WO2021179733A1

WO2021179733A1 - Soft packing battery module and assembly method therefor

Info

Publication number: WO2021179733A1
Application number: PCT/CN2020/138353
Authority: WO
Inventors: 李峥; 冯玉川; 高伟; 何泓材; 陈凯; 杨帆
Original assignee: 苏州清陶新能源科技有限公司
Priority date: 2020-03-13
Filing date: 2020-12-22
Publication date: 2021-09-16
Also published as: CN111341954B; CN111341954A

Abstract

Provided are a soft packing battery module and an assembly method therefor. The soft packing battery module comprises a cell group (7), and left and right side panels (11, 15), upper and lower cover panels (1, 8), and front and rear end covers arranged on external sides of the cell group (7); the left and right side panels (11, 15) and the upper and lower cover panels (1, 8) or the left and right side panels (11, 15) and front and rear side panels may push hard against the internal cell group (7) by means of adjustable and removable engagement and connection, such that the left and right side panels (11, 15) are continuously restricted by the upper and lower cover panels (1, 8) or the left and right side panels (11, 15) to produce a pressure for clamping the cell group (7), thereby pushing hard on the cell group (7), the pressure being 5 kPa-300 kPa; the left and right side panels (11, 15), the upper and lower cover panels (1, 8), and the front and rear end covers are all detachably connected so as to encapsulate the cell group (7) to form the soft packing battery module; the cell group (7) comprises a foam, the left and right side panels (11, 15) are in a direction parallel to or consistent with that of the plane of the cell plates, and the front and rear side panels are perpendicular to the left and right side panels (11, 15) and the horizontal plane.

Description

Soft pack battery module and its assembling method

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office with an application number of 202010176515.2 on March 13, 2020. The entire content of this application is incorporated into this application by reference.

Technical field

This application relates to the field of battery technology, and relates to a soft-packed battery module and an assembly method thereof, for example, to a soft-packed battery module that is convenient for pre-tightening and assembly.

Background technique

As the core component of today's new energy vehicles, the performance of lithium-ion power batteries directly determines the key to the development of new energy vehicles. When a lithium-ion battery is charged, lithium ions are extracted from the positive electrode and inserted into the graphite of the negative electrode, and the negative electrode expands; during discharge, lithium ions are extracted from the negative electrode and inserted into the layered positive electrode material, and the negative electrode expansion is relieved; at the same time, during the aging process of the battery, the electrolyte Gas will be generated and the thickness of the battery will increase. This not only affects the electrochemical performance and service life of the battery, but also has a great impact on the reliability design of the module. Experiments have shown that applying a certain pre-tightening force to the battery cell has a greater improvement in performance retention and cycle life compared to no pre-tightening force.

In the actual assembly process, it is necessary to first add the battery cell to the outer frame, and then apply a pre-tightening force to the outer frame from the side.

The outer frame design needs to meet both the ease of assembly and the ability to apply pre-tightening force well. The outer frame structure of the soft pack battery module generally has "n", "u, and "mouth"; the above three structures have some technical and structural defects. In order to enable the outer frame to continuously apply pretension to the cells, the electric The technical solution that the size of the core is equivalent to the inner size of the outer frame or even slightly larger than the size of the outer frame is advantageous, but in actual operation, if the size of the cell is greater than or equal to the size of the outer frame, the outer frame structure and the cell are both rigid The structure and the elastic deformation are small. Therefore, the installation is very difficult. It is difficult to put the battery cell into the outer frame by manpower. If mechanical force is applied by mechanical tooling, on the one hand, it is easy to cause damage to the outer frame or the battery cell, on the other hand, It is difficult for tooling to enter or withdraw from the outer frame. This defect is particularly prominent in the "mouth"-shaped outer frame.

If the cell size is smaller than the outer frame size, although the assembly efficiency can be improved, in this case, a considerable part of the pre-tightening force is absorbed by the outer frame, and the effect of the pre-tightening force is not good. After the outer frame absorbs the pre-tightening force, there is no internal Applying the corresponding pressure can easily cause deformation, causing the product to fail to meet the design requirements.

Therefore, for the three outer frame structures of "n", "u", and "口", the assembly efficiency and the effective application of preload are an irreconcilable contradiction.

