Photosensitive developing method of battery management system control circuit board

Abstract

The invention relates to the field of photosensitive development, in particular to a photosensitive development method of a battery management system control circuit board, which comprises the following steps: acquiring development abnormity indexes and signal abnormity indexes of different areas of the circuit board, and acquiring target temperature distribution and target stirring distribution when each area has the minimum development abnormity index and the minimum signal abnormity index; the change trend of the signal anomaly index of each area along with the development anomaly index is recorded as the development attention of each area; and obtaining a parameter influence area of each area, fusing the target temperature distribution and the target stirring distribution in the parameter influence areas of all the areas by utilizing the development attention to obtain optimal target temperature distribution and optimal target stirring distribution, and carrying out next development by utilizing the optimal target temperature distribution and the optimal target stirring distribution. Different developing temperatures and stirring frequencies are set for different positions, so that the abnormality of photosensitive developing is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of photosensitive development, and in particular to a photosensitive development method for a control circuit board of a battery management system. Background Art

[0002] The battery management system (BMS) control circuit board uses sensors to continuously collect battery cell voltage, current, temperature, and other parameters. Based on this data, it estimates the battery's state of charge (SOC) and state of health (SOH), providing a basis for battery charging and discharging strategies. To better maintain battery health and prevent a shortened lifespan, the reliability and accuracy of the photosensitive development process during control circuit board manufacturing must be ensured.

[0003] Photosensitive development specifically refers to the process of using ultraviolet light or a specific light source to induce a photochemical reaction in the photoresist, removing the unexposed areas of the photoresist through chemical dissolution, and revealing the copper foil circuit pattern. This process requires preparing a developer solution of appropriate concentration. The exposed plate film is immersed face-up in the developer solution at a certain temperature, stirred for a certain period of time, and then removed and rinsed and dried.

[0004] During this process, too high a concentration can lead to rough edges on the circuit boards, while too low a concentration can leave undissolved photoresist residue. Excessively high temperatures can cause the photoresist to swell and deform, while too low a temperature can reduce development efficiency. This makes it impossible to ensure the reliability and accuracy of the photosensitive development process during control circuit board production, affecting the quality of the finished board, hindering its proper function, and compromising battery health. In particular, the BMS control circuit board has varying distribution densities of wiring and vias (pads). These distribution densities may require different developer concentrations and temperatures during development, making it impossible to achieve uniform development across all locations on the board using a uniform temperature and stirring frequency. Summary of the Invention

[0005] In order to solve the problem of circuit board abnormality caused by inappropriate developer concentration and stirring frequency (especially inappropriate developer concentration and stirring frequency in different areas of the circuit board), the present invention provides a battery management system to control the photosensitive development method of the circuit board.

[0006] The photosensitive development method of the battery management system control circuit board of the present invention adopts the following technical solutions: One embodiment of the present invention provides a photosensitive development method for a battery management system control circuit board, the method comprising the following steps: During each photosensitive development, the developer solution is set at different development temperatures and stirring frequencies at different locations, which are recorded as temperature distribution and stirring distribution. After development, visual inspection and circuit signal inspection are performed to obtain development abnormality indicators and signal abnormality indicators for different areas of the circuit board respectively. After photosensitive development of several circuit boards with the same layout, the temperature distribution and stirring distribution of each area with the minimum development abnormality index and signal abnormality index are obtained and recorded as the target temperature distribution and target stirring distribution; the trend of the signal abnormality index of each area along with the development abnormality index is recorded as the development attention level of each area; Obtaining a parameter influence region of each region, wherein the parameter influence region has a correlation coefficient greater than a first preset threshold with a development temperature and a stirring frequency at each position and a development abnormality index and an electrical signal abnormality index of each region; The development attention is used to fuse the target temperature distribution and target stirring distribution in the parameter-affecting area of all areas to obtain the optimal target temperature distribution and the optimal target stirring distribution, which are used for the next development.

[0007] Preferably, the target temperature distribution and target stirring distribution in the parameter-affecting region of all regions are integrated by utilizing the development attention, so as to obtain the optimal target temperature distribution and the optimal target stirring distribution, which includes the following specific steps: During the process of performing several photosensitive developments on several circuit boards of the same layout, the area where the development abnormality index and the signal abnormality index do not decrease during two adjacent photosensitive developments is recorded as an index non-optimized area; The error position is obtained based on the position change within the parameter-affected area of the indicator non-optimized area; During the photosensitive development process of several circuit boards with the same layout, the ratio of the number of times the error position appears to the total number of times the photosensitive development is performed is recorded as the abnormal frequency of each position; the average of the abnormal frequencies of all positions in each area is obtained and recorded as the attention error of each area; The target temperature distribution and target stirring distribution in the parameter influence area of all regions are fused by using the development attention, the attention error and the abnormal frequency of each position to obtain the optimal target temperature distribution and the optimal target stirring distribution.

[0008] Preferably, obtaining the error position according to the position change in the parameter influence area of the non-optimized indicator area includes the following specific steps: The parameter influence area of the non-optimized index area during the i-th photosensitive development process is recorded as , the parameter influence area of the same indicator in the non-optimized area during the i+1th photosensitive development process is recorded as , will belong to Within but not belonging to , or belongs to Within but not belonging to The position within is marked as the error position, which belongs to within and belongs to The position is no longer marked as an error position.

