Battery pack

Abstract

The utility model discloses a battery pack. The battery pack comprises a box body, battery cells, a bracket and a heating piece, a containing groove is formed in the inner side wall of the box body, the support is arranged in the containing groove, the heating piece is located in the containing groove and connected to the support, the battery cell is arranged on the heating piece, and further, a heat insulation space is formed between the heating piece and the groove wall of the containing groove. According to the arrangement, on one hand, the containing groove is formed in the inner side wall of the box body to contain the support and the heating piece, the space utilization rate in the box body can be increased, and therefore the energy density in the box body is guaranteed, and on the other hand, more importantly, the support is arranged to support the heating piece so that a heat insulation space can be formed between the heating piece and the containing groove; therefore, the heating element is prevented from being in direct contact with the inner side wall of the box body, so that the loss of heating heat can be reduced, and the heating effect and heating efficiency of the heating element on the battery cell are improved.

Description

Technical Field

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

[0002] When used in low-temperature environments, lithium-ion batteries have problems such as low capacity, severe attenuation, poor cycle rate performance, obvious lithium precipitation, and unbalanced lithium insertion and extraction. Therefore, a heating system needs to be added to the battery pack. The heat of the existing battery pack heating system will be directly transferred to the box, which will cause heat loss and affect the heating effect and efficiency of the battery cell. Utility Model Content

[0003] In order to overcome at least one of the defects of the prior art described above, the utility model provides a battery pack, aiming to solve the problem that the heat of the heating system of the existing battery pack is directly transferred to the box body.

[0004] The technical solution adopted by the utility model to solve the problem is:

[0005] A battery pack comprises: a box body, the inner side wall of which is provided with a receiving groove; a bracket, which is arranged in the receiving groove; a heating element, which is at least partially located in the receiving groove and connected to the bracket, and an insulating space is formed between the heating element and the groove wall of the receiving groove; a battery cell, which is located in the box body, and the heating element is thermally connected to the battery cell.

[0006] According to some embodiments of the utility model, the bracket includes a support plate and a cantilever, the support plate is arranged in the accommodating groove, the cantilever is connected to the support plate and suspended in the accommodating groove, and the heating element is connected to the cantilever; the insulation space includes a first insulation space, and the heating element forms the first insulation space between the cantilever and the accommodating groove.

[0007] According to some embodiments of the utility model, the thermal insulation space also includes a second thermal insulation space, the support plate is connected to the bottom wall of the accommodating groove, the heating element and the support plate are spaced apart, and the second thermal insulation space is formed between the heating element and the bottom wall of the accommodating groove.

[0008] According to some embodiments of the present invention, a supporting foot is provided at the end of the cantilever, and the supporting foot is connected to the bottom wall of the accommodating groove.

[0009] According to some embodiments of the utility model, the accommodating groove includes a groove bottom wall and two groove side walls, the two groove side walls are arranged opposite to each other, the groove bottom wall is connected between the two groove side walls, and the heating element is spaced apart from the groove bottom wall and the groove side walls respectively.

[0010] According to some embodiments of the utility model, the accommodating groove and the heating element extend along a first direction, which is the length direction or the width direction of the box body; there are multiple accommodating grooves and multiple heating elements, and the multiple accommodating grooves are arranged at intervals along a second direction, and the multiple heating elements are arranged in the multiple accommodating grooves one by one, and the second direction is perpendicular to the first direction.

[0011] According to some embodiments of the present invention, the bracket is made of heat insulating material.

[0012] According to some embodiments of the present invention, the heating element is a PTC heating element.

[0013] According to some embodiments of the present invention, the battery core is connected to the heating element via a thermally conductive adhesive.

[0014] According to some embodiments of the present invention, the thermally conductive adhesive extends into a gap between the battery core and the box body.

[0015] In summary, the battery pack provided by the utility model has at least the following technical effects:

[0016] On the one hand, by opening a receiving groove on the inner wall of the box to accommodate the bracket and the heating element, the space utilization inside the box can be improved, thereby ensuring the energy density inside the box. On the other hand, more importantly, by arranging a bracket to support the heating element so that an insulating space is formed between the heating element and the receiving groove, the heating element is prevented from directly contacting the inner wall of the box, thereby reducing the loss of heating heat and improving the heating effect and heating efficiency of the heating element on the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a battery pack (a battery module and a heating element thereof are not shown) according to an embodiment of the utility model;

[0018] Figure 2 A schematic diagram of the cross-sectional structure of a battery pack according to an embodiment of the present utility model;

[0019] Figure 3 for Figure 2 A partial enlarged view of the middle A part;

[0020] Figure 4 A control flow chart for controlling the heating of a battery cell provided by an embodiment of the utility model;

[0021] Figure 5 A control flow chart for heating element failure detection provided by an embodiment of the utility model.

