Circuit board assembly for battery apparatus

Abstract

The present application relates to the technical field of circuit boards, and specifically provides a circuit board assembly for a battery apparatus. The circuit board assembly comprises a circuit board main body, a branch structure, and a fixing plate. The circuit board main body comprises a plurality of parallel wires. The branch structure comprises a branch connection portion and a sampling portion. The sampling portion is used to collect battery information. The branch connection portion is provided with through holes, and a welding spot is formed within at least one through hole and is welded to a wire. The fixing plate is connected to the branch connection portion, the width of the fixing plate is W1, and the diameter of the through holes is R, such that 0.01≤R / W1≤2. In the present application, the branch connection portion is welded to a wire of the circuit board main body by means of a through hole having a welding spot, and is reinforced by using the fixing plate, so as to prevent bending and warping of the branch connection portion due to heat during welding. In addition, the ratio of the diameter of the through holes to the width of the fixing plate is properly designed, so that a sufficient fixing effect can be achieved for the branch connection portion, thus the occurrence of bending or even folding is eliminated, and welding is also made reliable, and large local resistance is prevented.

Description

Circuit board assembly for battery devices

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411406517.0, filed on October 10, 2024, entitled “Circuit Board Assembly for Battery Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of circuit boards, and specifically proposes a circuit board assembly for a battery device. Background Technology

[0004] Currently, the low-voltage acquisition harnesses used in battery devices are mainly of two types: FPC (Flexible Printed Circuit) and FFC (Flat Flexible Cable).

[0005] FPC is made of etched copper wire as core and encapsulated with insulating material as protective film. It has the advantages of thinness and small size, but its production cost is high and a lot of core material needs to be cut off when forming branches during the forming process.

[0006] FFC uses tin-plated copper as its core and is encapsulated by a protective film. It has the advantage of being flexible and bendable, but it usually uses stamped fuses, which can generate sparks when the fuse melts, increasing the risk of short circuits in the battery pack. While etched fuses do not have the spark problem, they are more expensive. Summary of the Invention

[0007] The purpose of this application is to solve at least some of the technical problems mentioned above, and this purpose is achieved through the following technical solutions:

[0008] In a first aspect, this application proposes a circuit board assembly for a battery device, comprising a circuit board body, a branch structure, and a fixing plate. The circuit board body includes multiple parallel-arranged conductors, each conductor comprising a first metal and a second metal covering the outer surface of the first metal, the second metal having a lower hardness than the first metal. The branch structure includes a branch connection portion formed by the first metal and a sampling portion connected to the branch connection portion, the sampling portion being used to connect to the battery and collect battery information. The branch connection portion has at least two rows of through holes along the arrangement direction of the multiple conductors, the positions of the through holes corresponding to the positions of the conductors, and at least one through hole having a solder joint formed therein, the solder joint being welded to the conductor. The fixing plate is connected to the branch connection portion, the dimension of the fixing plate along the arrangement direction of the multiple conductors is W1, and the dimension of the through holes along the arrangement direction of the multiple conductors is R, then 0.01≤R / W1≤2.

[0009] The technical solution proposed in this application has at least the following technical effects:

[0010] In this application, the branch connection is soldered to the main conductor of the circuit board through the solder joint through hole and reinforced by the fixing plate to prevent the branch connection from bending or warping due to heat during soldering; in addition, the ratio of the diameter of the through hole to the width of the fixing plate is designed appropriately, which can not only provide sufficient fixation for the branch connection and eliminate bending or even flipping, but also make the soldering reliable and avoid large local resistance. Attached Figure Description

[0011] To better integrate the content illustrated in the accompanying drawings with the description of the specific embodiments, a brief introduction to the drawings is provided below. It is understood that the accompanying drawings mentioned below are merely schematic illustrations of some embodiments of the relevant technical solutions and the technical solutions of this application. Without creative effort, those skilled in the art can create drawings illustrating other embodiments.

