Battery pack

Abstract

The utility model relates to a battery pack. The battery pack comprises a battery cell shell, the battery cell assembly comprises a plurality of laminated sheet-shaped battery cells, and the sheet-shaped battery cells are accommodated in the battery cell shell; the battery pack further comprises supports arranged at the two longitudinal ends of the battery cell assembly, gaps without fillers are formed between the adjacent sheet-shaped battery cells, the supports comprise partition pieces extending to the gaps, the partition pieces are elastic pieces, the gaps account for 5%-30% of the volume of the battery cell assembly, and the gaps account for 5%-30% of the volume of the battery cell assembly. And the volume of the battery cell assembly accounts for 60%-70% of the volume of the battery pack. The battery pack has the advantages of high energy density, good safety performance and long cycle life.

Description

Technical Field

[0001] The utility model relates to the technical field of battery packs, in particular to a lightweight battery pack. Background Art

[0002] In the prior art, cylindrical battery cells are mostly used for battery packs that supply power to electrical devices. As the energy density requirement of electrical devices for battery packs increases day by day, non-cylindrical battery cells have a higher energy density. Therefore, using non-cylindrical battery cells in a battery pack can improve the performance of the battery pack and reduce its weight.

[0003] Non-cylindrical battery cells are generally stacked and fixed by potting. However, fixing battery cells by potting will cause the overall weight of the battery pack to be too heavy and not easy to carry.

[0004] In view of this, it is necessary to provide an improved battery pack to overcome the defects of the prior art. Summary of the Utility Model

[0005] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a lightweight battery pack.

[0006] The technical solution adopted by the utility model to solve the problems of the prior art is: a battery pack, comprising a cell housing; a cell assembly including a plurality of sheet-shaped battery cells arranged in layers, the sheet-shaped battery cells being received in the cell housing; the battery pack further includes brackets disposed at the longitudinal ends of the cell assembly, there is a gap without filler between adjacent sheet-shaped battery cells, the bracket includes a partition member extending into the gap, the partition member is an elastic member, wherein the volume percentage range of the gap in the cell assembly is 5%-30%, and the volume percentage range of the cell assembly in the battery pack is 60%-70%.

[0007] A further improvement is: the nominal capacity of the sheet-shaped battery cell is 2Ah - 6Ah, and the weight energy density range of the sheet-shaped battery cell is 160 - 260 Wh / Kg.

[0008] A further improvement is: the weight energy density range of the battery pack is 160 - 170 Wh / Kg.

[0009] A further improvement is: the sum of the masses of the cell assembly and the bracket accounts for 50% - 60% of the mass of the battery pack.

[0010] A further improvement is: the voltage of the battery pack is greater than or equal to 35 volts.

[0011] A further improvement solution is as follows: when the energy W of the battery pack is greater than or equal to 400 watt-hours, the mass M1 of the battery pack is less than or equal to 4 kilograms.

[0012] A further improvement solution is as follows: the ratio of the energy W of the battery pack to the mass M1 of the battery pack satisfies: 130 watt-hours / kg ≤ W / M1 ≤ 170 watt-hours / kg.

[0013] A further improvement solution is as follows: the battery pack includes a battery pack housing that houses the battery cell assembly and the battery cell housing, and the mass percentage range of the battery cell housing in the mass of the battery pack housing is 40% - 50%.

[0014] A further improvement solution is as follows: the volume percentage range of the volume of the battery cell assembly and the overall volume of the bracket in the volume of the battery pack is 60% - 70%.

[0015] A further improvement solution is as follows: the partition member is foam, silica gel or rubber.

[0016] Compared with the prior art, the present utility model has the following beneficial effects: the battery pack further includes brackets provided at the longitudinal two ends of the battery cell assembly, there are gaps without fillers between adjacent sheet-shaped battery cells, the bracket includes a partition member extending into the gaps, wherein, the volume percentage range of the gaps in the volume of the battery cell assembly is 5% - 30%, and the volume percentage range of the battery cell assembly in the volume of the battery pack is 60% - 70%. The battery pack has the advantages of high energy density, good safety performance and long cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following further describes in detail the specific embodiments of the present utility model with reference to the drawings:

[0018] Figure 1 It is a schematic structural diagram of the battery pack according to a preferred embodiment of the present invention;

[0019] Figure 2 It is Figure 1 a schematic structural diagram of the battery pack shown after removing the battery pack housing;

[0020] Figure 3 It is Figure 2 a partial disassembly schematic diagram of the battery pack shown;

[0021] Figure 4 It is Figure 3 a disassembly schematic diagram of the bracket and the battery cell assembly in the battery pack shown;

[0022] Figure 5 It is Figure 4 a schematic structural diagram of the bracket shown.

