JP3229404U - Fire spread prevention structure for pouch lithium battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire spread prevention structure of a pouch lithium battery pack capable of preventing fire spread due to thermal runaway. A fire spread prevention structure of a pouch lithium battery pack includes a plurality of cell cells, and the plurality of cell cells are mounted in a battery housing. A heat insulating material is attached between the adjacent cells, and a glass fiber cloth for protecting the cells in the outermost layer is attached to the surfaces of the two cells in the outermost layer. The positive electrode aluminum tab of the cell is subjected to nickel surface treatment, and the positive electrode aluminum tab after the nickel surface treatment is folded back into the recess of the cell and fixed with an adhesive. EVA foam is attached to the recess of the cell, and the positive electrode aluminum tab and the negative electrode tab of the cell are attached to the EVA foam. A printed wiring board is provided above the plurality of cells, and the positive electrode aluminum tab and the negative electrode tab of the cell pass through the wiring board. [Selection diagram] Fig. 1

Description

The present invention relates to the technical field of the pouch lithium battery pack, and particularly to the fire spread prevention structure of the pouch lithium battery pack.

Pouch lithium batteries have been applied to electrically assisted bicycles and electric scooters, and battery modules in the current market are generally constructed by stacking batteries one by one to prevent the spread of fire due to thermal runaway between the batteries of the battery module. This is the reason why the mass use of pouch lithium battery in the electric bicycle market was hindered by the safety problem that the thermal runaway of the pouch lithium battery pack caused the explosion and ignition because the structure was not designed. Against this background, it has become an important issue that finished vehicle manufacturers and battery companies need to solve urgently.
Therefore, in order to solve the above problems in the prior art, there is an urgent need to provide a fire spread prevention structure for a new pouch lithium battery pack.

An object of the present invention is to provide a fire spread prevention structure for a pouch lithium battery pack in order to solve a safety problem of fire spread due to thermal runaway of a pouch lithium polymer battery pack module.

In order to achieve the above object, the present invention provides the following solutions. The present invention provides a fire spread prevention structure for a pouch lithium battery pack, the pouch lithium battery pack includes a plurality of cells, and the plurality of cells are mounted in a battery housing. A heat insulating material is attached between the adjacent cells, and a glass fiber cloth for protecting the cells in the outermost layer is attached to the surfaces of the two cells in the outermost layer. The positive electrode aluminum tab of the cell is subjected to nickel surface treatment, and the positive electrode aluminum tab after the nickel surface treatment is folded back into the recess of the cell and fixed with an adhesive. EVA foam is attached to the recess of the cell, and the positive electrode aluminum tab and the negative electrode tab of the cell are attached to the EVA foam. A printed wiring board is provided above the plurality of cells, and the positive electrode aluminum tab and the negative electrode tab of the cell pass through the printed wiring board.
Preferably, the positive electrode aluminum tab and the negative electrode tab of the cell are shaped into an L shape and attached to the EVA foam.
Preferably, the wiring board is a printed wiring board, and a nickel block is attached to the printed wiring board.
Preferably, the positive electrode aluminum tab and the negative electrode tab of the cell are connected to the printed wiring board by spot welding.
Preferably, the printed wiring board is provided with heat dissipation vents, and an insulating sheet is attached to the upper surface of the printed wiring board.

Preferably, the positive and negative lead wires of the power supply of the pouch lithium battery pack are connected by the terminals of the wiring board and fixed in the wiring duct in the battery plastic frame.
Preferably, the size of the heat insulating material is larger than the size of the cell, and flameproof double-sided tape is attached to both sides of the heat insulating material.

Preferably, at a position where the head and tail of the pouch lithium battery pack come into contact with the battery housing, the recess formed by the cell and the heat insulating material is filled with a thermally conductive silicone gel, and the battery housing is filled. It is tightly glued.

Preferably, the battery housing is an openwork battery plastic frame, the battery plastic frame includes a left battery plastic frame and a right battery plastic frame, and the left battery plastic frame and the right battery plastic frame are connected by a buckle. ..

Preferably, the battery housing is a sealed plastic housing, the sealed plastic housing includes a left sealed plastic housing and a right sealed plastic housing, and the left sealed plastic housing and the right sealed plastic housing are connected by a buckle. A sealing groove is provided in the connection portion.

