Flexible circuit board and battery module

Abstract

The embodiment of the utility model discloses a flexible circuit board and a battery module, and the flexible circuit board comprises a circuit board body; the buffer gap is arranged in the circuit board body; the connecting piece comprises a first end connected in the buffer gap and a second end extending in a direction far away from the circuit board body; and the temperature acquisition part is arranged at the second end, is electrically connected with the circuit board body, and is used for detecting the temperature of the large surface of the single battery. According to the flexible circuit board provided by the embodiment of the invention, through the arrangement of the buffer gap, when the connecting piece is subjected to the extrusion force opposite to the extension direction of the connecting piece, avoiding can be formed at the joint, used for being connected with the circuit board body, of the connecting piece, so that the connecting piece can move in the direction of the extrusion force received by the connecting piece; therefore, the situation that the joint of the connecting piece and the circuit board body is easy to tear due to the resistance borne by the temperature acquisition piece and / or the connecting piece in the process of extruding the connecting piece into the box is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a flexible circuit board and a battery module. Background Art

[0002] In the existing technical solutions, most of the temperature monitoring points of battery cells are arranged at the busbars or the top covers of the battery cells. However, the current arrangement schemes all have the following problems:

[0003] 1. Temperature acquisition deviation: If the temperature acquisition sensor (NTC) is arranged at the busbar position of the battery cell, during the process of current flowing from the battery cell electrode plate through the internal transfer sheet and the pole column to the busbar, due to the limitation of the welding area, at the same time, all the existing busbar temperature acquisition schemes require nickel sheet transfer, that is, the NTC is welded to the nickel sheet and then welded to the busbar. The numerous path transfer structures will inevitably lead to factors such as large path internal resistance, which will cause the busbar temperature to be much higher than the actual temperature of the battery cell; if the NTC is arranged at the top cover position of the battery cell, the ohmic thermal resistance of the busbar and the pole column is removed. Compared with the busbar arrangement scheme, the temperature acquisition value will decrease. However, since the electrolyte inside the battery cell is not completely filled (considering the gas expansion factor), there is an air layer between the top cover of the battery cell and the wound core, so the temperature of the top cover of the battery cell cannot truly represent the temperature of the middle wound core of the battery cell. In addition, the top cover area includes structures such as the explosion-proof valve, liquid injection port, positive and negative pole columns of the battery cell, and the area for arranging the temperature acquisition point is small, and the fixing and installation process of the NTC is difficult.

[0004] 2. Poor reliability: Since the temperature acquisition sensor (NTC) is a semiconductor device, the current schemes are all NTC protection designs. The NTC is in hard physical contact with the top cover and the busbar of the battery cell, and there is a risk of falling off or damage during the production and installation process of the battery pack and the actual vibration condition of the whole pack.

[0005] In response to the above problems, some battery cell large surface temperature acquisition schemes have been proposed. In this scheme, the temperature acquisition sensor (NTC) needs to be extended into the battery module to acquire the temperature of the large surface of the battery cell. However, since most of the current battery module assemblies adopt the extrusion into the box scheme, during the extrusion process, the connecting piece connecting the temperature acquisition sensor (NTC) and the circuit board is prone to tearing at the connection with the circuit board due to the inability to freely extend. Summary of the Utility Model

[0006] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a new flexible circuit board and a battery module to solve the problem that the connecting piece connecting the temperature acquisition sensor (NTC) and the circuit board in the existing battery cell large surface temperature acquisition scheme is prone to tearing at the connection with the circuit board due to the inability to freely extend.

[0007] In a first aspect, the present utility model provides a flexible circuit board, comprising:

[0008] A circuit board body;

[0009] A buffer notch, which is arranged in the circuit board body;

[0010] A connecting member, comprising a first end connected in the buffer notch and a second end extending in a direction away from the circuit board body;

[0011] A temperature acquisition member, which is arranged at the second end and electrically connected to the circuit board body for detecting the large surface temperature of a battery cell.

[0012] Based on the above flexible circuit board, a buffer notch is arranged on the circuit board body at the connection between the circuit board body and the connecting member, and the size of the buffer notch is determined according to the size of the connecting member. Through the arrangement of the buffer notch, when the connecting member is subjected to a squeezing force opposite to its extending direction, it can form an avoidance for the connection part on the connecting member for connecting with the circuit board body, so that the connecting member can move a certain distance along the direction of the squeezing force it receives, thereby reducing the situation that the connection part between the connecting member and the circuit board body is easily torn due to the resistance received by the temperature acquisition member and / or the connecting member itself during the process of squeezing the connecting member into the box.