[0012] Specifically, the annotations for the accompanying drawings are as follows:

[0013] Figure 1 is a schematic diagram of the structure of a circuit board assembly for a battery device according to some embodiments of this application;

[0014] Figure 2 is an enlarged structural diagram of point A in Figure 1;

[0015] Figure 3 is a schematic diagram of the branch structure described in some embodiments of this application;

[0016] Figure 4 is a schematic diagram of the connection between the branch structure and the fixing plate described in some embodiments of this application;

[0017] Figure 5 is a schematic diagram of the main structure of the circuit board described in some embodiments of this application.

[0018] Specifically, the annotations for the figure marks in the instruction manual are as follows:

[0019] 100. Circuit board assembly for battery device; 110. Circuit board body; 111. Wire; 120. Branch structure; 121. Branch connection part; 122. Sampling part; 123. Buffer arm; 130. Fixing plate; 140. Connector seat; 150. Battery aluminum busbar; a. Through hole; g. Fuse structure; B1. First main body layer; B2. Second main body layer; E1. First branch structure; E2. Second branch structure; K1. First fixing plate; K2. Second fixing plate; X. First direction; Y. Second direction; Z. Third direction. Detailed Implementation

[0020] To make the embodiments of this application clearer, they will be described below in conjunction with the accompanying drawings. It is to be understood that the content mentioned below is only a partial embodiment of this application, while the complete list of all embodiments is provided. Therefore, other embodiments obtained based on the following embodiments without any inventive effort all fall within the protection scope of this application.

[0021] It should be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to impose strict limitations on the technical solutions unless the context clearly indicates otherwise. For example, the use of "a," "an," and "the" to modify a feature does not preclude the possibility that the feature may be plural in other embodiments.

[0022] It should be understood that the terms "comprising," "including," and "having" are open-ended, indicating the presence of the stated features but not excluding the possibility of other features in the embodiment. Similarly, the use of terms such as "first," "second," etc., to describe multiple features only indicates the distinction between one feature and another, and such terms do not imply order or sequence unless explicitly stated in the context.

[0023] It should be understood that, unless the context clearly indicates otherwise, the terms "setup," "connection," and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrated connection; they can refer to a direct connection or an indirect connection via a medium. Those skilled in the art will understand the specific meaning of these terms in this document based on the specific circumstances.

[0024] In addition, for ease of description, the text will use terms of spatial relative relationship to describe the position of one feature relative to another feature, such as "inner", "outer", "end", "side", "upper", "middle", "lower", "high", "low", "axial", "circumferential", "radial", "horizontal", "vertical", "first direction", "second direction", etc. It can be understood that the spatial relative relationship between two features should include other specific situations besides those shown in the accompanying drawings of the specification.

[0025] The embodiments of this application will now be described with reference to the accompanying drawings.

[0026] Referring to Figures 1 to 5, this application proposes a circuit board assembly 100 for a battery device, which includes a circuit board body 110, a branch structure 120, and a fixing plate 130. The circuit board body 110 includes multiple parallel-arranged conductors 111. Each conductor 111 includes a first metal and a second metal covering the outer surface of the first metal. The second metal has a lower hardness than the first metal. The branch structure 120 includes a branch connection part 121 formed by the first metal and a sampling part 122 connected to the branch connection part 121. The sampling part 122 is used to connect to the battery and collect battery information. The branch connection part 121 has at least two rows of through holes a along the arrangement direction of the multiple conductors 111. The position of the through holes a corresponds to the position of the conductors 111. At least one through hole a has a solder joint formed in it, and the solder joint is welded to the conductors 111. The fixing plate 130 is connected to the branch connection part 121. The dimension of the fixing plate 130 along the arrangement direction of the multiple conductors 111 is W1, and the dimension of the through hole a along the arrangement direction of the multiple conductors 111 is R. Then, 0.01≤R / W1≤2.

[0027] In this application, the branch connection 121 is soldered to the conductor 111 of the circuit board body 110 using solder joints in the through hole a, and is reinforced by a fixing plate 130 to prevent the branch connection 121 from bending or warping due to heat during soldering. In addition, the ratio of the diameter of the through hole a to the width of the fixing plate 130 is designed appropriately. The fixing plate 130 can not only provide sufficient fixation for the branch connection 121 to eliminate bending or even flipping, but also ensure that the solder joints in the through hole a are firmly soldered to the conductor 111, thereby avoiding large local resistance.

