阅读说明：本技术 组合式电池组及其装配方法 (Combined battery pack and assembling method thereof ) 是由 王爱萍 于 2021-01-11 设计创作，主要内容包括：本发明提供了一种组合式电池组及其装配方法,包括塑料壳体和至少一盖板,塑料壳体外表面设置有金属箔材,塑料壳体内部设置至少两个内腔,每一内腔内部均安装一电池单体,盖板固定于所述内腔顶端开口处,盖板上设置若干正极柱和若干负极柱,每一电池单体与一正极柱和一负极柱连接,相邻的电池单体串联连接,本发明采用塑料壳体,降低了组合式电池壳的成本,保证了电池的稳定性,电池单体固定更加牢靠,结构简单,加工成本低,设置金属箔材,提高了电池壳体的密封性的同时,提高电池的散热速度,提高电池的使用寿命,提高了电池组的装配效率。(The invention provides a combined battery pack and an assembling method thereof, wherein the combined battery pack comprises a plastic shell and at least one cover plate, metal foil is arranged on the outer surface of the plastic shell, at least two inner cavities are arranged in the plastic shell, a battery monomer is arranged in each inner cavity, the cover plate is fixed at an opening at the top end of the inner cavity, a plurality of positive poles and a plurality of negative poles are arranged on the cover plate, each battery monomer is connected with one positive pole and one negative pole, and adjacent battery monomers are connected in series.)

1. The utility model provides a modular group battery, its characterized in that includes a plastic casing and an at least apron, the plastic casing surface is provided with the metal foil, inside two at least inner chambers that set up of plastic casing, each the inside battery monomer of all installing of inner chamber, the apron is fixed in on the inner chamber opening, set up a plurality of positive posts and a plurality of negative pole post on the apron, each battery monomer and one positive post and one the negative pole support is connected, adjacent two the battery monomer is established ties.

2. The assembled battery pack according to claim 1, wherein the number of the cover plates is several, and each cover plate corresponds to one of the inner cavities and is connected to one of the battery cells; or each cover plate corresponds to a plurality of continuous inner cavities and is connected with a plurality of battery monomers.

3. The assembled battery pack according to claim 1, wherein the number of the cap plates is one, and all the battery cells are connected to the same cap plate.

4. The assembled battery pack according to claim 1, wherein the battery cells comprise pole cores, the pole cores comprise a positive plate, a separator paper and a negative plate, and the positive plate, the separator paper and the negative plate are connected in sequence; the positive plate is connected with a positive leading-out end, and the negative plate is connected with a negative leading-out end; the positive leading-out end is connected with the positive pole column through a first connecting piece, and the negative leading-out end is connected with the negative pole column through a second connecting piece.

5. The assembled battery as set forth in claim 4, wherein the first connecting tab and the second connecting tab are fixedly connected to the cap plate.

6. The assembled battery pack according to claim 1, wherein the plastic case is made of any one of polyamide, polyethylene, polypropylene, and polyimide.

7. The assembled battery of claim 1, wherein the metal foil covers more than 10% of the area of the outer surface of the plastic case.

8. The assembled battery pack according to claim 1, wherein the cover plate is a plastic cover plate, the cover plate is hermetically connected to the plastic case, and the cover plate is provided with a plurality of explosion-proof valves.

9. A method of assembling a modular battery pack according to any one of claims 1 to 8, the method comprising the steps of:

s1, connecting an electrode leading-out end of a pole core of the battery monomer with a cover plate, and electrically connecting the electrode leading-out end of the pole core with the pole;

s2, injecting electrolyte into the inner cavity, inserting the pole core into the inner cavity, and covering the cover plate on the opening of the inner cavity;

s3, connecting the positive pole column and the adjacent negative pole column in series;

and S4, sealing the cover plate and the plastic shell, and fixing a metal foil on the outer side of the plastic shell.

10. The assembling method of the assembled battery pack according to claim 9, wherein the cap plate is hermetically fixed to the plastic case by thermal welding, and the metal foil is fixed to the outer surface of the plastic case by thermal welding.

Technical Field

The invention relates to the technical field of batteries, in particular to a combined battery pack and an assembly method thereof.