[0009] Preferably, the target temperature distribution and target stirring distribution in the parameter-affecting regions of all regions are integrated by utilizing the development attention, the attention error, and the abnormal frequency of each position to obtain the optimal target temperature distribution and the optimal target stirring distribution, which includes the following specific steps: The parameters corresponding to each region affect any position within the region, which is recorded as the reference position; The number of parameter influence regions at the reference position is recorded as N, where the target temperature distribution and target stirring distribution of the i-th parameter influence region and the development temperature and stirring frequency below the reference position are recorded as the reference development temperature and reference stirring frequency ; Obtain the difference between the development attention and the attention error corresponding to each parameter-affected area, and record it as the corrected development attention of each parameter-affected area. The difference between the corrected development attention and the abnormal frequency of the reference position in each parameter-affected area is recorded as the attention coefficient of the reference position in each parameter-affected area. The attention coefficients of the reference positions in the N parameter-affected areas are normalized using the softmax formula to obtain the corrected attention weight of the reference position in each parameter-affected area. The corrected attention weight of the reference position in the i-th parameter-affected area is recorded as , optimal developing temperature ;Optimal stirring frequency .

[0010] Preferably, the specific steps for obtaining the abnormal imaging index are as follows: The circuit board is divided into several areas, and the grayscale image of the circuit board after photosensitive development is collected using an industrial camera. The grayscale image of the circuit board is segmented into a binary image using the Otsu threshold segmentation algorithm. Edge abnormal pixels and non-edge abnormal pixels are obtained in each area of the binary image. The ratio of the number of edge abnormal pixels in each area to the number of non-edge abnormal pixels in each area is recorded as the development abnormality index of each area.

[0011] Preferably, the specific steps for obtaining the signal abnormality indicator are as follows: A test signal is input into one end of each area, and the frequency and amplitude of the received signal are measured at the other end. The difference in frequency and amplitude between the test signal and the received signal is used as a signal anomaly indicator.

[0012] Preferably, after the plurality of circuit boards of the same layout are subjected to photosensitive development, the temperature distribution and stirring distribution when each area has the minimum development abnormality index and signal abnormality index are obtained and recorded as the target temperature distribution and target stirring distribution, including the following specific steps: The average of the development abnormality index and signal abnormality index of each area is recorded as the comprehensive abnormality index of each area; for any area on the circuit board, after several circuit boards with the same layout are photosensitively developed several times, among the several comprehensive abnormality indicators obtained for the area on the circuit board, the photosensitive development with the minimum comprehensive abnormality index is obtained, and the temperature distribution and stirring distribution used during the photosensitive projection are recorded as the target temperature distribution and target stirring distribution.

[0013] Preferably, the changing trend of the signal abnormality index of each region along with the development abnormality index is recorded as the development attention degree of each region, which includes the following specific steps: For any area on the circuit board, during the process of several photosensitive developments on several circuit boards with the same layout, the time series of the signal anomaly index of the area is obtained in chronological order, recorded as the first series, and the time series of the development anomaly index is recorded as the second series; the absolute value of the Piel selection correlation coefficient of the first series and the second series is used as the development attention of each area.

[0014] Preferably, obtaining the parameter influence area of each area, wherein the development temperature and stirring frequency at each position within the parameter influence area have a correlation coefficient greater than a first preset threshold with the development abnormality index and the electrical signal abnormality index of each area, comprises the following specific steps: During the process of performing photosensitive development on several circuit boards of the same layout, a time sequence consisting of the development temperature and stirring frequency at each position is obtained, which are recorded as a third sequence and a fourth sequence; Obtain the Pearson correlation coefficient between the first sequence and the third sequence, denoted as r1, obtain the Pearson correlation coefficient between the second sequence and the third sequence, denoted as r2, and use |r1|+|r2| as the development temperature interference index for each position; Obtain the Pearson correlation coefficient between the first sequence and the fourth sequence, recorded as r3, obtain the Pearson correlation coefficient between the second sequence and the fourth sequence, recorded as r4, and use |r3|+|r4| as the stirring frequency interference index at each position; The mean of the development temperature interference index at each position and the stirring frequency interference index at each position is recorded as the parameter influence factor of each position on each area; Obtain the parameter influence factors of all positions on each region, record the position whose parameter influence factor on each region is greater than a first preset threshold as the target position, and record the set of target positions as the parameter influence region of each region.

[0015] Preferably, the step of obtaining edge abnormal pixel points and non-edge abnormal pixel points in each region on the binary image includes the following specific steps: In each area, the Hough line transform algorithm is used to obtain all lines, and the Hough circle transform algorithm is used to obtain all circles. The line or circle closest to each pixel point is obtained, and the closest distance between each pixel point and the closest line or circle is recorded as the abnormal distribution amplitude of each pixel point. Pixels in each area whose abnormal distribution amplitude is greater than the preset distance and are on the edge of the connected domain are recorded as edge abnormal pixels. Pixels in each area whose abnormal distribution amplitude is less than or equal to the preset distance and are on the edge of the connected domain are recorded as non-edge abnormal pixels.

[0016] The beneficial effects of the technical solution of the present invention are: During each photosensitive development, different developing temperatures and stirring frequencies are set at different positions of the developer, which are recorded as the temperature distribution and stirring distribution. Finally, the developing temperature and stirring frequency of the next photosensitive development are obtained based on the developing temperatures and stirring frequencies at different positions during the historical photosensitive development process, so that subsequent photosensitive development can have better developing temperatures and stirring frequencies at different positions. Even if the wiring and vias (pads) in different areas of the circuit board have different distribution densities, defects such as rough line edges, deformed and undissolved photoresist, and signal loss can be avoided as much as possible.