[0013] In an embodiment of the above flexible circuit board, the connecting member and the circuit board body are integrally formed, and the first end of the connecting member has a bending part.

[0014] In an embodiment of the above flexible circuit board, the length of the buffer notch extends along a first direction, the connecting member is arranged at one end of the buffer notch along the first direction, and the length L of the buffer notch satisfies: L / R≥1.5, where R is the bending radius of the bending part, and the first direction is the length direction of the circuit board body.

[0015] In an embodiment of the above flexible circuit board, the width of the buffer notch extends along a second direction, the connecting member is arranged at the center of the buffer notch along the second direction, and the width W of the buffer notch satisfies: W≥3D, where D is the width of the bending part, and the second direction is the width direction of the circuit board body.

[0016] In one embodiment of the flexible circuit board described above, the buffer notch includes a first notch portion and a second notch portion. The width of the first notch portion increases along the first direction. The second notch portion is connected to the end with a larger width of the first notch portion and has a constant width along the first direction. And the connecting member is disposed at the end of the first notch portion away from the second notch portion, where W1 > W2 > 2D, W1 is the maximum width of the first notch portion, W2 is the width of the second notch portion, and D is the width of the bending portion.

[0017] In one embodiment of the flexible circuit board described above, the connecting member has a buffer section in a curved shape, and the buffer section is located between the bending portion and the temperature acquisition member.

[0018] Based on the above flexible circuit board, through the arrangement of the buffer section, it can be ensured that when the thickness of the battery cell expands, under the pulling force on the connecting member, its curved shape can form an anti-pulling buffer structure, thereby avoiding the tearing and damage of the bending portion.

[0019] In one embodiment of the flexible circuit board described above, the buffer section is at least one of an arc shape or an S shape.

[0020] In one embodiment of the flexible circuit board described above, the turning radius of the buffer section is determined according to the width of the connecting member.

[0021] In one embodiment of the flexible circuit board described above, the flexible circuit board further includes a support frame;

[0022] The support frame is provided with a through hole, the second end of the connecting member passes through the through hole, and the temperature acquisition member is disposed at the second end.

[0023] In a second aspect, the present invention provides a battery module, including a plurality of battery cells, a plurality of heat insulation members, and the flexible circuit board as described above;

[0024] The plurality of battery cells and the plurality of heat insulation members are sequentially arranged at intervals along a first direction. The flexible circuit board is arranged along a third direction with the plurality of battery cells and the plurality of heat insulation members, and the first direction is perpendicular to the third direction;

[0025] At least part of the end surface of the heat insulation member facing the large surface of the battery cell is provided with a groove, and the groove is provided with an opening corresponding to the flexible circuit board. The second end of the connecting member and the temperature acquisition member extend from the opening into the groove.

[0026] In one embodiment of the battery module described above, the groove includes:

[0027] A first groove for setting the connecting member;

[0028] A second groove is provided on a side of the first groove away from the large surface of the battery cell, and is used for arranging the temperature acquisition component.

[0029] The temperature acquisition component is arranged on a side of the connecting piece close to the second groove.

[0030] Based on the above battery module, it can be ensured that during the entire life cycle of the battery module, the temperature acquisition component is completely attached to the large surface of the battery cell under the action of compressive force. Moreover, since the heat insulation component made of foam material is relatively soft and the first groove and the second groove are designed, it can also provide good protection for the connecting piece and the temperature acquisition component, avoiding damage to the temperature acquisition component during vibration.

[0031] In an embodiment of the above battery module, the depth of the first groove is greater than the thickness of the connecting piece and less than the sum of the thickness of the connecting piece and the compression amount of the heat insulation component, where the compression amount of the heat insulation component is the compression amount of the heat insulation component along the first direction after the battery module is assembled; the depth of the second groove is greater than the thickness of the temperature acquisition component and less than the sum of the thickness of the connecting piece, the thickness of the temperature acquisition component, and the compression amount of the heat insulation component, where the compression amount of the heat insulation component is the compression amount of the heat insulation component along the first direction after the battery module is assembled.

[0032] In an embodiment of the above battery module, along the third direction, the size of the opening gradually increases in a direction close to the flexible circuit board.

[0033] In an embodiment of the above battery module, the length of the connecting piece is determined according to the height of the support frame and the battery cell.