The heat conductive silicone gel is applied to the periphery of the pouch lithium battery pack and the nickel block in the printed wiring board, and the heat conductive silicone gel is applied to the inner wall of the plastic housing.

Compared with the prior art, the present invention has the following technical effects.

The present invention solves the safety problem of fire spread due to thermal runaway of the pouch lithium polymer battery pack module. Innovative design for the stacking method used in the battery module design, using a configuration in which they are arranged in order, such as cell-insulation-cell, the cell tab is via a printed wiring board. , Connected in series or in parallel by spot welding, and finally the entire battery pack is fixed by applying an adhesive to the battery housing. When a thermal runaway occurs in a cell and causes an explosion or fire, the heat is cut off, the spread is prevented, the thermal runaway of the adjacent cell is prevented, and the danger of ignition and fire is avoided. During normal operation, the cells in the battery pack do not conduct heat to each other, so the temperature can be made uniform, the performance of the entire battery pack is improved, and the service life is extended.

In order to more clearly explain the examples of the present invention or the technical solutions in the prior art, the drawings used in the examples will be briefly introduced next. Of course, the drawings described below are merely embodiments of the present invention, and one of ordinary skill in the art can conceive other drawings based on these drawings without the need for creative effort.

The schematic diagram of the fire spread prevention structure of the pouch lithium battery pack according to Example 1. FIG. 6 is a schematic view of a case where the positive electrode and negative electrode tabs of the cell according to the first embodiment are bent into an L shape. FIG. 6 is a schematic view of a case where the nickel surface treatment of the aluminum tab for the positive electrode of a cell according to Example 1 is performed and fixed with an adhesive. The schematic diagram in the case of applying a thermal conductive silicone gel to the pouch lithium battery pack according to Example 1. The schematic view of the case where the left and right plastic frame structures are attached to the pouch lithium battery pack according to Example 1. The structural schematic view in the case where the left and right plastic frames are attached to the pouch lithium battery pack according to Example 1, and the buckles of the left and right plastic frames are fastened. Schematic diagram of the bottom structure when the left and right plastic frames are attached to the pouch lithium battery pack according to the first embodiment. The structural schematic diagram of the printed wiring board according to Example 1. FIG. The schematic diagram of the external structure in the case of mounting the battery plastic frame according to Example 1. FIG. 6 is a schematic view of a power supply lead wire terminal when the positive and negative lead wires of the battery pack according to the first embodiment are fixed in a wiring duct in a plastic frame and connected to a printed wiring board. FIG. 6 is a schematic view of a case where an insulating sheet is attached to the upper surface of the printed wiring board according to the first embodiment. The first schematic view of the pouch lithium battery pack after the fire spread test by this invention. The second schematic view of the pouch lithium battery pack after the fire spread test by this invention. The third schematic diagram of the pouch lithium battery pack after the fire spread test by this invention. A cross-sectional view taken along the line AA of FIG. The schematic diagram of the fire spread prevention structure of the pouch lithium battery pack according to Example 2. FIG.

Hereinafter, the technical solutions of the embodiments of the present invention will be clearly and completely described by combining the drawings of the embodiments of the present invention, and of course, the described examples are merely examples of the present invention, and all the embodiments. Not an example. Based on the embodiments of the present invention, all other embodiments that can be conceived by those skilled in the art without the need for creative effort are all within the technical scope of the present invention.

In order to clarify and clarify the above-mentioned objectives, features and advantages of the present invention, the present invention will be described in more detail in combination with the drawings and embodiments of the present invention.
Example 1

As shown in FIG. 1, this embodiment provides a fire spread prevention structure for a pouch lithium battery pack. Here, the pouch lithium battery pack module is composed of a plurality of single batteries connected in series or in parallel. However, the number of cells connected in series in the embodiment of the present invention is not limited. The pouch lithium battery pack is mounted inside the battery housing.

In this embodiment, the battery housing is an openwork battery plastic frame, the battery plastic frame includes a left battery plastic frame and a right battery plastic frame, and the left battery plastic frame and the right battery plastic frame are connected by a buckle. Will be done. Insulate between each cell. The heat insulating material (thermal conductivity 0.02 W / m.k) exhibits ultra-high heat insulating properties, flame retardancy, impact resistance and the like. The size of the insulation is designed to be slightly larger than the size of the cell (L1> L2, D1 = D2), and the insulation is attached between all the cells of the battery module in this manner. See FIGS. 13 and 15.

