Cell holder for holding battery cells

Description

State of the art

[0001] The present invention relates to a cell holder for holding battery cells and a cell block.

[0002] Cylindrical battery cells, such as lithium-ion cells used as energy storage devices in vehicles, are largely standardized in their dimensions. Common battery cells are available in the formats "18650" (diameter 18 mm, height 65 mm) or "21700" (diameter 21 mm, height 70 mm). Such battery cells are usually stored using simple cell holders. However, such conventional cell holders often cannot compensate for the tolerances in the dimensions of the battery cells resulting from manufacturing or volume changes, and thus cannot ensure defined and safe storage of the battery cells.

[0003] The document US 2014 / 0287288 A1 discloses a battery holder with retaining elements which are arranged in a space between battery cells and have a bevelled surface running in the axial direction of the battery cell.

[0004] The document DE10 2015 006297 A1 discloses a receiving device for an energy storage arrangement, with a terminal block for fastening the energy storage devices.

[0005] The present invention aims to improve the holding of battery cells in a battery cell holder. Disclosure of the invention

[0006] The cell holder according to the invention with the features of claim 1 offers the advantage of improved storage of battery cells. The battery cells are held particularly securely and stably in the cell holder. In particular, manufacturing-related tolerances or changes in the external dimensions of the battery cells caused during operation can be compensated for by the cell holder in the range of several percent in order to permanently ensure stable and defined storage of the battery cells. This is achieved according to the invention in that the cell holder comprises a first holder, a second holder and a first spring element. The first holder is designed to hold a first battery cell. The second holder is designed to hold a second battery cell.The first holder and the second holder can be designed like a housing and are essentially cylindrical, so that the holders enclose the respective battery cells. In particular, the first holder and the second holder are designed parallel to each other, so that the respective longitudinal axes of the two battery cells are parallel to each other and also parallel to a longitudinal axis of the cell holder.

[0007] The first spring element has a first spring section and a second spring section. The first spring section is configured to clamp the first battery cell in the first holder by means of a first spring force. The first spring force is essentially parallel to the axial direction of the first battery cell. Thus, the first spring section engages with an end face of the first battery cell. The second spring section is further configured to clamp the second battery cell in the second holder by means of a second spring force. The second spring force is present in a radial direction of the second battery cell. Thus, the second spring section engages with a circumference of the second battery cell. Preferably, the first spring element is arranged between the first holder and the second holder, in particular centrally on a perpendicular which connects the parallel longitudinal axes of the two battery cells.

[0008] The first spring element thus forms a dual spring system, designed to engage the first battery cell at the front and the second battery cell at the periphery. This allows the battery cells to be held in the cell holder in a particularly simple yet effective manner. The first spring element can accommodate battery cell tolerances in multiple directions and compensate for both length and thickness changes during battery cell operation over a wide tolerance range.

[0009] In addition, strong mechanical stresses on the battery cells, which can occur in applications such as vehicles, can be specifically avoided. Thus, the cell holder according to the invention enables particularly effective damping of external mechanical forces on the battery cells, such as oscillations, shocks, or vibrations. Furthermore, the cell holder is preferably made of a plastic, which is in particular a flame-retardant plastic, to ensure secure attachment of the battery cells.

[0010] According to the invention, the first spring element is designed such that an increase in the first spring force causes an increase in the second spring force. This means that the first spring section and the second spring section of the first spring element are coupled to one another such that an increase in the first spring force results in an increase in the second spring force. The first spring element thus effects a self-reinforcing mounting of the two battery cells. If the axial first spring force on the first battery cell is increased, the radial second spring force on the second battery cell also increases, thereby achieving a particularly stable arrangement of the two battery cells in the cell holder.

[0011] The subclaims contain preferred developments of the invention.

[0012] The cell holder preferably further comprises a second spring element. The second spring element has a third spring section. The third spring section is configured to clamp the first battery cell in the first holder by means of a third spring force. The third spring force is in a radial direction of the first battery cell. Thus, the first battery cell is clamped both in the axial direction by the first spring element and in the radial direction by the second spring element, and is thus located in a defined and stable position in the first holder.

[0013] Preferably, the first spring element is configured such that an increase in the second spring force results in an increase in the first spring force. This means that the first spring section and the second spring section of the first spring element are also coupled inversely such that an increase in the second spring force results in an increase in the first spring force. This further improves the self-reinforcing mounting of the first battery cell and the second battery cell, enabling both battery cells to be securely held in the cell holder.