Background

The lithium ion battery has the advantages of high working voltage, large energy density, long cycle life, no memory effect and the like, and becomes a main power supply of various portable electronic products. With the further popularization of new energy industries such as energy storage batteries, the demand of power and energy storage type lithium ion batteries will increase remarkably.

With the development of new energy vehicles and energy storage markets, lithium ion batteries are basically connected in series and parallel in the current application. The existing traditional battery shell materials are mainly made of aluminum shells, steel shells or aluminum-plastic films, and are basically produced in a single body (the most basic elements forming battery packs and battery packs). This results in complex assembly process of the single cells, and the need to match the single cells into groups, which results in low production line efficiency of the battery, complex process and high cost.

In the prior art, a plastic shell is also taken as a single shell, but the electrical property of the battery is poor due to the water permeability problem of the plastic shell.

The patent with publication number CN210167393U entitled as a new energy combined lithium battery discloses a new energy combined lithium battery, and through setting up compoboard, anodal power cord, negative pole power cord, placing box, connection piece and connecting wire, can be convenient for make up a plurality of lithium batteries at the in-process that the lithium cell used for this combined lithium battery can satisfy the demand of high-power electric energy. This new forms of energy combination lithium cell through setting up fixed spring and splint, can adjust fixedly according to battery body's size of a dimension at the in-process of battery body installation, has not only strengthened the fastness when the battery body installation, also makes to place the battery body that the box can be applicable to the different grade type moreover to this box of placing's practicality has been improved. But this utility model discloses a new forms of energy combination lithium cell is owing to adopt fixed spring and splint to fix the battery body, because the spring has elasticity, when consequently assembled battery receives external impact, the battery body can rock in placing the box, is unfavorable for the stability of battery.

Therefore, there is a need for a novel assembled battery and an assembling method thereof to solve the above-mentioned problems in the prior art.

Disclosure of Invention

The invention aims to provide a combined battery pack and an assembly method thereof, which are used for improving the waterproofness of the battery pack, reducing the cost of the battery pack and improving the assembly efficiency of the battery pack.

In order to achieve the purpose, the combined battery pack comprises a plastic shell and at least one cover plate, wherein a metal foil is arranged on the outer surface of the plastic shell, at least two inner cavities are formed in the plastic shell, a battery single body is arranged in each inner cavity, the cover plate is fixed on an opening of each inner cavity, a plurality of positive posts and a plurality of negative posts are arranged on the cover plate, each battery single body is connected with one positive post and one negative post, and two adjacent battery single bodies are connected in series.

The combined battery has the beneficial effects that:

the shell of the combined battery pack adopts the plastic shell, so that the cost of the combined battery shell is reduced, the plurality of inner cavities are arranged in the plastic shell to independently install the battery monomer, the top of each inner cavity is sealed and fixed with the cover plate, and the battery monomer is connected with the positive pole column and the negative pole column on the cover plate, so that the battery monomer can be stably fixed in the inner cavities, the stability of the battery is ensured, the fixation of the battery monomer is firmer, the structure is simple, and the processing cost is low. Set up the metal foil at the plastic casing surface, both solved the problem of plastic casing water permeability, when having improved battery case's leakproofness, the metal foil can also play certain heat conduction heat dissipation function to improve the radiating rate of battery, improve the life of battery.

Preferably, the number of the cover plates is several, and each cover plate corresponds to one inner cavity and is connected with one battery monomer; or each cover plate corresponds to a plurality of continuous inner cavities and is connected with a plurality of battery monomers. The beneficial effects are that: one cover plate is correspondingly connected with one or a plurality of battery monomers, so that the grouping assembly of the battery pack is facilitated.

Preferably, the number of the cover plate is one, and all the battery cells are connected with the same cover plate together. The beneficial effects are that: one cover plate is connected with all the battery monomers, so that the stability of the whole structure of the combined battery pack is improved.

Preferably, the battery monomer comprises a pole core, the pole core comprises a positive plate, diaphragm paper and a negative plate, and the positive plate, the diaphragm paper and the negative plate are sequentially connected; the positive plate is connected with a positive leading-out end, and the negative plate is connected with a negative leading-out end; the positive leading-out end is connected with the positive pole column through a first connecting piece, and the negative leading-out end is connected with the negative pole column through a second connecting piece.