CN109346630A discloses a soft pack battery module structure, which includes an aluminum shell outer frame and an integrally formed reverse S-shaped aluminum plate. The upper end surface, the lower end surface and the opening position of the reverse S-shaped aluminum plate are filled with a soft package battery core group The soft-pack battery pack includes two soft-pack batteries; the soft-pack battery and the reverse S-shaped aluminum plate are fixed and inserted into the outer frame of the aluminum shell as a whole, and the sides of the reverse S-shaped aluminum plate and the aluminum shell The inner side of the frame is in contact; one end of the outer frame of the aluminum shell is provided with an integrated cover plate, and the tabs of the soft-packed batteries are embedded in the integrated cover plate and led out through the insulating plate, and then pass through the right insulating cover plate and the right fixed end The plate is fixed and sealed; the other end of the outer frame of the aluminum shell is fixed and sealed by the left insulating cover plate and the left fixed end plate; the reverse S-shaped aluminum plates are all integrally formed. The soft pack battery has a simple assembly process, is easy to operate, and improves the production efficiency of the product.

CN109411667A discloses a soft pack battery module, comprising: a bottom plate, a protective frame assembly, at least two soft pack cells arranged in parallel, at least one first insulating plate, at least one second insulating plate, and at least one The first bus bar of the positive poles of the two soft-packed batteries and at least one second bus bar for leading out the negative poles of the at least two soft-packed batteries, the protection frame assembly is arranged on the bottom plate, and the first bus An insulating plate, the second insulating plate, the first bus bar and the second bus bar are all arranged on the bottom plate, and spacers for heat insulation are provided between at least two soft-packed cells, The bottoms of at least two soft-pack batteries are connected to the bottom plate through a thermally conductive adhesive material, and the positive ears of at least two soft-pack batteries are connected to the first side surface of the first busbar through a first adhesive, and at least two The negative ear of a soft-packed battery cell is connected to the first side surface of the second bus bar through the first adhesive, and the second side surface of the first bus bar is insulated from the first side through the first adhesive The first side surface of the board is fixedly connected, the second side surface of the second bus bar is fixedly connected to the first side surface of the second insulating board through the first adhesive, and the second side surface of the first insulating board is fixedly connected to the The second side surfaces of the second insulating board are respectively fixedly connected to the inner side of the protection frame assembly by a second adhesive. The gap between the insulating plate and the bus bar of the soft-packed battery module, and the gap between the bus bar and the soft-packed cell is filled with a first adhesive, the insulating plate and the side plate are bonded together by a second adhesive, and the first adhesive and The second adhesive can replace the outer frame and other fixing structural parts in the battery module, and not only ensures the fixing of the battery module structure, but also greatly reduces the weight of the soft-packed battery module. However, it only uses the exploded diagram to reveal the positional relationship of the multiple modules of the module, and does not involve the connection relationship of the multiple modules of the module, nor can it overcome the problem of the module's inability to install and pre-tighten.

Summary of the invention

The present application provides a soft-pack battery module and an assembly method thereof, for example, provides a soft-pack battery module that is convenient for pre-tightening and assembly.

The present application provides a soft-packed battery module. The soft-packed battery module includes a battery cell group, left and right side plates, upper and lower cover plates, and front and rear side plates arranged on the outside of the battery core group. The left and right side plates include The left side panel and the right side panel, the upper and lower cover panels include an upper cover panel and a lower cover panel, and the front and rear side panels include a front side panel and a rear side panel;

The left and right side plates are detachably connected with the upper and lower cover plates by interference fit, or the left and right side plates are detachably connected with the front and rear side plates by interference fit, so that the left and right side plates are continuously constrained by the upper and lower cover plates or the front and rear side plates. Clamp the pressure of the battery pack to tighten the battery pack, the pressure is 5-300kPa;

The left and right side plates, the upper and lower cover plates, and the front and rear side plates can be detachably connected to encapsulate the battery pack to form a soft pack battery module;

The battery cell group includes foam, the left and right side plates are in a direction parallel or consistent with the plane of the battery sheet, and the front and rear side plates are perpendicular to the left and right side plates and the horizontal plane.

The present application provides a method for assembling the above-mentioned soft-pack battery module, and the method includes:

Lay the left side board and the right side board on the side of the battery cell group respectively, and apply a pre-tightening force in the width direction of the module to clamp;

Under the condition of maintaining the clamping, the upper cover and the lower cover are detachably connected to the left and right panels, or the front and rear panels are connected to the left and right panels, respectively Make a detachable connection;

Release the clamping. At this time, the upper and lower cover plates and the left and right side plates are in a tightly fitted state and have been pre-tightened, so that the left and right side plates continue to receive the pressure from the upper and lower cover plates to the battery core. The pressure is 5kPa-300kPa. Continue to connect so that the left side The board, the right side board, the upper cover board, the lower cover board, the front side board and the rear side board can all be detached and connected to form a soft pack battery module.