[0023] Meanings of the reference numerals in the figures:

[0024] Cell housing 1, end cap 11

[0025] Sheet-like cell 21, tab 22

[0026] Adapter plate 3, nickel sheet 31

[0027] Fixing plate 4, second opening 41

[0028] Bracket 5, first bracket 51

[0029] Second bracket 52, first opening 53

[0030] Main frame 54, side wall 541

[0031] Receiving space 542, slot / jack 543

[0032] Partition part 55, partition member 551

[0033] Gap 56, battery pack housing 6

[0034] First housing 61, second housing 62

[0035] Terminal groove 63, battery pack interface 7

[0036] Guide rail 71, electrical connector 72 Detailed implementation manners

[0037] The terms used in the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. For example, the terms indicating orientation or positional relationship such as "upper", "lower", "front", "rear", etc. are only based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device / component referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present utility model.

[0038] Please refer to Figures 1 to 5 Shown is a battery pack according to a preferred embodiment of the present utility model, which can be detachably connected to an external device.

[0039] The external device can be an electrical device or a charger. When the battery pack is connected to the electrical device, the battery pack can supply electrical energy to the electrical device. Optionally, the electrical device can be a power tool, a household appliance, etc. The power tool can be a handheld power tool, such as a hammer drill, an electric drill, an angle grinder, etc., and can also be a garden power tool, such as a blower, a chainsaw, an intelligent lawn mower, etc. The household appliance can be a vacuum cleaner, a floor mopping machine, a fan, etc. The present utility model does not limit this. When the battery pack is connected to the charger, the charger connected to the power supply can supply electrical energy to the battery pack.

[0040] Please refer to Figure 1 As shown, the battery pack includes a battery pack housing 6 and a battery pack interface 7 for connecting to an external device. The battery pack housing 6 includes a first housing 61 and a second housing 62 that are connected to each other, and the first housing 61 and the second housing 62 are fixed by screws.

[0041] Specifically, the battery pack interface 7 includes a pair of guide rails 71 and an electrical connector 72. The pair of guide rails 71 are provided on the second housing 62 for guiding the mechanical connection between the battery pack and the external device, so that the battery pack can be detachably mounted on the external device. The electrical connector 72 is provided between the pair of guide rails 71. The electrical connector 72 includes a plurality of battery pack terminals for electrically connecting to the corresponding terminals of the external device to input or output electrical energy. The battery pack housing 6 is provided with a plurality of terminal slots 63, and at least part of the battery pack terminals are received in the terminal slots 63. When the battery pack is connected to the external device, the battery pack terminals are inserted into the corresponding terminals of the external device, thereby realizing the electrical connection between the battery pack and the external device.

[0042] Please refer to Figure 2 As shown in Figure 3 As shown, the battery pack includes a cell housing 1 and a cell assembly 2 received in the battery pack housing 6. The cell housing 1 includes an end cover 11 and a box body, and the end cover 11 is fixedly connected to the box body by screws to form an internal space, and the cell assembly 2 is received in the internal space formed by the end cover 11 and the box body.

[0043] Specifically, the cell assembly 2 includes a plurality of interconnected cells, and the cells are non-cylindrical cells. In this embodiment, the cells are sheet-shaped cells, and the cells can be bent into an arc shape. The cell is a sheet-shaped cell 21, and a single sheet-shaped cell 21 extends along the longitudinal direction. Optionally, the longitudinal direction is set as the up-down direction shown in the figure.

[0044] Further, the plurality of sheet-shaped cells 21 are stacked, and each sheet-shaped cell 21 is provided with a tab 22 extending outward from one longitudinal end, and the tab 22 is bent so that adjacent sheet-shaped cells 21 overlap and are welded to each other.

[0045] Please refer to Figures 2 to 5As shown, the battery pack further includes brackets 5 disposed at the longitudinal two ends of the battery cell assembly 2. The brackets 5 include a first bracket 51 and a second bracket 52 which are oppositely arranged. The first bracket 51 and the second bracket 52 respectively at least partially wrap the two ends of the battery cell assembly 2, so that the two ends of the battery cell assembly 2 can be stably supported inside the battery cell housing 1.

[0046] Specifically, the bracket 5 includes a main frame 54 and a partition portion 55 connected to the main frame 54. The main frame 54 and the partition portion 55 space out a certain gap 56 between multiple sheet-shaped battery cells 21 and there is no filler in the gap 56, so that the sheet-shaped battery cells 21 have good heat dissipation on the premise of stable installation. Moreover, there is no direct contact between adjacent sheet-shaped battery cells 21. Therefore, under the supporting action of the bracket 5, the safety performance of the battery pack is improved.

