Power battery unit, battery pack comprising power battery unit and working machine

Abstract

The invention relates to a power battery unit. The power battery unit (100) comprises a shell (10); and the at least two battery cells (3) are accommodated in the shell. The power battery unit further comprises at least one heat conduction element (4) arranged between two adjacent battery cells (3), and the heat conduction element comprises a part in contact with the opposite surfaces of the two adjacent battery cells and further comprises a part in contact with the shell (10). The invention also provides a battery pack comprising the power battery unit and an operation machine comprising the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to thermal management of power batteries. Background Art

[0002] Power batteries are an important part of electric vehicles. The performance of power batteries directly affects the power, safety and economy of the vehicle. The charging and discharging efficiency and battery life of power batteries are closely related to temperature. Too high or too low temperature directly affects the efficiency, service life and safety of power battery units.

[0003] Taking lithium-ion power batteries as an example, temperature changes will cause changes in electrochemical performance, thus affecting battery performance and life. As the temperature rises, the electrochemical reaction rate increases, exacerbating battery capacity decay; low temperature environments will also cause battery performance decay, the migration ability of lithium ions in electrode active materials will weaken, and the charge and discharge capacity will drop rapidly. In addition, too high or too low temperatures will accelerate battery aging and affect battery life. Especially under high-rate charge and discharge conditions, the impact of temperature on battery life is more significant.

[0004] Therefore, battery thermal management is one of the key technologies for developing high-performance power battery systems.

[0005] The power battery can be constructed in the form of a battery pack (or battery package), which may include a plurality of battery cells (or battery modules), each battery cell including a battery cell shell and at least one battery cell encapsulated in the battery cell shell.

[0006] In the current power battery unit structure, the heat generated by the battery cell is transferred to the shell of the power battery unit, and then transferred from the shell to the heat dissipation device for the battery pack (such as a heat sink located outside the power battery unit and shared by multiple power battery units).

[0007] However, the current structure cannot ensure that the battery cells can operate at a uniform temperature quickly. At the same time, it is impossible to efficiently heat the power battery cells to an economical operating temperature under low temperature conditions.

[0008] Therefore, an improved power battery unit structure is needed. Summary of the invention

[0009] The concept of the present invention is based on the fact that the battery cell generates heat during operation, and the inventor of the present invention has found that when more than one battery cell is packaged in the same battery unit housing, the heat is generally concentrated in the middle part of the battery cell, especially in the center part between adjacent battery cells. Therefore, the present invention proposes an improved thermal management measure.

[0010] According to one aspect of the present invention, there is provided a power battery unit, the power battery unit comprising a housing and at least two battery cells contained in the housing. The power battery unit further comprises at least one heat-conducting element arranged between two adjacent battery cells, the heat-conducting element comprising a portion in contact with mutually opposing surfaces of the two adjacent battery cells, and also comprising a portion in contact with the housing.

[0011] Optionally, the heat conducting element is an L-shaped heat pipe.

[0012] Optionally, the L-shaped heat pipe includes an elongated extension portion and a bent portion bent relative to the extension portion, wherein the extension portion is arranged between two adjacent battery cells to contact surfaces of the two battery cells that are opposite to each other, and the bent portion is arranged between the bottom of the battery cell and the bottom of the shell to contact the shell.

[0013] Optionally, the housing is composed of a first housing and a second housing.

[0014] Optionally, the first shell is configured in the form of a cover, and the second shell is configured as a cavity with an opening at one end, the cavity having a recess for accommodating the battery cell, and the opening can be closed by the first shell.

[0015] Optionally, the power battery unit further includes electrodes arranged on the first shell.

[0016] Optionally, a plurality of heat pipes are provided between two adjacent battery cells, and the plurality of heat pipes are arranged side by side along the length direction of the battery cells.

[0017] Optionally, the bent portions of the plurality of heat pipes are alternately arranged between the bottom of one of two adjacent battery cells and the bottom of the shell along the length direction of the battery cell.

[0018] According to another aspect of the present invention, a battery pack including the power battery unit is also provided.

[0019] According to yet another aspect of the present invention, there is provided a working machine comprising the aforementioned battery pack.