[0017] The present invention further obtains a parameter influence region for each area, wherein the development temperature and stirring frequency at each location within the parameter influence region have a correlation coefficient greater than a first preset threshold with the development abnormality index and electrical signal abnormality index for each area. This process ensures that the generation or change of the development abnormality index and electrical signal abnormality index corresponding to each area is related to the development temperature and stirring frequency at all locations within the parameter influence region, and is not significantly affected by the development temperature and stirring frequency at locations outside the parameter influence region.

[0018] Based on the above, the present invention further provides that after several circuit boards of the same layout are photosensitively developed, the target temperature distribution and target stirring distribution are obtained when each area has the minimum development abnormality index and signal abnormality index; the change trend of the signal abnormality index of each area along with the development abnormality index is recorded as the development attention of each area; using the development attention, the target temperature distribution and target stirring distribution in the parameter influence area of all areas are integrated to obtain the optimal target temperature distribution and the optimal target stirring distribution, and the optimal target temperature distribution and the optimal target stirring distribution are used for the next development. This process allows, when faced with circuit boards with large differences in wiring density, on the one hand, to avoid defects such as rough line edges, photoresist deformation and insolubility as much as possible; on the other hand, based on the generation or change of the development abnormality index and the electrical signal abnormality index, and the relationship between the development temperature and stirring frequency of all positions in the parameter influence area, the development temperature and stirring frequency of different positions are more reliably adjusted, further ensuring the reliability of the circuit board after photosensitive development, avoiding circuit board abnormalities, and enabling it to better maintain battery health and avoid battery life being too short. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A flowchart of a method for controlling the photosensitive development of a circuit board in a battery management system according to an embodiment of the present invention is provided. DETAILED DESCRIPTION

[0021] To further illustrate the technical means and effectiveness of the present invention in achieving its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of the photosensitive development method for a battery management system control circuit board according to the present invention. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0023] The specific scheme of the photosensitive development method of the battery management system control circuit board provided by the present invention is described in detail below with reference to the accompanying drawings.

[0024] Example 1: See also Figure 1 , which shows a flowchart of a method for photosensitive development of a control circuit board of a battery management system provided by an embodiment of the present invention, the method comprising the following steps: Step S101 : Each time the developer is exposed to light and developed, different developing temperatures and stirring frequencies are set at different positions of the developer, which are recorded as temperature distribution and stirring distribution.

[0025] The developer is consumed at different rates by wiring and vias (pads) with different distribution densities, which can cause the local developer concentration or temperature to be too high or too low, leading to problems such as rough circuit edges, deformation of the photoresist, and insolubility.

[0026] In this embodiment, multiple groups of heating units are disposed within a container containing developer solution, arranged in an array pattern. Each group of heating units has independently controlled temperature (this temperature is referred to as the developing temperature). In this embodiment, each group of heating units is a heating wire, and the closest two heating units are 2 cm apart. Other embodiments may utilize other heating units and spacings, and this embodiment is not specifically limited thereto.

[0027] Furthermore, this embodiment includes multiple stirring units arranged in a display pattern within the developer container, with the stirring frequency of each stirring unit independently controlled. In this embodiment, each stirring unit is a small propeller blade driven by a variable frequency motor. In this embodiment, the closest two stirring units are 2 cm apart (consistent with the spacing between the heating units). Other stirring units (e.g., a small air pump) may be used in other embodiments, and this embodiment is not intended to be limiting.

[0028] In this embodiment, when the heating units at all locations are set to different development temperatures, different locations in the developer solution can be heated to different temperatures. When the stirring units at all locations are set to different stirring frequencies, different locations in the developer solution can be stirred to different amplitudes (the different amplitudes of stirring change the penetration and diffusion of the developer solution in the local area, thereby changing the local developer solution concentration). In this embodiment, the development temperatures and stirring frequencies set at all locations are recorded as the temperature distribution and stirring distribution.

[0029] In this embodiment, when a circuit board of a certain layout is first exposed and developed, the heating temperature at all positions is set to the maximum allowable heating temperature (for example, 40°C), and the stirring frequency at all positions is set to the maximum allowable stirring frequency (for example, 2, i.e., 2 revolutions per second).

[0030] In this embodiment, when a circuit board of a certain layout is subjected to a second photosensitive development, the heating temperature at all positions is set to the minimum allowable heating temperature (e.g., 24°C), and the stirring frequency at all positions is set to the maximum allowable stirring frequency (e.g., 0.25, i.e., 0.25 cycles per second).

[0031] In this embodiment, the development time for all exposures and developments of the same layout circuit board is set to 1.5 minutes, and the developer used is 1% to 1.5% sodium carbonate. Other embodiments may use other development temperatures or developers with different compositions and concentrations, and this embodiment is not specifically limited. In this embodiment, when performing multiple exposures and developments on multiple circuit boards with the same layout, it is necessary to ensure that the circuit boards are placed in the same position. For multi-layer circuit boards, all steps in this embodiment are for each layer of the circuit board.

[0032] The positions described subsequently in this embodiment all refer to the positions of the heating unit and the stirring unit.

[0033] Step S102: After development, visual inspection and circuit signal inspection are performed to obtain development abnormality indicators and signal abnormality indicators of different areas of the circuit board.