[0034] In an embodiment of the above battery module, the battery module further includes:

[0035] Two end plates are arranged at both ends of the plurality of battery cells along the first direction, and the large surface of each battery cell faces the end plate.

[0036] One or more of the above technical solutions of the present utility model have at least one or more of the following beneficial effects:

[0037] In implementing the technical solution of the present utility model, a buffer notch is provided at the connection between the circuit board body and the connector on the circuit board body, and the size of the buffer notch is determined according to the size of the connector. Through the setting of the buffer notch, when the connector is subjected to a squeezing force opposite to its extending direction, it can form an avoidance for the connection part on the connector used to connect with the circuit board body, enabling the connector to move a certain distance along the direction of the squeezing force it receives. Thus, during the process of squeezing the connector into the box, the situation where the connection between the connector and the circuit board body is easily torn due to the resistance received by the temperature acquisition part and / or the connector itself can be reduced.

[0038] Additional aspects and advantages of the present utility model will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Referring to the accompanying drawings, the disclosure of the present utility model will become more understandable. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the protection scope of the present utility model. In addition, similar numbers in the drawings are used to represent similar components, where:

[0040] Figure 1 is a schematic structural diagram of the flexible circuit board according to the embodiment of the present application;

[0041] Figure 2 is a schematic structural diagram of the connection between the circuit board body and the connector according to the embodiment of the present application;

[0042] Figure 3 is a top view of a part of the flexible circuit board structure according to the embodiment of the present application;

[0043] Figure 4 is a side view of the flexible circuit board according to the embodiment of the present application;

[0044] Figure 5 is a front view of the connection between the circuit board body and the connector according to the embodiment of the present application;

[0045] Figure 6 is a schematic structural diagram of the integrated busbar acquisition component connected to one of the heat insulation parts according to the embodiment of the present application;

[0046] Figure 7 is Figure 6 a structural diagram from another angle;

[0047] Figure 8 is a schematic structural diagram of a part of the integrated busbar acquisition component according to the embodiment of the present application;

[0048] Figure 9Schematic structural diagram of the heat insulation member according to the embodiment of the present application;

[0049] Figure 10 Schematic structural diagram of the connecting member according to the embodiment of the present application inserted onto the heat insulation member between the large surfaces of two battery cells;

[0050] Figure 11 Schematic structural diagram of the battery module according to the embodiment of the present application;

[0051] Figure 12 Schematic structural diagram of the partial flexible circuit board structure with a buffer notch according to the embodiment of the present application.

[0052] Explanation of reference numerals

[0053] 1. Flexible circuit board; 11. Circuit board body; 111. Buffer notch; 1111. First notch part; 1112. Second notch part; 12. Connecting member; 121. Bending part; 122. Buffer section; 2. Support frame; 3. Temperature acquisition member; 4. Heat insulation member; 41. Groove; 411. First groove; 412. Second groove; 413. Buffer chamfer; 5. Battery cell; 6. End plate. Detailed implementation manners

[0054] Some implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.

[0055] Currently, in the temperature acquisition solution for the large surface of the battery cell, there is a problem that the connecting member connecting the temperature acquisition sensor (NTC) and the circuit board is prone to tearing at the connection with the circuit board due to its inability to freely extend.

[0056] Based on this, the present application provides a flexible circuit board and a battery module. A buffer notch is provided on the circuit board body at the connection between the circuit board body and the connecting member, and the size of the buffer notch is determined according to the size of the connecting member. Through the setting of the buffer notch, when the connecting member is subjected to a squeezing force opposite to its extending direction, it can form an avoidance for the connection part on the connecting member used to connect with the circuit board body, enabling the connecting member to move a certain distance along the direction of the squeezing force it receives. Thus, during the process of squeezing the connecting member into the box, the situation where the connection between the connecting member and the circuit board body is prone to tearing due to the resistance received by the temperature acquisition member and / or the connecting member itself is reduced.

[0057] The present application will be specifically elaborated through specific embodiments below.

[0058] Refer to Figures 1 to 8As shown, in a first aspect, this embodiment provides a flexible circuit board 1, which includes: a circuit board body 11; a buffer notch 111 disposed in the circuit board body 11; a connecting member 12 including a first end connected to the buffer notch 111 and a second end extending away from the circuit board body 11, and the size of the buffer notch 111 is determined according to the size of the connecting member 12; a temperature acquisition member 3 disposed at the second end of the connecting member 12 and electrically connected to the circuit board body 11 for detecting the large surface temperature of the battery cell 5.

