CN114725483A

CN114725483A - High-voltage battery with novel structure

Info

Publication number: CN114725483A
Application number: CN202210322557.1A
Authority: CN
Inventors: 曾士哲
Original assignee: Weilai Automobile Technology Anhui Co Ltd
Current assignee: Weilai Automobile Technology Anhui Co Ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2022-07-08

Abstract

The invention relates to a single battery, a battery pack and an electric vehicle. The single battery comprises a shell and two pole cores, wherein the shell is provided with a partition board and four pole columns, the two pole columns are positive pole columns, the other two pole columns are negative pole columns, and the partition board separates the inside of the shell into two cavities. Each of the two pole pieces has a positive tab and a negative tab disposed on the same side of the pole piece at an interval from each other, and the two pole pieces are oppositely disposed in the case with respect to the positive tab and the negative tab such that the positive tabs and the negative tabs of the two pole pieces are staggered from each other. The four polar columns are arranged in a polar manner, the four polar lugs are respectively connected in a polar manner and arranged on the four polar columns, and the four polar columns are separated by the partition plates so that the two polar cores are respectively positioned in the two cavities. In addition, the middle two positive and negative posts are connected to each other such that the two pole pieces are connected in series, and the other two positive and negative posts serve as the positive and negative posts of the unit cell, respectively.

Description

High-voltage battery with novel structure

Technical Field

The invention relates to the field of single batteries, in particular to a single battery, a battery pack provided with the single battery and an electric vehicle provided with the battery pack.

Background

Nowadays, with the continuous development of new energy automobiles, the requirement for vehicle-mounted batteries is higher and higher. The demand is reflected in that the demand for the total electric quantity of the battery pack of the new energy automobile is continuously increasing, and all of the demand is based on the continuously increasing demand for the continuous mileage of the new energy automobile. For example, in order to improve power performance, electric vehicles employ high voltage battery packs, the battery capacity of which is typically greater than 800V.

Traditionally, only be equipped with a naked electric core or a plurality of naked electric core that are in parallel state in the shell of battery, and single naked electric core or a plurality of naked electric cores of parallelly connecting all can't improve the voltage of whole battery. Since the cell voltage is typically <4.5V (e.g., the voltage of a lithium titanate-based battery is 2.4V, the voltage of a lithium iron phosphate-based battery is 3.2V, the voltage of a ternary-based battery is 3.7V, and the voltage of a multipolymer-based battery is 4.3V), it is generally necessary to increase the number of batteries in a battery pack. The greater the number of cells, the higher the weight fraction of the battery case, which results in a significant reduction in the energy density of the battery pack.

There are generally two current approaches to addressing cell high voltage, the first is to develop a high voltage chemical system (> 5V); the second is to multiply the battery voltage by the form of "inner string" of bare cells. However, the first method has a limited voltage increase degree, and the high-voltage liquid electrolyte technology is not mature, so that industrialization cannot be realized for a while; the second method adopts an 'inner string' mode, if all 'inner string' units in the battery are communicated, the liquid electrolyte cannot bear high voltage, and then the electrolyte is decomposed, so that the battery fails. Therefore, the use of solid electrolytes is required, but the technology is not yet mature at present. If all the 'inner string' units are isolated, the space utilization rate of the single battery cell is low, and the weight-to-weight ratio of the isolated part is high. The cell voltage increases, but the energy density decreases.

Disclosure of Invention

The invention aims to provide a single battery which can overcome the defects, wherein the voltage of the single battery is 2 times of that of a conventional battery core, the energy density is improved compared with that of the battery with the conventional structure, and the normal operation of the battery can be realized by using the conventional low-voltage electrolyte.

Furthermore, the present invention is also directed to solve or alleviate other technical problems of the prior art.

According to a first aspect of the present invention, the technical solution adopted by the present invention is to provide a single battery, which comprises a shell and two pole cores, wherein the shell is provided with a clapboard and four poles, two poles are positive poles, the other two poles are negative poles, and the separator separates the interior of the case into two cavities, each of the two pole cores having positive and negative electrode tabs disposed on the same side of the pole core at an interval from each other, and the two pole pieces are oppositely disposed in the case with respect to the positive electrode tab and the negative electrode tab so that the positive electrode tabs and the negative electrode tabs of the two pole pieces are interleaved with each other, wherein the four poles are arranged according to polarity, the four tabs are respectively connected according to polarity and are arranged on the four poles, and are separated by the partition plate so that the two pole cores are respectively positioned in the two cavities; and wherein the middle two positive and negative posts are connected to each other such that the two pole cores are connected in series, and the other two positive and negative posts serve as positive and negative posts of the unit cell, respectively.