[0028] Furthermore, if the R / W1 ratio is too large, it indicates that the solder joints are large and the fixing plate 130 is narrow, resulting in insufficient fixing of the branch connection 121. The branch connection 121 may still bend or even flip. If the R / W1 ratio is too small, it indicates that the solder joints are small and the fixing plate 130 is too wide. Although the fixing effect is sufficient, small solder joints may lead to weak welding and high local resistance. Moreover, an excessively wide fixing plate 130 will occupy more internal space of the battery pack. Therefore, the R / W1 ratio should be moderate, for example, it can be 0.01, 1, or 2.

[0029] It should be noted that the fixing plate 130 can be a single piece or multiple smaller pieces. In some embodiments, the length of the single fixing plate 130 or the total length of the overlapping smaller pieces is approximately equal to the length of the straight section of the circuit board body 110. In addition, in some embodiments, R is the diameter of the through hole a, W1 is the width of the fixing plate 130, and the fixing plate 130 is a heat-pressed film.

[0030] In particular, in some embodiments, the direction in which the multiple wires 111 are arranged in parallel is the first direction X, the direction of the guiding extension is the second direction Y, and the thickness direction of the fixing plate 130 is the third direction Z. Then the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0031] In some embodiments, the distance between the wire 111 with solder joints and its adjacent wire 111 is H1, then 0.3mm≤H1≤2mm.

[0032] In the above embodiments, if the spacing of the wires 111 is too small, short circuits are likely to occur; if the spacing is too large, the number of wires that can be routed in the circuit board body 110 will be too small, making it impossible to match the acquisition of multiple battery cells. In addition, the spacing of the wires 111 also determines the spacing of the through holes a. If the through holes a are too close, the strength of the branch connection 121 will be insufficient. Therefore, the value of the wire spacing H1 should be appropriate, for example, it can be 0.3mm, 1mm, or 2mm.

[0033] In some embodiments, referring to FIG3, each branch connection portion 121 is provided with multiple rows of through holes a along the extension direction of the wire 111.

[0034] In some embodiments, the dimension of the branch connection portion 121 along the extension direction of the wire 111 is L1, the number of through holes a is n, and the area of ​​through holes a is S, then 0.3≤L1 / (n*S)≤0.6.

[0035] In the above embodiments, if the value of L1 / (n*S) is too small, it is equivalent to the through-hole a of the branch connection 121 being too large, which makes the branch connection 121 prone to breakage and damage during transportation, forming, and welding. If the value of L1 / (n*S) is too large, it means that the through-hole a of the branch connection 121 is less and / or smaller, resulting in fewer and / or smaller weld joints, which is detrimental to the reliability of welding and will lead to a larger local resistance. Therefore, the ratio of L1 / (n*S) should be moderate, for example, it can be 0.3, 0.5, or 0.6.

[0036] It should be noted that each branch connection 121 is provided with at least two columns of through holes a, and the multiple through holes a in each column are spaced apart along the second direction Y, and the multiple through holes a in each row are spaced apart along the first direction X.

[0037] In some embodiments, if the spacing between two adjacent columns of through holes a is P along the extension direction of the conductor 111, then 0.5mm ≤ P ≤ 1.5mm.

[0038] In some embodiments, the thickness of the fixing plate 130 is d, where d ≥ 0.03 mm and P ≤ 1.2 mm.

[0039] In the above embodiment, if the through hole a is too close, the branch connection 121 is not strong enough and is prone to warping, so the fixing plate 130 needs to be thicker.

[0040] It should be noted that the shape of the through hole 'a' does not have to be circular; it can also be rectangular or other shapes, and there are no restrictions here.

[0041] In some embodiments, the dimension of the fixing plate 130 along the extension direction of the wire 111 is L2, then 0.01≤L1 / L2≤1.

[0042] In the above embodiments, if the L1 / L2 ratio is too small, it indicates that the width of the branch connection 121 is too small, resulting in a smaller number or size of solder joints, which is detrimental to improving welding reliability and current carrying capacity. Conversely, if the L1 / L2 ratio is too large, it indicates that the width of the branch connection 121 is too large while the fixing plate 130 is too small, making the positioning of the fixing plate 130 cumbersome during installation and potentially causing inaccurate positioning and failure to properly press the branch structure 120 together. Therefore, the L1 / L2 ratio should be appropriate, for example, 0.01, 0.5, or 1.