[0047] Further, the main frame 54 includes a side wall 541 formed by surrounding in a circumferential direction. An accommodation space 542 is formed on the inner wall surface of the side wall 541. The partition portion 55 divides the accommodation space 542 into multiple slots or sockets 543 for inserting the sheet-shaped battery cells 21. The partition portion 55 includes multiple partition members 551. The multiple partition members 551 are arranged side by side at equal intervals in the accommodation space 542, and slots or sockets 543 are formed between adjacent partition members 551. The slots or sockets 543 are formed between the partition members 551 and the side wall 541. The partition portion 55 includes 4 - 16 partition members 551. The ends of the sheet-shaped battery cells 21 are sequentially inserted into the slots or sockets 543. This installation method improves the convenience of assembling the battery cell assembly 2, thereby improving the installation efficiency of the battery cells.

[0048] After being inserted, the battery cells at least partially abut against the partition members 551. The abutting surface between the battery cells and the partition members 551 is a non-smooth plane. Optionally, the abutting surface between the battery cells and the partition members 551 is wavy.

[0049] Specifically, the partition portion 55 and the main frame 54 are made of an elastic material, and the elastic material is foam, silica gel or rubber.

[0050] Please refer to Figure 2 and Figure 3 As shown, the battery pack includes a transfer board 3 and a fixing board 4 disposed in the battery cell housing 1. The transfer board 3 is used to form an electrical connection with the battery cell assembly 2. The sheet-shaped battery cell 21 includes a tab 22 extending outward from the end. The tab 22 is connected to the transfer board 3, thereby realizing the electrical connection between the battery cell assembly 2 and the transfer board 3.

[0051] Specifically, a first opening 53 is provided on the first bracket 51 of the bracket 5, and the tab 22 is connected to the adapter plate 3 through the first opening 53. Usually, a nickel sheet 31 is provided on the adapter plate 3, and the tab 22 is welded to the nickel sheet 31 of the adapter plate 3, which improves the reliability of welding.

[0052] Furthermore, in order to better connect the tab 22 to the adapter plate 3, the length of the tab 22 is set to be greater than the sum of the longitudinal height of the first bracket 51, the thickness of the fixing plate 4, and the thickness of the adapter plate 3. The fixing plate 4 is located between the adapter plate 3 and the bracket 5 and is made of an elastic material to prevent the tab 22 from being overly pulled when the battery pack is impacted. A second opening 41 corresponding to the first opening 53 is also provided on the fixing plate 4 for the tab 22 to pass through. Optionally, a foam can also be provided between the adapter plate 3 and the bracket 5 to fill the gap caused by the length of the tab 22, thereby preventing the tab 22 from being damaged and improving the safety performance of the battery pack.

[0053] The energy of a battery refers to the electrical energy output by the battery when doing external work under certain discharge conditions, and the unit is usually expressed in watt-hours or kilowatt-hours. As the power source of an electric tool, the energy, weight, or volume of the battery pack are two important factors affecting the user experience.

[0054] In this embodiment, the bracket 5 includes a partition member 551 extending into the gap 56. Among them, the applicant has found through research that in the embodiment of this application, when the volume percentage range of the gap 56 in the cell assembly 2 is 5%-30%, and the volume percentage range of the cell assembly 2 in the battery pack is 60%-70%, the electrical device can not only meet the user's energy requirements but also meet the user's volume requirements for the electrical device, and is conducive to the miniaturization and lightweight of the electrical device.

[0055] In the embodiment of this application, the nominal capacity of the sheet-like cell 21 is 2Ah-6Ah, and the weight energy density range of the sheet-like cell 21 is 160-260Wh / Kg. In a specific embodiment, when the nominal capacity of the sheet-like cell 21 is 4Ah, the weight energy density of the sheet-like cell 21 is 240Wh / kg. In a specific embodiment, when the nominal capacity of the sheet-like cell 21 is 6Ah, the weight energy density of the sheet-like cell 21 is 245Wh / kg.

[0056] The applicant has found through research that in the embodiment of this application, the weight energy density range of the battery pack is 160-170Wh / Kg. At this time, under the same weight, the battery pack can provide more energy for the electrical device, thereby improving the working efficiency.

[0057] In the embodiment of the present application, the sum of the masses of the battery cell assembly 2 and the bracket 5 accounts for 50%-60% of the mass of the battery pack, meeting the lightweight requirement of the overall battery pack and improving the user experience during use.

[0058] The greater the voltage of the battery pack, the higher the power of the electrical device. The applicant found that in the embodiment of the present application, if it is set that when the voltage of the battery pack is greater than or equal to 35 volts, the working requirements of the electrical device under most working conditions can be met.