[0022] The meanings of the reference numerals are as follows:

[0023] 1. Box body; 11. Accommodating groove; 111. Groove bottom wall; 112. Groove side wall; 2. Bracket; 21. Support plate; 22. Cantilever; 23. Support foot; 3. Insulation space; 31. First insulation space; 32. Second insulation space; 4. Spacing space; 5. Thermal conductive adhesive; 6. Battery cell; 7. Heating element. DETAILED DESCRIPTION

[0024] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0027] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0028] See also Figure 1 , Figure 2 and Figure 3 The utility model discloses a battery pack, including a box body 1, a battery cell 6, a bracket 2 and a heating element 7; the inner side wall of the box body 1 is provided with a receiving groove 11, the bracket 2 is arranged in the receiving groove 11, the heating element 7 is located in the receiving groove 11 and is connected to the bracket 2, the battery cell 6 is in thermal contact with the heating element 7, and further, a heat insulating space 3 is formed between the heating element 7 and the groove wall of the receiving groove 11.

[0029] A battery pack disclosed in this embodiment, on the one hand, can improve the space utilization rate inside the box body 1 by opening a receiving groove 11 on the inner wall of the box body 1 to accommodate the bracket 2 and the heating element 7, thereby ensuring the energy density inside the box body 1; on the other hand, more importantly, by arranging the bracket 2 to support the heating element 7 so that an insulating space 3 is formed between the heating element 7 and the receiving groove 11, so as to avoid the heating element 7 directly contacting the inner wall of the box body 1, thereby reducing the loss of heating heat and improving the heating effect and heating efficiency of the heating element 7 on the battery cell 6.

[0030] It should be noted that the heating element 7 may be completely located in the accommodating groove 11 or partially located in the accommodating groove 11 , which can be selected according to actual needs.

[0031] like Figure 2 and Figure 3 As shown, in this embodiment, the battery cell 6 is connected to the heating element 7 through the thermal conductive adhesive 5 to achieve thermal contact, thereby improving the heat transfer efficiency between the battery cell 6 and the heating element 7. In addition, the thermal conductive adhesive 5 extends into the gap between the battery cell 6 and the box 1, thereby improving the connection stability between the heating element 7 and the battery cell 6. In other embodiments, the battery cell 6 may also directly abut the heating element 7 to achieve thermal contact.

[0032] Furthermore, in the present embodiment, the bracket 2 includes a support plate 21 and two cantilevers 22, the support plate 21 is arranged in the receiving groove 11, the two cantilevers 22 are spaced and connected to the side of the support plate 21 away from the box body 1 and suspended in the receiving groove 11, the heating element 7 is connected to the two cantilevers 22, the heat-insulating space 3 includes a first heat-insulating space 31 and a second heat-insulating space 32, and the heating element 7 forms the first heat-insulating space 31 through the cantilever 22 and the groove wall of the receiving groove 11. It can be understood that the cantilever 22 is suspended in the receiving groove 11 and is spaced from the groove wall of the receiving groove 11, and the heating element 7 is connected to the cantilever 22, so that the heating element 7 is also spaced from the groove wall of the receiving groove 11. Specifically, the support plate 21 is connected to the bottom wall 111 of the accommodating groove 11, the heating element 7 is spaced apart from the support plate 21, and a second insulation space 32 is formed between the heating element 7 and the bottom wall 111 connected to the support plate 21. In this way, the two cantilevers 22 can form a good support for the heating element 7, thereby ensuring the heating efficiency of the heating element 7 on the battery cell 6, and the volume of the insulation space 3 can be increased without affecting the supporting effect on the heating element 7, thereby further improving the insulation effect.

[0033] It should be noted that, in some other embodiments, only one of the first heat insulating space 31 and the second heat insulating space 32 may be provided, and the selection can be made according to actual needs.

[0034] Specifically, in this embodiment, the accommodating groove 11 includes a groove bottom wall 111 and two groove side walls 112. The two groove side walls 112 are arranged opposite to each other, and the groove bottom wall 111 is connected between the two groove side walls 112. The heating element 7 is respectively spaced apart from the groove bottom wall 111 and the groove side walls 112 to further increase the volume of the insulation space 3.

[0035] like Figure 1 As shown, preferably, in this embodiment, support feet 23 are provided at both ends of the cantilever 22 , and the support feet 23 are connected to the bottom wall 111 of the accommodating groove 11 to better support the cantilever 22 to float in the accommodating groove 11 .

