CN114122588A

CN114122588A - Battery and battery pack

Info

Publication number: CN114122588A
Application number: CN202111332512.4A
Authority: CN
Inventors: 宋宁; 王高武; 林文生; 张芳芳
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2022-03-01

Abstract

The application discloses battery and battery package, a battery include the casing and accept in at least one utmost point core group in the casing, utmost point core group includes: an isolation air bag; the pole core is accommodated by the isolating air bag and is sealed in the isolating air bag; the isolating air bag is suitable for containing gas generated by the pole cores in the using process and expanding, and when the number of the pole core groups is one, the isolating air bag expands to isolate at least one part of the pole core groups from the shell; when the number of the pole core groups is multiple, the pole core groups are electrically connected, and the isolating air bag is inflated to isolate at least one part of the pole core group from other pole core groups and/or the shell.

Description

Battery and battery pack

Technical Field

The present application relates to the field of battery technology, and more particularly, to a battery and a battery pack.

Background

When a module or a battery pack consisting of batteries is abused, one battery cell generates a thermal runaway reaction, and the generated heat is directly transferred to a nearby adjacent battery cell, so that the thermal diffusion reaction inside the battery is caused.

And the shell of the battery further transfers the heat to the pole core inside the adjacent battery to cause the thermal runaway reaction of the pole core of the adjacent battery, and further the thermal diffusion reaction between the batteries occurs.

That is, heat diffusion tends to occur inside the battery or in the adjacent battery in the battery pack in the related art.

Disclosure of Invention

An object of the present application is to provide a novel technical solution for a battery, which can solve the problem in the prior art that heat diffusion easily occurs in a battery or a battery pack.

It is yet another object of the present application to provide a new solution for a battery pack.

According to an object of the present application, there is provided a battery including a case and at least one pole core pack accommodated in the case, the pole core pack including: an isolation air bag; the pole core is accommodated by the isolating air bag and is sealed in the isolating air bag; the isolating air bag is suitable for containing gas generated by the pole cores in the using process and expanding, and when the number of the pole core groups is one, the isolating air bag expands to isolate at least one part of the pole core groups from the shell; when the number of the pole core groups is multiple, the pole core groups are electrically connected, and the isolating air bag is inflated to isolate at least one part of the pole core group from other pole core groups and/or the shell.

Optionally, two of said pole-core groups are connected in series.

Optionally, two of the pole core sets are connected in parallel.

Optionally, the number of the pole cores corresponding to the pole core group is multiple, the number of the isolation air bags corresponding to the pole core group is multiple, and the pole cores are in one-to-one correspondence with the isolation air bags.

Optionally, the insulation gas bag has a heat resistant layer.

Optionally, the air-isolating bag is an aluminum plastic film or a polyethylene film.

Optionally, the housing comprises: the body is provided with an accommodating cavity and an opening communicated with the accommodating cavity; the cover plate is arranged on the opening to seal the accommodating cavity and is connected with the pole lugs of the pole core group; the cover plate and/or the isolating air bag are/is provided with a liquid injection hole, and the liquid injection hole is communicated with the inside of the isolating air bag.

Optionally, the pole piece has a first side surface and a second side surface, the first side surface is disposed opposite to the cover plate, the second side surface is disposed opposite to the body, the area of the second side surface is larger than that of the first side surface, and the portion of the airbag corresponding to the second side surface is inflated to a greater extent than the portion of the airbag corresponding to the first side surface.

Optionally, the body is an aluminum shell.

According to a further object of the present application, there is provided a battery pack including the battery according to any one of the above embodiments.

According to one embodiment of the present disclosure, by providing the insulating gas bag at the outer side of the pole core group, it is possible to prevent the pole core group having thermal runaway from transferring heat to the nearby pole core group and/or case and from occurring a thermal diffusion reaction between the batteries, by utilizing the elastic deformation property of the insulating gas bag.

Further features of the present application and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which is to be read in connection with the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic view of the internal structure of a battery according to an embodiment of the present application;

FIG. 2 is a schematic illustration of pole piece gas generation for a battery according to one embodiment of the present application;

fig. 3 is a schematic view of the internal structure of a battery according to yet another embodiment of the present application;

fig. 4 is a schematic illustration of pole piece gas generation for a battery according to one embodiment of the present application.