Alternatively, according to an embodiment of the present invention, the middle two positive and negative posts are connected to each other by a metal conductor, and an insulating sleeve covers the middle two positive and negative posts such that the middle two positive and negative posts are spaced from the outside of the battery.

Alternatively, according to an embodiment of the present invention, at a position of the housing where the partition is provided, the upper housing cover of the housing is provided with a concave portion, and the four poles are arranged on the concave portion in a spaced and staggered manner.

Alternatively, according to an embodiment of the present invention, the case has a separator located in a middle region of the case to separate the positive electrode tabs and the negative electrode tabs of the two pole pieces.

Optionally, according to an embodiment of the invention, the material constituting the shell is aluminum, steel or a polymer material, and the pole core is in the form of a winding core or a lamination.

Alternatively, according to an embodiment of the present invention, the separator is made of an insulating material, and the insulating material is polyvinyl chloride, polyethylene, polytetrafluoroethylene, polyimide, or polyamideimide.

Alternatively, according to an embodiment of the present invention, when the unit cell is a lithium ion battery, the electrode core includes a positive electrode, a negative electrode, a separator, and an electrolyte, and the positive electrode is a lithium-containing compound and the negative electrode includes a carbon material.

Optionally, according to an embodiment of the invention, a liquid injection hole and an explosion-proof valve are provided in the two cavities of the housing.

According to a second aspect of the present invention, there is provided a battery pack including the above-described unit battery.

According to a third aspect of the present invention, there is provided an electric vehicle having a battery pack including the above-described unit battery.

Compared with the prior art, the single battery has the following beneficial effects: the present invention can shorten the interval between the adjacent pole cores and further improve the energy density, and can omit the connecting through holes in the separator and the packaging structure required for sealing the connecting through holes and further simplify the structure of the battery. In addition, the present invention can preset the position where the electrode cores are connected in series, and facilitate the pre-manufacture of the separator and thus the mass production of the battery.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

Drawings

The invention may be more particularly described, by way of example, with reference to the accompanying drawings, which are not drawn to scale, and in which:

fig. 1 shows a schematic view of two pole pieces constituting a unit cell according to the present invention;

FIG. 2 shows a side view of a single pole piece as shown in FIG. 1 in accordance with the present invention;

fig. 3 shows a top view of a housing of a battery cell according to the invention;

fig. 4 shows a front view of the housing of the battery cell as shown in fig. 3;

fig. 5 shows a bottom view of the housing of the battery cell as shown in fig. 3;

fig. 6 shows a top view of the two pole pieces of fig. 1 inserted into the housing of fig. 3;

FIG. 7 shows a top view of the housing after installation of the insulating sleeve;

FIG. 8 shows a cross-sectional view of the housing taken along line A-A' in FIG. 7; and

figure 9 shows an alternative partition dividing the interior of the housing into two chambers.

Detailed Description

It is easily understood that according to the technical solution of the present invention, a person skilled in the art can propose various alternative structures and implementation ways without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as limiting or restricting the technical aspects of the present invention.

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like referred to or may be referred to in this specification are defined relative to the configuration shown in the drawings, and are relative terms, and thus may be changed correspondingly according to the position and the use state of the device. Therefore, these and other directional terms should not be construed as limiting terms. Furthermore, the terms "first," "second," "third," and the like are used for descriptive and descriptive purposes only and not for purposes of indication or implication as to the relative importance of the respective components.

As clearly shown in fig. 1, a schematic view of two pole pieces constituting a unit cell according to the present invention is provided. The unit cells may be lithium ion batteries. In a pole core of a lithium ion battery, at least a positive electrode, a negative electrode, a separator, and an electrolyte are present. The positive electrode may be a lithium-containing compound, and the negative electrode may include a carbon material. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. When the battery is discharged, lithium ions embedded in the negative carbon layer are extracted and move back to the positive electrode. Additionally, the pole core may be wound into a form, and thus may be referred to as a jellyroll. Alternatively, the pole core may be in the form of a lamination.