Preferably, the first connecting piece and the second connecting piece are fixedly connected with the cover plate.

Preferably, the plastic shell is made of any one of polyamide, polyethylene, polypropylene and polyimide.

Preferably, the coverage area of the metal foil is more than 10% of the area of the outer surface of the plastic shell. The beneficial effects are that: the sealing performance of the plastic cover body is guaranteed, and the waterproofness of the battery pack is improved.

Preferably, the cover plate is a plastic cover plate, and the cover plate is connected with the plastic shell in a sealing mode. The beneficial effects are that: the sealing performance of the battery pack is ensured.

Preferably, a plurality of explosion-proof valves are arranged on the cover plate.

The assembling method comprises the following steps:

s1, connecting an electrode leading-out end of a pole core of the battery monomer with a cover plate, and electrically connecting the electrode leading-out end of the pole core with the pole;

s2, injecting electrolyte into the inner cavity, inserting the pole core into the inner cavity, and covering the cover plate on the opening of the inner cavity;

s3, connecting the positive pole column and the adjacent negative pole column in series;

and S4, sealing the cover plate and the plastic shell, and fixing a metal foil on the outer side of the plastic shell.

The packaging method of the combined battery pack has the beneficial effects that:

fix in the one end of apron towards the inner chamber with the free utmost point core of battery earlier, make utmost point post and utmost point core electricity be connected, then pour into electrolyte when inserting the inner chamber with utmost point core, and cover the apron lid on the inner chamber opening, and accomplish the series connection between the battery monomer, accomplish the sealing connection of apron and plastic casing at last, whole assembly process is simple quick, has guaranteed the free stability of battery, has improved the assembly efficiency of group battery, has also improved the overall stability, the fastness of group battery.

Preferably, the cover plate is hermetically fixed on the plastic housing through thermal welding, and the metal foil is fixed on the outer surface of the plastic housing through thermal welding. The beneficial effects are that: the sealability and waterproofness of the battery pack are improved.

Drawings

Fig. 1 is a schematic top view of a combined battery pack according to a first embodiment of the invention;

fig. 2 is a schematic front sectional view of a combined battery pack according to a first embodiment of the invention;

fig. 3 is a flowchart of an assembling method of the assembled battery pack according to a first embodiment of the present invention;

fig. 4 is a schematic top view of a combined battery pack according to a second embodiment of the present invention;

fig. 5 is a schematic top view of a combined battery pack according to another embodiment of the second embodiment of the present invention;

fig. 6 is a schematic top view of a combined battery pack according to a third embodiment of the present invention;

fig. 7 is a schematic front sectional view of a combined battery pack according to a third embodiment of the present invention;

fig. 8 is a graph of normal temperature cycle curves for a lithium iron phosphate battery made in accordance with the present invention.

In the figure: 1-a plastic housing; 10-lumen; 101-a first lumen; 102-a second lumen; 103-a third lumen; 104-a fourth lumen; 105-a fifth lumen; 106-sixth lumen; 2-metal foil; 3-an explosion-proof valve;

4-cover plate; 40-positive pole column; 41-negative pole column; 42-a third connecting sheet; 43-a bump;

5-a battery cell; 50-a first connecting tab; 51-second connecting piece.

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.

Example one

To solve the problems in the prior art, an embodiment of the present invention provides a combined battery pack, as shown in fig. 1, fig. 1 is a schematic top view of the combined battery pack according to the first embodiment of the present invention, and includes a plastic casing 1, a metal foil 2 is disposed on an outer surface of the plastic casing 1, and at least two inner cavities 10 are disposed inside the plastic casing 1.

As shown in fig. 2, fig. 2 is a schematic front sectional view of a combined battery pack according to a first embodiment of the present invention, a battery cell 5 is installed inside each inner cavity 10, and a cover plate 4 is hermetically fixed at an opening at the top of each inner cavity 10.

As shown in fig. 1, each cover plate 4 is provided with at least one positive post 40 and one negative post 41, each battery cell 5 is connected with one positive post 40 and one negative post 41, and the positive post 40 on the cover plate 4 is connected with the negative post 41 on the adjacent cover plate 4 in series.

