CN211858778U

CN211858778U - Flame retardant separator for lithium battery module with suppression of thermal runaway diffusion

Info

Publication number: CN211858778U
Application number: CN202020288575.9U
Authority: CN
Inventors: 陈勳森
Original assignee: Nytex Composites Co Ltd
Current assignee: Nytex Composites Co Ltd
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2020-11-03
Anticipated expiration: 2030-03-10

Abstract

The utility model provides a fire-retardant baffle that is used for lithium cell module and has suppression thermal runaway diffusion for separate lithium cell module's electric core. The flame-retardant partition plate comprises a plate-like body formed by injection molding, and the heat conductivity of the body is abruptly reduced after the material reaches a critical temperature. When a certain electric core in the lithium battery module generates thermal runaway, the generated high energy is effectively blocked by the flame-retardant partition plate, and the chain effect of the thermal runaway of adjacent normal electric cores in the lithium battery module is avoided.

Description

Flame retardant separator for lithium battery module with suppression of thermal runaway diffusion

Technical Field

The present invention relates to a flame-retardant separator, and more particularly to a flame-retardant separator for a lithium battery module and having a function of suppressing thermal runaway diffusion.

Background

The lithium battery is widely applied to 3C products, power vehicles, energy storage systems and the like. Therefore, the safety of the lithium battery is a global issue, and even under multiple protections such as a Battery Management System (BMS) and a mechanical structure, the lithium battery still has the potential risk of spontaneous combustion due to heat generation, and in recent years, the fire accident of energy storage power plants and electric vehicles still continues to occur. Therefore, a test method for the thermal runaway of the lithium battery is established in international standards such as IEC 62619, UL 1973, UL 2580, JIS8715-2, CNS 15387, GB/T31485-.

Thermal Runaway (Thermal Runaway), IEC 62619, is defined as the phenomenon in which the exothermic reaction inside the cell causes a sudden rise in temperature Runaway. The lithium battery has high energy density, the electrolyte is flammable, and the ignition is caused by thermal runaway of the lithium battery due to factors such as high temperature, overcharge, impact, errors of an electronic control system or process defects. The high temperature generated by the thermal runaway of the lithium battery can reach 500-1200 ℃, when heat energy diffuses to the periphery, the adjacent battery cell is heated at the same time, and if the temperature exceeds the upper limit temperature of the battery cell (about 100-150 ℃), the adjacent battery cell can automatically release heat to cause the thermal runaway chain reaction of the comprehensive burning of the battery system.

In view of the above, thermal management is very important for lithium battery modules, and affects the service life of lithium batteries and the use safety of products. When the lithium battery is charged and discharged, chemical energy and electric energy are mutually converted to generate energy loss, the energy loss is released in a waste heat mode, and the battery cell continuously releasing the waste heat raises the temperature of the battery cell and needs a proper heat conduction way to dissipate heat to the environment. Therefore, in order to control the safety of the lithium battery module and prevent the lithium battery module from diffusing under thermal runaway to affect the life and property safety of users, it is imperative to develop a structure and a method for effectively inhibiting thermal runaway diffusion so as to improve the safety of the lithium battery module.

SUMMERY OF THE UTILITY MODEL

In view of this, in an embodiment of the present invention, a flame retardant partition plate for a lithium battery module is provided, which can effectively suppress thermal runaway diffusion.

The utility model provides a fire-retardant baffle that is used for lithium cell module and has suppression thermal runaway diffusion for separate lithium cell module's electric core, its characterized in that: the flame-retardant partition plate comprises a plate-shaped body, and the heat conduction coefficient of the body is reduced along with the temperature rise of the body.

Furthermore, the body has a first heat conduction coefficient when the temperature of the body is lower than a first temperature, and the body has a second heat conduction coefficient when the temperature of the body is higher than a second temperature. The first temperature is lower than the second temperature, and the first heat conduction coefficient is not lower than four times of the second heat conduction coefficient.

Further, the first temperature is about 100 ℃ and the second temperature is about 500 ℃.

Further, the body is made of a semi-crystalline thermoplastic material.

Further, the semi-crystalline thermoplastic material has a crystallinity of between 10% and 80%.

In an embodiment of the present invention, the body has two first end surfaces extending along the length direction and two second end surfaces extending along the width direction, and two opposite sides of each first end surface are respectively connected to the two second end surfaces.

Furthermore, two opposite sides of each first end surface are respectively perpendicular to the two second end surfaces.

In another embodiment of the present invention, the body has at least one cavity extending along the length direction and formed between the two first end surfaces and the two second end surfaces.

Furthermore, two opposite sides of the cavity respectively penetrate through the two second end faces.

In another embodiment of the present invention, the body has two reinforcing portions extending from the two second end surfaces along the width direction, so that the body has a cross-sectional shape that is substantially I-shaped.