[0059] The applicant found through research that in the embodiment of the present application, if it is set that when the energy W of the battery pack is greater than or equal to 400 watt-hours, and the mass M1 of the battery pack is less than or equal to 4 kilograms, the electrical device can not only meet the user's energy requirements but also meet the user's requirements for the mass of the electrical device, and is conducive to the miniaturization and lightweight of the electrical device. In a specific embodiment, the energy of the battery pack is 403 watt-hours, and the mass of the battery pack is 2.5 kilograms.

[0060] As a mature energy storage device, it is very difficult to change the structure or manufacturing process of the battery pack. The applicant found that in the embodiment of the present application, if it is set that the ratio of the energy W of the battery pack to the mass M1 of the battery pack satisfies: 130 watt-hours / kg ≤ W / M1 ≤ 170 watt-hours / kg, it can not only meet the user's requirements for the miniaturization and light load of the power tool 10 but also is not difficult to achieve due to excessive requirements. In some embodiments, the ratio of the energy W of the battery pack to the mass M1 of the battery pack can be set to 130.4 watt-hours / kg and 161.2 watt-hours / kg.

[0061] In the embodiment of the present application, the mass percentage range of the battery cell housing 1 in the battery pack housing 6 is 40%-50%. In some embodiments, the mass percentage of the battery cell housing 1 in the battery pack housing 6 can be set to 46%.

[0062] In the embodiment of the present application, the total volume percentage of the battery cell assembly 2 and the bracket 5 in the battery pack is 60%-70%. In some embodiments, the total volume percentage of the battery cell assembly 2 and the bracket 5 in the battery pack can be set to 66%.

[0063] In the present utility model, the battery pack further includes brackets 5 disposed at the longitudinal two ends of the battery cell assembly 2. There is a gap 56 without filler between adjacent sheet-shaped battery cells 21. The bracket 5 includes a partition member 551 extending into the gap 56. Among them, the volume percentage range of the gap 56 in the battery cell assembly 2 is 5%-30%, and the volume percentage range of the battery cell assembly 2 in the battery pack is 60%-70%. The battery pack has the advantages of high energy density, good safety performance and long cycle life.

[0064] The present utility model is not limited to the above specific embodiments. Those of ordinary skill in the art can easily understand that there are many alternative solutions for the battery pack of the present utility model without departing from the principle and scope of the present utility model. The protection scope of the present utility model shall be subject to the content of the claims.

Claims

1. A battery pack, comprising: Battery cell housing; A battery cell assembly, comprising a plurality of stacked sheet-shaped battery cells, wherein the sheet-shaped battery cells are accommodated in the battery cell housing; It is characterized in that the battery pack also includes brackets arranged at both longitudinal ends of the battery cell assembly, there is a gap without filler between adjacent sheet-like battery cells, the bracket includes a partition member extending to the gap, the partition member is an elastic member, wherein the gap accounts for a volume percentage interval of 5%-30% of the battery cell assembly, and the volume of the battery cell assembly accounts for a volume percentage interval of 60%-70% of the battery pack.

2. The battery pack according to claim 1, characterized in that: The nominal capacity of the sheet-shaped battery core is 2Ah-6Ah, and the weight energy density range of the sheet-shaped battery core is 160-260Wh / Kg.

3. The battery pack according to claim 2, characterized in that: The weight energy density range of the battery pack is 160-170Wh / Kg.

4. The battery pack according to claim 2, characterized in that: The sum of the mass of the battery cell assembly and the bracket accounts for 50%-60% of the mass of the battery pack.

5. The battery pack according to claim 1, characterized in that: The voltage of the battery pack is greater than or equal to 35 volts.

6. The battery pack according to claim 1, characterized in that: When the energy W of the battery pack is greater than or equal to 400 watt-hours, the mass M1 of the battery pack is less than or equal to 4 kilograms.

7. The battery pack according to claim 1, characterized in that: The ratio of the energy W of the battery pack to the mass of the battery pack M1 satisfies: 130 Wh / kg≤W / M1≤170 Wh / kg.

8. The battery pack according to claim 1, characterized in that: The battery pack includes a battery pack shell for accommodating the battery cell assembly and the battery cell shell, and the mass of the battery cell shell accounts for 40%-50% of the mass of the battery pack shell.

9. The battery pack according to claim 1, characterized in that: The volume of the battery cell assembly and the total volume of the bracket account for 60%-70% of the volume of the battery pack.

10. The battery pack according to claim 1, characterized in that: The partition piece is made of foam, silica gel or rubber.

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