[0020] According to the new power battery unit design of the present invention, the heat conducting element can make the heat generated by the battery cell be directly conducted from near the center of the power battery cell to the shell of the power battery cell and dissipated through the shell, thereby achieving rapid, effective and sufficient cooling; when the power battery cell needs to be heated up, the heat pipe will transfer the heat from the shell of the power battery cell to the battery cell, thereby achieving efficient, deep and relatively uniform heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will now be described in detail by way of non-limiting examples with reference to the accompanying drawings, in which:

[0022] Figure 1 is a schematic three-dimensional view of a power battery unit according to an embodiment of the present invention.

[0023] Figure 2 yes Figure 1 A schematic exploded view of a power battery unit is shown. DETAILED DESCRIPTION

[0024] The power battery unit according to the present invention is described below with reference to the accompanying drawings. In the following description, many specific details are described so that a person skilled in the art can more fully understand the present invention. However, it is obvious to a person skilled in the art that the present invention may be implemented without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, it is contemplated that the present invention is implemented with any combination of the following features and elements, whether or not they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims unless explicitly stated in the claims.

[0025] Figure 1 and Figure 2 An embodiment of a power battery unit of the present invention is schematically shown. Figure 1 and Figure 2 As shown, the power battery unit 100 includes a housing 10, which may be composed of a first housing 1 and a second housing 2. The first housing 1 may be configured in the form of a cover. The second housing 2 may be configured as a cavity with an opening at one end, the cavity may have a concave cavity for accommodating a battery cell 3, and the opening may be closed by the first housing 1 in the form of a cover.

[0026] It is conceivable that the housing 10 may also have other forms. For example, in another embodiment not shown, the housing may be composed of two substantially identical or mirror-symmetrical half-shells.

[0027] like Figure 2 As shown, the electrode 5 can be arranged on the first housing 1 .

[0028] The power battery unit 100 further includes a battery cell 3 housed in the housing 10. Figure 2 In the illustrated embodiment, two battery cells 3 are shown, but in other embodiments not shown, the power battery unit may also include more than two battery cells.

[0029] The power battery unit 100 may further include at least one heat conducting element 4 disposed between two adjacent battery cells 3 . A portion of the heat conducting element 4 may contact the surfaces of the two adjacent battery cells facing each other, and another portion may contact the housing 10 .

[0030] The heat conducting element 4 may be a heat pipe. In the field of battery thermal management, heat pipes have strong advantages in terms of heat dissipation / heating rate and battery pack temperature uniformity. The heat pipe may be made of a metal material that is easily heat-conducting (e.g., copper or aluminum).

[0031] According to this embodiment, the heat pipe may have a substantially "L" shape, such as Figure 2 As shown. Specifically, the heat pipe may include an elongated extension portion 41 and a bent portion 42 that is bent relative to the extension portion 41, especially extends vertically relative to the extension portion 41. The extension portion 41 can be arranged between two adjacent battery cells 3 to contact the surfaces of the two battery cells that are opposite to each other. The bent portion 42 can be arranged between the bottom of the battery cell 3 and the bottom of the shell 10 (that is, the bottom surface of the concave cavity of the shell 10) to contact the shell 10. In other words, the L-shaped heat pipe can be arranged in a manner that fits the side surface of the battery cell 3 and the bottom surface adjacent to the side surface, and because the bottom surface of the battery cell 3 faces the bottom of the shell 10 and is supported by the bottom of the shell 10, this part of the L-shaped heat pipe that fits the bottom surface of the battery cell 3 is also adjacent to and contacts the bottom of the shell 10.

[0032] Therefore, the heat pipe can efficiently conduct the heat generated by the battery cell 3 directly from the inner center of the power battery unit 100 to the shell 10 and dissipate it through the shell 10; conversely, when the power battery unit 100 needs to be heated up, the heat pipe will transfer the heat from the shell 10 to the battery cell 3, especially to the battery cell part near the inner center of the power battery unit 100.

[0033] In this embodiment, a plurality of ( Figure 2 4 L-shaped heat pipes are shown in the figure, and these heat pipes are arranged side by side along the length direction of the battery core 3.