Furthermore, the body extends along the height direction on the two opposite sides of each reinforcing part to form two connecting parts, and each connecting part is suitable for being mutually lapped with the connecting parts of other flame-retardant partition plates.

Further, the body is made by injection molding or extrusion molding.

Based on the foregoing, in the above-mentioned embodiment of the utility model, rely on the heat conduction coefficient of body to rise along with the body temperature and reduce, when certain electric core produced thermal runaway in the lithium battery module, produced high energy was hindered to fire the baffle separation effectively, avoided the inside adjacent normal electric core of lithium battery module to take place thermal runaway's chain effect.

In order to make the aforementioned and other features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 and fig. 2 are schematic diagrams of manufacturing methods of the flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention, respectively.

Fig. 3 is a schematic view of a first embodiment of a flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention.

Fig. 4 is a schematic view of the use of the fire retardant separator shown in fig. 3.

Fig. 5 is a schematic diagram of a lithium battery module with a flame retardant separator for inhibiting thermal runaway diffusion according to the present invention.

Fig. 6 is a schematic external view of a second embodiment of a flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention.

Fig. 7 is a schematic view of a third embodiment of a flame retardant separator for a lithium battery module having means for inhibiting thermal runaway diffusion according to the present invention.

Description of reference numerals: 1. 1a, 1 b-a flame retardant separator; 10. 10a, 10 b-a body; 11. 11a, 11 b-a first end face; 12. 12a, 12 b-a second end face; 13 a-a chamber; 13 b-a reinforcement; 14 b-a connecting portion; 2-electric core; 3-covering the cover; 4-shell.

Detailed Description

Fig. 1 and fig. 2 are schematic diagrams of manufacturing methods of the flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention, respectively. Fig. 3 is a schematic view of a first embodiment of a flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention. Fig. 4 is a schematic view of the use of the fire retardant separator shown in fig. 3. Referring to fig. 1 to 3, the flame retardant partition board 1 of the present invention includes a board-shaped body 10 formed by injection molding, the body 10 can have two first end surfaces 11 extending along a length direction and two second end surfaces 12 extending along a width direction, and two opposite sides of each first end surface 11 are respectively connected to the two second end surfaces 12. In the present embodiment, two opposite sides of each first end surface 11 can be perpendicular to the two second end surfaces 12, respectively, so that the body 10 has a rectangular plate shape. FIGS. 1 and 2 show various mold gate configurations for forming the body 10, and the body 10 can be made of a semi-crystalline thermoplastic material having a crystallinity of between 10-80%. In addition, the thermal conductivity of the semi-crystalline thermoplastic material decreases dramatically after a critical temperature is reached. Referring to fig. 4, the body 10 of the flame-retardant partition board 1 can be used to separate the battery cells 2 of the lithium battery module for being accommodated in the upper cover 3 and the casing 4.

The thermal conductivity of the body 10 decreases as the temperature of the body 10 increases. Further, the body 10 has a first thermal conductivity coefficient when the temperature is lower than a first temperature, and the body 10 has a second thermal conductivity coefficient when the temperature is higher than a second temperature. The first temperature is lower than the second temperature, and the first heat conduction coefficient is not lower than four times of the second heat conduction coefficient. For example, the first temperature is about 100 ℃, which is the normal operating temperature of the battery cell 2; the second temperature is about 500 ℃, that is, the battery cell 2 generates a thermal runaway high temperature state. In addition, the body 10 of the present embodiment can be attached to other materials, such as fiberglass cloth, mica board, metal plate … …, etc.

Rely on the heat conduction coefficient of body 10 to produce the change because of the temperature and restrain the diffusion of thermal runaway effectively, when certain electricity core 2 produced the thermal runaway in the lithium battery module, produced high energy receives fire-retardant baffle 1 separation limitedly, and adjacent normal electricity core 2 also receives its divided fire-retardant baffle 1 protection, avoids the inside adjacent normal electricity core 2 of lithium battery module to take place the chain effect of thermal runaway. Referring to fig. 5, a blue curve is a thermal runaway temperature rise curve of a lithium battery; the green curve is the back temperature curve of the flame-retardant partition plate 1; the yellow line segment is the area of the flame-retardant partition plate 1 for inhibiting the thermal runaway of the lithium battery; t1 is the maximum temperature of the lithium battery after thermal runaway, and is about 500-1200 ℃; t2 is the continuous high temperature of the lithium battery after thermal runaway, and is about 200-400 ℃; t3 is the temperature for triggering the thermal runaway chain reaction of the lithium battery, and is about 100-150 ℃; t1 is the effective protection time of the flame-retardant partition board 1 at the temperature of T1; t2 is the effective protection time of the flame retardant partition board 1 at the temperature of T2. The utility model discloses fire-retardant baffle 1 provides like the protective capacities in the yellow frame of figure 5. Have electric core 2 thermal runaway to produce in lithium battery module, the high temperature of production can be controlled in the utility model discloses a fire-retardant baffle 1 does not influence its neighbouring electric core 2, and neighbouring electric core 2 temperature rise that is heated will be controlled like green curve, effectively restraines below its thermal runaway trigger temperature.