[0014] Furthermore, it is advantageous if the first spring force depends on a deflection of the first spring section in the axial direction. This means that the more the first spring section is deflected in the axial direction, the higher the first spring force. In this way, a particularly favorable bearing can be achieved, whereby with greater deflection of the first spring section, a higher first spring force acts on the first battery cell and returns it to the intended position. With increasing size of the first battery cell in the axial direction, or with increasing displacement of the first battery cell in the first holder, the first spring force that holds and positions the first battery cell in the first holder increases. In this way, a particularly reliable and defined positioning of the first battery cell in the first holder can be achieved.

[0015] Preferably, the second spring force is also dependent on a deflection of the second spring section in the radial direction. Analogous to the increase in the spring force of the first spring section in the axial direction, the second spring force is thus also increased with increasing deflection of the second spring section in the radial direction. This further improves the positioning and retention of the second battery cell in the second holder.

[0016] The second holder preferably comprises two radial stops. The two radial stops and the second spring section are preferably arranged distributed around the circumference of the second holder. The second battery cell is clamped between the second spring section and the two radial stops by the pretensioning force of the second spring section, which leads to a statically determined clamping of the second battery cell in the second holder. This results in a radial three-point fastening of the second battery cell in the second holder. This allows the second battery cell to be positioned particularly precisely, and any relative movement within the second holder is reliably suppressed.It is particularly advantageous if each holder of the cell holder has two radial stops, whereby the battery cell that can be accommodated in the holder can be clamped by a corresponding spring element between a spring section of the spring element and the two radial stops.

[0017] Furthermore, it is particularly advantageous if the first spring section is designed such that it engages with a shoulder region of the first battery cell. Advantageously, the first spring section engages exclusively with the shoulder region. The shoulder region is considered to be a radially outer annular housing region of an end face of the battery cell, which annularly surrounds a positive pole or a negative pole of the battery cell. As a result, the positive pole or the negative pole remains freely accessible for electrical contact and is also not mechanically stressed by the pretensioning force of the spring element. Furthermore, the first spring section is preferably designed and engaged with the shoulder region of the battery cell such that the battery cell can degas unhindered in the event of excess pressure inside.

[0018] The cell holder preferably further comprises a third holder configured to accommodate a third battery cell. The third holder is preferably parallel to the first holder and the second holder. Furthermore, it is advantageous if the first holder, the second holder, and the third holder are arranged in a triangle when viewed in the axial direction. This allows for a particularly space-saving design of the cell holder.

[0019] Particularly preferably, the cell holder further comprises at least a third spring element. The first spring element, the second spring element, and the third spring element are each designed to clamp one of the battery cells in the axial direction in the corresponding holder. Furthermore, the first spring element, the second spring element, and the third spring element are each designed to clamp one of the immediately adjacent battery cells in the radial direction in the corresponding immediately adjacent holder. In other words, each of the three spring elements is designed to clamp two adjacent or juxtaposed battery cells. In this case, one of the two adjacent battery cells is clamped in the axial direction by the spring element, and the other battery cell is clamped in the radial direction.The triangular arrangement of the three holders and the special design of the spring elements allow for a particularly simple clamping of each battery cell both axially and radially, ensuring optimal arrangement of the battery cells in the cell holder. This allows for a particularly simple cell holder design while still guaranteeing effective and secure storage of all battery cells.

[0020] It is also particularly advantageous if the cell holder is constructed in several parts. The cell holder is particularly preferably two-part. In particular, the cell holder is divided into two parts in a plane perpendicular to the longitudinal axis. This results in particularly simple and cost-effective production of the cell holder. Furthermore, it ensures easy assembly.

[0021] Preferably, a first cell holder part of the cell holder has one axial fixed stop for each holder. The fixed stop forms a fixed contact point on the cell holder against which the battery cells are placed in the axial direction. A second cell holder part has at least the first spring element. If multiple spring elements are provided, all spring elements are formed on the second cell holder part. The battery cells are clamped in place by pre-tensioning the two cell holder parts against each other in the axial direction. The spring elements press the battery cells against the fixed stop. This allows the battery cells to be arranged and clamped in the cell holder in a particularly simple manner.In addition, the spring forces by means of which the battery cells are clamped into the holders can be adapted particularly easily and flexibly to the respective requirements by moving the two cell holder parts against each other along the longitudinal axis of the cell holder.

[0022] It is particularly advantageous if the first cell holder part is a contact plate for tapping current from the battery cells. The contact plate is preferably a flat plate. The contact plate is particularly preferably made of metal to enable easy current tapping from the battery cells. For this purpose, the corresponding end face, which has the negative or positive pole of the battery cells, can advantageously rest flat against the contact plate. This allows for a particularly simple and cost-effective design of the cell holder.

