CN111883715A - Battery protection baffle and group battery - Google Patents

Abstract

The invention provides a battery protection clapboard and a battery pack comprising the battery protection clapboard, wherein the battery protection clapboard comprises a rigid support part and two elastic sheets, the elastic sheets are of arc structures, two ends of the rigid support part are respectively connected with the end parts of the elastic sheets, a closed space is formed between the rigid support part and the elastic sheets, the battery pack comprises the battery protection clapboard, the batteries are independently separated by the battery protection clapboard, and in the life cycle of the batteries, the gap and the pressure between battery cores are effectively regulated and controlled, so that the batteries are ensured to have sufficient expansion space, and uncontrollable deformation caused by direct mutual extrusion of the batteries due to expansion is avoided; and each battery has an independent thermal environment, so that thermal diffusion among the batteries can be effectively blocked, and flame spread when the batteries are out of control due to heat can be prevented.

Description

Battery protection baffle and group battery

Technical Field

The invention relates to the technical field of battery protection, in particular to a battery protection clapboard and a battery pack comprising the same.

Background

With the increasing prominence of the problems of environmental protection and energy shortage in modern society, more and more transportation, transportation and engineering vehicles begin to adopt energy-saving and clean energy technologies, such as hybrid power, pure electric drive and fuel cell technologies. Among them, secondary batteries, particularly lithium ion batteries, have been widely used as a core power source. Meanwhile, the requirements for the safety and the service life of the lithium ion battery are also higher and higher. Among the many considerations, cell volume change and heat diffusion are two very important key points.

First, lithium ion batteries undergo significant volume changes during charging and discharging, which are determined by the intrinsic properties of the materials that make up the lithium ion batteries. For example, graphite, which is the most commonly used negative electrode material of lithium ion batteries, undergoes about 7% -10% volume expansion from a discharge state to a full charge state, and lithium nickel manganese cobalt oxide, which is a positive electrode material of ternary lithium ion batteries, undergoes about 5% -10% volume expansion from a discharge state to a full charge state. The volume change of the silicon-containing cathode material is more severe. In addition, the lithium ion battery generates certain gas by side reaction in the recycling process, and the internal pressure of the battery is increased and the volume change of the battery is accelerated. Among them, due to the limiting effect of the structural members at the two ends of the battery, such as the cover plate, etc., the change in volume of the battery is more likely to appear at the middle of the side surface of the battery, i.e., the closer to the center of the side surface, the greater the deformation.

The volume change of the battery can generate large and uncontrollable extrusion force between the single batteries which are tightly attached to each other, so that the battery shell and the internal pole core are uncontrollably deformed, the distance between the diaphragm and the positive and negative pole pieces is influenced, and the serious problems of impedance rise, cycle life reduction, lithium dendrite precipitation and the like are caused. In particular, lithium dendrite precipitation is easy to form internal short circuit between a positive electrode and a negative electrode, thermal runaway is caused, and serious safety accidents are caused. However, it is still necessary to apply a limited and controllable restraining force to the sides of the cell. Therefore, the problems of impedance rise, cycle life reduction and the like caused by the fact that the distance between the diaphragm and the positive and negative pole pieces is enlarged when the battery is in a free expansion state can be avoided.

In order to avoid the influence of extrusion force among the single batteries, the battery module is generally restrained in the battery industry at present, and a method of arranging a certain gap among the single batteries is adopted to reserve a sufficient deformation space for the batteries. However, this method has the following disadvantages: 1. when the battery is in a discharge state or a partial discharge state, a gap is left between the single batteries, and the adverse effect exists when the battery is in a free expansion state; 2. in order to maintain the fastening of each single battery, the reserved gap usually depends on the elastic deformation, i.e. the compression amount, of the filling material, such as the heat insulation partition plate, and if the arrangement is not reasonable, a large and uncontrollable extrusion force may still occur when the battery is in a charging state, which brings about the above-mentioned adverse effects; 3. the compressible amount of the gap filling material is limited, and in order to ensure a reserved deformation space, the thickness required by the gap filling material is large, so that the overall volume energy density of the battery module is influenced; 4. when the batteries are repeatedly recycled, if the resilience performance of the gap filling material is aged and changed, gaps among the batteries are still likely to occur; 5. the deformation of the gap filling material does not well conform to the characteristic of large deformation of the center position of the side surface of the battery.