Fig. 6 is a schematic external view of a second embodiment of a flame retardant separator for a lithium battery module and having thermal runaway diffusion suppression according to the present invention. The difference between this embodiment and the first embodiment is: the body 10a of the flame-retardant partition board 1a has at least one chamber 13a extending in the longitudinal direction and formed between two first end faces 11a and two second end faces 12 a. Further, two opposite sides of the cavity 13a can respectively penetrate through the two second end faces 12a, so that air is provided inside the cavity 13a to prevent the thermal runaway electric core 2 from being ignited. In addition, the body 10a can also have several chambers 13 a. In the present embodiment, the body 10a can have three chambers 13a spaced apart from each other in the height direction. Further, the inside of the chamber 13a can be filled with gas, aerogel, foaming material … …, or the like.

Fig. 7 is a schematic view of a third embodiment of a flame retardant separator for a lithium battery module having means for inhibiting thermal runaway diffusion according to the present invention. The difference between this embodiment and the first embodiment is: the main body 10b of the fire-retardant partition board 1b extends two reinforcing portions 13b from the two second end surfaces 12b along the width direction, and each reinforcing portion 13b is perpendicular to the two first end surfaces 11b, so that the main body 10b has a cross-sectional shape that is substantially I-shaped, thereby enhancing the structural strength and the support of the main body 10 b. In this embodiment, the main body 10b further extends to form two connecting portions 14b on two opposite sides of each reinforcing portion 13b along the height direction, and each connecting portion 14b is suitable for being overlapped with the connecting portions 14b of other flame-retardant partition boards 1b, so that the flame-retardant partition board 1b has higher versatility.

In summary, in the above embodiments of the present invention, the thermal conductivity coefficient of the

bodies

10, 10a, 10b is reduced along with the temperature rise of the

bodies

10, 10a, 10b, when a certain electric core 2 in the lithium battery module generates thermal runaway, the generated high energy is effectively blocked by the flame-retardant partition boards 1, 1a, 1b, so as to avoid the chain effect of thermal runaway occurring in the adjacent normal electric core 2 in the lithium battery module.

The foregoing description is intended to be illustrative rather than limiting, and it will be appreciated by those skilled in the art that many modifications, variations or equivalents may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A flame retardant separator for a lithium battery module and having a thermal runaway diffusion suppression for separating the cells of the lithium battery module, characterized in that: the flame-retardant partition plate comprises a plate-shaped body, and the heat conduction coefficient of the body is reduced along with the temperature rise of the body.

2. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 1, wherein: the body has a first heat conduction coefficient when the temperature of the body is lower than a first temperature, and the body has a second heat conduction coefficient when the temperature of the body is higher than a second temperature, wherein the first temperature is lower than the second temperature, and the first heat conduction coefficient is not lower than four times of the second heat conduction coefficient.

3. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 2, wherein: the first temperature is about 100 deg.C and the second temperature is about 500 deg.C.

4. The flame-retardant separator for a lithium battery cell module having thermal runaway diffusion suppressed as claimed in any one of claims 1 to 3, wherein: the body is made of a semi-crystalline thermoplastic material.

5. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 4, wherein: the semi-crystalline thermoplastic material has a crystallinity of between 10% and 80%.

6. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 4, wherein: the body is provided with two first end faces extending along the length direction and two second end faces extending along the width direction, and two opposite sides of each first end face are respectively connected with the two second end faces.

7. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 6, wherein: the two opposite sides of each first end surface are respectively vertical to the two second end surfaces.

8. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 6, wherein: the body is provided with at least one cavity extending along the length direction and formed between the two first end faces and the two second end faces.

9. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 8, wherein: two opposite sides of the at least one chamber respectively penetrate through the two second end faces.

10. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 6, wherein: the body extends two reinforcing parts from the two second end faces along the width direction respectively, so that the body has an I-shaped cross section.

11. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 10, wherein: the body extends along the height direction on the two opposite sides of each reinforcing part to form two connecting parts, and each connecting part is suitable for being mutually lapped with the connecting parts of other flame-retardant partition plates.

12. The flame retardant separator for a lithium battery cell module having thermal runaway diffusion inhibited as claimed in claim 1, wherein: the body is made by injection molding or extrusion molding.