Reference numerals

A battery 100;

a housing 10; a housing chamber 11; a body 12; a cover plate 13;

a pole core group 20;

an insulating air bag 21; a chamber 211;

a pole piece 22; a first side 221; a second side 222.

Detailed Description

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

The battery 100 according to an embodiment of the present application will be described in detail below with reference to the drawings.

As shown in fig. 1 to 4, the battery according to the embodiment of the present application includes a case 10 and at least one pole core group 20 housed in the case 10. The pole core group 20 includes an isolation gas pocket 21 and a pole core 22.

Specifically, the pole core 22 is housed in the separator bag 21 and sealed in the separator bag 21. The gas bag 21 is adapted to receive gas generated during use of the pole core 22 and to expand, and when the number of the pole core groups 20 is one, the gas bag 21 expands to isolate at least a part of the pole core group 20 from the case 10. When the number of the pole core groups 20 is plural, the plural pole core groups 20 are electrically connected, and the insulating air bag 21 is inflated to insulate at least a part of the pole core group 20 from other pole core groups 20 and/or the case 10.

In other words, the battery 100 according to the embodiment of the present application is mainly composed of the case 10 and the pole core group 20. The pole core group 20 is mainly composed of an isolation gas bag 21 and a pole core 22. The housing 10 encloses a receiving chamber 11, and an airbag 21 is accommodated in the receiving chamber 11. The accommodating cavity 11 can play a role in storage and accommodation. The housing 10 can serve as a protection.

A chamber 211 is defined in the insulating bag 21, and the pole piece 22 can be placed through the chamber 211. That is, pole piece 22 may be placed within chamber 211. Each pole core set 20 comprises at least one pole core 22, and at least one pole core 22 is arranged in each chamber 211. One or more pole pieces 22 may be disposed within one chamber 211. When the number of the pole pieces 22 is plural, plural pole pieces 22 may be located in different chambers 211 or the same chamber 211. During use of the pole piece 22, gases may be generated, for example, the pole piece 22 is susceptible to gas generation under low temperature heating, and gas generation occurs when thermal runaway of the pole piece occurs.

Since the airbag 21 has elasticity, it can be elastically deformed. Therefore, when the pole piece 22 is enclosed in the airbag 21, the airbag 21 is inflated by the internal gas. That is, the chamber 211 is a closed chamber 211. By adopting the closed chamber 211, the pole core group 20 located in the chamber 211 can be completely sealed, thereby further reducing the heat transfer efficiency between the pole core groups 20 in the two chambers 211 and between the pole core group 20 and the housing 10. When the closed chamber 211 is adopted, the pole core group 20 is sealed in the chamber 211, and gas generated by the pole core group 20 in the using process is restrained by the isolation gas bag 21. When the air bag 21 is inflated by the gas inside, the pole core group 20 and the pole core group 20, and/or the pole core group 20 and the housing 10 are physically separated to some extent, so that the heat transfer efficiency between the batteries 100 and the pole core group 20 is reduced, and the heat diffusion is suppressed.

For example, as shown in fig. 2 and 4, the separator bag 21 can be switched between the first state and the second state by the driving force of the gas inside the separator bag 21. With the airbag 21 in the first state, the volume of the chamber 211 is defined as a first volume V1. With the airbag 21 in the second state, the volume of the chamber 211 is defined as a second volume V2, V1 < V2. That is, the amount of elastic deformation of the airbag 21 in the second state is large, and the amount of elastic deformation of the airbag 21 in the first state is small.

Specifically, when the airbag 21 is in the first state, the distance between the inner surface of the portion of the airbag 21 where inflation occurs and the outer surface of the corresponding pole piece 22 is defined as a first distance S1. When the separator bag 21 is in the first state, at least a part (for example, the portion a) of the separator bag 21 is in contact with the outer surface of the pole piece 22 and the inner wall surface of the case 10, and the first distance S1 is 0. When the airbag 21 is in the second state, the airbag 21 and the case 10 are deformed and expanded outward, and the distance between the inner surface of the expanded portion (portion a) of the airbag 21 and the outer surface of the corresponding pole piece 22 is defined as a second distance S2, S1 < S2. That is, when the airbag 21 is switched from the first state to the second state by the internal gas, a large air gap is generated between the inner wall surface of the inflated portion (a portion) of the airbag 21 and the outer surface of the pole core 22, and the case 10 corresponding to the portion a is spaced from the pole core 22. It should be noted that other structures may be combined to achieve zero direct contact between the housing 10 and the pole piece 22.