[0059] For the flexible circuit board 1 provided in this embodiment, a buffer notch 111 is provided at the connection between the circuit board body 11 and the connecting member 12 on the circuit board body 11, and the size of the buffer notch 111 is determined according to the size of the connecting member 12. Through the setting of the buffer notch 111, when the connecting member 12 is subjected to a squeezing force in the direction opposite to its extending direction, it can form an avoidance for the connection part of the connecting member 12 used to connect with the circuit board body 11, enabling the connecting member 12 to move a certain distance along the direction of the squeezing force it receives, thereby reducing the occurrence of the situation that the connection between the connecting member 12 and the circuit board body 11 is easily torn due to the resistance received by the temperature acquisition member 3 and / or the connecting member 12 itself during the process of squeezing the connecting member 12 into the box.

[0060] In some embodiments, the connecting member 12 and the circuit board body 11 are integrally formed, and a bending portion 121 is provided at the first end of the connecting member 12. That is to say, the connecting member 12 and the circuit board body 11 can be an integral structure. By means of the bending portion 121 provided at the first end of the connecting member 12, the extending direction of the connecting member 12 forms a set angle with the plane where the circuit board body 11 is located. Specifically, the extending direction of the connecting member 12 is perpendicular to the plane where the circuit board body 11 is located, so that the connecting member 12 can be inserted between the large surfaces of two adjacent battery cells 5, and after the connecting member 12 is inserted in place, the circuit board body 11 can be attached to the end face of the battery cell 5, and the overall structure is more stable and reliable.

[0061] Continue to refer to Figure 3 and Figure 5As shown, the length of the buffer notch 111 extends in the first direction. The connecting member 12 is disposed at one end of the buffer notch 111 along the first direction, and the length L / R of the buffer notch 111 ≥ 1.5, where R is the bending radius of the bending portion 121. The first direction is the length direction of the circuit board body 11. The length L of the buffer notch 111 refers to the length of the buffer notch 111 extending in the direction perpendicular to the large surface of the battery cell 5. When the connecting member 12 is inserted between the large surfaces of two adjacent battery cells 5 and is subjected to a resistance in the opposite direction of its insertion direction, the bending portion 121 will deform or rotate. At this time, the length L of the buffer notch can be set to be greater than the turning radius R of the bending portion 121, so that when the bending portion 121 deforms or rotates, it can be avoided from colliding with the side of the buffer notch 111, thereby causing damage to the connecting member 12 and / or the circuit board body 11. Since the extending direction of the connecting member 12 is perpendicular to the plane where the circuit board body 11 is located, at this time, the bending portion 121 can be in the shape of a sector ring with a central angle of 90 degrees.

[0062] Continue to refer to Figure 3 and Figure 4 As shown, further, the width of the buffer notch 111 extends in the second direction. The connecting member 12 is disposed at the center of the buffer notch 111 along the second direction, and the width W of the buffer notch 111 satisfies: W ≥ 3D, where D is the width of the bending portion 121. The second direction is the width direction of the circuit board body 11. Specifically, the buffer notch 111 can be a rectangular notch with a length of L and a width of W. Due to the assembly deviation, the extrusion force cannot completely ensure that it is always along the thickness direction of the battery cell 5, that is, there is an extrusion angle, which will cause the bending portion 121 to be slightly distorted. Therefore, it is necessary to design the width W of the buffer notch 111. Specifically, the width W of the buffer notch 111 can be set to be greater than the width D of the bending portion 121, so as to avoid the connecting member 12 from colliding and wearing with the circuit board body 11, resulting in tearing of the connecting member 12.

[0063] Continue to refer to Figure 12As shown, further, the buffer notch 111 includes a first notch portion 1111 and a second notch portion 1112. The width of the first notch portion 1111 increases along the first direction. The second notch portion 1112 is connected to the end with a larger width of the first notch portion 1111 and its width remains unchanged along the first direction. And the connecting member 12 is disposed at the end of the first notch portion 1111 away from the second notch portion 1112. Wherein, W1>W2>2D, W1 is the maximum width of the first notch portion 1111, W2 is the width of the second notch portion 1112, and D is the width of the bending portion. By setting the relationship among the three, it is avoided that the buffer notch 111 is too large, which is not conducive to the wiring of the flexible circuit board 1. The notch is supplemented by the second notch portion 1112 to improve the strength of the flexible circuit board 1. At the same time, it is ensured that the width W2 of the second notch portion 1112>D to prevent the collision of the bending portion 121. Again, through the inclined side setting of the first notch portion 1111, compared with the right-angle side, tearing is further prevented.