In this embodiment, flameproof double-sided tape is attached to both sides of the heat insulating material, thereby adhering and fixing between the heat insulating material and the cell, and a glass fiber cloth on the surface of the first and last cell in the outermost layer. To protect the cell cells in the outermost layer. See FIG.

In this embodiment, the positive electrode aluminum tab of each cell is subjected to nickel surface treatment, and the tab that has undergone the nickel surface treatment is folded back into the sealed recess and fixed with an adhesive. EVA foam for cushioning, isolation and insulation is attached to the recess of each cell. The positive electrode and negative electrode tabs are shaped into an L shape and attached to EVA foam to prevent vibration and dropping during use of the battery pack, and to serve as cushioning, vibration isolation, and tab tear prevention. See Figure 2-3.

In this embodiment, as shown in FIG. 8, a printed wiring board is provided above the cell, each cell tab passes through the printed wiring board, a nickel block is attached to the printed wiring board, and a spot welding method is used. A battery module is configured by connecting batteries in series or in parallel, and a heat dissipation vent for reducing heat accumulation by conducting heat from the combustion of a battery in which a thermal runaway has occurred to the outside on a printed wiring board. Is provided. Here, two nickel blocks are provided on the positive electrode and the negative electrode of each cell, and the number of nickel blocks provided is determined by the number of batteries connected in series or in parallel. By providing the nickel block, electrical connection by spot welding of the positive electrode and negative electrode tabs of the cell can be facilitated, and the heat inside the cell can be conducted to the nickel block and the printed wiring board to dissipate constant heat. , And play a role in fixing the module structure.

In this embodiment, as shown in FIG. 11, an insulating sheet is further included, which is attached to the upper surface of the printed wiring board and used for insulating the battery pack and preventing short circuits.

In this embodiment, the positive and negative lead wires of the battery pack power supply are connected by the terminals of the wiring board and fixed in the battery plastic frame wiring duct to prevent the lead wires from falling off or the connection terminals from cracking due to vibration or dropping. To do. In the head and tail of the battery pack, the heat conductive silicone gel (see FIG. 4) is filled and fitted in the recessed portion due to the difference in width between the cell and the heat insulating material in the portion in contact with the housing. Conductivity K = 1.8-10 W / m. k, It is tightly adhered to the flame-retardant UL94-V0 thermal conductive battery plastic frame. The battery plastic frame has two parts, which are fastened by buckles and serve to reinforce the battery module and dissipate heat.
Example 2

This embodiment is an improvement based on the first embodiment, and the points to be improved are as follows. The battery housing is a sealed plastic housing and a fully sealed structure is used, the sealed plastic housing includes a left sealed plastic housing and a right sealed plastic housing, the left sealed plastic housing and the right sealed plastic housing. Are connected by the buckle method. Further, a sealing groove is provided and fixed with an adhesive.

Heat dissipation ribs are provided on the outside of the battery housing so as to be uniformly distributed, a ventilation hole of Φ10 mm is bored at the top of the battery housing (above the printed wiring board), and a waterproof ventilation film of Φ20 mm is attached. Can be attached. If the battery pack operates normally and dissipates heat, the thermally expanded air can be discharged from the waterproof ventilation membrane, and the moist air cannot enter the housing. The waterproof level has reached IP67. It can also act as a safety relief valve in the event of an abnormal thermal runaway in the battery.

The heat conductive silicone gel is uniformly applied to the periphery of the pouch lithium battery pack and the nickel block in the printed wiring board, and the heat conductive silicone gel is applied to the inner wall of the sealed plastic housing, and adhered and fixed. However, it can play a role of conducting heat to the housing and releasing heat to the outside.

In the present invention, a fully charged battery pack module is placed in a case or housing, and one of them is pierced with a needle as an overcharged cell to simulate combustion or smoke ejection due to battery heat runaway. The spread of the battery is not caused, and as shown in FIG. 12-15, the adjacent cell is in good condition, the battery voltage is 4.15V, and the maximum temperature of the adjacent cell is acceptable for the cell. Much lower than the temperature of a thermal runaway that can occur.
As the material of the housing, a modified heat conductive engineering plastic PA6 or PC can be selected, and the heat conductivity K = 1.8 to 10 W / m. k, flame-retardant UL94-V0.
The heat radiating rib material is the above material, is designed as a heat radiating rib in the plastic housing structure, and is configured by injection molding, and can enhance the strength of the plastic housing and the function of the radiator.

