particularly high, which means that the anomaly can be detected with high accuracy. Further, identifying anomalies that may lead to a faulty battery cell at the beginning of battery cell manufacturing has the benefit that the formation process of the battery cell can be cancelled in advance, thereby reducing the waste of resources that would otherwise be required to fully run the battery cell manufacturing process. Depending on the manufacturing equipment used to manufacture the battery cells, the manufacture of a single battery cell may be cancelled or the manufacture of an entire batch of battery cells may be cancelled. In the latter case, manufacturing may be cancelled once an anomaly is identified in a majority of the battery cells in the batch (e.g., more than 20% or 30% of the battery cells).

[0021] In some preferred embodiments, determining the current within the battery cell includes: moving the contactless current sensor and the battery cell relative to each other within the manufacturing equipment, and determining the current by scanning the current during the relative movement of the contactless current sensor and the battery cell. By performing relative movement between the current sensor and the battery cell, the spatial sensitivity of the current sensor can be improved. For example, a single current sensor can be moved relative to the battery cell to determine the current in a spatially resolved manner. In other examples, the current sensor may include an array having a plurality of current sensing elements, as will be described in more detail below. For example, if the spatial range of the array is smaller than the spatial range of the current sensor, the array can be moved relatively to achieve the above-mentioned spatial resolution. Additionally, the relative movement allows the measurement of the current in a battery cell having a larger spatial range than the current sensor.

[0022] In some preferred embodiments, the method may include identifying a deviation in the determined current. For example, this may be achieved by comparing the determined current with an expected current and identifying that the determined current is less than the expected current.

[0023] Additionally or alternatively, identifying a deviation in the measured current may include generating a current measurement map for one or more regions of the battery cell based on the determined current. The above-mentioned problem of storing large amounts of data may be particularly relevant to some embodiments in which current measurement maps are generated with high spatial resolution, which means that the above-mentioned aspects of selectively storing data may be applicable to these embodiments in which current measurement maps are generated. The spatial resolution required to generate the current measurement map can be achieved by including a current sensor having an array of multiple current sensing elements as mentioned in some of the above-mentioned preferred embodiments or performing relative movement of the current sensor relative to the battery cell. The current measurement map can be evaluated based on various algorithms.

[0024] One example of evaluating a current measurement graph is to compare each individual point in the current measurement graph with a threshold value. In this way, anomalies can be identified by identifying "hot spots". Different current sensors can have the same or individual threshold values. In addition, the threshold value may vary for different locations of the battery cell, for example, the threshold value may be different in the center area and the edge area of ​​the battery cell. Alternatively or additionally, each individual point of the first current measurement graph can be compared with a corresponding point in a second (e.g., subsequent) current measurement graph.

[0025] In other examples, regions of the battery cell (eg, regions of interest) may be defined, and the current measurement map may be evaluated based on the defined regions. For example, for each region, the measured current may be compared to the expected current.

[0026] Furthermore, in embodiments where multiple battery cells are formed in a manufacturing facility, a current sensor may be provided for each battery cell. In these embodiments, the current measurement profile may be evaluated by comparing the current measurement profiles of multiple battery cells and identifying deviations.

[0027] In some embodiments, two or more current sensors may be used to evaluate a single battery cell. In such cases, a combination of the measurements of the two or more current sensors (e.g., an average) may be evaluated, for example, by comparison with a predetermined threshold. Alternatively, the measurements of each of the two or more current sensors may be compared to each other. In a specific example, an average value of two or more current sensors may be calculated, and a deviation from the average value may be determined for each current sensor.

[0028] Additionally, some algorithms may use statistical methods to determine anomalies in current measurements.For example, a cross-correlation may be performed based on a current measurement map obtained by one or more current sensors and a predetermined (eg, reference) map.

[0029] Some other algorithms may be based on artificial intelligence models. Artificial intelligence can be trained using training data and can be configured to determine the deviation of current. The training data may include a set of current maps, which include current maps for normally operating cells and current maps for faulty cells. Further, the training data may include information related to the life of the cell. Therefore, artificial intelligence can be configured to predict the expected service life of the battery cell. The process of training an artificial intelligence model may also be referred to as machine learning. Artificial intelligence can operate, for example, based on the recognition of patterns in the current measurement map. The training of artificial intelligence can be performed using a reference battery cell. Further, artificial intelligence can be configured to redefine its operation during application. In some embodiments, artificial intelligence can not only redefine the identification of anomalies in current measurement, but also redefine the time behavior of the measurement (for example, the frequency of measurement can be redefined), or additionally or alternatively, artificial intelligence can redefine the parameters of the spatial behavior of the measurement (for example, the area of ​​interest can be redefined).