The combined battery pack of the first embodiment is taken as an example to illustrate the advantages of the invention:

(1) the shell of the combined battery pack shown in fig. 1 and 2 adopts a plastic shell 1, the cost of the combined battery case is reduced, a plurality of inner cavities 10 are arranged in the plastic shell 1 to independently install the battery monomer 5, the top of each inner cavity 5 is sealed and fixed with the cover plate 4, the battery monomer 5 is connected with the positive pole column and the negative pole column on the cover plate 4, the battery monomer can be stably fixed in the inner cavities, the stability of the battery is ensured, the battery monomer is more firm to fix, the structure is simple, and the processing cost is low.

(2) Set up metal foil 2 at 1 surface of plastic casing, both solved the problem of plastic casing water permeability, when having improved battery case's leakproofness, metal foil can also play certain heat conduction heat dissipation function to improve the radiating rate of battery, improve the life of battery.

It is to be added that the lumens 10 in fig. 1 each include a first lumen 101, a second lumen 102, a third lumen 103, a fourth lumen 104, a fifth lumen 105, and a sixth lumen 106. Six cavities, namely a first cavity, a second cavity, a third cavity, a fourth cavity, a fifth cavity and a sixth cavity, are sequentially arranged in the plastic shell from left to right. And two adjacent cavities are sealed and isolated from each other, so that the independence between each single battery is ensured.

The connection mode of the pole column on the inner cavity is as follows: the positive post 40 on the cover plate on the first inner cavity 101 is connected with the negative post 41 on the cover plate on the second inner cavity 102, the positive post on the cover plate on the second inner cavity 102 is connected with the negative post on the third inner cavity 103, the positive post on the third inner cavity 103 is connected with the negative post on the fourth inner cavity 104, the positive post on the fourth inner cavity 104 is connected with the negative post on the fifth inner cavity 105, and the positive post on the fifth inner cavity 105 is connected with the negative post on the sixth inner cavity 106.

Each inner cavity 10 is sealed and isolated, so that the electrolyte in each inner cavity is isolated from each other, the battery monomers 5 in each inner cavity are also isolated from each other, and each battery monomer 5 is connected in series by connecting the positive pole 40 and the negative pole 41 in series.

As shown in fig. 2, as a preferred embodiment of the present invention, the positive terminal of the battery cell 5 is connected to the positive post 40 through a first connecting piece 50, the negative terminal of the battery cell 5 is connected to the negative post 41 through a second connecting piece 51, and the positive post 40 on the cover plate 4 and the negative post 41 on the adjacent cover plate 4 are connected in series through a third connecting piece 42. The first connecting sheet 50, the second connecting sheet 51 and the third connecting sheet 42 are made of metal materials such as copper, aluminum and other conductive materials, and have the function of electrically connecting the battery cells with the poles and between the battery cells.

Preferably, each cover plate of the battery pack of the present invention is manufactured by including the cover plate 4, the positive post and the negative post fixed on the cover plate 4, wherein the end of the positive post 40 facing the inner cavity 10 is fixedly connected with the first connecting piece 50, and the end of the negative post 10 facing the inner cavity is fixedly connected with the second connecting piece 51. The first connecting tab 50 and the second connecting tab 51 are laser welded to their cover plates 4.

Like this when installing battery monomer, only need to draw forth the end with every battery monomer 5 positive pole and carry out ultrasonic bonding with first connection piece 50, the free negative pole of battery draws forth the end and carries out ultrasonic bonding with second connection piece 51, can accomplish the electric connection of battery monomer and utmost point post, also makes battery monomer 5 be fixed in apron 4 one side towards the inner chamber simultaneously, has improved the assembly efficiency of combination formula group battery.

