CN114284645A

CN114284645A - Integrated FPC assembly of power battery module and manufacturing method

Info

Publication number: CN114284645A
Application number: CN202110263493.8A
Authority: CN
Inventors: 吴永进; 王文宝; 洪诗阅; 宋悦明
Original assignee: Xiamen Bolion Tech Co ltd
Current assignee: Xiamen Bolion Tech Co ltd
Priority date: 2021-03-11
Filing date: 2021-03-11
Publication date: 2022-04-05

Abstract

The invention relates to an integrated FPC assembly of a power battery module and a manufacturing method thereof, wherein the power battery module is provided with a plurality of battery cores, the battery cores are transversely arranged into two rows, so that the expansion direction of the battery cores is consistent with the width direction of the power battery module, and the integrated FPC assembly comprises an upper-layer insulating film, an FPC acquisition line, a plurality of busbars and a lower-layer insulating film which are sequentially overlapped and laminated together from top to bottom. In the invention, the FPC acquisition line, the temperature sensor and the bus bar are highly integrated, and the degree of automation is high and the precision is good during assembly; and the insulation film is adopted to replace an injection molding isolation plate, so that the assembly is lighter and thinner, and the energy density of the battery can be effectively improved.

Description

Integrated FPC assembly of power battery module and manufacturing method

Technical Field

The invention belongs to the technical field of power batteries, and particularly relates to an integrated FPC assembly of a power battery module and a manufacturing method of the integrated FPC assembly.

Background

With the increasing of energy density of new energy power batteries and the increasing demand of technical development functions of BMS systems, voltage and temperature acquisition and monitoring are carried out on power battery modules for ensuring the safety of the power batteries. Due to the advantages of light weight, miniaturization, integration and safety of the FPC, the application of the FPC acquisition line is increased day by day.

The existing FPC acquisition lines are all placed on the injection molding isolation plate, the assembly formed by the mode is thick and heavy, and the defects of long development period, high cost, high flatness control difficulty of the isolation plate material and the like of the injection mold of the isolation plate exist.

Disclosure of Invention

The invention aims to provide an integrated FPC assembly of a power battery module and a manufacturing method thereof, so as to solve the problems. Therefore, the invention adopts the following specific technical scheme:

according to an aspect of the present invention, there is provided an integrated FPC assembly for a power battery module, wherein the power battery module has a plurality of battery cells, the plurality of battery cells are arranged in two rows in a transverse direction such that the expansion direction of the battery cells coincides with the width direction of the power battery module, the integrated FPC assembly includes an upper insulating film, an FPC pickup line, a plurality of bus bars, and a lower insulating film, which are stacked and laminated in this order from top to bottom, wherein the FPC pickup line is integrated with a connector, a voltage pickup terminal, and a temperature sensor, the voltage pickup terminal is welded to the bus bar to pick up the voltage of the battery cells, the temperature sensor is used to detect the temperature of the battery cells, the bus bar is used to connect the plurality of battery cells in series, and has electrode welding areas and protrusions between the electrode welding areas, the electrode welding areas are used to be welded to the electrodes of the battery cells, the upper and lower insulating films have fenestrations corresponding to desired exposed portions of the cells, the FPC pickup lines, and the bus bars.

Further, the FPC-integrated assembly may further include an intermediate insulating film between the FPC pickup line and the bus bar, the intermediate insulating film having a shape and a size substantially identical to those of the main body of the FPC pickup line.

Further, the inner surfaces of the upper insulating film and the lower insulating film are coated with thermosetting saturated resin glue, and the two sides of the middle insulating film are coated with thermosetting saturated resin glue.

Furthermore, the thickness of the thermosetting saturated resin adhesive is 30-50 microns.

Furthermore, the upper insulating film and the lower insulating film are made of PET insulating materials with the thickness of 0.07-0.25 mm.

Further, a plurality of the electric cores are connected in series in a zigzag manner, the busbar comprises an oblique busbar and a horizontal busbar, wherein the oblique busbar is used for connecting two adjacent electric cores in the width direction of the power battery module in series, and the horizontal busbar is used for connecting two adjacent electric cores in the length direction of the power battery module in series.