Description of the drawings

Figure 1 is an exploded view of the detachable module of this application;

FIG. 2 is a schematic diagram of a snap-fit structure adopted for connecting the upper and lower cover plates and the left and right side plates of the detachable module of the present application;

Figure 3 is a schematic diagram of the structure of the FPC assembly board of the present application;

4 is a schematic diagram of the structure of the front cover assembly plate of the present application;

Figure 5 is a schematic diagram of the structure of the front end cover assembly plate of the present application;

Figure 6 is the stress-strain fitting curve of PU foam used to calculate the foam pre-tightening compression x%;

Among them, 1-upper cover, 2-FPC assembly board, 3-rear cover assembly board, 4-rear cover assembly board, 5-right side board, 6-thermal conductive structural adhesive, 7-cell group, 8- Lower cover, 9-Front cover assembly board, 10-Front cover assembly board, 11-Left side board, 12-Voltage acquisition sheet, 13-Temperature acquisition sheet, 14-Limit structure, 15-Flexible circuit board, 16 -FPC support board, 17-copper bar, 18-board slot, 19-insulation board, 20-end cover, 21-insulation board, 22-coordination structure.

Detailed ways

The technical solutions of the present application will be described below in conjunction with the drawings and through implementations.

In the description of this application, the terms "upper", "lower", "left", "front", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for ease of description This application and the simplified description do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the application.

Example 1

This embodiment provides a soft-packed battery module, which relates to a detachable module. The exploded view of the soft-packed battery module is shown in FIG. The left and right side plates, the upper and lower cover plates and the front and rear side plates on the outer side of the battery pack 7;

The left and right side panels include a left side panel 11 and a right side panel 5 arranged oppositely, the upper and lower cover panels include an upper cover panel 1 and a lower cover panel 8 arranged oppositely, and the front and rear side panels include: front end covers arranged oppositely The assembly board 10 (see Figure 5 for the structural diagram) and the rear cover assembly plate 3, and the front cover assembly board 9 (see Figure 4 for the structural schematic diagram) and the rear cover assembly board 4 arranged oppositely, and the front cover assembly The plate 9 and the rear cover assembly plate 4 are respectively located on the side of the front cover assembly plate 10 and the rear cover assembly plate 3 close to the battery cell group;

In the soft pack battery module of the present application, the left and right side plates are continuously constrained by the upper and lower cover plates to generate pressure for clamping the battery cells. The pressure is 5kPa-300kPa (for example, 5kPa, 10kPa, 20kPa, 30kPa, 40kPa, 50kPa, 60kPa, 70kPa, 80kPa, 100kPa, 135kPa, 160kPa, 200kPa, 240kPa, 265kPa or 290kPa, etc.), in order to better take into account the structural rigidity, processing feasibility and pre-tightening effect, you can choose 10-100kPa, and then choose 20 -50kPa.

In the soft-pack battery module of the present application, the battery cell group 7 includes a plurality of (that is, at least two) battery cells, at least two battery cells are a group, and foam is arranged at intervals between each group of battery cells.

In the soft pack battery module of the present application, the left and right side plates and the upper and lower cover plates or the left and right side plates and the front and rear side plates are connected in an adjustable and detachable manner to tighten the internal battery pack, the left and right side plates and the interior containing foam The battery pack is in a clamped state, and the upper and lower cover plates or the front and rear side plates are detachably connected with the left and right side plates by interference fit, so that the left and right side plates are continuously restrained by the upper and lower cover plates or the front and rear side plates to generate pressure to clamp the batteries. The left and right side plates transmit the pressure to the battery core, so that the battery core is always subjected to corresponding pre-tightening pressure during the assembly process, which effectively overcomes the problems caused by the expansion of the battery core.

In this application, the left side plate 11 and the right side plate 5 are arranged oppositely, the upper cover plate 1 and the lower cover plate 8 are arranged oppositely, and the front side plate and the rear side plate are arranged oppositely.

Optionally, the front and rear side panels are in any one of the following two forms:

First, the front and rear side panels are front and rear end cover assembly plates, and the front and rear end cover assembly plates are the front end cover assembly plate 10 and the rear end cover assembly plate 3 that are opposed to each other;

Second, the front and rear side panels include: a front cover assembly plate 10 and a rear cover assembly plate 3 arranged opposite, and a front cover assembly plate 9 and a rear cover assembly plate 4 arranged oppositely, and the front cover plate The assembly board 9 and the rear cover assembly board 4 are respectively located on the side of the front cover assembly board 10 and the rear cover assembly board 3 close to the battery cell group 7.

Optionally, the front cover assembly board 9 includes a copper bar 17 and a board slot 18 supporting the copper bar 17, the battery pack 7 is connected to the copper bar to form a complete circuit loop, and the board slot 18 is arranged in In the front cover assembly board 9, the plate slot 18 functions to support the copper bar 17, and at the same time isolates the copper bar 17 and the battery core lugs to prevent the copper bar 17 from contacting the battery lugs.