Unlike the positive and negative electrode tabs of the prior art, which are disposed on opposite sides of the pole piece, respectively, as shown in fig. 1 and 2, according to one embodiment of the present invention, each pole piece 1,1 'has a positive electrode tab 2,2' and a negative electrode tab 3,3', and the positive electrode tabs 2,2' and the negative electrode tabs 3,3 'are disposed on the same side of the pole piece 1,1' and spaced apart from each other. In addition, in contrast to the conventional "end-to-end" arrangement of multiple pole pieces in the housing, the two pole pieces 1,1 'of the present invention are oppositely disposed in spaced cavities 8,8' of the housing 4 with respect to the side on which the tabs are disposed, so that the positive tabs 2,2 'and the negative tabs 3,3' are interleaved or meshed with each other, thereby increasing space utilization within the housing 4, and thus increasing battery energy density. This relative placement is further clearly shown in fig. 6 and 9.

In fig. 3 showing the case 4 of the unit cell according to the present invention, the case 4 serves to increase the strength of the battery and ensure safe use of the battery to prevent electrolyte having corrosiveness from overflowing to the outside of the battery, causing negative effects. The case 4 may be made of plastic or metal, and in case the case 4 is made of metal, the metal is preferably aluminum or steel to facilitate heat dissipation of the battery and to improve the strength of the battery, and in case the case 4 is made of plastic, the plastic may be a polymer material such as polypropylene (PP). The housing 4 may be a rectangular parallelepiped, a cube, or a rectangular parallelepiped or a cube having a chamfer, a partial arc, a partial bend.

A partition 9 of a saw-tooth type is provided inside the housing 4 to divide the interior of the housing 4 into two chambers 8, 8'. The separator 9 is made of an insulating material, and the insulating material may be, for example, polyvinyl chloride, polyethylene, polytetrafluoroethylene, polyimide, polyamideimide, or the like. Alternatively, in addition to the above-described zigzag shape, the separator 9 may take other shapes that completely separate the positive electrode tabs 2,2' and the negative electrode tabs 3,3' facing each other, which are disposed on the same side of the pole cores 1,1', such as a step-type separator 19 as shown in fig. 9. In addition, preferably, the housing 4 may be a housing having an inner surface insulated.

The separator 9 includes a side surface facing the adjacent pole core 1,1' and a circumferential surface adjoining the side surface. The circumferential surface cooperates with the housing 4 to separate the interior of the housing 4 into two cavities 8, 8'.

The two cavities 8,8' can be used to receive the oppositely arranged pole pieces 1,1' and thus significantly reduce the spacing between the two pole pieces 1,1' and effectively increase the space utilization of the housing 4. In this case, the endurance of the electric vehicle using the unit battery and the battery pack can be effectively improved.

In addition, as further shown in fig. 3 and 4, the upper cover of the housing 4 is provided with a recess at the location of the housing 4 where the partition 9 is provided, i.e. preferably at an intermediate position of the housing 4. Four

poles

6,6 'and 7,7' (i.e. positive poles 6,6 'and negative poles 7, 7') are arranged spaced apart and staggered on the recess so as to receive the positive ears 2,2 'and negative ears 3,3' of the poles 1,1', respectively, when the two poles 1,1' are placed in the two cavities 8,8 'of the casing 4, thereby achieving electrical connection between the positive ears 2,2' and negative ears 3,3 'of the poles 1,1' and the positive poles 6,6 'and negative poles 7,7' of the casing 4.

As shown in fig. 5, the edge of the lower case cover 5 of the case 4 is hermetically connected to the case 4, and the circumferential surface of the partition plate 9 and the lower case cover 5 are connected by laser welding, thereby achieving isolation of the cavity 8 from the cavity 8'. Of course, the connection may be a soldered connection, a brazed connection, an adhesive connection, a snap-fit connection, or other forms of connection known to those skilled in the art, in addition to laser welding.

In another embodiment, the unit cell may further include a separator having insulation and electrolyte corrosion resistance inside the case 4. The material of the release film may include polypropylene, polyethylene, and the like. In addition, the separator may include a plurality of layers such as an outer layer, an intermediate layer, and an inner layer, wherein the outer layer may be made of a polyester or nylon material to prevent damage to the battery from an external force, such as puncturing the battery; the intermediate layer may be made of a metal material to prevent moisture permeation and electrolyte overflow from the outside of the battery; and the inner layer may be made of polypropylene, polyethylene, or other material that is less reactive with the electrolyte of the battery and has insulation properties.