Furthermore, a plurality of slotted holes are formed between the two protrusions in the oblique busbar, so that the oblique busbar deforms along with the expansion of the battery core.

Furthermore, an electric core explosion-proof valve avoiding position is arranged on the oblique busbar.

Further, the oblique bus bar and the horizontal bus bar are made of 1060-O state aluminum.

According to another aspect of the present invention, there is also provided a method for manufacturing the FPC-integrated assembly for a power battery module, which may include the following steps:

preparing an upper insulating film and a lower insulating film, windowing and drilling positioning holes at corresponding positions of the upper insulating film and the lower insulating film, and coating thermosetting saturated resin glue on the inner surfaces of the upper insulating film and the lower insulating film;

preparing a pressing jig, wherein the pressing jig comprises an upper die and a lower die, an engraving and milling sinking is carried out on a bus bar protruding position corresponding area on the inner surface of the upper die and a bus bar corresponding area on the inner surface of the lower die by adopting an engraving and milling machine, and silica gel and glass fiber cloth are sequentially superposed on the inner surfaces of the upper die and the lower die;

assembling, namely assembling a positioning pin on a lower die, sequentially superposing a lower-layer insulating film, a busbar, an intermediate-layer insulating film, an FPC (flexible printed circuit) acquisition line and an upper-layer insulating film on the lower die from bottom to top through the positioning pin, and finally covering an upper die;

laminating, namely putting the assembled jig into a laminating machine for laminating, wherein the laminating temperature is 160-180 ℃, the laminating time is 600-1200 seconds, and the pressure is 5-20 kg/cm 2;

and laser welding, namely performing laser welding on the voltage acquisition end and the bus bar to obtain the integrated FPC assembly of the required power battery module.

By adopting the technical scheme, the invention has the beneficial effects that:

1) the FPC acquisition line, the temperature sensor and the bus bar are highly integrated, and the device is high in automation degree and good in precision during assembly.

2) The insulating film is adopted to replace an injection molding isolation plate, so that the assembly is lighter and thinner, and the energy density of the battery can be effectively improved.

3) The assembly processing cost is lower, especially long modules, and is particularly remarkable.

4) The subassembly roughness is high, has avoided the deformation warpage of injection molding etc. to lead to the installation component difficulty.

5) And an injection mold of the isolation plate is cancelled, so that the mold cost is reduced, and the development period is shortened.

Drawings

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

Fig. 1 is a schematic diagram of a cell arrangement of a power battery module;

fig. 2 is an exploded view of the integrated FPC assembly of the present invention applied to the power battery module shown in fig. 1;

fig. 3 is a plan view of an upper insulating film of the FPC integrated assembly of the power battery module shown in fig. 2;

fig. 4 is a top view of the FPC pickup lines of the FPC integrated assembly of the power battery module shown in fig. 2;

fig. 5 is a top view of an intermediate insulating film of the FPC integrated assembly of the power battery module shown in fig. 2;

fig. 6 is a schematic view of a bus arrangement of the FPC integrated assembly of the power cell module shown in fig. 2;

fig. 7 is a top view of the underlying insulating film of the FPC integrated assembly of the power battery module shown in fig. 2;

fig. 8 is an equivalent circuit diagram of a power battery module connected in series using the integrated FPC assembly of the power battery module shown in fig. 2;

fig. 9 is a schematic perspective view of an upper mold of a jig for manufacturing the FPC-integrated assembly of the power battery module shown in fig. 2;

fig. 10 is a schematic perspective view of a lower mold of a jig for manufacturing the FPC-integrated assembly of the power battery module shown in fig. 2;

fig. 11 is a schematic view illustrating lamination and bonding of the FPC integrated assembly of the power battery module shown in fig. 2.

Detailed Description

The invention will now be further described with reference to the accompanying drawings and detailed description.