Secondly, when the lithium ion battery is abused or has manufacturing defects inside, an internal short circuit between the positive electrode and the negative electrode can occur to generate a large amount of heat, and thus various side reactions between components inside the battery are initiated, further more heat and gas are generated, the temperature and pressure inside the battery are increased sharply, and finally the battery is ignited and exploded. This process is referred to as thermal runaway of the lithium ion battery. Common abuse conditions include mechanical abuse such as puncture/crush/impact, thermal abuse such as heating/burning, and electrical abuse such as overcharge/overdischarge/external short circuits, etc. Thermal runaway is considered to be the root cause of serious safety accidents in lithium ion batteries.

In various pure electric vehicles and hybrid vehicles driven by lithium ion batteries, a lithium ion battery pack is a high-voltage system formed by connecting a plurality of single batteries in series (or in parallel and in series). If the heat generated by the thermal runaway of the single battery can be rapidly transferred to other single batteries in the battery pack, a chain reaction can be rapidly initiated to cause the thermal runaway of other single batteries, namely the thermal diffusion and the thermal spread of the lithium ion battery. Therefore, in order to improve the safety of the lithium ion battery pack, it is necessary to effectively isolate the heat diffusion between the unit cells and prevent the heat spread in the battery pack.

Therefore, it is desirable to provide a battery protection separator and a battery pack including the same to solve the above-mentioned problems in the prior art.

Disclosure of Invention

The invention aims to provide a battery protection separator and a battery pack comprising the same, so as to solve the problem that a lithium ion battery is uncontrollably deformed due to thermal expansion.

In order to achieve the purpose, the invention provides a battery protection separator which comprises a rigid supporting piece and two elastic pieces, wherein the elastic pieces are of arc structures, and a closed space is formed between the rigid supporting piece and the two elastic pieces.

The beneficial effects are that: adopt rigidity support piece and flexure strip to constitute fire barrier and separate the battery in the group battery, utilize the elastic action of flexure strip, in whole battery life cycle, the flexure strip directly produces the effort to the battery outside through the elastic action to clearance and pressure between the effectual regulation and the control electric core guarantee that the battery has abundant inflation space, avoid the battery because the inflation and the uncontrollable deformation that direct mutual extrusion caused.

Preferably, the elastic sheet further comprises a fireproof composite layer, and the fireproof composite layer is arranged on at least the outer surface of the elastic sheet. When the surface of the battery is overheated or has fire, the fireproof composite layer on the surface of the outer wall of the battery, close to the whole partition plate, directly isolates heat, blocks the fire propagation and ensures that the adjacent batteries cannot be influenced by the heat propagation.

In a possible implementation manner, a contact part is arranged at the middle position of the elastic sheet, and when the battery is deformed during charging and discharging, the contact part is preferentially contacted with the middle part of the battery. When deformation takes place at battery charge-discharge, because the contact site in the middle of the flexure strip and the preferential contact of battery middle part, the contact site is deformation earlier and produce the effort when the flexure strip takes place deformation, make the flexure strip be the biggest to the effort that the battery middle part produced, and the battery is at the charge-discharge in-process, it is main that the battery middle part is the biggest to outside inflation effort, the contact site through the flexure strip directly produces the biggest effort to the battery middle part, play the limiting displacement to the battery, and all the other positions of follow-up in-process flexure strip contact and produce the effort with the battery respectively, guarantee that the battery takes place the holistic stability of deformation back.

In one possible implementation, the inner wall of the spring steel sheet is provided with a plurality of concave hole-shaped structures. Due to the concave hole-shaped structure of the inner wall of the spring steel sheet, the volume of the closed space is increased, so that after a battery is overheated to generate a fire source, the vacuum volume or the inert gas volume in the closed space is increased, the flame retardant capability of the fire source is improved, the flame retardant effect of the closed space is improved, gases with arc-pulling resistance such as SF6 and the like or other non-metallic materials can be filled, and the heat insulation or arc-pulling resistance effect is ensured.

In a possible realization, an inflation port is provided on the rigid support. The beneficial effects are that: the inside of the closed space is conveniently pumped or inflated.

In one possible implementation, the enclosed space is filled with an inert gas or evacuated. When the batteries are out of control due to thermal runaway and fire occurs among the batteries, the inert gas carries out flame-retardant protection in an oxygen isolation mode, prevents the fire from spreading and plays a role in preventing fire and retarding flame among the batteries; when the batteries are out of control due to thermal runaway and fire occurs between the batteries, the vacuum state is adopted in the closed space, and the vacuum state is lack of oxygen, so that the fire can be prevented from spreading in time, and the fireproof and flame-retardant effects are achieved between the batteries.

In a possible implementation manner, the elastic sheet body includes a spring steel sheet, and the implementation manner is not limited to the form of an elastic sheet, but may also be a plate material plus an elastic sheet, and mainly can implement similar functions.

In a possible implementation manner, the spring steel sheet and the rigid support piece are fixed together by welding.

In a possible implementation manner, the fireproof composite layer comprises a heat insulation layer and a fireproof insulation layer which are sequentially arranged from inside to outside, and the heat insulation layer is fixedly attached to the fireproof insulation layer. The beneficial effects are that: the battery in the group battery is kept apart to the heat insulation layer of fire prevention composite bed with the fire prevention insulating layer, and direct every battery of fire prevention composite bed itself is kept apart alone on the one hand, constructs the independent thermal environment of every battery, thermal diffusion between the separation battery effectively, and on the other hand when the intensity of a fire stretches to being close to the fire prevention composite bed, the heat is isolated to the heat insulation layer, and the fire prevention insulating layer prevents the burning of fire source to the intensity of a fire when preventing battery thermal runaway stretches to other batteries.

The invention also discloses a battery pack which comprises batteries and the battery protection clapboard, wherein the batteries are independently separated by the battery protection clapboard.

Drawings

FIG. 1 is a schematic view of a vertical cross-section of the fire barrier of the present invention;

fig. 2 is a graph showing the relationship between the capacity retention rate and the number of cycles of a battery when the separator of the present invention is applied to a battery pack, as compared with a prior art separator.

In the figure: 1-a rigid support; 2-an elastic sheet; 3-fireproof composite layer; 4-a closed space; 5-an inflation inlet; 301-a thermal insulation layer; 302-fire-proof insulating layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, the word "comprising" and similar words are intended to mean that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items.

As shown in fig. 1, to solve the problems in the prior art, an embodiment of the present invention provides a battery protection separator, which includes a rigid support member 1, an elastic sheet 2, and a fireproof composite layer 3, where the elastic sheet 2 is an arc-shaped structure, a closed space 4 is formed between the rigid support member 1 and the elastic sheet 2, and the fireproof composite layer 3 is disposed on an arc-shaped surface of an outer wall of the elastic sheet 2; in the battery full life cycle, adjust and control clearance and pressure between the battery cell effectively, guarantee that the battery cell possesses abundant inflation space, and receive controllable constraining force all the time, can enough avoid casing and inside pole piece directly to extrude the uncontrollable deformation that causes each other because the inflation like this, interval grow between diaphragm and the positive and negative pole piece when can avoid the battery to be in free expansion state again, and construct the independent thermal environment of every battery cell through this kind of protection baffle, thermal diffusion between the separation battery effectively, thermal stretching and flame when preventing the battery cell to take place thermal runaway spreads.

In this example, the fireproof composite layer 3 is preferably provided on at least the outer surface of the one elastic sheet 2. As a further preferable mode, as shown in the drawing, a fireproof composite layer 3 is preferably provided on the outer surface of each of the two elastic sheets 2.

The rigid support member 1 in this example is a square hollow frame structure, which may be integrally formed or may be formed by splicing a plurality of support blocks. The rigid support can also be formed by splicing hollow tubular pieces as members.

In the embodiment, a stable partition plate structure is formed between two rigid support members 1 positioned at the upper end and the lower end of two elastic sheets 2 to isolate a single battery positioned in a battery pack, the rigid support members 1 are used for supporting the whole partition plate structure, and when the elastic sheets 2 are extruded to deform, the internal dimension of the partition plate structure is ensured to be unchanged; and under the elastic action of flexure strip 2 itself, when the isolated battery takes place the inflation deformation, flexure strip 2 produces the effort to the battery outer wall, make the battery external pressure unanimous all the time at the in-process of use circulation, thereby according to the inflation or the deformation degree of battery itself, flexure strip 2 self-adaptation ground is adjusted and is controlled clearance and pressure between the battery under the elastic action, guarantee that the battery has abundant inflation space, avoid the battery because the inflation and the directly uncontrollable deformation that mutual extrusion caused, guarantee the interval between inside diaphragm of battery and the pole piece, extension battery life, avoid appearing the battery short circuit safety problem.

In the specific embodiment, comparing the separator in the technical scheme with the separator in the prior art, the comparison graph of the capacity retention rate of the battery after the battery is cycled for a certain number of times is shown in fig. 2, so that it can be seen that the separator of the invention has a good protection effect on the battery capacity, the battery pack has a good capacity retention rate after being used for multiple times, and the battery performance is good and stable.

It should be noted that, when the protective separator of the present invention is used to protect a battery, compared to the separator of the prior art, the impedance of the separator of the present invention in the full-charge state and the discharge state is smaller, and compared to the capacity of the battery of the prior art, the capacity is larger, and the performance is better, taking a battery of a module of 48V and 100Ah as an example, the impedance parameters of the battery in the full-charge state and the discharge state are calculated, and the specific blocking comparison is shown in the following table:

48V100Ah module	Conventional separator	The invention
			Impedance (full electric state)	7.81	7.45
Impedance (discharge state)	8.45	7.93

It should be noted that the rigid support member 1 in the present application scheme is mainly used for supporting the entire partition board, wherein the rigidity mainly refers to the ability of the material structure not to deform under the action of an external force, i.e., the ability to resist deformation, and common metals and alloy materials can meet the requirements, such as aluminum alloy, stainless steel material, titanium alloy, copper alloy, and the like, and other non-metallic materials with similar strength can also be used.

Preferably, the rigid support member 1 in this embodiment is mainly used to support the whole separator structure, so as to ensure that heat transfer between adjacent batteries is reduced, and the thickness of the rigid support member is controlled within a certain range, so that the thickness can be reduced while the isolation and fire prevention are realized, and the size of the whole structure is reduced.

Further, fire prevention composite bed 3 itself mainly plays thermal-insulated, fire prevention and insulating effect, fire prevention composite bed 3 sets up outermost at whole baffle structure as outer layer structure, when the battery generates heat or thermal runaway, heat between the adjacent battery is isolated, avoid heat mutual transmission and the condition that a plurality of batteries generate heat or thermal runaway appears, in time cut off the propagation path around the flame source when flame appears, the impaired condition with whole group battery falls to minimumly, play the thermal protection effect to whole group battery.

Preferably, the fireproof composite layer 3 comprises a heat insulation layer 301 for isolating heat and a fireproof insulation layer 302 for preventing the battery from being fireproof and flame retardant, the heat insulation layer 301 is fixedly attached to the fireproof insulation layer 302, and the heat insulation layer 301 and the fireproof insulation layer 302 are sequentially arranged from inside to outside.

The heat insulation layer 301 is made of heat insulation materials and is mainly used for preventing heat transfer caused by thermal runaway, when heat generated by the battery is close to the outer surface of the whole separator, the heat insulation layer 301 isolates the heat transfer, and the risk of subsequent combustion is reduced; the fireproof insulating layer 302 mainly plays a role of fireproof insulation, and even if a fire source is generated, flame retardance is carried out on a propagation path of the fire source under the blocking effect of the fireproof insulating layer 302, so that the fire is prevented from being expanded when the fire source appears in the battery.

In an embodiment of the present disclosure, the thermal insulation layer 301 may be a silicon aerogel, and a fine nano-network structure of the silicon aerogel effectively limits propagation of local thermal excitation, and the solid thermal conductivity of the silicon aerogel is 2 to 3 orders of magnitude lower than that of a corresponding glassy material. The nanopores suppress the contribution of gas molecules to heat conduction. The refractive index of the silica aerogel is close to l, and the ratio of annihilation coefficients of the silica aerogel to infrared light and visible light reaches more than 100, so that the silica aerogel can effectively transmit sunlight and prevent infrared heat radiation of ambient temperature, becomes an ideal transparent heat-insulating material, and has been applied to the aspects of solar energy utilization and building energy conservation. The radiation heat conduction of the silicon aerogel can be further reduced by means of doping, the thermal conductivity of the carbon-doped aerogel can be as low as 0.013 w/m.K at normal temperature and normal pressure, and the carbon-doped aerogel is a solid material with the lowest thermal conductivity. The silicon aerogel can become a novel high-temperature heat-insulating material by doping titanium dioxide, and the thermal conductivity at 800K is only 0.03 w/m.K.

The fireproof insulation layer 302 is used to insulate the fire source, and any material with fireproof insulation performance can be used.

In this embodiment, the fireproof insulating layer 302 is specifically made of chlorinated rubber, which refers to a chlorinated product of natural rubber, and a mixture of trichloride and tetrachloride with a chlorine content of 65%. The chlorinated rubber has good compatibility with alkyd resin with similar linearity and low polarity, and the alkyd resin containing more than 54 percent of fatty acid and the chlorinated rubber have better compatibility in aromatic hydrocarbon diluent.

The chlorinated rubber is one of chlorinated polymers obtained by chlorination modification of natural rubber or synthetic rubber. Because of its excellent film-forming property, adhesion, corrosion resistance, fire resistance and insulativity, it can be extensively used for making adhesive, ship paint, container paint, chemical anticorrosion paint, road marking paint, fire-resisting paint, building coating and printing ink.

By utilizing the flame retardance and the insulating property of the chlorinated rubber, the battery is flame-retarded when the battery is in fire, the propagation of the fire is blocked, and the battery pack is protected.

In an embodiment of the present disclosure, during charging and discharging of the battery, a contact portion (not shown) close to the battery is disposed at a middle position of the elastic sheet, and when the battery deforms during charging and discharging, the contact portion preferentially contacts with a middle portion of the battery.

When deformation takes place at battery charge-discharge, because the contact site in the middle of the flexure strip and the preferential contact of battery middle part, the contact site is deformation earlier and produce the effort when the flexure strip takes place deformation, make the flexure strip be the biggest to the effort that the battery middle part produced, and the battery is at the charge-discharge in-process, it is main that the battery middle part is the biggest to outside inflation effort, the contact site through the flexure strip produces the biggest effort to the battery middle part, with the effort interact of battery middle part, thereby play the limiting action to the battery, guarantee the stability after the battery takes place deformation.

Further, because battery electricity core is at the charge-discharge in-process, and the effort of the middle department of battery is the biggest mainly, consequently through designing into the arc structure at the certain limit radian with flexure strip 2, when the power that receives in the middle of the battery is the biggest in the contact site assurance, all the other positions of flexure strip 2 produce even deformation effort, play the limiting action to the deformation of battery charge-discharge, when the battery generates heat and produces deformation, guarantee that all the other positions of battery atress is even.

In the present embodiment, the spring plate 2 may be a spring steel plate, and spring steel generally refers to steel specially used for manufacturing springs and elastic members due to elasticity in a quenched and tempered state, which has excellent comprehensive properties, and spring steel has excellent metallurgical quality (high purity and uniformity), good surface quality (strict control of surface defects and decarburization), and precise shape and size.

When the elastic sheet 2 adopts the spring steel sheet, because elasticity and rigidity that spring steel itself possessed, contact with the spring steel sheet when external battery takes place deformation, when guaranteeing to produce elastic force, also make whole baffle structure remain stable to can rebound fast and reset after whole baffle surface takes place to warp.

The spring steel sheet and the rigid support member 1 can be fixed together by welding, that is, the spring steel sheet and the rigid support member 1 are fixedly installed, so that the stability of the whole partition plate structure is ensured, the installation mode comprises but is not limited to welding and is only used for fixing the spring steel sheet and the rigid support member 1, and other suitable fixing modes can be applied to the scheme.

In a preferred embodiment, the enclosed space 4 is filled with inert gas, and when the external battery generates a flame due to thermal runaway, the inert gas filled in the enclosed space 4 further plays a role in insulating heat or extinguishing the fire, so as to prevent the flame from spreading around the battery.