[0030] Regardless of the specific algorithm or model used to determine anomalies in current measurements, the information obtained by the corresponding algorithm or model can also be used to grade battery cells. Typically, the decision whether a battery cell is faulty is a clear-cut case. However, normally operating battery cells may have different qualities. These above-mentioned results obtained by the disclosed algorithms and models can be used to determine the quality of battery cells, thereby enabling the cells to be graded into different quality levels. In order to determine different quality levels, parameters for grading battery cells can be predetermined or provided by an artificial intelligence model, where the artificial intelligence model can readjust these parameters during application.

[0031] In some preferred embodiments, the method includes applying pressure to the battery cell during the formation of the battery cell. For example, a support structure may be provided that is configured to apply pressure to the battery cell during the formation. Applying pressure to the battery cell during the formation may increase the resistance of the battery cell during the charging and discharging process of the battery cell in the formation cycle. The increased resistance due to the applied pressure can improve the formation of the battery cell, for example by increasing the capacity of the battery cell.

[0032] The above preferred embodiments are not exclusive. On the contrary, the combination of two or more aspects of the above preferred embodiments is within the scope of the present invention. Thus, all the above aspects or embodiments can be freely combined.

[0033] The above needs are also met by a contactless current sensor configured for use according to the above method. The current sensor can have any of the configurations disclosed in conjunction with the above method, including, for example, an array including a plurality of current sensing elements, wherein the current sensing elements can be uniformly or non-uniformly distributed.

[0034] The above needs are also met by a manufacturing equipment configured to perform at least one step of manufacturing one or more battery cells. The at least one step of manufacturing one or more battery cells includes filling the battery cell with electrolyte, charging the battery cell, and discharging the battery cell. The manufacturing equipment includes one or more non-contact current sensors, wherein each current sensor includes at least one current sensing element for determining a current within at least one battery cell of the one or more battery cells during or after the at least one manufacturing step.

[0035] The manufacturing equipment may also include one or more support structures. One or more non-contact current sensors may be arranged on one or more support structures. Further, one or more support structures may be movable relative to one or more battery cells, thereby allowing relative movement between one or more current sensors and one or more battery cells as described above.

[0036] Additionally or alternatively, one or more support structures may be configured to apply pressure to one or more battery cells during formation to enhance the formation process. For example, a manufacturing apparatus may include a stack of battery cells and support structures, wherein the support structures are configured to apply pressure to the battery cells throughout the stack. In some examples, multiple support structures may be rigidly connected so that when a force is applied to one of the support structures, the force is transmitted to all of the support structures through the rigid connection, thereby pressing the support structures onto the battery cells.

[0037] However, in some embodiments, each of the one or more support structures may be configured to support one of the current sensors and to simultaneously apply force to the battery cell, and in some other embodiments, the manufacturing equipment may include a first group of support structures configured to support the current sensors and a second group of support structures configured to apply force to the battery cell.

[0038] In some example embodiments, the manufacturing equipment includes a plurality of current sensors and a plurality of battery cells. In some embodiments, the current sensors and battery cells may be stacked in an alternating manner. In some embodiments, each current sensor may be configured to determine the current in a single directly adjacent battery cell, but in some other embodiments, each current sensor may be configured to determine the current in two directly adjacent battery cells. In these cases, the current sensor may be configured to determine the current in two adjacent battery cells simultaneously or sequentially.

[0039] In an embodiment example in which a battery cell is formed under pressure, the manufacturing equipment may preferably be a forming equipment for forming a battery cell, or may include such a forming equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The following description and the accompanying drawings set forth in detail certain illustrative aspects of the (contactless) current sensor according to the present invention. However, these aspects are only indicative of several of the various ways in which the principles of the various embodiments may be employed, and the described embodiments are intended to include all such aspects and their equivalents.