Optionally, the front end cover assembly plate 10 is composed of a front end cover and an insulating plate 19, and the insulating plate 19 is arranged to physically isolate the copper bars 17 to prevent leakage and short circuit.

Optionally, the rear cover assembly board 4 includes a copper bar 17 and a board slot 18 supporting the copper bar 17. The battery pack 7 is connected to the copper bar 17 to form a complete circuit loop, and the board slot 18 is provided In the rear cover assembly board 4, the plate slot 18 functions to support the copper bar 17, and at the same time isolate the copper bar 17 and the battery core lugs to prevent the copper bar 17 from contacting the battery lugs.

Optionally, the rear cover assembly plate 3 is composed of a rear cover and an insulating plate 19, and the insulating plate 19 is arranged to physically isolate the copper bars 17 to prevent leakage and short circuit.

The present application does not limit the detachable connection mode, and it may be a common connection mode in related technologies, such as a conventional mechanical fitting mode, which may optionally include buckle, snap, or bolt and/or nut connection. Taking the connection between the left and right side plates and the upper and lower cover plates as an example, the contact part of the upper cover plate 1 and the side plates can be set as a bent part, and the distance between the two bent parts of the cover plate is slightly smaller than that of the entire module. With lateral width, the upper cover plate 1 and the side plates form an interference fit to form a compact structure. It is also possible to provide protrusions on the upper cover plate 1 and the lower cover plate 8 (the shape is not limited, such as a cone), and the left and right side plates are provided with grooves capable of accommodating the protrusions, so that the upper and lower cover plates can interact with the side plates. Make a snap.

Optionally, the joints formed by the detachable connection of the left and right side plates and the upper and lower cover plates/front and rear side plates are also connected by welding to ensure that the frame structure will not fail due to the expansion and deformation of the batteries at the end of the battery life. The welding includes laser welding.

Optionally, an FPC assembly board is further provided between the upper cover plate 1 and the battery cell group 7. The FPC assembly board includes a flexible circuit board 15 and an FPC support board 16, and a limit structure 14 is provided on the FPC support board 16. , The limiting structure 14 is configured to fix the flexible circuit board 15, and the flexible circuit board 15 is provided with a temperature collecting sheet 13 and a voltage collecting sheet 12.

Optionally, the FPC assembly board is detachably connected to the upper cover 1 by one of hot melt, snaps, and glue.

The connection mode of the temperature collecting piece 13 and the voltage collecting piece 12 and the flexible circuit board 15 and the selection of the setting position are known, and can be selected according to the assembly requirements of the battery module. Optionally, the connection can be made by welding.

Optionally, a heat insulation plate 21 is further provided between the left side plate 11 and the battery pack 7, and the heat insulation plate 21 and the left side plate 11 are connected by a thermally conductive structural glue 6.

Optionally, a heat insulation plate 21 is further provided between the right side plate 5 and the battery pack 7, and the heat insulation plate 21 and the right side plate 5 are connected by a thermally conductive structural glue 6.

By arranging the heat insulation plate 21 between the left and right side plates and the battery pack 7, it is possible to avoid the impact of high temperature on the performance of the battery core during the welding (for example, laser welding) process of the left and right side plates and the upper and lower cover plates or the front and rear cover assembly plates.

Optionally, the heat insulation board 21 is made of a high temperature resistant material, which may be mica flakes or an aerogel with heat insulation, which can withstand high temperatures of 1000° C. for a short time and high temperatures above 500° C. for a long time.

The soft-pack battery module of the present application forms a whole with a certain strength and rigidity through welding and gluing, so as to ensure the overall reliability of the module.

Optionally, the left and right side plates, the upper and lower cover plates, the front end cover, and the rear end cover are made of aluminum materials, optionally high-strength aluminum materials, and the high-strength aluminum materials meet the following two points: first, left and right side panels and When the upper and lower cover plates or the front and rear end cover assembly plates are interference fit, suitable deformation occurs; second, the upper and lower cover plates or the front and rear end plates are detachably connected to the left and right side plates without deformation when pressure is applied to the high-strength aluminum material. .

Optionally, the left and right side plates are formed by stamping or extrusion.

Optionally, the upper and lower cover plates are formed by stamping or bending.

Optionally, the front end cover and the rear end cover are formed by extrusion or casting.

As an optional technical solution of the soft-pack battery module described in the present application, the width of the upper and lower cover plates can be adjusted according to the pre-tightening requirements of the battery pack 7 and the foam.