[0064] In some embodiments, the size of the buffer notch 111 is determined according to the size of the connecting member 12; specifically, the size of the buffer notch 111 and the size of the connecting member 12 may conform to the relationships of Formula 1 and Formula 2 below;

[0065] W = Ψ * ln(D 2 - 0.36 * D + 1.35)------------------------------Formula 1;

[0066] L = ω * e 1.1*R3+0.42*R2-6.8*R+0.82 + 0.32----------------------------Formula 2;

[0067] Wherein, W is the width dimension of the buffer notch; D is the width dimension of the connecting member; R is the radius dimension of the bending portion; L is the length dimension of the buffer notch; Ψ is the distortion correction coefficient in the width direction of the connecting member assembly, which is related to the stacking and grouping deviation in the width direction of the battery module, and takes 1.01 to 1.25; ω is the length extension coefficient, which is positively correlated with the length compression amount, and takes 2 to 5.

[0068] Continue to refer to Figure 1 、 Figure 2 and Figure 4As shown, in some embodiments, the connecting member 12 has a buffer section 122 in a bent shape, and the buffer section 122 is located between the bent portion 121 and the temperature acquisition member 3; it should be noted that, as a buffer structure between the bent portion 121 and the second end, the buffer section 122 is not adhesively fixed to the groove 41; through the setting of the buffer section 122, when the battery cell 5 expands in thickness and the connecting member 12 is subjected to a pulling force, its bent shape can form an anti-pulling buffer structure, thereby preventing the bent portion 121 from being torn and damaged.

[0069] In some further embodiments, the buffer section 122 is at least one of an arc shape or an S shape. The buffer section 122 can also be formed by splicing an arc shape and an S shape, or can also be formed by splicing multiple arc-shaped or multiple S-shaped structures. As long as it can utilize its own deformable characteristics to solve the stress concentration problem at the connection between the connecting member 12 and the circuit board body 11 and achieve the effect of protecting the structural integrity of the connection between the connecting member 12 and the circuit board body 11.

[0070] Continue to refer to Figure 4 As shown, in some embodiments, the turning radius R' of the buffer section 122 is determined according to the width D of the bent portion 121; the turning radius R' of the buffer section 122 can have a linear relationship with the width D of the bent portion 121. Specifically, the dimensions of the two can conform to the relationship of the following formula three;

[0071] R’=k*D+b--------------------------------------Formula three;

[0072] Wherein, the linear coefficient k takes 2 to 5; b takes 0.5 to 0.8;

[0073] When the dimensions of the two conform to the relationship of the above formula three, the tearing problem at the connection between the connecting member 12 and the top circuit board body 11 caused by the movement of the connecting member 12 during the thickness expansion of the battery cell 5 can be avoided.

[0074] In some embodiments, the buffer notch 111 can be arrow-shaped. Among them, the tip of the arrow is a plane matching the width of the connecting member 12, and the tip of the arrow extends along an inclined plane to both sides, thereby forming an open structure for avoiding the connecting member 12. This can prevent the connecting member 12 from colliding with the buffer notch 111 when it shakes in the direction parallel to the large surface of the battery cell 5. At the tail end of the arrow, an open structure for avoiding the connecting member 12 can also be provided to ensure that the connecting member 12 collides with the buffer notch 111 when it deforms due to resistance when inserted between the large surfaces of two battery cells 5.

[0075] Continue to refer to Figures 6 to 8As shown, the flexible circuit board 1 also includes a support frame 2; a through hole is provided on the support frame 2, the second end of the connector 12 is arranged through the through hole, and the temperature collection component 3 is arranged at the second end; wherein, in the vertical direction, the projection of the through hole can coincide with the projection of the buffer notch 111 on the circuit board body 11, or the projection of the buffer notch 111 can be located within the range of the projection of the through hole, as long as it is ensured that the connector 12 can pass through the support frame 2 and extend between the large surfaces of two adjacent battery cells 5, and at the same time, the through hole can not be in direct contact with the connector 12 during the entire working process.