[0043] In some embodiments, the width of the conductor 111 is W2, then 0.5mm≤R / W2≤2mm.

[0044] In the above embodiments, if the R / W2 ratio is too large, it indicates that the solder joint is too wide relative to the wire 111. If the spacing between wires 111 is small, they are prone to overlapping with adjacent wires 111, causing data acquisition errors. If the R / W2 ratio is too small, it indicates that the solder joint is too narrow relative to the wire 111, which may lead to insufficient current flow. Therefore, the R / W2 ratio should be appropriate, for example, it can be 0.5mm, 1mm, or 2mm.

[0045] It should be noted that the first metal in the conductor 111 can be flat, with its width direction being the first direction X. The function of the second metal is to facilitate soldering. It can completely cover the first metal along its periphery or partially cover it. In addition, the second metal can continuously or intermittently cover the first metal along the second direction Y. The conductor 111 as a whole can also be flat, with its width direction being the first direction X.

[0046] In some embodiments, the thickness of the fixing plate 130 is d, then 0.03mm≤d≤0.1mm, and 0.0006≤d / W1≤0.05.

[0047] In some embodiments, if the fixing plate 130 is too thin, the fixing effect will be insufficient and it will be easy to fold over. If the fixing plate 130 is too thick, it will occupy more space in the third direction Z and be heavier. Therefore, the thickness d of the fixing plate 130 should be appropriate, for example, it can be 0.03mm, 0.05mm, or 0.1mm.

[0048] Furthermore, if the d / W1 ratio is too large, it indicates that the fixing plate 130 is too thick and too narrow, which is not conducive to saving space, reducing weight, and positioning the fixing plate 130. On the other hand, if the d / W1 ratio is too small, it indicates that the fixing plate 130 is too thin and too wide, making the fixing plate 130 more prone to bending or breaking due to insufficient strength. Therefore, the d / W1 ratio should be moderate, for example, it can be 0.0006, 0.01, or 0.05.

[0049] In some embodiments, the dimension of the branch connection portion 121 along the arrangement direction of the plurality of wires 111 is W2, then W2≤W1, and 0.03mm≤d≤0.06mm.

[0050] In the above embodiment, in the first direction X, the size of the fixing plate 130 is larger than the size of the branch connection portion 121. The fixing plate 130 completely covers and extends beyond the branch connection portion 121 to ensure that the branch connection portion 121 does not warp. Therefore, the thickness of the fixing plate 130 can be set to be slightly thinner, for example, d can be 0.03mm, 0.05mm, or 0.06mm.

[0051] In some embodiments, the branch connection portion 121 is provided with fixing plates 130 at both ends in the thickness direction, then 0.03mm≤d≤0.05mm.

[0052] In the above embodiment, the branch connection 121 is fixed on both sides of the third direction Z by the fixing plate 130, so the overall structure is stronger. Therefore, the thickness of the fixing plate 130 can be further reduced, for example, d can be 0.03mm, 0.04mm, or 0.05mm.

[0053] In some embodiments, the fixing plate 130 is bonded and fixed to the branch connection portion 121 and the circuit board body 110.

[0054] In some embodiments, multiple wires 111 are connected one-to-one with multiple branch connection portions 121, and each branch connection portion 121 is soldered to the wire 111 through a solder joint formed by a through hole a corresponding to a wire 111.

[0055] In some embodiments, the fixing plate 130 covers the solder joints on the plurality of branch connections 121.

[0056] In the above embodiment, the fixing plate 130 directly presses the weld point, which not only fixes the branch connection part 121 to prevent it from warping, but also ensures the insulation, dustproof and dewproof effects of the weld point.

[0057] In some embodiments, referring to FIG2, the circuit board body 110 includes a first main layer B1 and a second main layer B2 stacked together, and the first main layer B1 is connected to a first branch structure E1, and the second main layer B2 is connected to a second branch structure E2; the first branch structure E1 and the second branch structure E2 are distributed on both sides of the extension direction of the circuit board body 110.