In the actual application of the product, avoid the risk of more adjacent batteries spreading, exploding, igniting and causing fire if any cell in the battery module undergoes thermal runaway and burns. Can solve the problem of heat conduction between cells, reduce heat accumulation, thus greatly improve the safety of the battery pack, reduce the safety risk, and avoid personal and property damage. .. The test gives good results and is practical and creative.

In the present invention, the principle and the embodiment of the present invention have been described using specific examples, but the above description of the examples is merely used to understand the method of the present invention and its core idea. At the same time, for those skilled in the art, there are parts that can be changed in both the embodiment and the scope of application of the invention based on the idea of the present invention. To summarize the above, the content of this specification should not be construed as a limitation to the present invention.

Claims (10)

The pouch lithium battery pack contains a plurality of cells, and the plurality of cells are mounted in the battery housing. The pouch lithium battery pack has a fire spread prevention structure.
A heat insulating material is attached between the adjacent cells.
A glass fiber cloth for protecting the cell in the outermost layer is attached to the surfaces of the two cells in the outermost layer.
The positive electrode aluminum tab of the cell is subjected to nickel surface treatment, and the positive electrode aluminum tab after the nickel surface treatment is folded back into the recess of the cell and fixed with an adhesive.
EVA foam is attached to the recess of the cell, and the positive electrode aluminum tab and the negative electrode tab of the cell are attached to the EVA foam.
A printed wiring board is provided above the plurality of the cells.
The aluminum tab for the positive electrode and the tab for the negative electrode of the cell cell pass through the printed wiring board, and have a fire spread prevention structure for the pouch lithium battery pack. The positive electrode aluminum tab and the negative electrode tab of the cell are shaped into an L shape.
The fire spread prevention structure for a pouch lithium battery pack according to claim 1, wherein the pouch lithium battery pack is attached to the EVA foam. The fire spread prevention structure for a pouch lithium battery pack according to claim 1, wherein a nickel block is attached to the printed wiring board. The fire spread prevention structure for a pouch lithium battery pack according to claim 3, wherein the positive electrode aluminum tab and the negative electrode tab of the cell are connected to the printed wiring board by spot welding. The fire spread prevention structure for a pouch lithium battery pack according to claim 4, wherein the printed wiring board is provided with heat-dissipating ventilation holes, and an insulating sheet is attached to the upper surface of the printed wiring board. The positive and negative lead wires of the power supply of the pouch lithium battery pack are connected by the terminals of the printed wiring board.
The structure for preventing the spread of fire of the pouch lithium battery pack according to claim 1, wherein the pouch lithium battery pack is fixed in a wiring duct in a battery plastic frame. The fire spread prevention structure for a pouch lithium battery pack according to claim 1, wherein the size of the heat insulating material is larger than the size of the cell, and flameproof double-sided tape is attached to both sides of the heat insulating material. At a position where the head and tail of the pouch lithium battery pack come into contact with the battery housing, the recess formed by the cell and the heat insulating material is filled with a thermally conductive silicone gel and adheres tightly to the battery housing. The fire spread prevention structure of the pouch lithium battery pack according to claim 1, wherein the pouch lithium battery pack is provided. The battery housing is an open-cut battery plastic frame, the battery plastic frame includes a left battery plastic frame and a right battery plastic frame, and the left battery plastic frame and the right battery plastic frame are connected by a buckle. The structure for preventing the spread of fire of the pouch lithium battery pack according to any one of claims 1 to 8. The battery housing is a sealed plastic housing.
The sealed plastic housing includes a left sealed plastic housing and a right sealed plastic housing.
The left sealed plastic housing and the right sealed plastic housing are connected by a buckle, and a sealing groove is provided at the connection portion.
A thermal conductive silicone gel is applied around the pouch lithium battery pack and a nickel block in the printed wiring board, and a thermal conductive silicone gel is applied to the inner wall of the plastic housing.
Claim 1 is characterized in that heat radiation ribs are provided so as to be uniformly distributed on the outside of the battery housing, vent holes are formed in the top of the battery housing, and a waterproof ventilation film is provided on the vent holes. The structure for preventing the spread of fire of the pouch lithium battery pack according to any one of 8 to 8.