[0034] After each development (and after rinsing and drying), the PCB is visually inspected using image processing technology to obtain development anomaly indicators for different areas of the PCB. Circuit signal testing is then performed to obtain signal anomaly indicators for different areas of the PCB.

[0035] The larger the development abnormality index of each area, the more defects there are in the area after development (for example, rough line edges, deformed and undissolved photoresist, etc.). The larger the signal abnormality index of each area, the less expected the electrical signal transmission ability of each area after development (for example, serious signal loss, obvious resistance abnormality, etc.).

[0036] As an example, the method for obtaining different areas of the circuit board is as follows: When designing the circuit board layout or before the circuit board is photosensitive developed, several areas are automatically generated, for example, each wiring (and its connected vias or pads) is regarded as an area.

[0037] As another example, the method for obtaining different areas of the circuit board is: Several areas can be artificially divided according to the layout and routing. For example, all wiring of the same module or the same function on the circuit board can be artificially regarded as one area. For example, all wiring, via pads, etc. of the battery temperature monitoring module can be regarded as one area.

[0038] In other examples, the method for obtaining different areas of the circuit board is as follows: Four adjacent heating units or stirring units are considered as the vertices of a rectangle, and each rectangle is considered as a region. This example is the simplest method and is particularly suitable for circuit boards with densely distributed via pads.

[0039] In some examples, overlapping regions are allowed. For example, all regions obtained from all the previous examples are used as the regions obtained in this example. This example can make the traces and via pads in the same part of the circuit board correspond to regions of different sizes.

[0040] Furthermore, this embodiment dilates all the regions obtained above using a 9×9 structuring element, with all structuring elements taking values of 1. Dilation is a well-known morphological processing method and will not be described in detail in this embodiment. The regional mean value described later refers to each region after dilation.

[0041] As an example, a visual inspection of a circuit board is performed using image processing technology to obtain development abnormality indicators of different areas of the circuit board, including the following methods: An industrial camera is used to capture the grayscale image of the circuit board after development, and the Otsu threshold segmentation algorithm is used to segment the grayscale image of the circuit board into a binary image. The area with a pixel point of 1 in the binary image is the wiring, via, or pad.

[0042] In each region of the binary image, edge abnormal pixels and non-edge abnormal pixels are obtained, and the ratio of the number of edge abnormal pixels in each region to the number of non-edge abnormal pixels in each region is recorded as the development abnormality index of each region.

[0043] As an example, edge abnormal pixel points and non-edge abnormal pixel points are obtained in each area, including: In each region, the Hough line transform algorithm is used to obtain all lines, and the Hough circle transform algorithm is used to obtain all circles. The line or circle closest to each pixel point is obtained, and the closest distance between each pixel point and the closest line or circle is recorded as the abnormal distribution amplitude of each pixel point. Pixels in each region whose abnormal distribution amplitude is greater than a preset distance (for example, greater than 3) and are on the edge of the connected domain are recorded as edge abnormal pixels. Pixels in each region whose abnormal distribution amplitude is less than or equal to a preset distance (for example, less than or equal to 3) and are on the edge of the connected domain are recorded as non-edge abnormal pixels.

[0044] For example, if a pixel is closest to a straight line or a circle, the larger the distance between the pixel and the straight line or the circle, the more likely it is that the pixel has defects such as rough line edges, deformed photoresist, and undissolved photoresist.

[0045] As an example, a circuit signal detection is performed on a circuit board to obtain signal anomaly indicators in different areas of the circuit board, including the following methods: Place two electrodes on either end of any area on the circuit board, input a test signal into one end, and measure the frequency and amplitude of the received signal at the other end. The signal abnormality index for each area is ,in 、 represents the frequency and amplitude of the test signal, 、 Indicates the frequency and amplitude of the received signal.

[0046] In other examples, if each region in a binary image has only one connected domain, all corner points in each region are obtained, and the two corner points farthest apart are used as the two ends of the region. A robotic arm is then used to drive electrodes to contact the two ends of the region, thereby achieving automated circuit signal detection. If each region has multiple connected domains, a signal anomaly index can be obtained for each connected domain using the above example. The sum of the signal anomaly indices obtained for all connected domains in each region is used as the signal anomaly index for each region in this example.

[0047] Step S103 : After several circuit boards with the same layout are photosensitively developed, the temperature distribution and stirring distribution when each area has the minimum development abnormality index and signal abnormality index are obtained and recorded as the target temperature distribution and target stirring distribution.

[0048] After multiple photosensitive developments are performed on several circuit boards with the same layout, a temperature distribution and a stirring distribution are set before each photosensitive development. After development is performed under this temperature distribution and a stirring distribution, a set of development abnormality indicators and signal abnormality indicators are obtained for each area on the circuit board; the average of the development abnormality indicators and signal abnormality indicators is recorded as the comprehensive abnormality index of each area.

[0049] For any area on the circuit board, after multiple photosensitive developments, the area on the circuit board is tested for multiple sets of development abnormality indicators and multiple signal abnormality indicators, and multiple comprehensive abnormality indicators are also obtained. The photosensitive development with the minimum comprehensive abnormality indicator is obtained, and the temperature distribution and stirring distribution used during this photosensitive development are recorded as the target temperature distribution and target stirring distribution.

[0050] Among them, the comprehensive abnormality index is the smallest, which means that this photosensitive development has the smallest development abnormality index and signal abnormality index compared with other photosensitive development processes. The target temperature distribution and target stirring distribution can be used as a reference for subsequent photosensitive development in this area.