[0076] Continue to refer to Figures 9 to 11 As shown, in the second aspect, the utility model provides a battery module, which includes multiple battery cells 5, multiple thermal insulation members 4 and the above flexible circuit board 1; the multiple battery cells 5 and the multiple thermal insulation members 4 are arranged in sequence along a first direction, and the flexible circuit board 1 and the multiple battery cells 5 and the multiple thermal insulation members 4 are arranged along a third direction, and the first direction is perpendicular to the third direction, wherein the first direction may be a direction perpendicular to the large surface of the battery cell 5, and the third direction may be a vertical direction, that is, a direction perpendicular to the end surface of the battery cell 5; at least part of the thermal insulation member 4 is provided with a groove 41 on the end surface of the large surface facing the battery cell 5, and the groove 41 corresponds to an opening provided on the flexible circuit board 1, and the second end of the connecting member 12 and the temperature collecting member 3 extend from the opening into the groove 41.

[0077] Specifically, the thermal insulation member 4 can be a structure such as foam or thermal insulation board. The temperature collection member 3 is away from the top of the circuit board body 11 and is pressed against the large surface of the battery cell 5 through the thermal insulation member 4. The thermal insulation member 4 can protect the temperature collection member 3 and provide thermal insulation.

[0078] Furthermore, a groove 41 can be provided on each thermal insulation member 4, and a groove 41 can also be provided on thermal insulation members 4 separated by one or more thermal insulation members 4. That is to say, the connecting member 12 and the temperature collection member 3 can be provided in a one-to-one correspondence with each thermal insulation member 4, and can also be provided separated by one or more thermal insulation members 4. It should be noted that the connecting member 12 and the temperature collection member 3 are only connected to the thermal insulation member 4 provided with the groove 41.

[0079] Continue to refer to Figure 6 , Figure 9 and Figure 10As shown, in some embodiments, the groove 41 includes: a first groove 411 for arranging the connecting member 12; a second groove 412 which is arranged on a side of the first groove 411 away from the large surface of the battery cell 5 and is used for arranging the temperature acquisition member 3; the temperature acquisition member 3 is arranged on a side of the connecting member 12 close to the second groove 412; it should be noted that the second groove 412 can be formed on the surface of the first groove 411, that is to say, the first groove 411 for accommodating the connecting member 12 is formed between the groove 41 and the large surface of a battery cell 5, and the temperature acquisition member 3 is arranged on the side surface of the connecting member 12 facing the second groove 412, that is to say, the temperature acquisition member 3 and the battery cell 5 to be measured for temperature are respectively located on both sides of the connecting member 12.

[0080] Continue to refer to Figure 9 As shown, in some embodiments, along the third direction, the size of the opening on the groove 41 gradually increases towards the direction close to the flexible circuit board 1; specifically, a buffer chamfer 413 can be provided at the top of the groove 41, that is to say, the top surface of the heat insulation member 4 is smoothly transitioned with the first groove 411 through the buffer chamfer 413. Among them, the buffer chamfer 413 can be an oblique angle structure or a rounded corner structure. When the buffer chamfer 413 is an oblique angle structure, the slope angle of the buffer chamfer 413 can be 5-20°, and the maximum edge depth can be 0.5-1 mm. Through the setting of the buffer chamfer 413, when the connecting member 12 with the temperature acquisition member 3 is inserted into the first groove 411, the buffer chamfer 413 can guide the second end of the connecting member 12 and the temperature acquisition member 3, so that it can enter the first groove 411 more smoothly, thereby protecting the temperature acquisition member 3 and the connecting member 12. The buffer chamfer 413 can also form an avoidance gap between the heat insulation member 4 and the bending part 121, thereby avoiding collision between the heat insulation member 4 and the bending part 121.

[0081] Furthermore, the depth of the first groove 411 is greater than the thickness of the connecting member 12 and less than the sum of the thickness of the connecting member 12 and the compression amount of the heat insulation member 4; the compression amount of the heat insulation member 4 is the compression amount of the heat insulation member 4 along the first direction after the battery module is assembled; such a setting can ensure that the connecting member 12 is stably fixed between the first groove 411 and the battery cell 5 by the compressed heat insulation member 4, which can not only ensure the stability of the entire battery module, but also protect the connecting member 12. At the same time, it can also ensure that the connecting member 12 and the large surface of the battery cell 5 always remain in a fitting state, thereby improving the temperature detection accuracy.

[0082] In some embodiments, the depth of the second groove 412 is greater than the thickness of the temperature acquisition member 3 and less than the sum of the thickness of the connecting member 12, the thickness of the temperature acquisition member 3, and the compression amount of the heat insulation member 4. The compression amount of the heat insulation member 4 is the compression amount of the heat insulation member 4 along the first direction after the battery module is assembled. Specifically, the above-mentioned respective dimensions may conform to the relationships of Formula 4 to Formula 7.