[0023] Particularly preferably, the first cell holder part and the second cell holder part each have at least one spring element per holder. Thus, a spring element is provided at each axial end of each holder, which is configured to clamp the respective battery cell in the axial direction in the corresponding holder and to clamp an adjacent battery cell in the radial direction in the adjacent holder.

[0024] The invention further relates to a cell block comprising at least one cell holder according to the invention. Furthermore, the cell block comprises one battery cell per cell holder. The battery cells can be in the standardized 18650 or 21700 format, or in any other format. Short description of the drawings

[0025] The invention is described below using exemplary embodiments in conjunction with the figures. In the figures, functionally identical components are identified by the same reference numerals. Here: Figure 1 shows a simplified schematic view of a cell holder according to a first embodiment of the invention, Figure 2 shows a detail of a sectional view of the Figure 1 along the line II, Figure 3 shows a simplified schematic sectional view of a cell holder according to a second embodiment of the invention, Figure 4 shows a simplified schematic sectional view of a cell holder according to a third embodiment of the invention, and Figure 5 shows a simplified schematic sectional view of a cell holder according to a fourth embodiment of the invention. Preferred embodiments of the invention

[0026] The Figure 1shows a simplified schematic view of a cell holder 1 according to a first embodiment of the invention. It shows a plan view of the cell holder 1. The cell holder 1 comprises a first holder 2, a second holder 3, and a third holder 4. A first battery cell 21, a second battery cell 31, and a third battery cell 41 are arranged in the three holders 2, 3, 4, respectively. The three holders 2, 3, 4 are formed within a circumferential housing wall 10 and arranged parallel to one another, so that the longitudinal axes of the three battery cells 21, 31, 41 are each arranged parallel to one another. Figure 2A first longitudinal axis 28 of the first battery cell 21 is shown as an example, wherein the longitudinal axis 28 is representative as a reference axis for the alignment of the longitudinal axes of the entire cell holder 1 and all battery cells 21, 31, 41. Furthermore, the first holder 2, the second holder 3 and the third holder 4 are as in the Figure 1 visibly triangular and arranged next to each other in a clockwise direction. A spacer 15 is arranged in the center between the three battery cells 21, 31, and 41, which fills the remaining, otherwise empty space.

[0027] In order to enable a secure and stable arrangement of the three battery cells 21, 31, 41 in the respective holders 2, 3, 4, the cell holder 1 comprises three spring elements 5, 6, 7. A first spring element 5 is arranged between the first holder 2 and the second holder 3. Furthermore, a second spring element 6 is arranged between the first holder 2 and the third holder 4. In addition, a third spring element 7 is arranged between the second holder 3 and the third holder 4. The three spring elements 5, 6, 7 enable each of the three battery cells 21, 31, 41 to be clamped both in the axial direction and in the radial direction in the corresponding holder 2, 3, 4 and is thus held in a defined and stable position in the cell holder 1. The precise design and functioning of the spring elements 5, 6, 7 is described in relation to the Figure 2 described in more detail below using the first spring element 5.

[0028] The Figure 2 shows a detail of a sectional view of the Figure 1 along the line II. The first spring element 5 is rod-shaped in the region between the first holder 2 and the second holder 3. At the upper end in the direction of the longitudinal axis 28, the first spring element 5 has a hook-shaped region 50. A first spring section 51 and a second spring section 52 of the first spring element 5 are formed on this hook-shaped region 50. At least the first spring section 51 and the second spring section 52 are made of an elastic material, so that they can exert spring forces on the two adjacent battery cells 21, 31 through flexibility in order to clamp them in the holders 2, 3, as described below.

[0029] The first spring section 51 of the first spring element 5 is configured to clamp the first battery cell 21 in the axial direction in the first holder 2. This means that the first spring section 51 exerts a first spring force in the direction A parallel to the longitudinal axis 28 on the first battery cell 21 in order to clamp it in the first holder 2. The first spring force is dependent on a deflection of the first spring section 51 in the axial direction, i.e., along the longitudinal axis 28. The first spring section 51 is shaped such that it rests exclusively on a circumferential shoulder region 210 of the first battery cell 21. As a result, a positive pole 211, which is arranged centrally on the upper end face of the first battery cell 21 and radially within the shoulder region 210, is freely accessible, for example, for electrically contacting the first battery cell 21.

[0030] Furthermore, the first spring element 5 has a second spring portion 52, which is configured to clamp the second battery cell 31 in the radial direction in the second holder 3. This means that the second spring portion 52 exerts a second spring force in the direction B on the second battery cell 31 in order to clamp it in the second holder 3. The second spring force depends on a deflection of the second spring portion 52 in the radial direction, i.e., parallel to the direction B.