[0051] At this point, each area on the circuit board corresponds to a target temperature distribution and a target stirring distribution. The target temperature distribution and target stirring distribution corresponding to different areas may come from different photosensitive development processes.

[0052] Step S104 : The changing trend of the signal abnormality index of each region along with the development abnormality index is recorded as the development attention degree of each region.

[0053] The development concern level for each area describes the extent to which issues such as rough trace edges, deformed photoresist, and undissolved photoresist can interfere with severe signal loss and abnormal resistance. A higher value indicates the presence of rough trace edges, deformed photoresist, and undissolved photoresist, significantly increasing the risk of severe signal loss and abnormal resistance.

[0054] For any area on the circuit board, during multiple photosensitization and development processes on several circuit boards with the same layout, a time sequence of signal anomaly indicators of the area is obtained in chronological order, which is recorded as the first sequence, and a time sequence of development anomaly indicators is recorded as the second sequence.

[0055] As an example, the absolute value of the Pielson correlation coefficient between the first sequence and the second sequence is used as the development attention level of each region.

[0056] Step S105 : obtaining a parameter influence region of each region, wherein the development temperature and stirring frequency at each position in the parameter influence region have a maximum correlation coefficient with the development abnormality index and the electrical signal abnormality index of each region.

[0057] In this embodiment, each region corresponds to a parameter influence region, and the development temperature and stirring frequency at each position within the parameter influence region have a large correlation coefficient with the development abnormality index and electrical signal abnormality index of each region, indicating that the generation or change of the development abnormality index and electrical signal abnormality index corresponding to each region is related to the development temperature and stirring frequency of all positions within the parameter influence region, and is not obviously affected by the development temperature and stirring frequency of other positions outside the parameter influence region.

[0058] As an example, the method to obtain the parameter influence area of each area is as follows: For any area on a circuit board, during the process of performing multiple exposure and development on a number of circuit boards with the same layout, the first sequence and the second sequence corresponding to the area are obtained.

[0059] Furthermore, during the process of performing multiple photosensitization and development on several circuit boards with the same layout, a time sequence consisting of the development temperature and stirring frequency at each position is obtained, which are recorded as a third sequence and a fourth sequence.

[0060] Obtain the Pearson correlation coefficient between the first sequence and the third sequence, denoted as r1, obtain the Pearson correlation coefficient between the second sequence and the third sequence, denoted as r2, and use |r1|+|r2| as the development temperature interference index for each position; Obtain the Pearson correlation coefficient between the first sequence and the fourth sequence, recorded as r3, obtain the Pearson correlation coefficient between the second sequence and the fourth sequence, recorded as r4, and use |r3|+|r4| as the stirring frequency interference index at each position; The average of the development temperature interference index at each position and the stirring frequency interference index at each position is recorded as the parameter influence factor of each position on each area.

[0061] Obtain the parameter influence factors of all positions on each region, record the position whose parameter influence factor on each region is greater than the first preset threshold th1 as the target position, and record the set of target positions as the parameter influence region of each region.

[0062] In particular, when there is no position with a parameter greater than the first preset threshold th1, a position with the largest parameter influence factor is recorded as the target position.

[0063] This embodiment is described by taking th1=0.6 as an example. In other embodiments, it can be set to other values, which is not limited in this embodiment.

[0064] Step S106 : using the development attention, integrating the target temperature distribution and the target stirring distribution in the parameter-affecting area of all regions to obtain the optimal development parameters, and using the optimal development parameters for the next development.

[0065] In the above process, each region corresponds to a parameter influence region, a target temperature distribution, and a target stirring distribution. At the same time, each region corresponds to a development attention level. Therefore, it can be considered that each parameter influence region corresponds to a target temperature distribution, a target stirring distribution, and a development attention level.

[0066] The parameter influence area corresponding to each area, and any position within the parameter influence area, are recorded as reference positions.

[0067] Note that the reference position may belong to different areas at the same time, that is, the reference position may also be included in other parameter-affected areas of the circuit board.

[0068] For all parameter influence areas (at least one parameter influence area) where the reference position is located, each parameter influence area has a corresponding development temperature and stirring frequency in the target temperature distribution and target stirring distribution of each parameter influence area, which are recorded as the reference development temperature and reference stirring frequency.

[0069] Assuming that there are N parameter influence regions at the reference position, for the i-th parameter influence region, the target temperature distribution and target stirring distribution of the i-th parameter influence region, and the development temperature and stirring frequency at the reference position are recorded as the reference development temperature and reference stirring frequency .

[0070] At the same time, each parameter-affected region in the N parameter-affected regions corresponds to a development attention degree, and the development attention degrees of all parameter-affected regions are normalized using the softmax formula to obtain the attention weight of each parameter-affected region. The attention weight of the i-th parameter-affected region is recorded as , the reference developing temperature of all parameter-affected areas is weighted summed using the attention weight of each parameter-affected area to obtain the optimal developing temperature ; Use the attention weight of each parameter influence area to weighted sum the reference stirring frequencies of all parameter influence areas to obtain the optimal stirring frequency .

[0071] At this point, the parameters corresponding to each region have an optimal development temperature and optimal stirring frequency for each position within that region. The optimal development temperatures and optimal stirring frequencies for all positions within the parameter-affecting regions of all regions on the circuit board are then obtained. These optimal development temperatures and optimal stirring frequencies at these positions are the optimal development parameters for photosensitive development, and are used as the development temperature and stirring frequency for the same positions during the next photosensitive development.