[0041] In the drawings, like reference numerals generally refer to like parts throughout the different drawings. The drawings are not necessarily drawn to scale. Instead, general emphasis is placed on explaining the general principles of the invention.

[0042] In the following description, various embodiments of the present invention are described with reference to the following drawings:

[0043] Figure 1 A pouch cell is shown as an example of a battery cell, wherein Figure 1Part (a) is a side view of a pouch cell, and Figure 1 Part (b) is a cross-sectional view of a pouch cell;

[0044] Figure 2 A first embodiment example of a non-contact current sensor is shown, wherein Figure 2 Part (a) is a top view of the non-contact current sensor, and Figure 2 Part (b) is a side view of the relative arrangement of the non-contact current sensor and the battery unit;

[0045] Figure 3 A second embodiment example of a non-contact current sensor is shown, wherein Figure 3 Part (a) is a top view of the non-contact current sensor, and Figure 3 Part (b) is a side view of the relative arrangement of the non-contact current sensor and the battery unit;

[0046] Figure 4 A third embodiment example of a non-contact current sensor is shown, wherein Figure 4 Part (a) is a top view of the non-contact current sensor, and Figure 4 Part (b) is a side view of the relative arrangement of the non-contact current sensor and the battery unit;

[0047] Figure 5 A fourth embodiment example of a contactless current sensor is shown, wherein the contactless current sensor moves relative to the battery cell, wherein Figure 5 The relative arrangement of the contactless current sensor and the battery unit is shown in a top view in part (a) and in a side view in part (b);

[0048] Figure 6 An embodiment of a system configured for determining current flow in a battery cell during formation under pressure is shown, wherein Figure 6 Part (a) shows the corresponding non-contact current sensor, the support structure for applying pressure, and the battery cell in a state without applied pressure, and part (b) shows the corresponding non-contact current sensor, the support structure for applying pressure, and the battery cell in a state with applied pressure;

[0049] Figure 7 Show Figure 6 An example of an embodiment of a stack of the system illustrated in . DETAILED DESCRIPTION

[0050] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced.

[0051] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0052] Figure 1 A pouch cell is shown as an example of a battery cell, wherein Figure 1 Part (a) is a side view of a pouch cell, and Figure 1 Part (b) is a cross-sectional view of a pouch battery. For reasons of simplicity, the present invention will be described with respect to the example of a contactless current sensor that determines the current in a pouch battery cell. Due to the shape of the pouch battery, in which the battery cell has a planar configuration that can be simplified to a stack of layered electrodes and separation layers, each of which extends in two-dimensional space, the present invention can be easily explained. However, those skilled in the art will understand that the present invention is not limited to pouch battery cells, even though these pouch battery cells represent important application examples.

[0053] exist Figure 1 In part (a) of FIG. 1 , a pouch-type battery cell is generally shown at 100. The battery cell 100 includes a cell housing 130 and a body portion 120. The battery housing 130 may be formed of a pouch-shaped foil. The body portion 120 is formed of a stack of layers. Examples of such layered structures are shown in FIG. Figure 1 1. The battery case 130 is shown in FIG. 1. The anode layer 140, the separator 150, and the cathode layer 160 are stacked and surrounded by the battery case 130. The anode layer 140 and the cathode layer 160 may be formed of an anode foil and a cathode foil, respectively. Each of the anode layer 140 and the cathode layer 160 ends with a battery tab 110a, 110b, respectively.

[0054] Figure 2 A first embodiment example of a non-contact current sensor is shown, wherein Figure 2 Part (a) is a top view of the non-contact current sensor, and Figure 2 Part (b) of FIG. 1 is a side view of the relative arrangement of the non-contact current sensor and the battery cell. As mentioned above, the battery cell may be as follows: Figure 1 Pouch-type battery cell shown.

[0055] In the depicted example of the embodiment, the current sensor is generally shown at 200. The current sensor includes a substrate 210 that provides support for a plurality of current sensing elements 220. In the depicted example of the embodiment, a plurality of current sensing elements 220 are arranged in the form of an array. In this example, the number of current sensing elements and their relative distances are selected so as to completely cover a single battery cell when the spatial resolution of the current measurement is substantially uniform. For data readout, the current sensor also includes a terminal 230, which can be used to connect the current sensor to a monitoring system. Those skilled in the art will appreciate that the current sensor can provide raw data that can be evaluated by the monitoring system, or the current sensor can include a dedicated evaluation circuit that is configured to analyze data corresponding to the current measurement. In some embodiments of the present invention, the substrate 210 can be a printed circuit board (PCB), and the current sensing element can be arranged as an integrated circuit (e.g., a packaged integrated circuit).