When the number of pole core groups 20 is one, that is, one pole core group 20 is provided in the housing 10. The pole core assembly 20 includes an air bag 21 and a pole core 22 disposed in the air bag 21. The number of the pole cores 22 corresponding to the pole core group 20 is one or more. When the insulating airbag 21 is inflated, the inflated portion expands toward the position of the housing 10, and thus an air gap, for example, a strip gap, is generated between the housing 10 and the pole core 22, which results in physical insulation between the housing 10 and the pole core 22 at the inflated portion, reduces the heat transfer efficiency between the housing 10 and the pole core group 20, and reduces the heat transfer from the pole core 22 to the housing 10, thereby achieving the purpose of suppressing heat diffusion. Since the amount of heat transferred from the pole core assembly 20 to the case 10 is reduced, it can be avoided that the pole core assembly 20 that is thermally out of control causes other batteries 100 nearby to be affected.

When the number of the pole core groups 20 is plural, that is, at least two pole core groups 20 are provided in the housing 10. It should be noted that each pole core group 20 in the casing 10 may be the pole core group 20 of the present application, or a part of the pole core groups 20 may be the pole core group 20 of the present application, and is not limited herein. When the pole core 22 of one pole core group 20 generates gas, the isolating air bag corresponding to the pole core group 20 expands, and an air gap is generated between the expanded part and other pole core groups 20 to isolate, so that the heat transfer efficiency between the two pole core groups 20 is reduced, the heat is prevented from being transferred from the pole core group 20 to other pole core groups 20, and the purpose of inhibiting heat diffusion is achieved; or, the expanded portion is isolated from the housing 10 by generating an air gap, so as to prevent heat from being transferred from the pole core assembly 20 to the housing 10; alternatively, the expanded portion is simultaneously isolated from the other pole-core groups 20 and the housing 10 by generating an air gap therebetween, while preventing heat from being transferred from the pole-core group 20 to the other pole-core groups 20 and the housing 10.

That is, when one pole core group 20 undergoes a thermal runaway reaction in the event of abuse of the battery 100, the insulating gas bag 21 is provided outside the pole core group 20, so that it is possible to prevent heat generated from the thermally runaway pole core group 20 from being directly transferred to the nearby pole core group 20 and/or the case 10.

The number of the pole core groups 20 is at least one, that is, the number of the pole core groups 20 is more than one, and may be an even number or an odd number, which is not limited herein.

Further, the air bag 21 is an insulating material, and the safety of the battery 100 can be improved.

Thus, in the present embodiment, by providing the separator bag 21 outside the pole core group 20, it is possible to prevent the pole core group 20, which is thermally runaway, from transmitting heat to the nearby pole core group 20 and/or the case 10 and to prevent the occurrence of a thermal diffusion reaction between the batteries 100, by utilizing the elastic deformation property of the separator bag 21.

According to one embodiment of the present application, as shown in fig. 3 and 4, two pole-core groups 20 are connected in series. That is, the number of the pole-core groups 20 is plural, and one of the pole-core groups 20 and another of the pole-core groups 20 are electrically connected in series. At this time, at least one of the two pole core groups 20 is provided with an insulating air bag 21, which is not limited herein. For example, the number of the pole core groups 20 is three, the three pole core groups 20 are connected in series, and each pole core group 20 is provided with an air separation bag 21.

In some embodiments of the present application, as shown in fig. 1 and 2, two pole-core sets 20 are connected in parallel. That is, the number of the pole core groups 20 is plural, and at least two pole core groups 20 in the plural pole core groups 20 are electrically connected in parallel. At this time, at least one of the two pole core groups 20 is provided with an insulating air bag 21, which is not limited herein. For example, the number of the pole core groups 20 is two, the two pole core groups 20 are connected in parallel, and each pole core group 20 is provided with an air separation bag 21.

In some embodiments of the present application, as shown in fig. 1 and 3, the number of the pole cores 22 corresponding to the pole core group 20 is plural, the number of the airbag 21 corresponding to the pole core group 20 is plural, and the plural pole cores 22 and the plural airbag 21 are in one-to-one correspondence. That is, a plurality of pole cores 22 and a plurality of separation air bags 21 may be provided in one pole core group 20, each pole core 22 corresponds to one separation air bag 21, each pole core 22 is provided in one chamber 211, and any two pole cores 22 are not located in the same chamber 211.