[0036] Preferably, in this embodiment, the receiving groove 11 and the heating element 7 are arranged along a first direction (see Figure 1 The first direction is the length direction of the box body 1, so as to increase the contact area between the heating element 7 and the battery cell 6, thereby ensuring and improving the heating effect and heating efficiency of the battery cell 6.

[0037] More preferably, in this embodiment, in order to further improve the heating effect and heating efficiency of the battery cell 6, a plurality of accommodating grooves 11 and heating elements 7 are provided, and the plurality of accommodating grooves 11 are arranged along the second direction (please refer to Figure 1 The plurality of heating elements 7 are arranged in a spaced-apart manner in a plurality of accommodating grooves 11 in a one-to-one correspondence, and the second direction is perpendicular to the first direction.

[0038] like Figure 1 As shown, preferably, in this embodiment, a plurality of brackets 2 are arranged in each accommodating groove 11, and the plurality of brackets 2 are arranged in the accommodating groove 11 at intervals along the first direction, and a spacing space 4 is formed between two adjacent brackets 2. In this way, on the one hand, each heating element 7 can be supported more stably, and on the other hand, more importantly, the spacing space 4 between two adjacent brackets 2 can also play a heat insulating role to avoid the heat of the heating element 7 from being directly transferred to the box body 1 as much as possible.

[0039] It should be noted that, in some other embodiments, the first direction may also be the width direction of the box body 1 , which can be selected according to actual needs.

[0040] Preferably, in this embodiment, the bracket 2 is made of insulating material, so as to avoid the heat of the heating element 7 from being transferred to the box body 1 through the bracket 2 as much as possible, so that the heat of the heating element 7 can be more fully transferred to the battery cell 6, thereby improving the heating effect and heating efficiency of the battery cell 6.

[0041] Specifically, in the present embodiment, the heating element 7 is in the form of a sheet, so that a larger contact area with the battery cell 6 can be ensured and a smaller space is occupied. More preferably, in the present embodiment, the heating element 7 is a PTC heating element; the PTC heating element is a positive temperature coefficient thermistor, and its resistance value increases in a step-like manner with increasing temperature. It is an automatic constant temperature, energy-saving heating element, which can effectively avoid dry burning of the heating element.

[0042] It should be noted that, in some other embodiments, the heating element 7 may also be, but is not limited to, a silicone heating film or a flexible electric heating film, etc., which can be selected according to actual needs and is not limited here.

[0043] Based on the fact that the heating element 7 is a PTC heating element, this embodiment also provides strategic control of system heating and strategic control of failure detection of the heating element 7. The specific implementation principle is as follows:

[0044] (1) Strategic control of system heating, such as Figure 4 As shown:

[0045] ① Before charging begins, the system will detect the temperature of battery cell 6. If the minimum temperature of battery cell 6 is T min <T1, the heating element 7 is started to avoid the problem of low charging efficiency of the battery cell 6 due to lithium deposition caused by charging the battery cell 6 at low temperature. The temperature range of T1 can be -5 to 15°C;

[0046] ②If the minimum cell temperature T1≤T min <T2, the heating element 7 starts, and the minimum temperature of the battery cell 6 is T min ≥T1, the probability of lithium deposition is small, and charging can be performed while heating. During the charging process, the battery cell 6 will also generate heat, which can increase the temperature rise rate of the battery cell 6;

[0047] ③ If the minimum temperature of cell 6 is T min ≥T2, the battery cell 6 is at a relatively high temperature, in which case the battery cell 6 may not be heated, and the heating element 7 stops working, and the temperature range of T2 may be 10-20°C;

[0048] ④ After the heating element 7 is started, if the battery cell is heated to the minimum temperature T min ≥T3 or maximum temperature T max >T4, it is considered that the battery cell does not need to be heated, and the heating element 7 can be turned off. The temperature range of T2 can be 10-20°C, the temperature range of T3 can be 20-30°C, and T4>T3>T2>T1.

[0049] (2) Control strategy for failure detection of heating element 7, such as Figure 5 As shown:

[0050] ① Perform failure detection of the heating element 7 during the heating stage;

[0051] ② When the heating time t>t1, and the battery temperature rise △T<T5, it is considered that the heating effect is not good. At this time, the heating element 7 may fail. The t1 time range can be 0~30min, and the T5 temperature range can be 0~5℃;

[0052] If the maximum cell temperature T is detected during the heating phase max <T6, and the current I of the heating element 7<I1, at this time the temperature of the battery cell 6 is relatively low, and the current of the heating element 7 is relatively low, it can be considered that the heating element 7 has a global or local poor contact with the battery cell 6, resulting in a global or local high temperature of the heating element 7 (the resistance value is relatively high at this time), and the current of the heating element 7 is low, and it is judged that the heating element 7 has failed. The temperature range of T6 can be -10~10℃, and the current range of I1 can be 0~5A.