The front cover assembly board 9 includes a copper bar 17 and a board slot 18 supporting the copper bar 17. The battery pack 7 is connected to the copper bar 17 to form a complete circuit loop. The board slot 18 is provided on the front cover. The assembly board 9 plays a role of supporting the copper bar 17 and at the same time isolates the copper bar 17 and the battery core tabs to prevent the copper bar 17 from contacting the battery tabs.

The front end cover assembly plate 10 is composed of an end cover 20 and an insulating plate 19, and the insulating plate 19 physically isolates the copper bars 17 to prevent leakage and short circuit.

The rear cover assembly board 4 includes a copper bar 17 and a board slot 18 supporting the copper bar 17. The battery pack 7 is connected to the copper bar 17 to form a complete circuit loop, and the board slot 18 is provided on the back cover. The assembly board 4 plays a role of supporting the copper bar 17 and at the same time isolates the copper bar 17 and the battery core lugs to prevent the copper bar 17 from contacting the battery lugs.

The rear cover assembly plate 3 is composed of an end cover 20 and an insulating plate 19, and the insulating plate 19 physically isolates the copper bars 17 to prevent leakage and short circuit.

A Flexible Printed Circuit (FPC) assembly board 2 is also provided between the upper cover plate 1 and the battery cell group 7 (see Figure 3 for the structure diagram), and the FPC assembly board 2 includes a flexible circuit board 15 and an FPC support board. 16. A limit structure 14 is provided on the FPC support board 16, and the limit structure 14 is set as a fixed flexible circuit board 15. The flexible circuit board 15 is provided with a temperature acquisition sheet 13 and a voltage acquisition sheet 12, the temperature acquisition The slice 13 is configured to collect temperature information, and the voltage collection chip 12 is configured to collect voltage information.

A heat insulation plate 21 is provided between the left side plate 11 and the right side plate 5 and the battery pack 7 respectively, and the heat insulation plate 21 is connected to the left side plate 11 and the right side plate 5 by a thermally conductive structural adhesive 6.

The left and right side plates and the upper and lower cover plates are connected by a snap-fit structure (see Figure 2 for a structural diagram), so that the left and right side plates are continuously subjected to the pressure of the upper and lower cover plates pointing towards the battery cell group, thereby pressing the battery cell group. The pressure is 5kPa-300kPa.

The left and right side plates, the upper and lower cover plates, and the front and rear side plates are all connected by a clamping structure to encapsulate the battery pack to form a soft pack battery module.

The battery pack 7 includes foam, the left and right side plates are in a direction parallel or consistent with the plane of the battery sheet, and the front and rear side plates are perpendicular to the left and right side plates and the horizontal plane.

Example 2

This application provides the method for assembling the above-mentioned soft-pack battery module, and the method includes the following steps:

(1) Stack the left side board and the right side board on the side of the battery pack, and apply a pre-tightening force in the width direction of the module to clamp.

(2) While maintaining the clamping condition, connect the upper cover and the lower cover to the left and right panels respectively, or connect the front and rear panels to the left and right panels, respectively. The right side panel is detachably connected.

(3) Release the clamping. At this time, the upper and lower cover plates and the left and right side plates are in a tightly fitted state and have been pre-tightened, so that the left and right side plates are continuously subjected to the pressure from the upper and lower cover plates to the battery core, and the pressure is 5kPa-300kPa, continue to connect The left side panel, the right side panel, the upper cover panel, the lower cover panel, the front side panel and the rear side panel can all be detached and connected to form a soft pack battery module.

The step (3) of this application is explained as follows: if step (2) connects the left side panel and the right side panel to the upper cover and the lower cover, here at least the front side panel and the rear side panel are connected to the left side panel respectively. The board and the right board are detachably connected; if step (2) connects the left board and the right board to the front side board and the rear side board, at least the upper cover and the lower cover are connected to the left The board and the right side board are detachably connected.

In the method of the present application, if the front side panel includes a front cover assembly panel and a front cover assembly panel, and the rear side panel includes a rear cover assembly panel and a rear cover assembly panel, the execution is performed in the following manner:

The connection of the front cover assembly board and the rear cover assembly board is prior to the connection of the front cover assembly board and the rear cover assembly board. The right side plate is detachably connected, and then the clamping is released, and finally the upper cover, lower cover, front cover assembly plate and rear cover assembly plate are connected to the left, right, and upper cover assembly plates. Connect with the lower cover assembly board.