[0083] △L = F / EX -------------------------------------- Formula 4;

[0084] EX = L / Σ(Li / EXi) -------------------------------------- Formula 5;

[0085] △LL = {△L - n*F / EX_cell - m*F / EX_poal1 - 2*F / EX_duan} / N -------- Formula 6;

[0086] (L5 - L2 - L3)*(η + μ) ≥ △LL ≥ λ*(L1 + L4 - L3) ------------------------ Formula 7;

[0087] Wherein, △L is the compression dimension of the battery module; F is the restraint force at the BOL stage (the initial stage of the life of the battery cell) of the battery cell module; EX is the comprehensive elastic modulus of the battery cell module; EXi is the elastic modulus of the end part, the heat insulation member, and the battery cell sub-component; L is the length dimension of the battery module; Li is the thickness dimension of the sub-component; △LL is the compression dimension of the heat insulation member with the temperature acquisition member; n is the number of battery cells in a single battery module; m is the number of heat insulation members without the temperature acquisition member in a single battery module; N is the number of heat insulation members with the temperature acquisition member in a single battery module; EX_cell, EX_poa l1, and EX_duan are the elastic moduli of the battery cell, the heat insulation member, and the end plate respectively; λ is the tolerance correction coefficient, taking 1.05 to 1.5; μ is the compression rate of the heat insulation member under the ultimate restraint force at the EOL stage (the end stage of the life of the battery cell); η is the durability aging attenuation factor of the heat insulation member; L1 is the difference between the depth of the first groove and the thickness of the connecting member; L2 is the thickness of the connecting member; L3 is the thickness of the temperature acquisition member; L4 is the depth of the second groove; L5 is the thickness of the heat insulation member.

[0088] Furthermore, since it is necessary to ensure that the temperature collection member 3 fits the large surface of the battery cell 5, firstly, the compression amount of the heat insulating member 4 must be greater than L1; secondly, the second groove 412 must fit the temperature collection member 3 to limit the left and right shaking of the temperature collection member 3 and ensure that the temperature collection member 3 fits the battery cell 5, that is, the compression amount L4-L3 needs to be increased on the basis of the compression amount L1. Since it is necessary to consider the tolerance assembly factor under the above principle conditions, a correction coefficient greater than 1 is introduced; it can be seen from the left side of Formula 7 (L5-L2-L3)*(η+μ), its result is The result is the remaining thickness of the thermal insulation component 4 except for the thickness of the collection connector 12 and the temperature collection component 3. Even if the thermal insulation component 4 is compressed, it is impossible to completely compress the remaining part. At the same time, the battery cell 5 will decay at the end of its life (EOL stage), and its restraint force will increase. That is to say, the battery cell 5 will expand, thereby increasing the degree of compression of the thermal insulation component 4. Moreover, the compressibility of the thermal insulation component 4 itself will decay with long-term aging. Therefore, considering the above principles and factors, the upper limit of the overall compression cannot exceed the value of (L5-L2-L3)*(η+μ).

[0089] Such an arrangement can ensure that the temperature collection component 3 and the large surface of the battery cell 5 are completely in contact with each other under the action of compression force during the entire life cycle of the battery module. In addition, since the thermal insulation component 4 made of foam material is relatively soft and is provided with the first groove 411 and the second groove 412, it can also provide better protection for the connector 12 and the temperature collection component 3, thereby preventing the temperature collection component 3 from being damaged during vibration.

[0090] In some further embodiments, the length of the connector 12 is determined according to the height of the support frame 2 and the battery cell 5; specifically, the length of the connector 12 may conform to the relationship of Formula 8 with the height of the support frame 2 and the battery cell 5;

[0091] H=τ*H_cell+H_SUPPORT----------------------------Formula 8;

[0092] Wherein, H is the length of the connector 12, H_cel is the height of the battery cell 5, H_SUPPORT is the height of the support frame 2, and τ is the depth coefficient of the temperature collection component 3, which is 1 / 2 to 3 / 4.

[0093] Among them, the depth coefficient of the temperature acquisition component 3 mainly considers the correction of the dimensional tolerances and assembly tolerances of various components, mainly to ensure that the temperature acquisition point is within the upper and lower ranges of the middle area of the battery cell 5; the selection of the acquisition point position is related to the cooling scheme. For example, in the bottom cooling scheme, since the temperature is relatively high near the upper part of the battery cell 5, it will be arranged at a position slightly above the center of the battery cell 5; in the top cooling scheme, the temperature at the bottom of the battery cell 5 is relatively high, and it will be arranged at a position slightly below the center of the battery cell 5.