It can be said that, as shown in fig. 1, in order to facilitate the series connection of the poles on the plurality of cap plates, two adjacent cap plates of the combined battery pack of the present invention are mounted upside down. Namely, when the positive post on the first cover plate 4 on the right side faces the back surface of the plastic shell and the negative post faces the front surface of the plastic shell, the directions of the positive post and the negative post on the adjacent cover plate 4 are just opposite to the directions of the positive post and the negative post on the first cover plate 4 on the right side. Namely, the positive pole on the second cover plate 4 on the right faces the front surface of the plastic shell, and the negative pole faces the back surface of the plastic shell. Therefore, the distance between the positive post and the negative post of the adjacent cover plates 4, i.e. the connection between the positive post of the second cover plate 4 on the right side and the negative post of the first cover plate 4 on the right side, can be shortened to the minimum, and the material consumption of the third connecting plate 42 is saved.

As a specific embodiment, the number of the inner cavities 10 of the combined battery pack is 6, and the number of the battery cells and the number of the cover plates are 6. As shown in fig. 1, from left to right, the positive post on the first cover plate 4 is connected to the negative post on the second cover plate 4, the positive post on the second cover plate is connected to the negative post on the third cover plate, the positive post on the third cover plate is connected to the negative post on the fourth cover plate, the positive post on the fourth cover plate is connected to the negative post on the fifth cover plate, and the positive post on the fifth cover plate is connected to the negative post on the sixth cover plate, thereby completing the series connection of six battery cells.

In a preferred embodiment of the present invention, the battery cell 5 includes a pole core, the pole core includes a positive plate, a separator paper and a negative plate, the positive plate, the separator paper and the negative plate are sequentially connected, and the pole core is assembled by sequentially stacking and connecting the positive plate, the separator paper, the negative plate and the separator paper. The positive plate is connected with the positive leading-out end, and the negative plate is connected with the negative leading-out end.

In a preferred embodiment of the present invention, the plastic case 1 is made of any one of polyamide, polyethylene, polypropylene, and polyimide, but the plastic case is not limited to the above materials, and other plastic materials may be used.

The plastic casing of the present invention may be made of acrylonitrile-butadiene-styrene (ABS) plastic, and the ABS is acrylonitrile-butadiene-styrene copolymer, and has excellent impact resistance, heat resistance, low temperature resistance, chemical resistance and electric performance, and is suitable for use as material for making casing of the combined battery pack of the present invention.

As shown in fig. 1, as a preferred embodiment of the present invention, the coverage area of the metal foil is more than 10% of the outer surface area of the plastic housing, reducing the water permeability of the plastic housing.

Preferably, the metal foil can be an aluminum foil, but is not limited to the aluminum foil, the aluminum foil has good heat conductivity, and the heat dissipation efficiency of the battery pack in the plastic shell is improved while the sealing performance of the plastic shell is improved and the water permeability of the plastic shell is reduced.

In a preferred embodiment of the present invention, the cover plate 4 is a plastic cover plate, and the cover plate 4 is hermetically connected to the plastic housing 1. The plastic shell and the cover plate are both made of plastic, and the plastic shell and the cover plate are connected and sealed more easily.

Referring to fig. 1, as a preferred embodiment of the present invention, each cover plate 4 is provided with an explosion-proof valve 3. When the battery monomer and the explosion-proof valve in the inner cavity of the invention work normally, gas flows from the area with high pressure to the area with low pressure, and the explosion-proof valve plays a role in water resistance and ventilation. When the pressure inside the inner cavity is greater than or equal to the preset explosion threshold value of the explosion-proof valve, the gas pressure inside the cavity jacks the piston body of the explosion-proof valve, so that the air discharge channel of the explosion-proof valve is directly opened, gas is discharged to the outside at the highest speed through the air discharge channel, the pressure of the inner cavity is rapidly reduced, and the cavity is prevented from exploding. And after the air is exhausted, when the gas pressure in the inner cavity is lower than the explosion threshold value of the explosion-proof valve, the explosion-proof valve returns to the normal working state.

As shown in fig. 3, fig. 3 is a flowchart of an assembling method of a combined battery pack according to a first embodiment of the present invention, and according to the combined battery pack, the present invention further provides an assembling method of a combined battery pack, including the steps of:

s1, fixedly connecting the leading-out end of the pole core of the battery monomer with the cover plate, and electrically connecting the leading-out end of the pole core with the pole;

s2, injecting electrolyte into the inner cavity, inserting the pole core into the inner cavity, and covering the cover plate on the opening of the inner cavity;

s3, connecting the positive pole column on the cover plate and the negative pole column on the adjacent cover plate in series;

s4, a sealing cover plate and a plastic shell, wherein the metal foil is fixed on the outer side of the plastic shell.