The pressure test method is: measure the width of the battery module after the clamping is released to obtain the width A1, and then remove the upper and lower covers while keeping the left or right side of the battery module fixed, and use a pressure device to Pressure is applied on one side so that the width of the battery module becomes A1. At this time, the pressure displayed by the pressure device can be understood as approximately equal to the pressure of the upper and lower cover plates restraining the left and right side plates.

For batteries with foam compression between x% and z%, such as batteries that have just left the factory or have not been used for a long time, the pressure test method can be: first determine the foam material, and then according to the stress-strain curve of the foam And the actual deformation state of the foam to determine the stress.

In the assembly method of the present application, the left and right side plates and the battery cell group containing foam are in a clamped state during assembly, and the upper and lower cover plates/front and rear side plates and the left and right side plates have a detachable structure (such as a buckle structure). After the detachable connection, the clamping is released. At this time, the upper and lower cover plates/front and rear side plates and the left and right side plates are in a mating state.

This application abandons the pre-assembly of the upper and lower cover plates and side plates of "n", "u", "口". On the basis of fixing the battery cells, the pre-tightening force is applied to the cells through the side plates, and then The method of installing the upper and lower cover plates and the front and rear end cover plates avoids the problem of inconvenient installation when the size of the battery core is larger than the outer frame.

As an optional technical solution of the method described in this application, after step (3), the method further includes: connecting the front side plate, the rear side plate, the left side plate, the right side plate, the upper cover plate and the lower cover plate Place welding and sealing. Welding is carried out after the upper and lower cover plates, the front and rear end cover assembly plates and the left and right side plates are detachably connected to ensure that the frame will not fail due to the expansion and deformation of the cells at the end of the battery life.

Optionally, the welding includes laser welding.

As an optional technical solution of the method described in this application, the method further includes a module design step, and the module design step includes:

The test obtains the pre-tightening force of the battery cell group and the cell expansion space, and calculates the module width according to the pre-tightening force of the battery cell group and the cell expansion space.

(a) Use the cell pre-tension expansion detection device to test the pre-tightening force F and the cell expansion space of the cell group

(b) According to the pressure-strain curve of the foam, determine the strain x% of the foam under the pre-tightening force F, and determine the total compression of the foam z%, according to the formula

Calculate the thickness of the foam y.

(c) Calculate the pre-tensioned foam thickness dimension A according to the formula y×(1-x%)=A.

(d) Calculate the module width according to the formula, which is: module width=pre-tensioned foam thickness dimension A+cell size+dimensions of other parts, the above-mentioned dimensions refer to the dimensions along the width direction of the module.

in,

Is the cell expansion space, y is the thickness of the foam, z% is the total compression of the foam, and x% is the compression of the foam.

The strain in Figure 2 is numerically equal to the pre-tightening compression in the formula, which is just a different definition of foam deformation under pre-tightening force.

The module design steps provided by this technical solution can be widely used in the design of soft pack battery modules. The width of the module is calculated through the module design steps, and the module can be manufactured to achieve a simpler product structure, small parts and easy processing accuracy; product assembly is simple, one positioning can complete the assembly, the tooling required in the assembly process Few fixtures. The module developed by this solution perfectly solves the problem that the width of the soft pack battery module cannot be guaranteed and the difficulty of the assembly process; at the same time, the pre-tightening force of the module is effectively realized to ensure the function of the product Sex and reliability.

In this application, the pressure-strain curve of the foam is obtained by measuring the strain of the foam under different stress conditions, and fitting the result to a curve or characteristic equation to obtain the pressure deformation characteristics of the foam.

Optionally, the other components include any one or a combination of at least two of the heat shield, the frame, or the glue.

This application abandons the three outer frame structures of "n", "u" and "口" and combines three or four of the upper and lower cover plates and the left and right side plates to form an integrated device, and "plugs" the electric core into this structure The present application provides a detachable outer frame for a soft pack battery. The outer frame includes upper and lower cover plates, left and right side plates, and front and rear side plates. The parts are all independent structures, and the six parts are detachably connected (for example, connected to each other through a clamping device) to form an outer frame of the soft pack battery. At the same time, in order to better weld and assemble the multiple detachable plates in the outer frame, and to improve the heat exchange efficiency during the use of the cells, this application also provides an overall soft-pack battery module and design scheme.

In the method of the present application, because the left and right side plates are first stacked on the side of the battery cell group, the tooling can apply the required pretension to the battery cell group. After proper pretension, the overall performance of the battery is greatly improved; At the same time, in conjunction with the design method described in this application, because the upper and lower cover plates and the front and rear side plates are designed according to the actual size, the overall assembly efficiency of the battery is greatly improved, and there is no assembly of upper and lower cover plates or front and rear ends. Due to size problems when covering the plate, the tooling cannot be entered or withdrawn.