[0031] The second battery cell 31 is located, as shown in particular in the Figure 1As can be seen, it is not directly attached to the housing wall 10, but is clamped between the second spring section 52 and two radial stops 35, 36, which protrude radially inward from the housing wall 10. The two radial stops 35, 36 and the second spring section 52 are arranged distributed around the circumference of the second holder 3. This results in a radial three-point mounting of the second battery cell 31. The first battery cell 21 is similarly clamped in the radial direction between the third spring section 61 of the second spring element 6 and two radial stops 25, 26 of the first holder 2. Since the section line II runs through the stop 25 of the first holder 2, this stop 25 is in the Figure 2 The third battery cell 41 is clamped in the third holder 4 in the same way.

[0032] Due to the one-piece design of the first spring element 5 with the first spring section 51 and the second spring section 52, the first spring section 51 and the second spring section 52 are directly coupled to one another. This means that a deflection of the first spring section 51 in the axial direction, for example, opposite to direction A, causes a deflection of the second spring section 52, for example, in direction B (see. Figure 2 ). This also occurs in the reverse direction. This results in a self-reinforcing clamping of the two battery cells 21, 31 via the first spring element 5.

[0033] The second spring element 6 and the third spring element 7 function analogously to the just described function of the first spring element 5. Each of the three battery cells 21, 31, 41 is thus clamped in the axial direction in the corresponding holder 2, 3, 4 by a spring element 5, 6, 7. Each spring element 5, 6, 7 also clamps the immediately adjacent battery cell 21, 31, 41 in a clockwise direction in the radial direction (cf. Figure 1). Thus, the cell holder 1 very simply enables a particularly simple and effective holding of all battery cells 21, 31, 41 in the respective holder 2, 3, 4 with only a few components. Due to the special flexible design of the spring elements 5, 6, 7, even larger tolerances, for example in the range of 10%, in the external dimensions of the battery cells 21, 31, 41 can be compensated for. Furthermore, the cell holder 1 effectively dampens external mechanical forces on the battery cells 21, 31, 41, such as oscillations, shocks, or vibrations.

[0034] The Figure 3 shows a simplified schematic sectional view of a cell holder 1 according to a second embodiment of the invention. The second embodiment essentially corresponds to the first embodiment in the Figure 1 and 2, wherein the cell holder 1 is designed in two parts. In the second embodiment, the cell holder 1 comprises a first cell holder part 11 and a second cell holder part 12. The first cell holder part 11 has an axial fixed stop 111, 112 for each holder 2, 3, 4, wherein in the Figure 3 Only the two fixed stops 111, 112 of the first holder 2 and the second holder 3 are shown. The two fixed stops 111, 112 are designed as blind-hole-like recesses in the first cell holder part 11 and each form a fixed contact point for the axial ends of the battery cells 21, 31 on the first holder part 11.

[0035] The spring elements 5, 6, 7 are provided on the second cell holder part 12. The spring elements 5, 6, 7 are connected to the second cell holder part 12 by means of fastening points 120. The exact type of connection is not shown in detail and can be implemented in various ways, e.g., by means of rods or joints. All that is required is that the deflections of the first spring section 51 and the second spring section 52 are not restricted by the fastening points 120.

[0036] By preloading the two cell holder parts 11, 12 against each other parallel to the longitudinal axis 28 with an opposing preload force F1 and F2, respectively, the special design of the spring elements 5, 6, 7 allows the spring forces acting on the battery cells 21, 31, 41 to be influenced and adjusted as required. For example, the two cell holder parts 11, 12 can be preloaded more strongly in environments with greater vibration loads to ensure stable storage of the battery cells 21, 31, 41, whereas in other environments, a low preload force may be sufficient for secure storage.

[0037] The Figure 4 shows a simplified schematic sectional view of a cell holder 1 according to a third embodiment of the invention. The third embodiment essentially corresponds to the second embodiment in the Figure 3with an alternative design of the first cell holder part 11. In the third embodiment, the first cell holder part 11 is designed as a flat contact plate, which is arranged perpendicular to the longitudinal axis 28. The contact plate 11 is made of a metal and enables a simple current tap at a negative pole 212 of the battery cells 21, 31, 41. As in the second embodiment in the Figure 3 the contact plate 11 and the second cell holder part 12 can be preloaded against each other with opposite preload forces F1 and F2, respectively, in order to adjust the spring forces on the battery cell 21, 31, 41.