[0072] In particular, for positions outside all positions in the parameter-affected areas corresponding to all areas on the circuit board, the developing temperature and stirring frequency of these positions during the next photosensitive development are the same as the developing temperature and stirring frequency of the previous photosensitive development.

[0073] Thus, this embodiment optimizes the developing temperature and stirring frequency set for the next photosensitive development process based on the developing temperature and stirring frequency used in the historical photosensitive development process.

[0074] This concludes the present embodiment.

[0075] In summary, different developing temperatures and stirring frequencies are set for the developer at different positions during each photosensitive development, which are recorded as the temperature distribution and stirring distribution; finally, the developing temperature and stirring frequency for the next photosensitive development are obtained based on the developing temperatures and stirring frequencies at different positions during the historical photosensitive development process, so that subsequent photosensitive development can have better developing temperatures and stirring frequencies at different positions. Even if the wiring and vias (pads) in different areas of the circuit board have different distribution densities, defects such as rough line edges, deformation and insolubility of photoresist, and signal loss can be avoided as much as possible.

[0076] Furthermore, this embodiment obtains a parameter influence region for each area, wherein the development temperature and stirring frequency at each location within the parameter influence region have a correlation coefficient greater than a first preset threshold with the development abnormality index and electrical signal abnormality index for each area. This process ensures that the generation or change of the development abnormality index and electrical signal abnormality index corresponding to each area is related to the development temperature and stirring frequency at all locations within the parameter influence region, and is not significantly affected by the development temperature and stirring frequency at locations outside the parameter influence region.

[0077] Based on the above, after several circuit boards with the same layout in this embodiment are photosensitively developed, the target temperature distribution and target stirring distribution are obtained when each area has the minimum development abnormality index and signal abnormality index; the change trend of the signal abnormality index of each area along with the development abnormality index is recorded as the development attention of each area; using the development attention, the target temperature distribution and target stirring distribution in the parameter influence area of all areas are integrated to obtain the optimal target temperature distribution and optimal target stirring distribution, and the optimal target temperature distribution and optimal target stirring distribution are used for the next development. This process allows, when faced with circuit boards with large differences in wiring density, on the one hand, to avoid defects such as rough line edges, photoresist deformation and insolubility as much as possible; on the other hand, based on the generation or change of the development abnormality index and the electrical signal abnormality index, and the relationship between the development temperature and stirring frequency of all positions in the parameter influence area, the development temperature and stirring frequency of different positions are more reliably adjusted, further ensuring the reliability of the circuit board after photosensitive development, avoiding circuit board abnormalities, and better maintaining battery health and avoiding battery life being too short.

[0078] Example 2: This embodiment takes into account that since the circuit board photosensitive development process is a complex chemical treatment process, there is a certain degree of uncertainty when the developer is set to different temperatures and stirring speeds at different locations. For example, even with the same temperature distribution and stirring distribution, circuit boards with different defects or signal loss conditions may be obtained, and the same defect condition may also lead to different signal loss conditions, thereby causing errors in the development focus and parameter influence areas in Example 1. Ultimately, it is still impossible to obtain a stable optimal target temperature distribution and optimal target stirring distribution suitable for circuit boards with the same layout within a short period of time (that is, after a small number of photosensitive development times). This is not conducive to achieving efficient production of circuit boards while ensuring the quality of the finished circuit boards (that is, avoiding excessive defects such as rough line edges, deformed and undissolved photoresist, and avoiding severe signal loss, abnormal resistance, etc.).

[0079] This embodiment provides another method for fusing the target temperature distribution and target stirring distribution in the parameter-affecting regions of all regions to obtain the optimal target temperature distribution and the optimal target stirring distribution, and using the optimal target temperature distribution and the optimal target stirring distribution for the next development, including: During the photosensitive development of several circuit boards with the same layout, the development abnormality index and signal abnormality index of each area obtained during the i-th photosensitive development process are respectively recorded as and , the development abnormality index and signal abnormality index of each area obtained in the process of the i+1th photosensitive development are respectively recorded as and .when Less than ,and Less than , the area is recorded as the indicator non-optimized area.

[0080] Each non-optimized indicator region represents a region where the abnormal development index and the abnormal signal index do not decrease during two adjacent photosensitive development processes.

[0081] Get the parameter influence area of the non-optimized area in the process of the i-th photosensitive development, recorded as , obtain the parameter influence area of the same indicator in the non-optimized area during the i+1th photosensitive development process, recorded as If a location belongs to Within but not belonging to , or belongs to Within but not belonging to If a position belongs to within and belongs to , then the position is no longer marked as an error position.

[0082] During the photosensitive development process of several circuit boards with the same layout, the ratio of the number of times each position is marked as an error position to the total number of times the photosensitive development is performed is recorded as the abnormal frequency of each position. In particular, the abnormal frequency of a position that has never been marked as an error position is 0.

[0083] The greater the abnormal frequency at each position, the more obvious the uncertainty is between the development temperature and stirring frequency at that position and the development abnormality index and electrical signal abnormality index in the non-optimized area. In this case, we should not over-rely on that position in the non-optimized area to obtain the optimal target temperature distribution and the optimal target stirring distribution.

[0084] After the current photosensitive development process, the average of the abnormal frequencies of all positions in each area is obtained and recorded as the attention error of each area.

[0085] The parameter influence area corresponding to each area, and any position within the parameter influence area, are recorded as reference positions.