This embodiment provides a method for assembling the soft pack battery module described in Embodiment 1, which includes the following steps.

(1) Module design

This embodiment uses the VDA355 module, the module size is: 355×151×108.5mm, the cell size is: 310×102×11mm; the thickness of all the cells is: 11×12=132mm, other parts (heat insulation board) The sum of the thickness of the glue and glue is: 9mm.

(a) Use the battery cell detection device to test the pre-tightening force F of the cell and the expansion space of the cell

The best pre-tightening force F of the measured cell is 30KPa and the expansion space of the cell

Is 5%.

(b) According to the pressure-strain curve of the selected foam material (polyurethane (PU) is selected in this example), the curve is shown in Figure 6 (the ordinate is the stress and the abscissa is the strain) to determine the foam When the pressure is 30KPa, the pre-tightening compression of the foam x% is 15%, and with the use of the battery, the battery cell will gradually expand to

Therefore, the total compression of the foam can be understood as the maximum value of the strain in Figure 6, that is, z% is 71%.

according to

Calculate the foam thickness dimension y, according to the equation y×(1-x%)=A, calculate the pre-tightened foam size A=10mm, and the module width=pre-tightened foam size+cell size+others Comprehensive size of parts = 151mm.

Among them, A is the size of the foam pre-tightened, y is the thickness of the foam, x% is the pre-tightening compression of the foam, and z% is the total compression of the foam.

Expansion space for the battery.

(2) Attach the left side plate 11 and the right side plate 5 to the side of the battery pack 7 through tooling, and apply a pre-tightening force to clamp.

(3) Then, under the condition of maintaining the clamping, the FPC assembly board 2 is attached between the upper cover 1 and the battery pack 7, and the FPC assembly board 2 is attached between the left side board 11 and the right side board 5 and the battery pack 7 respectively. Close the heat insulation board 21, and engage the upper cover 1, the lower cover 8, the left side board 11 and the right side board 5. The engagement is achieved by arranging a matching structure 22 on the corresponding side of the board (the card See Figure 2 for a schematic diagram of the combined structure.

(4) It is then engaged with the front cover assembly plate 9, the rear cover assembly plate 4, the front cover assembly plate 10 and the rear cover assembly plate 3 to form a complete soft pack battery module.

(5) Welding and sealing the joints of the front end cover assembly plate 10, the rear end cover assembly plate 3, the upper cover plate 1, the lower cover plate 8, the left side plate 11 and the right side plate 5.

Claims

A soft-packed battery module, the soft-packed battery module includes a battery cell group, left and right side plates, upper and lower cover plates, and front and rear side plates arranged on the outside of the battery core group. The left and right side plates include a left side plate. And a right side plate, the upper and lower cover plates include an upper cover plate and a lower cover plate, the front and rear side plates include a front side plate and a rear side plate;

The left and right side plates are detachably connected with the upper and lower cover plates by interference fit, or the left and right side plates are detachably connected with the front and rear side plates by interference fit, so that the left and right side plates are continuously received by the upper and lower cover plates. Or the constraint of the front and rear side plates generates a pressure for clamping the battery pack to tighten the battery pack, and the pressure is 5kPa-300kPa;

The left and right side plates, the upper and lower cover plates, and the front and rear side plates can be detachably connected to encapsulate the battery pack to form the soft pack battery module;

The battery cell group includes foam, the left and right side plates are in a direction parallel or consistent with the plane of the battery sheet, and the front and rear side plates are perpendicular to the left and right side plates and the horizontal plane.
The soft-pack battery module according to claim 1, wherein the front and rear side plates are in any one of the following two forms:

The front and rear side panels are front and rear end cover assembly plates, and the front and rear end cover assembly plates are the front end cover assembly plate and the rear end cover assembly plate that are arranged opposite to each other;

The front and rear side panels include: a front cover assembly plate and a rear cover assembly plate disposed oppositely, and a front cover plate assembly plate and a rear cover plate assembly plate disposed oppositely, and the front cover plate assembly plate and the rear cover The board assembly boards are respectively located on the side of the front end cover assembly board and the rear end cover assembly board close to the battery core group.
The soft-pack battery module according to claim 2, wherein the soft-pack battery module comprises at least one of the following:

The front cover assembly board includes a copper bar and a board slot that supports the copper bar. The battery core group is connected to the copper bar to form a complete circuit loop; the board slot is arranged on the front cover In the board assembly board, the board slot is set to support the copper bar, while isolating the copper bar and the battery cell tabs to prevent the copper bar from contacting the cell tabs;