[0056] exist Figure 2 In the side view of part (b) of FIG. 1 , the arrangement of the current sensor 200 relative to the battery cell is illustrated. In the embodiment example shown in this figure, the current sensor determines the current by magnetic measurement (e.g., via a magnetoresistive element, a magneto-impedance sensing element, or a fluxgate magnetometer) or inductive measurement. Figure 2 As shown in part (b) of , no physical contact is required between the current sensor 200 and the battery cell. In general, it can also be said that the current sensor 200 indirectly measures the current or current distribution within the cell 120, i.e., via another physical property affected by the current within the cell 120, so that no contact is required. The physical properties that can be measured are all physical properties that are affected by the current or current distribution within the battery 120. For example, a magnetic field can be a physical property affected by the current or current distribution within the battery 120. Another physical property can be the ambient temperature affected by the current or current distribution within the battery 120. The so-called physical properties have in common that they can all be measured without the need for conductive contact between the sensor 200 or the sensor element 220 and the cell 120. Therefore, it can also be said that the sensor 200 is a contactless current sensor 200.

[0057] Figure 3 A second embodiment example of a non-contact current sensor is shown, wherein Figure 3 Part (a) is a top view of the non-contact current sensor, and Figure 3 Part (b) of FIG. 1 is a side view of the relative arrangement of the non-contact current sensor and the battery unit. The current sensor according to the second embodiment includes Figure 2Similar or identical features have the same reference numerals, whereas features of the second embodiment example that differ from the first embodiment example have an "a" added to the reference numerals.

[0058] Figure 3 The current sensor 200a shown in FIG. 1 includes a plurality of current sensing elements 220a also arranged in an array. Figure 2 In contrast to the multiple current sensing elements 220 of the current sensor 200, Figure 3 The multiple current sensing elements 220a of the current sensor 200a in the substrate 210 are not uniformly distributed throughout the entire spatial range of the substrate 210. Instead, the current sensor 200a includes a central region 225a in which the current sensing elements are more sparsely distributed. In other words, the multiple current sensing elements 220a of the current sensor 200a may include a first subset of current sensing elements arranged in the central region 225a of the current sensor 200a and a second subset of current sensing elements arranged in the edge region of the current sensor 200a, wherein the current sensing components are more densely arranged in the edge region compared to the central region 225b.

[0059] Figure 4 A third embodiment example of a non-contact current sensor is shown, wherein Figure 4 Part (a) is a top view of the non-contact current sensor, and Figure 4 Part (b) of FIG. 1 is a side view of the relative arrangement of the non-contact current sensor and the battery unit. The current sensor according to the third embodiment example includes Figure 2 Similar or identical features have the same reference numerals, whereas features of the third embodiment example that differ from the first embodiment example have a "b" added to the reference numerals.

[0060] Figure 4 The current sensor 200b shown in FIG. 1 includes a plurality of current sensing elements 220b also arranged in an array. Figure 3 Similar to the second embodiment example illustrated in , the current sensing elements 220b of the current sensor 200b are not evenly distributed over the entire range of the current sensor 200b. In the third embodiment example, the plurality of current sensing elements 220b are divided into two subsets, each of which forms an array, each array having a uniform pitch, but the pitch of the array in the central region 225b is different from the pitch of the array in the edge region or the pitch of the array in the central region 225b is offset from the pitch of the array in the edge region.

[0061] Those skilled in the art will appreciate that the above-described example embodiments are described to facilitate the reader's understanding and are not intended to limit the scope of the present disclosure. Various other ways of arranging multiple current sensing elements on the current sensor are possible and fall within the scope of the present invention. Additionally, in some examples, a single current sensing element may be sufficient to determine the current in the battery cell - for example, if the battery cell is relatively small or the current sensor is moved relative to the battery cell. Figure 5 The latter is explained in more detail.