Referring to fig. 1-7, an integrated FPC assembly 1 for a power battery module 100 is described. As shown in fig. 1, the power battery module includes a plurality of battery cells 101, and 6 battery cells 101 are taken as an example for description here. The 6 battery cells 101 are transversely arranged in two rows, so that the expansion direction of the battery cells 1 is consistent with the width direction of the power battery module 100, as shown by an arrow in fig. 1. Because only two electric cores 1 are arranged in the electric core expansion direction, the deformation of the battery module caused by the electric core expansion is small, the deformation of the battery module is controllable, and the safety coefficient of the battery module is greatly improved. The FPC-integrated assembly 1 may include an upper-layer insulating film 11, FPC collection lines 12, an intermediate insulating film 13, a plurality of bus bars 14, and a lower-layer insulating film 15, which are stacked and laminated in this order from top to bottom. The structures of the upper insulating film 11, the FPC pickup line 12, the intermediate insulating film 13, the plurality of bus bars 14, and the lower insulating film 15 will be described below.

The length and width dimensions of the upper insulating film 11 and the lower insulating film 15 substantially correspond to the length dimension of the power battery module 100, and the shape dimension of the intermediate insulating film 13 substantially corresponds to the shape dimension of the FPC pickup line. The upper insulating film 11 is arranged above the FPC acquisition line 12, the middle insulating film 13 is arranged between the FPC acquisition line 12 and the bus bar 14, and the lower insulating film 15 is arranged between the bus bar 14 and the battery cell 101, so that the battery cell 101, the FPC acquisition line 12 and the bus bar 14 are insulated from each other, and a short circuit phenomenon is avoided between the battery cell 101, the FPC acquisition line 12 and the bus bar 14. In the case where the FPC collection line 12 itself satisfies the requirement of the insulation strength, the intermediate insulation film 13 may be eliminated. The

insulating films

11, 13 and 15 are preferably made of 0.07-0.25 mm thick PET insulating material, and PEN, PI and other insulating materials can also be adopted according to the requirements of temperature-resistant environment and insulating strength. Preferably, the inner surfaces of the upper and lower

insulating films

11 and 15 may be coated with thermosetting saturated resin paste, and the intermediate insulating film 13 may be double-coated with thermosetting saturated resin paste to facilitate the press-filling. The thickness of the thermosetting saturated resin adhesive is preferably 30-50 um.

The upper-layer insulating film 11 and the lower-layer insulating film 15 have windows corresponding to desired exposed portions of the cell 101, the FPC pickup line 12, and the bus bar 13. Specifically, the upper-layer insulating film 11 and the lower-layer insulating film 15 are designed with

windows

111 and 151 corresponding to the bus bar and cell land areas to facilitate laser welding after combination;

windows

112 and 152 are designed in the area 1011 corresponding to the cell explosion-proof valve, so as to facilitate quick exhaust when the cell 101 is abnormal and avoid the exhaust from impacting the

insulating films

11 and 15; the

windows

113 and 153 are designed corresponding to the raised areas of the bus bars, so as to facilitate the lamination of the insulating films and ensure the quick heat dissipation of the bus bars in the battery module. Furthermore, the method is simple. The upper insulating film 11 is also provided with a window 114 at a bonding area corresponding to the voltage collecting terminal 121 of the FPC collecting line 12 and the bus bar 14, and after the combination, laser welding is performed to conduct the FPC collecting line 12 to the bus bar 14.

The upper insulating film 11, the lower insulating film 15 and the intermediate insulating film 13 are designed with

positioning holes

115, 154 and 131 for positioning and assembling the pressing jig pins 23 (see fig. 10) to ensure the assembly alignment precision.

The FPC collection line 12 is integrated with a connector 121, a voltage collection terminal 122, and a temperature sensor 123. The connector 121 is used for connecting a BMS system (not shown) of the power battery module, and the voltage collecting terminal 122 is welded to the bus bar 14 to collect the voltage of the battery core 101. The temperature sensor 123 is configured to detect a temperature of the battery cell 101. The temperature sensor 123 may adopt an NTC or PTC thermistor, and monitors the temperature of the battery cell through resistance value change.