In addition, the step of injecting the electrolyte into the cavity in step S2 is not limited to the step of covering the cover plate on the cavity, and the electrolyte injection operation of the battery may be performed after the cover plate is covered on the cavity.

The liquid can be injected into the battery cavity through the liquid injection hole: and a liquid injection hole communicated with the inner cavity is reserved on the plastic shell, and electrolyte is injected into each inner cavity through the liquid injection hole after the cover plate is hermetically connected with the plastic shell. And after the electrolyte is injected, sealing the injection hole.

The battery cavity can be filled with liquid through the cover plate: the mounting hole of explosion-proof valve is reserved on the apron, does not install explosion-proof valve earlier, treats apron and plastic housing sealing connection back, injects the electrolyte into each inner chamber through the mounting hole, annotates the liquid back that finishes, assembles explosion-proof valve to the mounting hole in again.

In a preferred embodiment of the present invention, step S1 includes welding the positive electrode tab of the core to the positive electrode tab via the first connecting tab and welding the negative electrode tab of the core to the negative electrode tab via the second connecting tab.

As a preferred embodiment of the present invention, the cover plate is hermetically fixed to the plastic housing by thermal welding, the metal foil is fixed to the outer surface of the plastic housing by thermal welding, and the plastic housing and the plastic cover plate are hermetically connected by thermal welding, so that the sealing performance is better.

The invention fixes the pole core of the battery monomer at one end of the cover plate facing to the inner cavity, so that the pole is electrically connected with the pole core, then the pole core is inserted into the inner cavity, meanwhile, electrolyte is injected, the cover plate covers the opening of the inner cavity, and the serial connection between the poles is completed, and finally, the sealing connection between the cover plate and the plastic shell is completed.

Example two

Fig. 4 is a schematic top view of a combined battery pack according to a second embodiment of the invention; including plastic housing 1, plastic housing 1 surface is provided with foil 2, and plastic housing 1 is inside to be set up six inner chambers 10, and a battery monomer 5 is all installed to each inner chamber 10 inside, and apron 4 quantity is three, and every apron 4 all covers on two adjacent inner chambers, all sets up two positive post 40 and two negative pole post 41 on every apron 4, and every apron 4 all connects its two battery monomer 5. Each battery cell 5 is connected to a positive post 40 and a negative post 41, specifically, a positive post and a negative post are disposed on the cover plate 4 directly above each cavity 10. The connection between the battery cell (not shown) in the inner cavity 10 and the positive pole, the connection between the negative lead-out end of the battery cell and the negative pole, and the connection between the positive pole and the negative pole on the cover plate are the same as those in the first embodiment, and the positive pole 40 on the cover plate 4 is connected with the negative pole 41 on the adjacent cover plate through the third connecting piece 42.

Optionally, as another implementation manner of the second embodiment of the present invention, as shown in fig. 5, fig. 5 is a schematic top view structure of a combined battery pack in another implementation manner of the second embodiment of the present invention; the number of the cover plates 4 of the combined battery pack is not limited to three, and can be two, each cover plate 4 correspondingly covers three inner cavities 10, each cover plate is provided with three positive poles and three negative poles, and each cover plate 4 is connected with three battery monomers 5.

EXAMPLE III

The invention provides a combined battery pack, as shown in fig. 6, fig. 6 is a schematic top view of the combined battery pack according to a third embodiment of the invention, and includes a plastic casing 1, a metal foil 2 is disposed on an outer surface of the plastic casing 1, and six inner cavities 10 are disposed inside the plastic casing 1. The top openings of the six inner cavities 10 are jointly sealed and fixed with a cover plate 4, and six positive poles 40 and six negative poles 41 are arranged on the cover plate 4. The positive posts 40 on the cover plate 4 are connected in series by the negative posts 41 adjacent to the third connecting piece 42.