[0062] Furthermore, those skilled in the art will appreciate that where the current sensor comprises multiple current sensing elements, the readout for the multiple current sensing elements may be performed simultaneously or sequentially. Further, the readout may be performed simultaneously for the current sensing elements in a subset at a time.

[0063] In the illustrated embodiment examples of current sensors 200, 200a, 200b, and 200c, current sensing elements are indicated by squares. In some applications, all current sensing elements of the current sensor may be of the same type (e.g., a Hall effect-based current sensing element or a magnetoresistance-based current sensing element). However, in some embodiment examples, different types of current sensing elements may be used in the current sensor. For example, the current sensor may include different current sensing elements in the center region and the edge region, but in other embodiment examples, the current sensor may include different types of current sensing elements in one region. As a non-limiting example, with Figure 3A current sensor similar to the current sensor 200a of the embodiment of the present invention may include two types of current sensing elements in the edge region and one type of current sensing element in the central region 225a; or include two types of current sensing elements in the edge region and include two types of current sensing elements in the central region 225a; or include one type of current sensing element in the edge region and include two types of current sensing elements in the central region 225a; or include one type of current sensing element in the edge region and include one type of current sensing element in the central region 225a. Further, the types of current sensing elements in the edge region and the central region may be the same or may be different. The combination of current sensing elements may include a type of current sensing element configured to perform magnetoresistance-based measurements and a combination of types of current sensing elements configured to perform temperature-based measurements. Further, different types of current sensing elements may also include current sensing elements that perform the same type of measurements but have different sensitivities, which may improve the resolution of current measurements in certain regions of the battery cell. Additionally or alternatively, different types of current sensing elements may have different measurement ranges, which may be particularly useful when the current is expected to be non-uniform in certain types of battery cells.

[0064] In some examples, each square 220, 220a, 225a, 220b (or a subset of these squares) of the current sensor 200, 200a, 200b can represent a combination of a magnetic-based current sensing element and a temperature-based current sensing element, which allows the current to be measured using the same sensor at the same time or at a subsequent time through magnetic-based measurements and temperature-based measurements.

[0065] Figure 5 A fourth embodiment example of a contactless current sensor is shown, wherein the contactless current sensor moves relative to the battery cell, wherein Figure 5 The relative arrangement of the contactless current sensor and the battery cell is shown in a top view in part (a) and in a side view in part (b).

[0066] exist Figure 5 In part (a) of FIG. 1 , a current sensor is generally shown at 200c. The current sensor 200c includes a substrate 210 that provides support for a plurality of current sensing elements 220c, and a terminal 230. In the depicted embodiment example, the plurality of current sensing elements 220c are arranged in a row, but those skilled in the art will appreciate that the disclosure of the present invention encompasses other configurations (including a single current sensing element).

[0067] The current sensor 200c is moved relative to the battery cell. Since the current during the formation of the battery cell is of interest, the current sensor 200c is moved relative to the main body 120 of the battery cell, where the stacked layers of the anode layer, the separator layer, and the cathode layer are located. The movement of the current sensor 200c is determined by Figure 5 Depending on the configuration of the battery cell and the current sensor 200c (particularly one or more current sensing elements 220c), the current sensing element 220c may be configured as follows: Figure 5 The movement may be performed in a linear manner as indicated in part (a) of or in other ways. For example, in the case where one or more current sensing elements do not cover the spatial extent of the battery cell in a particular direction, the movement in that direction may be performed. Figure 5 In part (b) of FIG. 1 , a plurality of current sensing elements 220c completely cover the battery cell in a second direction of the two-dimensional plane of the figure, and the second direction is perpendicular to the Figure 5 Therefore, no movement in this direction is required. If the current sensor 200c has a smaller number of current sensing elements 220c (e.g., only Figure 5 ), movement in a second spatial direction perpendicular to the arrow is required in order to obtain information about the current in the entire battery cell.

[0068] By the above-mentioned movement of the current sensor 200c relative to the battery cell, the battery cell can be scanned in order to obtain information about the current in the entire battery cell. Preferably, the movement is performed stepwise, which means that the current is determined when the current sensor 200c is in a first position, then the current sensor 200c is displaced and moved to a second position, at which another determination of the current is performed, and so on, until the battery cell is fully scanned.