The bus bar 14 is used for connecting a plurality of battery cells 101 in series, and in the present embodiment, the plurality of battery cells 101 are connected in series in a zigzag manner, and an equivalent circuit thereof is shown in fig. 8. The Z-shaped serial connection is adopted, so that the pressure difference between two adjacent battery cores 101 is small, and the risk of large current and thermal runaway caused under abnormal conditions is reduced. The bus bars 14 are preferably 1-3 mm aluminum bars, wherein the series bus bars 141 and 142 are preferably made of 1060-O state aluminum; the total positive and

negative output electrodes

143 and 144 are preferably made of 1060-H aluminum, and copper bars may be selected according to the current.

The series bus bar may include an oblique bus bar 141 and a horizontal bus bar 142, wherein the oblique bus bar 141 is used for connecting two adjacent battery cells 101 in the width direction of the power battery module 100 in series, and the horizontal bus bar 142 is used for connecting two adjacent battery cells 101 in the length direction of the power battery module 100 in series. The oblique bus bar 141 and the horizontal bus bar 142 may each include two

electrode lands

1411, 1421 and two

protrusions

1412, 1422 between the two electrode lands. The electrode lands 1411 and 1421 are circular and are used for welding with electrodes of the battery cell. The

protrusions

1412 and 1422 are arc-shaped, and when the cell expands in the charging and discharging process, the

protrusions

1412 and 1422 can stretch and deform along with the expansion stress of the cell, so that the phenomenon that the electrode welding area generates stress concentration to cause desoldering is avoided. The two protrusions 1412 of the oblique bus bar 141 are arranged in parallel, and the two protrusions 1422 of the horizontal bus bar 142 are arranged in a splayed shape. In addition, the oblique bus bar 141 is further provided with a plurality of slots 1413 between the two protrusions 1412, and the slots 1413 have the same function as the protrusions 1412.

Preferably, the oblique busbar 141 is provided with an avoidance position 1414 in a region corresponding to the explosion-proof valve 1011, so as to facilitate quick exhaust of the abnormal cell explosion-proof valve and avoid impact of the exhaust on the busbar.

Referring to fig. 9-11, a method for manufacturing the FPC-integrated assembly 1 for a power battery module as described above will be described, which may include the following steps:

1. an upper-layer insulating film 11, an intermediate-layer insulating film 13 and a lower-layer insulating film 15 are prepared, specifically, a window is opened and a positioning hole is drilled at corresponding positions of the upper-layer insulating film 11 and the lower-layer insulating film 12 and thermosetting type saturated resin glue is coated on the inner surfaces thereof, and a positioning hole is drilled on the intermediate-layer insulating film 13 and thermosetting type saturated resin glue is coated on the upper and lower surfaces thereof. Note here that in the case where the insulation strength of the FPC collecting line 12 itself satisfies the requirement, the intermediate insulating film 13 may be eliminated.

2. And preparing a pressing jig which can comprise an upper die 21 and a lower die 22, wherein the upper die 21 and the lower die 22 can be made of aluminum materials with the thickness of 5-25 mm or high-temperature-resistant materials such as FR4 and the like. As shown in fig. 9, the inner surface (lower surface) of the upper mold 21 is carved and milled in the corresponding area 211 of the bus bar protrusion position by using a carving machine, the sinking depth is consistent with the height of the

bus bar protrusions

1412 and 1422, and pin positioning holes 212 are formed in the positioning holes of the bus bar 14, the FPC collection line 12 and the

insulation films

11, 13 and 15, so as to ensure the assembly precision of the upper mold and the lower mold of the press-fit jig. Similarly, as shown in fig. 10, the inner surface (upper surface) of the lower mold 22 is engraved and sunk in the bus bar corresponding region 221 by using an engraving machine, the sinking depth is consistent with the thickness of the bus bar 14 (i.e., 141 and 144), and the pins 23 are disposed at the positioning holes of the bus bar 14, the FPC collecting line 12, and the insulating

films

11, 13, and 15.

As shown in fig. 11, the upper and lower dies 21 and 22 are used for placing a buffering adhesive material such as a silicone pad 24 for laminating and filling adhesive, so as to ensure that the pressed material is pressed tightly and uniformly. The buffering adhesive material is preferably silica gel with the thickness of 1.5-3.0 mm, and the silica gel 24 is provided with a pin positioning hole. Further, glass fiber cloth 25 is placed on the silica gel 24, a Teflon layer is coated on the glass fiber cloth, smooth separation of the pressed product and the jig after pressing is ensured, and pin positioning holes are formed in the glass fiber cloth.