[0038] The Figure 5 shows a simplified schematic sectional view of a cell holder 1 according to a fourth embodiment of the invention. The fourth embodiment essentially corresponds to the second embodiment in the Figure 3with a further alternative embodiment of the first cell holder part 11. In the fourth embodiment, the first cell holder part 11 is identical to the second cell holder part 12 and rotated by 180° relative to the vertical. Thus, a spring element 5, 6, 7, 5', 6', 7' is provided at both axial ends of each holder 2, 3, 4, wherein in the Figure 5 For illustration purposes, only three of the spring elements 5, 5', 7' are visible. As a result, each battery cell 21, 31, 41 is clamped resiliently at both axial ends. As in the second and third embodiments in the Figure 3 or 4, the two cell holder parts 11, 12 can be preloaded against each other with opposite preload forces F1 and F2 respectively in order to adjust the spring forces on the battery cell 21, 31, 41.

[0039] It should be noted that, for reasons of clarity, only three or two holders 2, 3, 4 of the cell holder 1 are shown in the exemplary embodiments. Instead, any desired number of holders 2, 3, 4, but at least two, can be provided in the cell holder 1 according to the invention.

Claims

1. Cell holder for holding battery cells, comprising: - a first mount (2), which is configured to take a first battery cell (21), - a second mount (3), which is configured to take a second battery cell (31), and - a first spring element (5), - wherein the first spring element (5) has a first spring section (51), which is designed to clamp the first battery cell (21) in the first mount (2) by means of a first spring force in an axial direction of the first battery cell (21), characterized in that - the spring element (5) has a second spring section (52), which is designed to clamp the second battery cell (31) in the second mount (3) by means of a second spring force in a radial direction of the second battery cell (31), wherein the first spring element (5) is configured such that an increase in the first spring force causes an increase in the second spring force.

2. Cell holder according to Claim 1, further comprising a second spring element (6), wherein the second spring element (6) has a third spring section (61), which is designed to clamp the first battery cell (21) in the first mount (2) by means of a third spring force in a radial direction of the first battery cell (21).

3. Cell holder according to either of the preceding claims, wherein the first spring element (5) is configured such that an increase in the second spring force causes an increase in the first spring force.

4. Cell holder according to one of the preceding claims, wherein the first spring force is dependent on a deflection of the first spring section (51) in an axial direction.

5. Cell holder according to one of the preceding claims, wherein the second spring force is dependent on a deflection of the second spring section (52) in a radial direction.

6. Cell holder according to one of the preceding claims, wherein the second mount (3) has two radial stops (25, 26), each of which forms a bearing point in a radial direction of the first battery cell (31), and wherein the two radial stops (25, 26) and the second spring section (52) are arranged in a manner distributed in particular around the circumference of the second mount (3).

7. Cell holder according to one of the preceding claims, wherein the first spring section (51) is configured such that the first spring section (51) is engaged, in particular exclusively, with a shoulder area (210) of the first battery cell (21).

8. Cell holder according to one of Claims 2 to 7, also comprising at least a third mount (4), which is configured to take a third battery cell (41), wherein in particular the first mount (2), the second mount (3) and the third mount (4) are arranged in a triangle.

9. Cell holder according to Claim 8, also comprising a third spring element (7), wherein the first spring element (5), the second spring element (6) and the third spring element (7) are configured to clamp in each case one of the battery cells (21, 31, 41) in an axial direction and to clamp in each case one of the immediately adjacent battery cells (21, 31, 41) in a radial direction.

10. Cell holder according to one of the preceding claims, wherein the cell holder (1) is formed in multiple parts, in particular in two parts.

11. Cell holder according to Claim 10, wherein a first cell holder part (11) comprises in each case one axial fixed stop (111, 112) per mount (2, 3, 4), and wherein a second cell holder part (12) comprises at least the first spring element (5).

12. Cell holder according to Claim 11, wherein the first cell holder part (11) is a contact plate for tapping current at the battery cells (21, 31, 41).

13. Cell holder according to Claim 12, wherein the first cell holder part (11) and the second cell holder part (12) each have at least one spring element (5, 6, 7) per mount (2, 3, 4), such that a spring element (5, 6, 7) is provided at each axial end of each of the mounts (2, 3, 4) in each case, said spring element (5, 6, 7) being designed to clamp the relevant battery cell (21, 31, 41) in an axial direction, and in particular to clamp in each case one adjacent battery cell (21, 31, 41) in a radial direction.

14. Cell block comprising at least one cell holder (1) according to one of the preceding claims and in each case one battery cell (21, 31, 41) per mount (2, 3, 4) of the cell holder (1).