[0058] In the above embodiment, the first branch structure E1 and the second branch structure E2 are symmetrically arranged to reduce branch warping; in addition, the first main body layer B1 and the second main body layer B2 are stacked, so the output end does not need to be bent, and the two layers are respectively provided with two output ends to facilitate subsequent direct insertion into the connector 140 of the BMS (Battery Management System).

[0059] It should be noted that in some embodiments, the straight segments of the two main layers are stacked in the third direction Z, and the two branch structures 120 can be staggered or symmetrically distributed in the first direction X.

[0060] In some embodiments, referring to FIG2, the first main body layer B1 and the second main body layer B2 are disposed between the two fixing plates 130, and the total thickness between the two fixing plates 130 is D, then D≤150μm.

[0061] In the above embodiment, the two main layers are respectively provided with a first fixing plate K1 and a second fixing plate K2 on both sides in the third direction Z, forming a stacked structure. If the total thickness is too large, it will occupy too much space and the sides are prone to cracking.

[0062] In some embodiments, the conductivity of the first metal is greater than that of the second metal, and the thickness of the first metal is d1 and the thickness of the second metal is d2, then 1≤d1 / d2≤2.5.

[0063] In the above embodiments, the main purpose of the second metal plating layer is to increase the weldability of the first metal and the branch connection 121, and also to prevent oxidation.

[0064] If the ratio of d1 / d2 is too large, it indicates that the thickness of the second metal is insufficient, and its effect will be insufficient; however, the conductivity of the second metal is not as good as that of the first metal. If the ratio of d1 / d2 is too small, that is, the thickness of the second metal is too large, it will cause the current carrying capacity of the wire 111 to deteriorate. In some embodiments, d1 / d2 can be 1, 2, or 2.5.

[0065] It should be noted that the first metal can be flat copper with a rectangular cross-section and a thickness direction of the third direction Z, and the second metal can be a tin layer applied to the surface of the first metal.

[0066] In addition, the actual product has a tin thickness of 0.2mm and a copper wire thickness of 0.1mm, which ensures that the tin can overflow from the through hole a and increases the soldering strength.

[0067] In some embodiments, the melting point of the first metal is greater than that of the second metal, and 0.1 ≤ R / W1 ≤ 2.

[0068] In the above embodiments, the solder joints of the second metal are lower, which facilitates welding. At this time, the solder joints can be set to be larger to reduce warping. For example, R / W1 is preferably 0.1, 1, or 2.

[0069] In some embodiments, referring to FIG3, a fuse protection structure g is provided on the branch structure 120.

[0070] In the above embodiment, a fuse structure g is provided on the branch structure 120, which can be closer to the sampling part 122. This is because when the battery temperature is too high and the electrical connection needs to be disconnected, the fuse structure g has a shorter reaction time, thus responding faster and providing better protection.

[0071] In some embodiments, referring to FIG3, a buffer arm 123 is provided between the branch connection portion 121 and the sampling portion 122, and a fusible fuse structure g is provided on the buffer arm 123. The minimum distance between the fusible fuse structure g and the sampling portion 122 is H2, where 1mm ≤ H2 ≤ 25mm. In some embodiments, H2 can be 1mm, 10mm, or 25mm.

[0072] In the above embodiment, due to battery expansion, the battery array extends along its arrangement direction. The main body size of the wiring harness assembly is fixed, and the sampling part 122 and the battery aluminum busbar 150 are welded and fixed. That is, the relative position of the branch connection part 121 and the sampling part 122 is fixed. Therefore, an S-shaped buffer arm 123 is designed between the two to absorb displacement through its deformation, thereby avoiding the risk of the branch connection part 121 being broken due to the expansion and contraction displacement of the battery.

[0073] It should be noted that the expansion and contraction direction of the battery pack when it is doing work is from the center point of the battery pack along the second direction Y to both sides; in addition, the buffer arm 123 has a curved structure.

[0074] In some embodiments, if the distance between the fusible fuse structure g and the solder joint is H3, then H3 ≥ 5 mm.

[0075] In the above embodiments, if the distance between the fusible fuse structure g and the solder joint is too close, the fusible fuse structure g may fail during soldering.

[0076] In some embodiments, the branch connection portion 121 is an FPC branch structure encapsulated by a thermoplastic film, and 0.2≤R / W1≤2.

[0077] In the above embodiments, the branch encapsulated by the hot-press film has increased hardness and reduced the probability of warping. Therefore, R / W1 can preferably be 0.2, 1, or 2.

[0078] In some embodiments, the circuit board body 110 is an FFC main layer structure, and the peel force after the FPC branch structure is welded to the FFC main layer structure is F, then F≥8N.

[0079] In the above embodiments, if the peeling force is too small, it will be easy to peel off.

[0080] In summary, in some embodiments, this application provides a circuit board assembly 100 for a battery device, which uses FFC (tin-plated copper) as the main body 110 of the circuit board and FPC (etched copper wire) as the branch structure 120, and is then encapsulated with a fixing plate 130. The overall design takes into account the flexibility of FFC and reduces production costs. At the same time, the fusible structure g formed by the etched FPC is located closer to the sampling part 122, which is safer and will not generate sparks. Moreover, it can form a stacked main body layer, such as two layers of FFC collecting batteries on both sides and forming two layers of plug-in structure to be directly plugged into the BMS, thereby reducing the overall width of the wiring harness and adapting to more battery pack internal space.

[0081] It should be noted that the embodiments of this application only illustrate the structure of the circuit board assembly 100 for the battery device related to the improvement points of this application, but it does not mean that it does not have other structures. For example, the circuit board assembly 100 for the battery device also includes a connector seat 140 that is electrically connected to the circuit board body 110, and / or a battery aluminum busbar 150 that is electrically connected to the sampling unit 122, etc. Other structures will not be described one by one here.

[0082] In particular, the term "and / or" in this application should be understood as follows:

[0083] In the first case, the term “and / or” located between the first subject and the second subject includes any of the following meanings: (1) only the first subject; (2) only the second subject; and (3) both the first subject and the second subject.

[0084] In the second case, the term "and / or" between the last two of three or more subjects means including at least any one of the subjects. For example, "first subject, second subject and / or third subject" has the same meaning as "first subject and / or second subject and / or third subject", specifically including the following combinations: (1) only the first subject; (2) only the second subject; (3) only the third subject; (4) the first subject and the second subject and no third subject; (5) the first subject and the third subject and no second subject; (6) the second subject and the third subject and no first subject; and (7) the first subject, the second subject and the third subject.

[0085] Furthermore, although the embodiments of this application have been described above in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the concept of this application, and such modifications and variations all fall within the scope of protection of this application.

Claims

1. A circuit board assembly for a battery device, characterized in that, include: The circuit board body (110) includes a plurality of parallel-arranged conductors (111), each conductor (111) including a first metal and a second metal covering the outer surface of the first metal, wherein the hardness of the second metal is less than that of the first metal. A branch structure (120) includes a branch connection portion (121) formed of the first metal and a sampling portion (122) connected to the branch connection portion (121). The sampling portion (122) is used to collect battery information. The branch connection portion (121) is provided with at least two rows of through holes (a) along the arrangement direction of the plurality of wires (111). The position of the through holes (a) corresponds to the position of the wires (111). At least one of the through holes (a) is formed with a solder joint, which is welded to the wires (111). A fixing plate (130) covers the surface of the solder joint and is fixedly connected to the branch connection (121). The fixing plate (130) has a dimension of W1 along the arrangement direction of the multiple wires (111), and the through hole (a) has a dimension of R along the arrangement direction of the multiple wires (111). Then 0.01≤R / W1≤2.

2. The circuit board assembly for a battery device according to claim 1, characterized in that, If the distance between the wire (111) with the solder joint and its adjacent wire (111) is H1, then 0.3mm≤H1≤2mm.

3. The circuit board assembly for a battery device according to claim 1, characterized in that, Each of the branch connection portions (121) is provided with multiple rows of through holes (a) along the extension direction of the conductor (111).

4. The circuit board assembly for a battery device according to claim 3, characterized in that, The dimension of the branch connection (121) along the extension direction of the conductor (111) is L1, the number of through holes (a) is n, and the area of ​​the through holes (a) is S. Then 0.3≤L1 / (n*S)≤0.