3. Assembling, fitting a positioning pin on the lower die 22, then stacking the lower layer insulating film 15, the bus bar 14, the interlayer insulating film 13, the FPC collecting line 12 and the upper layer insulating film 11 on the lower die 22 in this order from bottom to top through the positioning pin, and finally covering the upper die 21, as shown in fig. 11.

4. And (3) laminating, namely putting the assembled laminating jig into a laminating machine for laminating, wherein the laminating temperature is 160-180 ℃, the laminating time is 600-1200 seconds, and the pressure is 5-20 kg/cm 2.

5. And (3) laser welding, namely laser welding the voltage acquisition end 121 and the bus bar 14 to realize the electrical conduction of the assembly, so as to manufacture the integrated FPC assembly of the required power battery module.

The whole manufacturing process is very simple and convenient, the FPC acquisition line, the temperature sensor and the bus bar are highly integrated, and the degree of automation is high and the precision is good during assembly; and the insulation film is adopted to replace an injection molding isolation plate, so that on one hand, the assembly is lighter and thinner, and the energy density of the battery can be effectively improved; and on the other hand, an injection mold of the isolation plate is cancelled, so that the mold cost is reduced, and the development period is shortened.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An integrated FPC assembly of a power battery module, wherein the power battery module has a plurality of battery cells, and the plurality of battery cells are transversely arranged in two rows, so that the expansion direction of the battery cells is consistent with the width direction of the power battery module, the integrated FPC assembly comprises an upper insulating film, an FPC acquisition line, a plurality of busbars and a lower insulating film which are sequentially overlapped and laminated together from top to bottom, wherein the FPC acquisition line is integrated with a connector, a voltage acquisition end and a temperature sensor, the voltage acquisition end is welded with the busbars to acquire the voltage of the battery cells, the temperature sensor is used for detecting the temperature of the battery cells, the busbars are used for serially connecting the plurality of battery cells together and are provided with electrode welding areas and bulges positioned between the electrode welding areas, and the electrode welding areas are used for welding with the electrodes of the battery cells, the upper and lower insulating films have fenestrations corresponding to desired exposed portions of the cells, the FPC pickup lines, and the bus bars.

2. The FPC assembly of claim 1, further comprising an intermediate insulating film between the FPC pickup lines and the bus bars, the intermediate insulating film having a shape and size that substantially conforms to a shape and size of the main body of the FPC pickup lines.

3. The FPC assembly for integrating a power battery module according to claim 2, wherein inner surfaces of the upper insulating film and the lower insulating film are coated with thermosetting saturated resin paste, and both surfaces of the intermediate insulating film are coated with thermosetting saturated resin paste.

4. The FPC assembly of claim 3, wherein the thermosetting saturated resin adhesive has a thickness of 30-50 μm.

5. The integrated FPC assembly of a power battery module according to claim 2, wherein the upper insulating film and the lower insulating film are made of PET insulating material with a thickness of 0.07-0.25 mm.

6. The integrated FPC assembly of the power battery module of claim 1, wherein the plurality of cells are connected in a zigzag manner, and the bus bar comprises an oblique bus bar and a horizontal bus bar, wherein the oblique bus bar is used for connecting two adjacent cells in a width direction of the power battery module in series, and the horizontal bus bar is used for connecting two adjacent cells in a length direction of the power battery module in series.

7. The FPC assembly of claim 6, wherein a plurality of slots are formed in the oblique bus bar between two protrusions, so that the oblique bus bar deforms along with the expansion of the battery cells.

8. The integrated FPC assembly of the power battery module of claim 6, wherein a cell explosion-proof valve avoidance is disposed on the oblique busbar.

9. The FPC assembly for integrating a power battery module according to claim 6, wherein the oblique bus bar and the horizontal bus bar are made of 1060-O state aluminum.

10. The manufacturing method of the FPC assembly integrated of the power battery module as recited in claim 1, comprising the following steps: