CN215771237U

CN215771237U - Battery cell and battery pack

Info

Publication number: CN215771237U
Application number: CN202121194304.8U
Authority: CN
Inventors: 尹海旭; 苏树发; 刘道淦
Original assignee: Svolt Energy Technology Co Ltd
Current assignee: Svolt Energy Technology Co Ltd
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2022-02-08
Anticipated expiration: 2031-05-31

Abstract

The utility model belongs to the technical field of batteries, and discloses a battery core and a battery pack. This electric core sets up in battery case, and electric core includes: at least one first positive plate; two positive plates of second are located the outside of first positive plate respectively, and the negative pole piece is just to setting up with first positive plate, the positive plate parallel of second, between two adjacent first positive plates, all be provided with the negative pole piece between adjacent first positive plate and the positive plate of second, and the both sides face of first positive plate, the both sides face of negative pole piece and the positive plate of second have all coated the active layer towards the side of negative pole piece, and the side coating that the positive plate of second deviates from the negative pole piece has the heat-resistant layer. This electric core has played the effect of separation heat and thermal spread through having coated at the side that the second positive plate deviates from the negative pole piece with the heat resistance layer, cuts off the transfer path of thermal runaway back high heat to shell or other electric cores, avoids appearing the condition of chain thermal runaway.

Description

Battery cell and battery pack

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery core and a battery pack.

Background

With more and more attention paid to environmental problems, new energy resources are widely developed, and lithium ion batteries gradually take a leading position by virtue of the advantages of high energy density, large working voltage, no memory effect, long cycle life, environmental friendliness and the like.

The existing lithium ion power battery is developed towards the direction of a long battery core and a large module, the manufacturing process of the lithium ion power battery generally comprises a lamination type process and a winding type process, the lamination type process is adopted, the pole piece interface is smoother, the space utilization rate is high, the internal resistance is low, the current is uniform, but the following defects exist:

firstly, the whole surface pressure of the laminated battery cell is released more due to no binding of a winding fillet, so that the tolerance to foreign matters causing internal short circuit is lower, and the problem of short circuit caused by pole piece piercing can occur when slight foreign matters bear the pressure of pole piece expansion, so that the early warning time of a battery management system is shortened;

secondly, adopt the mode of "negative packet is positive" when the pole piece lamination, outmost being the negative pole piece promptly, the inlayer is the positive plate, because utmost point group outmost is the negative pole, electric core metal casing and anodal weak conduction or conducting state, if there is the foreign matter between casing and the utmost point group, electric core impales utmost point external insulation film in the use, can directly lead to positive negative pole short circuit and the condition of short circuit appears, and then takes place to corrode or thermal runaway. Meanwhile, after thermal runaway occurs, due to the fact that a corresponding heat insulation structure is not provided, thermal spread is not hindered, and the pole group directly transmits high heat to the aluminum shell after the thermal runaway occurs to cause linkage thermal runaway of adjacent battery cells in the battery pack;

thirdly, for the cell energy, the material layer coated on the outermost layer of the negative plate is redundant, and not only does the material layer occupy the space and lose the energy density, but also the surface of the negative plate is microscopically uneven and is stressed to pierce the negative plate under high pressure, so that the risk of short circuit is caused.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a battery cell and a battery pack, which improve tolerance to foreign matters and reduce risks of short circuit and thermal runaway.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a battery cell disposed within a battery housing, the battery cell comprising:

at least one first positive plate;

two second positive plates respectively positioned at the outermost sides of the first positive plates,

the negative pole piece, with first positive plate the parallel just setting of second positive plate, adjacent two between the first positive plate, adjacent first positive plate with all be provided with between the second positive plate the negative pole piece, the both sides face of first positive plate the both sides face of negative pole piece reaches the orientation of second positive plate the active layer has all been coated to a side of negative pole piece, the second positive plate deviates from a side coating of negative pole piece has heat-resistant layer.

Preferably, the thickness of the heat resistant layer is equal to or less than the thickness of the active layer.

Preferably, the heat resistant layer is a ceramic coating, a silicate coating or a heat resistant tape.

Preferably, the heat-resistant adhesive tape is made of heterocyclic polymer.

Preferably, the first positive plate and the second positive plate are made of one or more of lithium iron phosphate, ternary and cobalt-free batteries, lithium cobaltate and lithium manganate.

Preferably, the negative electrode sheet is made of one or more of graphite, silicon, tin and lithium titanate.

Preferably, the active layer is made of an active material.

In order to achieve the above purpose, the utility model further provides a battery pack, which includes a battery case, an isolation film and the above battery core, wherein the isolation film and the battery core are arranged inside the battery case, and the isolation film is wrapped outside the battery core and located between the battery case and the battery core.

Preferably, the isolation film is a mylar film or an insulating tape.

Preferably, the battery case is made of metal or plastic.

The utility model has the beneficial effects that:

according to the battery cell provided by the utility model, the two second positive plates are respectively positioned on the outermost sides of the first positive plates, the negative plates are respectively arranged between the two adjacent first positive plates and between the adjacent first positive plates and the adjacent second positive plates, so that the outermost layer is the second positive plate, and the inner layers are the first positive plate and the negative plate, namely, a positive wrapping negative mode is adopted, so that the outermost second positive plate is adjacent to the battery shell.

Meanwhile, one side face of the second positive plate is coated with the active layer, the other side face of the second positive plate is coated with the heat-resistant layer, the two side faces of the second positive plate have different functions, space waste is avoided, and the utilization rate is high. The heat-resistant layer is coated on one side face, deviating from the negative pole piece, of the second positive pole piece, the heat-resistant layer plays a role in heat and heat spreading separation, a transmission path of high heat to a battery shell or other battery cores after thermal runaway is cut off, and the situation of linkage thermal runaway is avoided.

According to the battery pack provided by the utility model, the isolating membrane and the battery core are arranged in the battery shell, the battery shell plays a role in protecting the isolating membrane and the battery core, and the isolating membrane is arranged outside the battery core and positioned between the battery shell and the battery core, so that the isolating membrane plays a role in protecting the battery core while playing a role in insulating heat and preventing heat transfer, and the situation that foreign matters are pierced is avoided. This battery package increases the foreign matter tolerance between battery case and electric core, reduces the short circuit risk, increases thermal-insulated effect simultaneously, improves the thermal-insulated security performance that stretchs, gives BMS more early warning time.

Drawings

Fig. 1 is a schematic structural view of a cell of the present invention;

fig. 2 is a schematic view of a structure of a viewing angle of a negative plate in a battery cell of the utility model;

fig. 3 is a schematic structural diagram of another view angle of the negative electrode plate in the battery cell of the utility model;

fig. 4 is a schematic view of a first positive plate in a cell according to the present invention;

fig. 5 is a schematic structural diagram of another view angle of the first positive plate in the battery cell of the utility model;

fig. 6 is a schematic view of a second positive plate in the battery cell of the present invention;

fig. 7 is a schematic structural diagram of another view angle of the second positive plate in the battery cell of the utility model;

fig. 8 is a schematic view of a battery pack according to the present invention;

fig. 9 is a schematic view of another aspect of the battery pack of the present invention.

In the figure:

100. a battery case; 200. an isolation film;

1. a first positive plate; 2. a second positive plate; 3. a negative plate; 4. an active layer; 5. and a heat resistant layer.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. 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.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical scheme of the utility model is further explained by the specific implementation mode in combination with the attached drawings.

The present embodiment provides a battery cell disposed in a battery case 100. As shown in fig. 1, the battery cell includes at least one first positive plate 1, two second positive plates 2 and a negative plate 3, the first positive plate 1, the second positive plates 2 and the negative plate 3 are arranged in parallel and opposite to each other, the two second positive plates 2 are respectively located at the outermost sides of the first positive plates 1, and the negative plates 3 are respectively arranged between two adjacent first positive plates 1 and between the adjacent first positive plates 1 and the adjacent second positive plates 2. Two side surfaces of the first positive plate 1, two side surfaces of the negative plate 3 and one side surface of the second positive plate 2 facing the negative plate 3 are coated with active layers 4, and one side surface of the second positive plate 2 departing from the negative plate 3 is coated with a heat-resistant layer 5.

It can be understood that, the first positive plate 1 and the second positive plate 2 are positive plates, both side surfaces of the first positive plate 1 are coated with the active layers 4, then the first positive plate 1 is a double-sided coated active layer 4, one side surface of the second positive plate 2 is coated with the active layers 4, then the second positive plate 2 is a single-sided coated active layer 4, the single-sided coated active layer 4 of the second positive plate 2 faces the inner side, namely the single-sided coated active layer 4 of the second positive plate 2 faces the negative plate 3 adjacent to the negative plate, and the side surface of the second positive plate 2 facing away from the negative plate 3 is coated with the heat resistance layer 5, namely the heat resistance layer 5 of the second positive plate 2 faces the outer side and faces away from the negative plate 3. And the two side surfaces of the negative plate 3 are coated with the active layers 4, so that the negative plate 3 is coated with the active layers 4 on the two sides.

The electric core provided by the embodiment is located on the outermost side of the first positive plate 1 through the two second positive plates 2, between the two adjacent first positive plates 1, the negative plate 3 is arranged between the adjacent first positive plates 1 and the second positive plates 2, the outermost layer is the second positive plate 2, the inner layer is the first positive plate 1 and the negative plate 3, namely, the positive wrapping negative mode is adopted, the outermost second positive plate 2 is adjacent to the battery shell 100 (as shown in fig. 9), when the battery shell 100 is in a weak conduction state, the polarities of the second positive plate 2 and the battery shell 100 are the same, even if the electric core is pierced in the using process, the short circuit between the second positive plate 2 and the battery shell 100 cannot occur, the tolerance of the electric core to foreign matters is improved, and the early warning time of the battery management system can be prolonged.

Meanwhile, one side surface of the second positive plate 2 is coated with the active layer 4, the other side surface of the second positive plate 2 is coated with the heat-resistant layer 5, and the two side surfaces of the second positive plate 2 have different functions, so that space waste is avoided, and the utilization rate is high. Through coating at the side of second positive plate 2 deviating from negative pole piece 3 with heat-resistant layer 5, heat-resistant layer 5 has played the effect of separation heat and thermal spread, cuts off the transfer path of high heat to battery case 100 or other electric cores after the thermal runaway, avoids appearing the condition of chain thermal runaway.

As shown in fig. 2 to fig. 7, when the battery cell is manufactured, the method includes the following steps:

the first step, homogenate coating, namely coating slurry on a current collector of a common positive plate, and homogenate coating into two forms of positive plates. The slurry is prepared from active substances, and the cost is low. Coating slurry on both sides of the positive plate to form a first positive plate 1; the second positive electrode tab 2 is formed by coating the slurry on only one side of the positive electrode tab and coating or attaching a heat-resistant layer 5 on the opposite side of the positive electrode tab on which the slurry is coated on one side. The positive plate is specially processed. The negative electrode sheet 3 is manufactured in a conventional manner, and slurry is coated on both sides of the negative electrode sheet 3, so that the details are not repeated.

And a second step of rolling, wherein after the first positive plate 1 and the second positive plate 2 are coated, rolling is performed according to a preset compaction density.

And thirdly, cutting and die-cutting the two positive plates to obtain two forms of positive plates applicable before lamination.

And fourthly, stacking, wherein two positive plates are respectively arranged in the stacking clamp, the second positive plate 2 coated with the active layer 4 on one side is positioned on the outermost layer, the first positive plate 1 coated with the active layer 4 on the two sides is positioned on the inner layer, and the negative plates 3 are respectively arranged between the two adjacent first positive plates 1 and between the adjacent first positive plates 1 and the second positive plate 2, so that the positive plates and the negative plates 3 are arranged at intervals.

By adopting the lamination process, the service life of the battery cell is longer, the interface of the pole piece is smoother, the internal resistance is lower and the current is more uniform.

It can be understood that, since the two second positive electrode sheets 2 are respectively positioned at the outermost sides of the first positive electrode sheet 1, after the positive electrode sheets are coated, the ratio of the theoretical number of sheets of the second positive electrode sheet 2 and the first positive electrode sheet 1 produced by the two coating methods is 2/a, where a is the number of sheets of the first positive electrode sheet 1 coated with the active layer 4 on both sides.

Furthermore, the battery core can adopt battery cores of different systems, and the first positive plate 1 and the second positive plate 2 are made of one or more of lithium iron phosphate, ternary, cobalt-free batteries, lithium cobaltate and lithium manganate. The negative plate 3 is made of one or more of graphite, silicon, tin and lithium titanate. The positive plate and the negative plate 3 are made of simple materials, and have the advantages of simple structure, convenient use and low production cost.

Further, as shown in fig. 6 to 7, the thickness of the heat resistant layer 5 is equal to or less than the thickness of the active layer 4. It is understood that the thickness of the active layer 4 specifically refers to the thickness of the second positive electrode sheet 2 after being rolled with the active material applied to one side. The adoption of the arrangement has the following two purposes that firstly, the occupation ratio of non-energy substances is reduced, the occupied space is small, the energy density loss caused by the large occupied space of the heat-resistant layer 5 is avoided, and the energy density is improved to a certain extent; secondly, because the heat-resistant layer 5 is positioned on the outermost layer, the heat-resistant layer 5 with smaller thickness avoids the situation of short circuit caused by puncture under larger pressure because of smaller corresponding coating.

Wherein, the heat resistant layer 5 is a ceramic coating, a silicate coating or a heat resistant adhesive tape. The heat resistant layer 5 may be applied as, but not limited to, a high temperature resistant and low thermal conductivity ceramic coating, such as Al₂O₃Or silicate coating, etc., and the thermal barrier layer 5 may be, but is not limited to, a tape made of heterocyclic polymer, such as polyimide-based tape. The heat resistant layer 5 has a simple structure and is convenient to use.

As shown in fig. 8 to 9, the battery pack includes a battery case 100, a separation film 200, and the battery core, where the separation film 200 and the battery core are disposed inside the battery case 100, and the separation film 200 is wrapped outside the battery core and located between the battery case 100 and the battery core.

The battery pack that this embodiment provided, battery case 100's inside is provided with barrier film 200 and electric core, and battery case 100 has played the effect to barrier film 200 and electric core protection, wraps up in the outside of electric core and lies in between battery case 100 and the electric core through setting up barrier film 200, and barrier film 200 has still played the effect to electric core protection when having played thermal-insulated and stop heat transfer effect, avoids the condition that the foreign matter impaled to appear. This battery pack increases the foreign matter tolerance between battery case 100 and the electric core, reduces the short circuit risk, increases thermal-insulated effect simultaneously, improves the thermal-insulated security performance that stretchs, gives more early warning time of battery management system.

Further, the isolation film 200 is a mylar film or an insulating tape, and has a simple structure and a low production cost.

Further, the battery case 100 is made of metal, plastic or aluminum plastic film, and has a simple structure and a low production cost.

In the description herein, it is to be understood that the terms "upper", "lower", "right", and the like are based on the orientations and positional relationships shown in the drawings and are used for convenience in description and simplicity in operation, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be constructed in a particular operation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive purposes and are not intended to have any special meaning.

In the description herein, references to the description of "an embodiment," "an example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

In addition, the foregoing is only the preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A battery cell disposed within a battery casing (100), the battery cell comprising:

at least one first positive electrode tab (1);

two second positive plates (2) are respectively positioned at the outermost sides of the first positive plates (1),

negative pole piece (3), with first positive plate (1), second positive plate (2) parallel just to setting up, adjacent two between first positive plate (1), adjacent first positive plate (1) with all be provided with between second positive plate (2) negative pole piece (3), the both sides face of first positive plate (1) the both sides face of negative pole piece (3) reaches second positive plate (2) orientation the side of negative pole piece (3) all coats and has active layer (4), second positive plate (2) deviate from the side coating of negative pole piece (3) has heat-resistant layer (5).

2. The electrical core according to claim 1, wherein the thickness of the thermal barrier layer (5) is equal to or less than the thickness of the active layer (4).

3. The electrical core according to claim 1, wherein the thermal barrier (5) is a ceramic coating, a silicate coating or a thermal barrier tape.

4. The electrical core of claim 3, wherein the heat resistant tape is made of a heterocyclic polymer.

5. The battery cell of claim 1, wherein the first positive plate (1) and the second positive plate (2) are made of one or more of lithium iron phosphate, ternary, cobalt-free batteries, lithium cobaltate and lithium manganate.

6. The battery cell of claim 1, wherein the negative electrode sheet (3) is made of one or more of graphite, silicon, tin and lithium titanate.

7. The electrical core according to claim 1, characterized in that the active layer (4) is made of an active substance.

8. A battery pack, comprising a battery casing (100), a separation film (200) and the battery core of any one of claims 1 to 7, wherein the separation film (200) and the battery core are disposed inside the battery casing (100), and the separation film (200) is wrapped outside the battery core and is located between the battery casing (100) and the battery core.

9. The battery pack according to claim 8, wherein the separator (200) is a mylar film or an insulating tape.

10. The battery pack according to claim 8, wherein the battery case (100) is made of metal or plastic.