The front end cover assembly board is composed of a front end cover and an insulating board, and the insulating board is arranged to physically isolate the copper bars to prevent leakage and short circuit.
The soft-pack battery module according to claim 2, wherein the soft-pack battery module comprises at least one of the following:

The rear cover assembly board includes a copper bar and a board slot that supports the copper bar. The battery core group is connected to the copper bar to form a complete circuit loop; the board slot is arranged on the back cover In the board assembly board, the board slot is set to support the copper bar, while isolating the copper bar and the battery cell tabs to prevent the copper bar from contacting the cell tabs;

The rear end cover assembly plate is composed of a rear end cover and an insulating plate, and the insulating plate is arranged to physically isolate the copper bars to prevent leakage and short circuit.
The soft-pack battery module according to any one of claims 1 to 4, wherein the detachable connection method includes snapping, snapping, or at least one of the following: bolt connection or nut connection.
The soft-pack battery module according to claim 5, wherein the soft-pack battery module comprises at least one of the following:

The joints formed by the detachable connection of the left and right side plates and the upper and lower cover plates or the front and rear side plates are also connected by welding, and the welding includes laser welding;

A flexible circuit board FPC assembly board is also provided between the upper cover plate and the battery cell group. The FPC assembly board includes a flexible circuit board and an FPC support board. A limit structure is provided on the FPC support board. The limit structure is configured to fix the flexible circuit board, and the flexible circuit board is provided with a temperature collection sheet and a voltage collection sheet;

A heat insulation board is also provided between the left side board and the battery core group, and the heat insulation board and the left side board are connected by a thermally conductive structural glue;

A heat insulation plate is also provided between the right side plate and the battery cell group, and the heat insulation plate and the right side plate are connected by a thermally conductive structural glue;

The heat insulation board is made of high temperature resistant material.
The soft-pack battery module according to claim 6, wherein the high temperature resistant material is mica flakes or aerogel with heat insulation effect.
The soft-pack battery module according to any one of claims 2 to 7, wherein the left and right side plates, the upper and lower cover plates, the front end cover and the rear end cover are made of aluminum.
The soft-pack battery module according to claim 8, wherein the soft-pack battery module comprises at least one of the following:

The aluminum material is a high-strength aluminum material;

The left and right side plates are formed by stamping or extrusion;

The upper and lower cover plates are formed by stamping or bending;

The front end cover and the rear end cover are formed by extrusion or casting.
9. The soft-pack battery module according to claim 9, wherein the width of the upper and lower cover plates is adjusted according to the pre-tightening requirements of the battery cell group and the foam.
An assembling method applied to the soft pack battery module of any one of claims 1-10, the method comprising:

Lay the left side board and the right side board on the side of the battery cell group respectively, and apply a pre-tightening force in the width direction of the module to clamp;

Under the condition of maintaining the clamping, the upper cover plate and the lower cover plate are detachably connected to the left side plate and the right side plate, or the front side plate and the rear side plate are respectively connected to the left side plate Detachably connect with the right side plate;

Release the clamping and continue to connect so that the left side plate, the right side plate, the upper cover plate, the lower cover plate, the front side plate and the rear side plate can all be detachably connected to form the Soft pack battery module.
The method according to claim 11, wherein after the clamping is released, the connection is continued so that the left side plate, the right side plate, the upper cover plate, the lower cover plate, and the front side plate And the rear side panel can be detachably connected. After the soft-pack battery module is formed, the method further includes: aligning the front side panel, the rear side panel, the left side panel, and the right side panel. The joints of the plate, the upper cover plate and the lower cover plate are welded and sealed.
The method of claim 12, wherein the welding comprises laser welding.
The method according to any one of claims 11 to 13, wherein the method further comprises: module design, the module design comprising: testing to obtain the pre-tightening force of the battery cell group and the cell expansion space, and The module width is calculated according to the pre-tightening force of the battery cell group and the expansion space of the battery cell.
The method according to claim 14, wherein the test obtains the pre-tightening force of the battery cell group and the cell expansion space, and the module width is calculated according to the pre-tightening force of the battery cell group and the cell expansion space ,include:

Test the pre-tightening force F of the battery pack and the expansion space of the battery using a cell pre-tensioning expansion detection device

According to the pressure-strain curve of the foam, determine the foam pre-tightening compression x% of the foam under the pre-tightening force F condition, and determine the total foam compression z%, according to the formula
Calculate the thickness of the foam y;

According to the formula y×(1-x%)=A, the pre-tightened foam thickness dimension A is calculated;

The module width is calculated according to the formula, and the formula is: module width=pre-tensioned foam thickness dimension A+cell size+dimensions of other parts.
The method according to claim 15, wherein the other parts include any one or a combination of at least two of the heat shield, the frame, and the glue.