[0053] Therefore, in this embodiment, by setting the heating element 7 as a PTC heating element, a heating strategy and a heater failure detection strategy can be added to perform effective heating and failure identification.

[0054] In summary, the battery pack disclosed in the present utility model can at least bring the following beneficial technical effects:

[0055] 1) By providing a receiving groove 11 on the inner side wall of the box body 1 to accommodate the bracket 2 and the heating element 7, the space utilization rate inside the box body 1 can be improved, thereby ensuring the energy density inside the box body 1;

[0056] 2) The bracket 2 is provided to support the heating element 7 so that a heat insulating space 3 is formed between the heating element 7 and the accommodating groove 11, so as to prevent the heating element 7 from directly contacting the inner wall of the box body 1, thereby reducing the loss of heating heat and improving the heating effect and heating efficiency of the heating element 7 on the battery cell 6;

[0057] 3) The two cantilevers 22 can provide good support for the heating element 7, thereby ensuring the heating efficiency of the heating element 7 on the battery cell 6;

[0058] 4) The heating element 7 is a PTC heating element. The PTC heating element is a positive temperature coefficient thermistor. Its resistance value increases stepwise with the increase of temperature. It is an automatic constant temperature and power-saving heating element, which can effectively avoid dry burning of the heating element;

[0059] 5) By setting the heating element 7 as a PTC heating element, a heating strategy and a heater failure detection strategy can be added to perform effective heating and failure identification.

[0060] The technical means disclosed in the solution of the utility model are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications are also regarded as the protection scope of the utility model.

Claims

1. A battery pack, characterized in that: include: A box body (1), wherein the inner side wall of the box body (1) is provided with a receiving groove (11); A bracket (2) is arranged in the accommodating groove (11); a heating element (7), at least partly located in the accommodating groove (11) and connected to the bracket (2), a heat-insulating space (3) being formed between the heating element (7) and the groove wall of the accommodating groove (11); The battery core (6) is located in the box body (1), and the heating element (7) is thermally connected to the battery core (6).

2. A battery pack according to claim 1, characterized in that: The bracket (2) comprises a support plate (21) and a cantilever (22), the support plate (21) being arranged on the accommodating groove (11), the cantilever (22) being connected to the support plate (21) and suspended above the accommodating groove (11), and the heating element (7) being connected to the cantilever (22); The heat-insulating space (3) comprises a first heat-insulating space (31), and the heating element (7) forms the first heat-insulating space (31) between the cantilever (22) and the groove wall of the accommodating groove (11).

3. A battery pack according to claim 2, characterized in that: The thermal insulation space (3) further comprises a second thermal insulation space (32); the support plate (21) is connected to the bottom wall (111) of the accommodating groove (11); the heating element (7) and the support plate (21) are spaced apart from each other; and the second thermal insulation space (32) is formed between the heating element (7) and the bottom wall (111) of the accommodating groove (11).

4. A battery pack according to claim 2, characterized in that: The cantilever (22) is provided with a supporting foot (23), and the supporting foot (23) is connected to the bottom wall (111) of the accommodating groove (11).

5. A battery pack according to any one of claims 1 to 4, characterized in that: The accommodating groove (11) comprises a groove bottom wall (111) and two groove side walls (112), the two groove side walls (112) are arranged opposite to each other, the groove bottom wall (111) is connected between the two groove side walls (112), and the heating element (7) is spaced apart from the groove bottom wall (111) and the groove side walls (112), respectively.

6. A battery pack according to claim 1, characterized in that: The accommodating groove (11) and the heating element (7) extend along a first direction, and the first direction is a length direction or a width direction of the box body (1); A plurality of the accommodating grooves (11) and the heating elements (7) are provided, the plurality of the accommodating grooves (11) are arranged in an interval arrangement along a second direction, the plurality of the heating elements (7) are arranged in a one-to-one correspondence in the plurality of the accommodating grooves (11), and the second direction is perpendicular to the first direction.

7. A battery pack according to claim 1 or 2 or 3 or 4 or 6, characterized in that: The support (2) is made of heat-insulating material.

8. A battery pack according to claim 1 or 2 or 3 or 4 or 6, characterized in that: The heating element (7) is a PTC heating element.

9. A battery pack according to claim 1 or 2 or 3 or 4 or 6, characterized in that: The battery core (6) is connected to the heating element (7) via a heat-conducting adhesive (5).

10. A battery pack according to claim 9, wherein the thermally conductive adhesive (5) extends into a gap between the battery cell (6) and the box body (1).

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