In the present embodiment, by arranging the pole cores 22 in one-to-one correspondence with the chambers 211, it is possible to further prevent one thermal runaway pole core 22 from affecting another pole core 22, further prevent the thermal runaway reaction of the pole core 22, and further prevent the thermal diffusion reaction in the pole core group 20.

In the present embodiment, the principle of expanding the gas-driven separation gas bag 21 is adopted, when heat diffusion occurs, the pole core 22 is heated to generate gas, so that the separation gas bag 21 near the surface of the pole core 22 is inflated to separate the pole core group 20 from the casing 10, and the heat transfer efficiency is reduced by reducing the physical contact between the pole cores 22 and/or between the pole cores 22 and the casing 10, thereby achieving the purpose of suppressing the heat diffusion.

In some embodiments of the present application, the insulation bag 21 has a heat-resistant layer. When thermal runaway occurs in the pole piece 22, the released gas typically has a high temperature. Therefore, the separator bag 21 is designed to have heat resistance, and the separator bag 21 can be prevented from being damaged during use.

According to one embodiment of the present application, the separation airbag 21 is a high molecular polymer film.

Further, an aluminum plastic film or a polyethylene film. By using the above materials, the air bag 21 can have elasticity and a certain strength. The airbag 21 is not easily broken when it is inflated. The material also has certain heat resistance, and can keep strength for a certain time without damage under the high temperature condition of 100-600 ℃.

Alternatively, as shown in fig. 1 to 4, the housing 10 includes: a body 12 and a cover 13. The body 12 is provided with an accommodating chamber 11 and has an opening communicating with the accommodating chamber 11. The cover plate 13 is provided at the opening to close the accommodation chamber 11. The cover plate 13 is connected to the tabs of the pole core assembly 20. The cover plate 13 and/or the separator bag 21 have a liquid injection hole, and the liquid injection hole communicates with the interior of the separator bag 21. That is, the housing chamber 11 is enclosed by the body 12, and the opening can be closed by the cover 13.

It should be noted that the battery 100 of the present application may be assembled in a variety of ways. One of the assembling modes is as follows: before the pole core group 20 is placed into the shell, the pole core group 20 is first placed into the chamber 211 of the corresponding isolation gas bag 21. Then, the extraction of the positive and negative electrode tabs is realized by welding tab extraction pieces. Specifically, tab glue is designed on the tab leading-out sheet, and the sealing between the tab position and the isolating air bag 21 can be completed in a hot pressing mode. Subsequently, the pole core assembly 20 packaged with the isolation airbag 21 is subjected to processes of liquid injection, formation, capacity grading, self-discharge, DCIR (direct current resistance) and the like, and is finally sealed and screened to be qualified, and then is assembled. One or more pole core groups 20 are placed in the case 10 to assemble the battery 100. After the battery 100 is assembled, it can be used directly. In this assembly, the pole core group 20 housed in the airbag 21 corresponds to an independent small battery 100.

When the cover plate 13 has at least one liquid inlet, each liquid inlet corresponds to one of the air bags 21 and communicates with the chamber 211 of the corresponding air bag 21. The battery 100 further includes a closing member provided to the pour hole for closing the pour hole.

In the present embodiment, a further assembly method of the battery 100 can be realized by providing the lid plate 13 with a pour hole. This kind of assembly mode specifically includes: first, the electrode core pack 20 is loaded into the separator bag 21, and the separator bag 21 is half-sealed. One or more pole core sets 20 with an insulating gas bag 21 are assembled into a battery 100. In the battery 100, each isolation air bag 21 is independently communicated with the liquid injection hole on the cover plate 13, so that balanced and accurate liquid injection is facilitated. In this assembly mode, the position of the separator bag 21 is sealed except for the portion communicating with the liquid inlet. The sealing mode of the pole lug position of the pole core is as follows: and welding the positive and negative electrode lugs with the lug leading-out pieces. The tab leading-out sheet is designed with tab glue. Sealing at this location is accomplished by hot pressing the tab compound against the isolation air bag 21. The number of the pour holes in the lid plate 13 is one or more. The number of the liquid injection holes is the same as that of the isolating air bags 21, and each liquid injection hole corresponds to one isolating air bag 21. After the battery 100 is completely assembled, each of the separator gas bags 21 is accurately filled with liquid through the liquid filling hole. After the formation is finished, the filling hole is sealed by a sealing piece, so that the isolation air bag 21 is kept in a vacuum state.