[0086] Note that the reference position may belong to different areas at the same time, that is, the reference position may also be included in other parameter-affected areas of the circuit board.

[0087] Assuming that there are N parameter influence regions at the reference position, for the i-th parameter influence region, the target temperature distribution and target stirring distribution of the i-th parameter influence region, and the development temperature and stirring frequency at the reference position are recorded as the reference development temperature and reference stirring frequency .

[0088] Each parameter-affected region in the N parameter-affected regions corresponds to a development attention and an attention error. The difference between the development attention and the attention error is obtained and recorded as the corrected development attention of each parameter-affected region. The difference between the corrected development attention and the abnormal frequency of the reference position in each parameter-affected region is recorded as the attention coefficient of the reference position in each parameter-affected region. The attention coefficients of the reference positions in the N parameter-affected regions are normalized using the softmax formula to obtain the corrected attention weight of the reference position in each parameter-affected region. The corrected attention weight of the reference position in the i-th parameter-affected region is recorded as , the reference developing temperatures of all parameter-affected areas are weighted summed using the modified attention weight of the reference position in each parameter-affected area to obtain the optimal developing temperature ; Use the attention weight of each parameter influence area to weighted sum the reference stirring frequencies of all parameter influence areas to obtain the optimal stirring frequency .

[0089] At this point, the parameters corresponding to each region affect an optimal developing temperature and optimal stirring frequency for each position within the region. The optimal developing temperatures and optimal stirring frequencies for all positions within the parameter-affecting regions of all regions on the circuit board are then obtained. These optimal developing temperatures and optimal stirring frequencies are used as the developing temperatures and stirring frequencies for the same positions during the next photosensitive development.

[0090] Compared with Example 1, the above process of obtaining the optimal development temperature and the optimal stirring frequency avoids to a certain extent: the errors in the development focus and the parameter influence area (the errors are caused by the uncertainty when different positions of the developer are set to different temperatures and stirring speeds), which ultimately leads to the following problems: within a short period of time (that is, after a short period of photosensitive development), it is still impossible to obtain a stable optimal target temperature distribution and optimal target stirring distribution suitable for the same layout circuit board, which is not conducive to ensuring the quality of the finished circuit board (that is, avoiding too many defects such as rough line edges, deformation and undissolved photoresist, and avoiding serious signal loss, abnormal resistance, etc.) to achieve efficient production of circuit boards.

[0091] In this embodiment, after N2 circuit boards of the same layout undergo N2 photosensitive developments, the obtained optimal target temperature distribution and optimal target stirring distribution are used as the temperature distribution and stirring distribution for each subsequent photosensitive development of the circuits of the same layout.

[0092] This embodiment is described by taking N2=8 as an example. In other embodiments, N2 may be set to other values, which is not limited in this embodiment.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A photosensitive development method for a battery management system control circuit board, characterized in that: The method comprises the following steps: During each photosensitive development, the developer solution is set at different development temperatures and stirring frequencies at different locations, which are recorded as temperature distribution and stirring distribution. After development, visual inspection and circuit signal inspection are performed to obtain development abnormality indicators and signal abnormality indicators for different areas of the circuit board respectively. After photosensitive development of several circuit boards with the same layout, the temperature distribution and stirring distribution of each area with the minimum development abnormality index and signal abnormality index are obtained and recorded as the target temperature distribution and target stirring distribution; the trend of the signal abnormality index of each area along with the development abnormality index is recorded as the development attention level of each area; Obtaining a parameter influence region of each region, wherein the parameter influence region has a correlation coefficient greater than a first preset threshold with a development temperature and a stirring frequency at each position and a development abnormality index and an electrical signal abnormality index of each region; The development attention is used to fuse the target temperature distribution and target stirring distribution in the parameter-affecting area of all areas to obtain the optimal target temperature distribution and the optimal target stirring distribution, which are used for the next development.

2. The photosensitive development method for a battery management system control circuit board according to claim 1, characterized in that: By utilizing the development attention, the target temperature distribution and target stirring distribution in the parameter-affecting regions of all regions are integrated to obtain the optimal target temperature distribution and the optimal target stirring distribution. The specific steps include the following: During the process of performing several photosensitive developments on several circuit boards of the same layout, the area where the development abnormality index and the signal abnormality index do not decrease during two adjacent photosensitive developments is recorded as an index non-optimized area; The error position is obtained based on the position change within the parameter-affected area of the indicator non-optimized area; During the photosensitive development process of several circuit boards with the same layout, the ratio of the number of times the error position appears to the total number of times the photosensitive development is performed is recorded as the abnormal frequency of each position; the average of the abnormal frequencies of all positions in each area is obtained and recorded as the attention error of each area; The target temperature distribution and target stirring distribution in the parameter influence area of all regions are fused by using the development attention, the attention error and the abnormal frequency of each position to obtain the optimal target temperature distribution and the optimal target stirring distribution.

3. The photosensitive development method for a battery management system control circuit board according to claim 2, characterized in that: The specific steps of obtaining the error position according to the position change in the parameter influence area of the non-optimized indicator area are as follows: The parameter influence area of the non-optimized index area during the i-th photosensitive development process is recorded as , the parameter influence area of the same indicator in the non-optimized area during the i+1th photosensitive development process is recorded as , will belong to Within but not belonging to , or belongs to Within but not belonging to The position within is marked as the error position, which belongs to within and belongs to The position is no longer marked as an error position.