In addition, the cavities 8,8' of the casing 4 may have a pour hole, and the pour hole may be located in the large face or side face of the battery as desired. For example, a pour hole may be provided in the separator 9 (preferably, provided or interposed in the circumferential face of the separator 9) to inject the electrolyte from outside the battery into the cavity 8,8' of the case 4, in which case the case 4 is provided with a through hole at a position corresponding to the pour hole of the separator 9 for bringing the pour hole into fluid communication with the outside of the battery. Further, in the case where the battery includes a separator, a passage corresponding to the liquid injection hole and the through hole is provided in the separator for injection of the electrolytic solution from the outside of the battery. The battery further includes a block piece or a sealing member for sealing the injection hole after the injection of the electrolyte is completed.

Next, referring to fig. 6 to 8, fig. 6 shows a top view of the two pole cores of fig. 1 inserted into the case of fig. 3, fig. 7 shows a top view of the case after the insulating sheath is mounted, and fig. 8 shows a cross-sectional view of the case taken along line a-a' of fig. 7.

Fig. 6-8 clearly depict the installation process of the unit cell, and the installation process includes the following three steps:

in a first step, the core 1 is placed into one cavity 8 of the case 4 separated by a zigzag-type separator 9, and the positive and

negative tabs

2 and 3 of the core 1 are received by the positive and

negative posts

6 and 7 of the case 4, respectively, and thus an electrical connection is formed therebetween. At the same time, the core 1' is placed in another cavity 8' of the case 4 separated by the partition 9 of the zigzag type, and the positive tab 2' and the negative tab 3' of the core 1' are received by the positive post 6' and the negative post 7' of the case 4, respectively, and thus an electrical connection is formed therebetween. The state in which the pole piece 1 and the pole piece 1 'are placed in two separate cavities 8,8' of the housing 4 is clearly shown in fig. 6. The positive electrode tabs 2,2' and the negative electrode tabs 3,3' of the pole cores 1,1' are arranged in series in the order of "positive, negative". Alternatively, in fig. 9, the positive electrode tabs 2,2' and the negative electrode tabs 3,3' of the pole cores 1,1' are arranged in series in the order of "positive, negative, positive, negative".

In a second step, the lower housing cover 5, preferably in the shape of a cuboid, is sealingly connected at the peripheral edge with the housing 4, which can be achieved via laser welding, soldering, brazing, adhesives, snap-fit connections or the like. At the same time, the partition 9 is connected in a sealing manner at the circumferential face to the lower housing cover 5, and thus isolates the two chambers 8,8' of the housing 4, which sealing connection can likewise be achieved via laser welding, soldering, brazing, adhesives, snap-fit connections or the like.

In a third step, in the recess of the housing 4 in the middle region, the positive 6' and negative 7 posts of the housing 4 are connected by an external metal conductor 11, so that a connection between the positive tab 2' of the pole piece 1' and the negative tab 3 of the pole piece 1 is achieved. In this case, the middle two tabs 2' and 3 are connected to each other such that the two pole cores 1 and 1' are connected in series, and the other two tabs 2 and 3' serve as a positive tab and a negative tab of the unit cell, respectively. Further, the separate insulation of the positive tab 6 'and the negative tab 7 of the case 4, and thus the positive tab 2' of the core 1 'and the negative tab 3 of the core 1, from the outside of the battery is achieved by covering the insulating sleeve 10 over the positive tab 6' and the negative tab 7 of the case 4, and thus the positive tab 2 'of the core 1' and the negative tab 3 of the core 1, and hermetically connecting the insulating sleeve 10 to the case 4. Likewise, the sealed connection of the insulating sleeve 10 to the housing 4 can be achieved via laser welding, soldering, brazing, adhesives, snap-fit connections, etc. The insulating sheath 10 may be made of the same material as the separator 9, and the material may be, for example, polyvinyl chloride, polyethylene, polytetrafluoroethylene, polyimide, polyamideimide, or the like.

After sealing the cell, a pour hole is provided in the cavity 8,8' of the casing 4, and the pour hole (and associated closure or seal) may be located in the large face or side of the cell as desired. For example, a liquid injection hole may be provided in the separator 9 (preferably, in the circumferential face of the separator 9) to inject the electrolyte into the cavity 8,8' of the case 4 from outside the battery.