[0034] like Figure 2 As shown, the bent portions 42 of the plurality of heat pipes are alternately arranged between the bottom of one of two adjacent battery cells 3 and the bottom of the housing 10 along the length direction of the battery cells 3. That is, the bent portions 42 of each of the two adjacently arranged heat pipes are bent toward the bottom of different battery cells 3, respectively, so that the heat pipes can transfer heat uniformly between each battery cell 3 and the housing 10 as a whole.

[0035] It can be imagined that in other embodiments not shown, four or more L-shaped heat pipes can be arranged in groups of two, so that the bending portions 42 of two adjacent and parallel heat pipes in the first group are bent toward the bottom of one battery cell 3, while the two adjacent and parallel heat pipes in the second group are the opposite, that is, their bending portions 42 are bent toward the bottom of another battery cell 3.

[0036] Industrial Applicability

[0037] According to the design of the new power battery unit 100 of the present invention, at least one heat-conducting element 4, such as a heat pipe, is installed between adjacently arranged battery cells 3. The heat pipe is configured so that at least a portion thereof (such as an elongated extension portion 41) contacts the mutually opposite surfaces of two battery cells 3 of the power battery unit 100, and one end thereof (such as a bent portion 42 extending perpendicularly to the extension portion 41) contacts the bottom surface of the concave cavity of the housing 10 of the power battery unit 100.

[0038] When the power battery unit 100 is working, the heat pipe can make the heat generated by the battery cell 3 directly conduct from the inner center of the power battery unit 100 to the shell 10 of the power battery unit 100, and dissipate through the shell 10, thereby achieving rapid, effective and sufficient cooling. Conversely, when the power battery unit 100 needs to be heated up, the heat pipe will transfer the heat from the shell 10 of the power battery unit 100 to the battery cell 3, thereby achieving efficient, deep and relatively uniform heating.

[0039] Therefore, the new power battery unit according to the present invention can efficiently realize the battery cell working at a uniform temperature. In addition, when the ambient temperature is low, the power battery unit can also be efficiently heated to an appropriate and economical working temperature.

[0040] Those skilled in the art can understand that the embodiments described above are exemplary and can be improved by those skilled in the art. The structures described in various embodiments can be freely combined without causing conflicts in structure or principle.

[0041] After describing the preferred embodiments of the present invention in detail, those skilled in the art can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the appended claims, and the present invention is not limited to the exemplary embodiments described in the specification.

Claims

1. A power battery unit, the power battery unit (100) comprising: Housing (10); and At least two battery cells (3) accommodated inside the housing; It is characterized in that The power battery unit further comprises at least one heat-conducting element (4) arranged between two adjacent battery cells (3), the heat-conducting element comprising a portion in contact with surfaces of the two adjacent battery cells facing each other, and also comprising a portion in contact with the housing (10).

2. The power battery unit according to claim 1, characterized in that: The heat conducting element (4) is an L-shaped heat pipe.

3. The power battery unit according to claim 2, characterized in that: The L-shaped heat pipe comprises an elongated extension portion (41) and a bent portion (42) bent relative to the extension portion, wherein the extension portion (41) is arranged between two adjacent battery cells (3) to contact mutually opposing surfaces of the two battery cells, and the bent portion (42) is arranged between the bottom of the battery cell (3) and the bottom of a shell (10) to contact the shell.

4. The power battery unit according to claim 1, characterized in that: The housing (10) consists of a first housing (1) and a second housing (2).

5. The power battery unit according to claim 4, characterized in that: The first shell (1) is configured in the form of a cover, and the second shell (2) is configured as a cavity with an opening at one end, the cavity having a recess for accommodating a battery cell (3), and the opening can be closed by the first shell (1).

6. The power battery unit according to claim 4 or 5, further comprising an electrode (5) arranged on the first shell (1).

7. The power battery unit according to any one of claims 3 to 5, characterized in that: A plurality of heat pipes are provided between two adjacent battery cores (3), and the plurality of heat pipes are arranged side by side along the length direction of the battery cores.

8. The power battery unit according to claim 7, characterized in that: The bent portions (42) of the plurality of heat pipes are alternately arranged along the length direction of the battery core between the bottom of one of two adjacent battery cores and the bottom of the housing (10). 9 . A battery pack, comprising the power battery unit according to claim 1 . 10 . A working machine comprising the battery pack according to claim 9 .

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