4. The photosensitive development method for a battery management system control circuit board according to claim 2, characterized in that: The target temperature distribution and the target stirring distribution in the parameter-affecting regions of all regions are integrated by using the development attention, the attention error, and the abnormal frequency of each position to obtain the optimal target temperature distribution and the optimal target stirring distribution. The specific steps include the following: The parameters corresponding to each region affect any position within the region, which is recorded as the reference position; The number of parameter influence regions at the reference position is recorded as N, where the target temperature distribution and target stirring distribution of the i-th parameter influence region and the development temperature and stirring frequency below the reference position are recorded as the reference development temperature and reference stirring frequency ; Obtain the difference between the development attention and the attention error corresponding to each parameter-affected area, and record it as the corrected development attention of each parameter-affected area. The difference between the corrected development attention and the abnormal frequency of the reference position in each parameter-affected area is recorded as the attention coefficient of the reference position in each parameter-affected area. The attention coefficients of the reference positions in the N parameter-affected areas are normalized using the softmax formula to obtain the corrected attention weight of the reference position in each parameter-affected area. The corrected attention weight of the reference position in the i-th parameter-affected area is recorded as , optimal developing temperature ;Optimal stirring frequency .

5. The photosensitive development method for a battery management system control circuit board according to claim 1, characterized in that: The specific steps for obtaining the abnormal imaging index are as follows: The circuit board is divided into several areas, and the grayscale image of the circuit board after photosensitive development is collected using an industrial camera. The grayscale image of the circuit board is segmented into a binary image using the Otsu threshold segmentation algorithm. Edge abnormal pixels and non-edge abnormal pixels are obtained in each area of the binary image. The ratio of the number of edge abnormal pixels in each area to the number of non-edge abnormal pixels in each area is recorded as the development abnormality index of each area.

6. The photosensitive development method for a battery management system control circuit board according to claim 1, characterized in that: The specific steps for obtaining the signal anomaly indicator are as follows: A test signal is input into one end of each area, and the frequency and amplitude of the received signal are measured at the other end. The difference in frequency and amplitude between the test signal and the received signal is used as a signal anomaly indicator.

7. The method for photosensitive development of a battery management system control circuit board according to claim 1, characterized in that: After the plurality of circuit boards of the same layout are subjected to photosensitive development, the temperature distribution and stirring distribution when each area has the minimum development abnormality index and signal abnormality index are obtained and recorded as the target temperature distribution and target stirring distribution. The specific steps include the following: The average of the development abnormality index and signal abnormality index of each area is recorded as the comprehensive abnormality index of each area; for any area on the circuit board, after several circuit boards with the same layout are photosensitively developed several times, among the several comprehensive abnormality indicators obtained for the area on the circuit board, the photosensitive development with the minimum comprehensive abnormality index is obtained, and the temperature distribution and stirring distribution used during the photosensitive projection are recorded as the target temperature distribution and target stirring distribution.

8. The method for photosensitive development of a battery management system control circuit board according to claim 1, characterized in that: The changing trend of the signal abnormality index of each area along with the development abnormality index is recorded as the development attention degree of each area, which includes the following specific steps: For any area on the circuit board, during the process of several photosensitive developments on several circuit boards with the same layout, the time series of the signal anomaly index of the area is obtained in chronological order, recorded as the first series, and the time series of the development anomaly index is recorded as the second series; the absolute value of the Piel selection correlation coefficient of the first series and the second series is used as the development attention of each area.

9. The method for photosensitive development of a battery management system control circuit board according to claim 8, characterized in that: The step of obtaining the parameter influence area of each area, wherein the parameter influence area includes the development temperature and stirring frequency at each position in the parameter influence area, and the correlation coefficient with the development abnormality index and the electrical signal abnormality index of each area is greater than a first preset threshold value, includes the following specific steps: During the process of performing photosensitive development on several circuit boards of the same layout, a time sequence consisting of the development temperature and stirring frequency at each position is obtained, which are recorded as a third sequence and a fourth sequence; Obtain the Pearson correlation coefficient between the first sequence and the third sequence, denoted as r1, obtain the Pearson correlation coefficient between the second sequence and the third sequence, denoted as r2, and use |r1|+|r2| as the development temperature interference index for each position; Obtain the Pearson correlation coefficient between the first sequence and the fourth sequence, recorded as r3, obtain the Pearson correlation coefficient between the second sequence and the fourth sequence, recorded as r4, and use |r3|+|r4| as the stirring frequency interference index at each position; The mean of the development temperature interference index at each position and the stirring frequency interference index at each position is recorded as the parameter influence factor of each position on each area; Obtain the parameter influence factors of all positions on each region, record the position whose parameter influence factor on each region is greater than a first preset threshold as the target position, and record the set of target positions as the parameter influence region of each region.

10. The method for photosensitive development of a battery management system control circuit board according to claim 5, characterized in that: The specific steps of obtaining edge abnormal pixel points and non-edge abnormal pixel points in each region on the binary image are as follows: In each area, the Hough line transform algorithm is used to obtain all lines, and the Hough circle transform algorithm is used to obtain all circles. The line or circle closest to each pixel point is obtained, and the closest distance between each pixel point and the closest line or circle is recorded as the abnormal distribution amplitude of each pixel point. Pixels in each area whose abnormal distribution amplitude is greater than the preset distance and are on the edge of the connected domain are recorded as edge abnormal pixels. Pixels in each area whose abnormal distribution amplitude is less than or equal to the preset distance and are on the edge of the connected domain are recorded as non-edge abnormal pixels.

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