In a preferred embodiment, the enclosed space 4 is evacuated to produce the same effects as described above, and the effects are to insulate heat and extinguish fire, and are not described herein again.

An inflation inlet 5 is formed in any one of the rigid supporting pieces in the closed space and used for pumping out or inflating gas so as to conveniently pump vacuum or inject inert gas.

In this embodiment, the spring steel inner wall is provided with a plurality of sunken cavernous structures (not drawn in the picture), because the spring steel in this application scheme is protected the battery on every side through its elastic action, avoid the battery to cause uncontrollable deformation because the inflation extrusion, and when taking place thermal runaway and produce the flame source, the heat obviously can transmit inside the enclosure space 4 between two spring steel, through set up sunken cavernous structure at the spring steel inner wall, increase whole enclosure space 4's volume, make after the battery is overheated to produce the flame source, vacuum volume or inert gas volume in the enclosure space increase, fire-retardant ability to the flame source improves, thereby improve enclosure space's thermal-insulated effect and fire prevention effect, the reinforcing is to the guard action of battery in the group battery.

As a preferred embodiment, the opening on the surface of the recessed porous structure is provided with a flame-retardant coating, when thermal runaway occurs and fire propagation occurs, and after a fire source contacts with the flame-retardant coating, the flame-retardant coating has high heat resistance and flame retardance and is not easy to burn, so that the flame-retardant effect of the closed space on the fire source is increased, and the adjacent batteries are protected; through the flame-retardant coating at the opening of the sunken porous structure, flame retardance is carried out in a distributed scattered point mode, so that a flame-retardant path is enlarged, and the protection effect on batteries in the battery pack is enhanced.

The invention also discloses a battery pack, which comprises the battery protection clapboard, wherein the battery protection clapboard is used for independently separating batteries, effectively adjusting and controlling the gap and pressure between single batteries in the whole life cycle of the batteries, ensuring that the single batteries have sufficient expansion space and are always subjected to controllable constraint force; the battery can avoid uncontrollable deformation caused by direct mutual extrusion of the shell and the internal pole core due to expansion, can also avoid the enlargement of the distance between the diaphragm and the positive and negative pole pieces when the battery is in a free expansion state, constructs an independent thermal environment of each single battery, effectively blocks thermal diffusion between the batteries, and prevents thermal spreading and flame spreading when the single batteries are out of control.

Although the embodiments of the present invention have been described in detail hereinabove, it is apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it is to be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the following claims. Moreover, the invention as described herein is capable of other embodiments and of being practiced or of being carried out in various ways.

Claims (10)

1. A battery protection separator is characterized by comprising a rigid support part and two elastic pieces, wherein the elastic pieces are of arc structures, and a closed space is formed between the rigid support part and the two elastic pieces.

2. The battery protection separator of claim 1 further comprising a fire-resistant composite layer disposed on at least an outer surface of said one elastomeric sheet.

3. The battery protection separator according to claim 1, wherein a contact portion is provided at an intermediate position of the elastic sheet, and the contact portion is preferentially brought into contact with an intermediate portion of the battery when the battery is deformed.

4. A battery protection separator according to claim 1, wherein said elastic sheet is provided with a plurality of concave hole-like structures on the inner wall surface inside said closed space.

5. A battery protection separator according to claim 1, wherein said rigid support member is provided with an inflation port.

6. A battery protection separator according to claim 5, wherein the interior of said enclosed space is filled with an inert gas or evacuated.

7. The battery protection separator of claim 4 wherein said elastomeric sheet comprises a sheet of spring steel.

8. The battery protection separator of claim 7 wherein said spring steel sheet and said rigid support member are secured together by welding.

9. The battery protection baffle of claim 2, wherein the fireproof composite layer comprises a heat insulating layer and a fireproof insulating layer which are sequentially arranged from inside to outside, the insulating layer is mutually attached to the arc-shaped surface of one side, close to the outer wall of the battery, of the elastic sheet, and the heat insulating layer is fixedly attached to the fireproof insulating layer.

10. A battery pack comprising two or more cells and the battery protective separator according to any one of claims 1 to 9, wherein the battery protective separator separates the cells independently from each other.

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