6.

5. The circuit board assembly for a battery device according to claim 3, characterized in that, Along the extension direction of the conductor (111), the spacing between two adjacent columns of through holes (a) is P, then 0.5mm≤P≤1.5mm.

6. The circuit board assembly for a battery device according to claim 5, characterized in that, The thickness of the fixing plate (130) is d, then d≥0.03mm and P≤1.2mm.

7. The circuit board assembly for a battery device according to claim 4, characterized in that, If the dimension of the fixing plate (130) along the extension direction of the conductor (111) is L2, then 0.01≤L1 / L2≤1.

8. The circuit board assembly for a battery device according to claim 1, characterized in that, The width of the conductor (111) is W2, then 0.5mm≤R / W2≤2mm.

9. The circuit board assembly for a battery device according to claim 1, characterized in that, The thickness of the fixing plate (130) is d, then 0.03mm≤d≤0.1mm, and 0.0006≤d / W1≤0.

05.

10. The circuit board assembly for a battery device according to claim 9, characterized in that, The dimension of the branch connection (121) along the arrangement direction of the multiple wires (111) is W2, then W2≤W1, and 0.03mm≤d≤0.06mm.

11. The circuit board assembly for a battery device according to claim 9, characterized in that, The branch connection part (121) is provided with the fixing plate (130) at both ends in the thickness direction, so 0.03mm≤d≤0.05mm.

12. The circuit board assembly for a battery device according to claim 1, characterized in that, The fixing plate (130) is bonded and fixed to the branch connection part (121) and the circuit board body (110).

13. The circuit board assembly for a battery device according to claim 1, characterized in that, The multiple wires (111) are connected one-to-one with the multiple branch connection parts (121), and each branch connection part (121) is welded to the wire (111) through a solder joint formed by a through hole (a) corresponding to one of the wires (111).

14. The circuit board assembly for a battery device according to claim 13, characterized in that, The fixing plate (130) covers the solder joints on the plurality of branch connections (121).

15. The circuit board assembly for a battery device according to claim 1, characterized in that, The circuit board body (110) includes a first main layer (B1) and a second main layer (B2) stacked together, and the first main layer (B1) is connected to a first branch structure (E1), and the second main layer (B2) is connected to a second branch structure (E2). The first branch structure (E1) and the second branch structure (E2) are distributed on both sides of the extension direction of the circuit board body (110).

16. The circuit board assembly for a battery device according to claim 15, characterized in that, The first main body layer (B1) and the second main body layer (B2) are disposed between the two fixing plates (130), and the total thickness between the two fixing plates (130) is D, then D≤150μm.

17. The circuit board assembly for a battery device according to claim 1, characterized in that, The conductivity of the first metal is greater than that of the second metal, and the thickness of the first metal is d1 and the thickness of the second metal is d2, then 1≤d1 / d2≤2.

5.

18. The circuit board assembly for a battery device according to claim 1, characterized in that, The melting point of the first metal is greater than that of the second metal, and 0.1 ≤ R / W1 ≤ 2.

19. The circuit board assembly for a battery device according to claim 1, characterized in that, The branch structure (120) is provided with a fusible safety structure (g).

20. The circuit board assembly for a battery device according to claim 19, characterized in that, A buffer arm (123) is provided between the branch connection part (121) and the sampling part (122). The fuse safety structure (g) is provided on the buffer arm (123). The minimum distance between the fuse safety structure (g) and the sampling part (122) is H2, then 1mm≤H2≤25mm.

21. The circuit board assembly for a battery device according to claim 20, characterized in that, If the distance between the fusible fuse structure (g) and the solder joint is H3, then H3 ≥ 5mm.

22. The circuit board assembly for a battery device according to any one of claims 1 to 21, characterized in that, The branch connection part (121) is an FPC branch structure encapsulated by hot-pressing film, and 0.2≤R / W1≤2.

23. The circuit board assembly for a battery device according to claim 22, characterized in that, The circuit board body (110) is an FFC main layer structure. The peel force after the FPC branch structure is welded to the FFC main layer structure is F, then F≥8N.

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