As shown in fig. 7, fig. 7 is a schematic front sectional view of a combined battery pack according to a third embodiment of the present invention; each cavity 10 is internally provided with a single battery 5, each single battery 5 is connected with a positive pole 40 and a negative pole 41, specifically, a positive pole and a negative pole are arranged on the cover plate right above each cavity 10, the positive pole leading-out end of the single battery 5 in the cavity 10 is connected with the positive pole 40 at the upper end thereof through a first connecting sheet 50, and the negative pole leading-out end of the single battery 5 in the cavity 10 is connected with the negative pole 41 through a second connecting sheet 51.

Additionally, the cover plate 4 is made of plastic material. The bottom of apron 4 sets up six parallel lugs 43, and lug 43 and apron 4 are the plastics material preparation, lug and apron seamless connection, accessible stamping die preparation. Or the shape of the projection 43, is adapted to the shape of the top opening of the cavity 10, facilitating the sealing of the cover plate 4 with each cavity 10.

Preferably, all the battery cells of the whole battery pack share one cover plate, so that the stability of the whole structure of the battery pack is enhanced.

Preferably, as shown in fig. 6 and 7, the cover plate of the battery pack of the present invention is manufactured by including the cover plate 4, the positive post and the negative post fixed on the cover plate 4, wherein the end of the positive post 40 facing the inner cavity 10 is fixedly connected to the first connecting piece 50, and the end of the negative post 10 facing the inner cavity is fixedly connected to the second connecting piece 51. The first connecting tab 50 and the second connecting tab 51 are laser welded to their cover plates 4. In addition, adjacent positive pole posts and negative pole posts, negative pole posts and positive pole posts are sequentially connected in series, and the positive pole posts and the negative pole posts are connected through third connecting pieces in a welded mode. The third connecting piece 42 is laser welded to the cover plate 4.

Preferably, six cavities of the plastic case share one cover plate 4, and since the series connection of the positive and negative posts can be completed in the production stage of the cover plate 4, the assembly time of the battery pack can be greatly reduced. And six battery monomers share a apron, accomplish apron and battery monomer's the back of being connected, accomplish and annotate the liquid operation, then cover the apron on plastic housing, seal the opening part of the bottom of apron 4 and every cavity again at last, avoided the trouble of apron assembly one by one, further improved the assembly efficiency of combination formula group battery.

The assembling method of the battery pack comprises the following steps:

the positive electrode lead-out end of each battery cell 5 is ultrasonically welded to the first connection piece 50, and the negative electrode lead-out end of the battery cell is ultrasonically welded to the second connection piece 51. The corresponding connection of the battery monomer 5 and the positive pole and the negative pole above the inner cavity of the battery monomer is completed, and the fixed connection of the battery monomer 5 and the cover plate 4 is also completed. And then, injecting electrolyte into the inner cavity, and covering the cover plate 4 on the plastic shell 1 after the injection is finished. Six lugs 43 under the cover plate are respectively inserted into the openings of the inner cavity 10, and the lugs 43 are hermetically connected with the inner wall of the inner cavity 10 by a hot melt welding mode to complete the sealing of the battery pack.

After the combined battery is assembled, the operations of aging, first charging, shelving, capacity grading and the like are carried out, so that the battery pack can meet normal working conditions.

The specific embodiment is as follows: through the experiments of the inventor, the lithium iron phosphate battery pack manufactured based on the structure and the principle of the invention is formed by connecting six lithium iron phosphate batteries in series, and the lithium iron phosphate battery pack is subjected to normal-temperature cycle test.

The test method is as follows: and controlling the charging and discharging voltage range of each single battery to be 2.0-3.8V, the charging and discharging current to be 1C and 100% DOD, and standing for 30min to obtain a graph shown in figure 8, wherein the graph shown in figure 8 is a normal-temperature cycle curve of the lithium iron phosphate battery pack.

It can be added that DOD is an abbreviation of Department of failure, which stands for cycle depth, 100% DOD, i.e. 100% of the actual capacity of the battery representing the capacity discharged each time by the battery.

By observing the normal temperature cycle curve as shown in fig. 8, it can be concluded that: under the condition of normal-temperature cycle test, the lithium iron phosphate battery pack manufactured based on the structure and the principle of the combined battery pack still keeps good cycle performance.

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.