[0094] Continue to refer to Figure 11 As shown, in some embodiments, the battery module further includes: two end plates 6, which are arranged at both ends of a plurality of battery cells 5 along the first direction, and the large surface of each battery cell 5 faces the end plate 6; it should be noted that the large surface of the battery cell 5 facing the end plate 6 means that it is in a parallel state with the end plate 6, so as to ensure the stability of the entire battery module when the two end plates 6 apply a squeezing force perpendicular to the large surface of the battery cell 5 to the stacked battery cells 5. The two end plates 6 only abut against the end faces of the two battery cells 5 located at the ends and apply a squeezing force to the side where the battery cells 5 are located, so that the heat insulation member 4 between all the battery cells 5 is squeezed into a compressed state, and then the entire length of the entire battery module is compressed to the length dimension for entering the box.

[0095] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0096] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0097] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A flexible circuit board, characterized in that, The flexible circuit board includes: A circuit board body; A buffer notch, provided in the circuit board body; A connecting member, including a first end connected in the buffer notch and a second end extending in a direction away from the circuit board body; A temperature acquisition member, provided at the second end and electrically connected to the circuit board body for detecting the large surface temperature of the battery cell.

2. The flexible circuit board according to claim 1, wherein The connecting member and the circuit board body are integrally formed, and a bending portion is provided at the first end of the connecting member.

3. The flexible circuit board according to claim 2, wherein, The length of the buffer notch extends in a first direction, the connecting member is provided at one end of the buffer notch along the first direction, and the length L of the buffer notch satisfies: L / R≥1.5, where R is the bending radius of the bending portion, and the first direction is the length direction of the circuit board body.

4. The flexible circuit board according to claim 2, wherein The width of the buffer notch extends in a second direction, the connecting member is provided at the center of the buffer notch along the second direction, and the width W of the buffer notch satisfies: W≥3D, where D is the width of the bending portion, and the second direction is the width direction of the circuit board body.

5. The flexible circuit board according to claim 3, characterized in that The buffer notch includes a first notch portion and a second notch portion. The width of the first notch portion increases along the first direction. The second notch portion is connected to the end with a larger width of the first notch portion and has a constant width along the first direction. The connecting member is provided at the end of the first notch portion away from the second notch portion. Wherein, W1>W2>2D, W1 is the maximum width of the first notch portion, W2 is the width of the second notch portion, and D is the width of the bending portion.

6. The flexible circuit board according to claim 2, wherein, The connecting member has a buffer section in a curved shape, and the buffer section is located between the bending portion and the temperature acquisition member.

7. A battery module, characterized in that, Comprising a plurality of battery cells, a plurality of heat insulation members, and a flexible circuit board according to any one of claims 1 to 6; The plurality of battery cells and the plurality of heat insulation members are sequentially arranged at intervals along a first direction. The flexible circuit board is arranged along a third direction with the plurality of battery cells and the plurality of heat insulation members. The first direction is perpendicular to the third direction; At least part of the end surface of the heat insulation member facing the large surface of the battery cell is provided with a groove, and the groove is provided with an opening corresponding to the flexible circuit board. The second end of the connecting member and the temperature acquisition member extend from the opening into the groove.

8. The battery module according to claim 7, wherein The groove includes: A first groove for setting the connecting member; A second groove, the second groove is provided on a side of the first groove away from the large surface of the battery cell and is used for setting the temperature acquisition member; The temperature acquisition member is provided on a side of the connecting member close to the second groove.

9. The battery module according to claim 8, wherein The depth of the first groove is greater than the thickness of the connecting member and less than the sum of the thickness of the connecting member and the compression amount of the heat insulation member, where the compression amount of the heat insulation member is the compression amount of the heat insulation member along the first direction after the battery module is assembled; the depth of the second groove is greater than the thickness of the temperature acquisition member and less than the sum of the thickness of the connecting member, the thickness of the temperature acquisition member, and the compression amount of the heat insulation member, where the compression amount of the heat insulation member is the compression amount of the heat insulation member along the first direction after the battery module is assembled.

10. The battery module according to claim 7, wherein, Along the third direction, the size of the opening gradually increases in the direction close to the flexible circuit board.

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