According to an embodiment of the present application, as shown in fig. 1 to 4, the pole core 22 has a first side surface 221 and a second side surface 222, the first side surface 222 is disposed opposite to the cover plate 13, the second side surface 222 is disposed opposite to the body 10, the area of the second side surface 222 is larger than that of the first side surface 221, and the portion of the airbag 21 corresponding to the second side surface 222 is inflated to a greater extent than the portion of the airbag 21 corresponding to the first side surface 221. For example, the pole piece 22 is a cube, such as a rectangular parallelepiped or a square, and the pole piece 22 has a first side 221 and a second side 222. The first side 221 may be referred to as a facet and the second side 222 may be referred to as a facet. The facets can be used for tab extraction and for a fixed connection to the airbag 21. The large face is disposed opposite the body 12. Since the area of the large surface is larger than that of the small surface, the heat emitted from the large surface is larger than that emitted from the small surface, and the small surface is in a fixed state, the degree of expansion of the portion of the airbag 21 corresponding to the large surface is larger than that of the portion of the airbag 21 corresponding to the small surface, and the average gap between the large surface and the housing is larger than that between the small surface and the housing.

In the present embodiment, by disposing the body 10 opposite to the second side surface 222, the difficulty of generating a gap between the pole core 22 and the housing 10 can be reduced by using the characteristics of the pole core 22 itself.

According to one embodiment of the present application, the body 12 is an aluminum shell. Because the body 12 is made of aluminum, the aluminum can deform, and therefore, when the airbag 21 expands, the body 12 can deform at the same time, increasing the distance between the body 12 and the pole piece 22. In addition, most of the existing battery cases are made of aluminum, so that the pole core assembly 20 of the present application can be installed in the existing case 10 without modifying the existing case 10, and the application range of the present application is expanded.

In summary, the battery according to the present application has a better thermal diffusion inhibition capability, and will have a better inhibition effect on the thermal diffusion inside the battery and/or in the battery pack, thereby reducing the design pressure of thermal diffusion protection on the battery and battery pack layers.

The embodiment of the present application further provides a battery pack, which includes the battery 100 according to any one of the above embodiments. Since the safety performance of the battery pack according to the embodiment of the present application is improved, the battery pack according to the embodiment of the present application also has the above advantages, which are not described herein again.

Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims

1. The utility model provides a battery, includes the casing and accept in at least one utmost point core group in the casing which characterized in that, utmost point core group includes:

an isolation air bag; and

the pole core is accommodated by the isolating air bag and is sealed in the isolating air bag;

the isolating air bag is suitable for containing gas generated by the pole cores in the using process and expanding, and when the number of the pole core groups is one, the isolating air bag expands to isolate at least one part of the pole core groups from the shell; when the number of the pole core groups is multiple, the pole core groups are electrically connected, and the isolating air bag is inflated to isolate at least one part of the pole core group from other pole core groups and/or the shell.

2. The battery of claim 1, wherein two of the pole core groups are connected in series.

3. The battery of claim 1, wherein two of the pole core sets are connected in parallel.

4. The battery of claim 2 or 3, wherein the number of the pole cores corresponding to the pole core group is plural, the number of the isolation air bags corresponding to the pole core group is plural, and the plural pole cores correspond to the plural isolation air bags one by one.

5. The battery of claim 1, wherein the separator gas pocket has a heat resistant layer.

6. The battery of claim 5, wherein the separator gas bag is an aluminum plastic film or a polyethylene film.

7. The battery of claim 1, wherein the housing comprises:

the body is provided with an accommodating cavity and an opening communicated with the accommodating cavity;

the cover plate is arranged on the opening to seal the accommodating cavity and is connected with the pole lugs of the pole core group;

the cover plate and/or the isolating air bag are/is provided with a liquid injection hole, and the liquid injection hole is communicated with the inside of the isolating air bag.

8. The battery of claim 7, wherein the pole piece has a first side and a second side, the first side being disposed opposite the cover plate, the second side being disposed opposite the body, the second side having an area greater than an area of the first side, and a portion of the isolation gas pocket corresponding to the second side being inflated to a greater degree than a portion of the isolation gas pocket corresponding to the first side.

9. The battery of claim 8, wherein the body is an aluminum can.

10. A battery pack comprising the battery according to any one of claims 1 to 9.