[0069] refer to Figures 2 to 4 The above comments on current sensing elements having different types or sensitivities also apply to current sensing elements having different types or sensitivities. Figure 5 The illustrated embodiment is an example in which the current sensor is movable relative to the battery cell.

[0070] Figure 6 An example embodiment of a system configured for determining current flow in a battery cell during formation under pressure is shown, wherein Figure 6 Part (a) shows the corresponding non-contact current sensor, the support structure for applying pressure, and the battery cell in a state without applied pressure, and part (b) shows the corresponding non-contact current sensor, the support structure for applying pressure, and the battery cell in a state with applied pressure.

[0071] exist Figure 6In part (a) of Figure 2 The current sensor 200 is similar to the current sensor and Figure 1 The support structure 300 is similar to the battery cell 100 in FIG. The current sensor is arranged in the support structure 300. For example, the current sensor is arranged in a recess or opening in the support structure. The support structure 300 is configured to apply pressure to the battery cell so that the battery cell can be formed under pressure, which has been shown to increase the efficiency of the forming process. The support structure has a top and a bottom rigidly connected. The current sensor can be located in the recess or opening between the top and the bottom. Figure 6 In part (b) of FIG. 1 , the applied pressure is illustrated by arrows. It is noteworthy that the support structure transfers the pressure from the top surface to the bottom surface to exert pressure on the battery cell, but does not exert pressure on the current sensor, as such pressure may damage the support structure. Instead, the current sensor is arranged within or held by the support structure, and pressure is only applied to the battery cell.

[0072] Figure 7 Show Figure 6 An example of an embodiment of a stack of the system illustrated in FIG. Since the forming equipment usually forms multiple battery cells at the same time, it is necessary to apply pressure to multiple battery cells at the same time. Figure 7 The battery cells formed in a stack in a forming apparatus are illustrated with support structures interleaved. Each support structure applies pressure to its adjacent battery cells - either by compressing the entire stack, and the force applied to the first support structure at the top of the stack is transferred through the battery cells to the adjacent support structure, which then applies pressure to the next battery cell, and so on, or the different support structures can be connected so that when a force is applied to one of the support structures, the force is transferred to all connected support structures.

[0073] In the depicted embodiment example, each support structure includes a receiver for a current sensor. Although it is preferred to have a dedicated current sensor for each battery cell, in some applications a smaller number of current sensors may be used, and each current sensor may determine the current in two directly adjacent battery cells in the stack.

[0074] In the case where each battery cell is evaluated using a dedicated current sensor, the support structure can be configured to reduce crosstalk between adjacent sensors. This can be achieved by increasing the distance d1, which is the distance at which the support structure holds the current sensor relative to adjacent cells of no interest, compared to the distance d2 (e.g., the distance d1 is determined by Figure 6The height of the upper portion of the support structure 300 in part (a) of FIG. 1 is represented), and the distance d2 is the distance of the support structure holding the current sensor relative to the adjacent battery for which the current sensor should determine the current (for example, the distance d2 is represented by Figure 6 The height of the lower portion of the support structure 300 in part (a) is represented).

[0075] In some example embodiments, the support structure 300 may include means for holding the current sensor 200 , wherein the means for holding is further configured to move the current sensor 200 relative to the battery cell 100 within the support structure 300 .

[0076] The foregoing includes examples of one or more embodiments. It is certainly not possible to describe every conceivable combination of components or methods for the purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that many other combinations and permutations of the embodiments are possible. Therefore, the described embodiments are intended to encompass all such substitutions, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A method for determining a current in a battery cell (100) during manufacture of the battery cell (100), the method comprising: A non-contact current sensor (200, 200a, 200b, 200c) is arranged relative to the battery cell (100), wherein the non-contact current sensor (200, 200a, 200b, 200c) includes at least one current sensing element (220, 220a, 225a, 220b, 225b, 220c); Do at least one of the following: filling the battery cell (100) with an electrolyte, charging the battery unit (100), and discharging the battery cell (100); and The current in the battery cell (100) is determined by the non-contact current sensor (200, 200a, 200b, 200c) during or after at least one of filling the battery cell (100) with the electrolyte, charging the battery cell (100), and discharging the battery cell (100).