The above-mentioned unit cell may further include other necessary components (e.g., an explosion-proof valve, a current interrupt device, etc.) for performing its functions, which are well known to those skilled in the art and will not be described herein.

Compared with the prior art, the single battery has the following beneficial effects. Although the prior art discloses the technical idea of arranging the pole core groups in the separated containing cavities and connecting the pole core groups in the containing cavities in series, thereby effectively improving the capacity and the voltage of the battery, the invention can further shorten the distance between the adjacent pole cores and further improve the energy density on the basis of the prior art, and can omit the connecting through holes in the partition boards and the packaging structure required for closing the connecting through holes and further simplify the structure of the battery. In addition, the electrode cores are directly connected in series through the electrode lugs without using the electrode posts of the shell as an intermediary in the prior art, but the electrode lugs of the electrode cores are connected with the electrode posts of the shell, and then the intermediate electrode posts are connected to form the electrode core series connection, so that the invention can preset the position of the electrode core series connection, and is convenient for the pre-manufacture of the separator and the batch production of the battery.

The invention also provides a battery pack containing the single battery and an electric vehicle using the battery pack as a power source. Due to the adoption of the battery pack according to the invention, the endurance of the electric vehicle is remarkably improved, and the production and manufacturing costs thereof are further reduced.

It should be understood that the foregoing description is only exemplary of the invention and is not intended to limit the invention. It should be noted that several improvements, modifications and variations of the present invention may be made by those skilled in the art, but these improvements, modifications and variations do not depart from the spirit of the present invention and are deemed to fall within the scope of the present invention.

Parts list

1,1' pole piece

2,2' anode ear

3,3' negative electrode tab

4 casing

5 lower shell cover

6,6' positive pole

7,7' negative pole column

8,8' Cavity

9,19 baffle

10 insulating sleeve

11 an outer metal conductor.

Claims

1. A single battery is characterized by comprising a shell and two pole cores, wherein the shell is provided with a partition board and four poles, two poles are positive poles, the other two poles are negative poles, the interior of the shell is divided into two cavities by the partition board,

each of the two pole pieces having a positive tab and a negative tab disposed on a same side of the pole piece at a distance from each other and the two pole pieces being oppositely disposed in the housing with respect to the positive tab and the negative tab such that the positive tabs and the negative tabs of the two pole pieces are interleaved with each other,

the four polar columns are arranged in a polar manner, four polar lugs are respectively connected in a polar manner and are arranged on the four polar columns, and the four polar columns are separated by the partition plate so that the two polar cores are respectively positioned in the two cavities; and

wherein the middle two positive and negative posts are connected to each other such that the two pole cores are connected in series, and the other two positive and negative posts serve as the positive and negative posts of the unit cell, respectively.

2. The battery cell according to claim 1, wherein the middle two positive and negative electrode posts are connected to each other by a metal conductor, and an insulating sleeve covers the middle two positive and negative electrode posts such that the middle two positive and negative electrode posts are spaced from the outside of the battery.

3. The battery cell according to claim 1, wherein a recess is provided in an upper case cover of the case at a position of the case where the separator is provided, and the four poles are arranged on the recess in a spaced and staggered manner from each other.

4. The battery cell according to claim 3, wherein the case has a separator at a middle region of the case separating the positive and negative electrode tabs of the two pole pieces.

5. The cell defined in claim 1, wherein the material of the housing is aluminum, steel, or a polymeric material, and the pole core is in the form of a rolled core or a laminate.

6. The cell defined in claim 1, wherein the separator is made of an insulating material, and the insulating material is polyvinyl chloride, polyethylene, polytetrafluoroethylene, polyimide, or polyamideimide.

7. The cell defined in claim 1, wherein when the cell is a lithium-ion battery, the core comprises a positive electrode, a negative electrode, a separator, and an electrolyte, and the positive electrode is a lithium-containing compound and the negative electrode comprises a carbon material.

8. The battery cell according to claim 1, wherein a liquid injection hole and an explosion-proof valve are provided in the two cavities of the case.

9. A battery pack characterized by having the unit battery according to any one of claims 1 to 8.

10. An electric vehicle characterized by having the battery pack according to claim 9.