2. The method according to claim 1, wherein: The at least one current sensing element (220, 220a, 225a, 220b, 225b, 220c) is any one of the following: Hall element; Magnetoresistive elements, including elements sensitive to colossal magnetoresistance (CMR), giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR), Magneto-impedance sensing element, Fluxgate magnetometer, MEMS magnetometer, or Inductive sensing element.

3. A method according to any one of the preceding claims, wherein: Determining the current within the battery cell (100) is based on measuring at least one magnetic field gradient.

4. A method according to any one of the preceding claims, wherein: The at least one contactless current sensor (200, 200a, 200b, 200c) comprises an array including a plurality of current sensing elements (220, 220a, 225a, 220b, 225b, 220c), wherein the current sensing elements (220, 220a, 225a, 220b, 225b, 220c) of the plurality of current sensing elements (220, 220a, 225a, 220b, 225b, 220c) are 0c) are uniformly distributed in a plane, or the current sensing elements (220, 220a, 225a, 220b, 225b, 220c) among the plurality of current sensing elements (220, 220a, 225a, 220b, 225b, 220c) are more densely distributed in an edge area of ​​the battery cell (100) than in a central area of ​​the battery cell (100) when arranged relative to the battery cell (100).

5. The method according to claim 4, wherein: Determining the current within the battery cell (100) is performed simultaneously for each current sensing element (220, 220a, 225a, 220b, 225b, 220c) in the array of current sensing elements (220, 220a, 225a, 220b, 225b, 220c) or sequentially for a subset of one or more sensing elements (220, 220a, 225a, 220b, 225b, 220c) in the array of current sensing elements (220, 220a, 225a, 220b, 225b, 220c).

6. The method according to any one of the preceding claims, wherein determining the current in the battery cell (100) comprises: moving the non-contact current sensor (200, 200a, 200b, 200c) and the battery unit (100) relative to each other; as well as The current is determined by scanning the current during relative movement of the non-contact current sensor (200, 200a, 200b, 200c) and the battery cell (100).

7. The method according to any one of the preceding claims, further comprising: Deviations in the determined current are identified.

8. The method according to claim 7, wherein: Identifying a deviation in the measured current includes at least one of: generating a current measurement map for one or more regions of the battery cell (100) based on the determined current; and The determined current is compared to one or more predetermined values.

9. The method according to any one of claims 7 or 8, wherein: Identifying deviations in the measured current involves the application of artificial intelligence.

10. A method according to any one of the preceding claims, wherein: Determining the current is performed during at least one of charging the battery cell (100) or discharging the battery cell (100), and wherein the method further comprises: During at least one of charging the battery cell (100) or discharging the battery cell (100), pressure is applied to the battery cell (100).

11. A contactless current sensor (200, 200a, 200b, 200c) configured to be used according to the method of any one of claims 1 to 10.

12. A manufacturing equipment, the manufacturing equipment being configured to perform at least one step of manufacturing one or more battery cells (100), the at least one step of manufacturing the one or more battery cells (100) comprising: filling the battery cell (100) with an electrolyte, charging the battery unit (100), and discharging the battery cell (100); and The manufacturing equipment includes one or more non-contact current sensors (200, 200a, 200b, 200c), each non-contact current sensor includes at least one current sensing element (220, 220a, 225a, 220b, 225b, 220c), and the at least one current sensing element (220, 220a, 225a, 220b, 225b, 220c) is used to determine the current in at least one battery cell (100) of the one or more battery cells (100) during or after the at least one step of manufacturing.

13. The manufacturing equipment according to claim 12, wherein: The one or more contactless current sensors (200, 200a, 200b, 200c) are arranged on one or more support structures (300), wherein the one or more support structures (200) are configured to apply pressure to the one or more battery cells (100) during manufacturing.

14. The manufacturing equipment according to any one of claims 12 or 13, wherein: A first current sensing element of the at least one current sensing element (220, 220a, 225a, 220b, 225b, 220c) is placed between two adjacent battery cells (100) in the battery cells (100) and is configured to determine the current within the two adjacent battery cells (100), wherein the first current sensing element is preferably configured to determine the current within the two adjacent battery cells (100) simultaneously or sequentially.

15. A battery cell (100) produced by a method according to any one of claims 1 to 10 involving determining an electric current during manufacture of the battery cell (100).

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